INFLUENCE OF STORAGE DURATION, HARVESTING STAGE

AND CALCIUM TREATMENT ON THE STORAGE

PERFORMANCE OF APPLE CULTIVARS

BY

IBADULLAH JAN

Dissertation submitted to Khyber Pakhtunkhwa Agricultural University Peshawar in

partial fulfillment of the requirement for the Degree of

DOCTOR OF PHILOSOPHY IN AGRICULTURE

(HORTICULTURE)

DEPARTMENT OF HORTICULTURE

FACULTY OF CROP PRODUCTION SCIENCES

KHYBER PAKHTUNKHWA AGRICULTURAL UNIVERSITY

PESHAWAR -PAKISTAN

JULY, 2011

TABLE OF CONTENTS

Chapter No. Title Page No.

ABSTRACT i

ACKNOWLEDGEMENTS iii

LIST OF TABLES iv

LIST OF FIGURES v

LIST OF APPENDICES ix

CHAPTER No. 1

GENERAL INTRODUCTION 1

CHAPTER No. 2

REVIEW OF LITERATURE 6

CHAPTER No. 3

INFLUENCE OF STORAGE DURATION ON OF PHYSICO-

CHEMICAL CHANGES IN FRUIT OF APPLE CULTIVARS

1. ABSTRACT 24

2. INTRODUCTION 25

3. MATERIALS AND METHODS 28

4. RESULTS 34

5. DISCUSSIONS 45

6. SUMMARY, CONCLUSIONS AND RECOMMENDATIONS 52

CHAPTER No. 4

STORAGE PERFORMANCE OF APPLE CULTIVARS

HARVESTED AT DIFFERENT STAGES OF MATURITY

1. ABSTRACT 54

2. INTRODUCTION 55

3. MATERIALS AND METHODS 57

4. RESULTS 60

5. DISCUSSIONS 77

6. SUMMARY, CONCLUSIONS AND RECOMMENDATIONS 85

CHAPTER No. 5

INFLUENCE OF CaCl2 CONCENTRATION AND DIPPING

DURATION ON PHYSICO CHEMICAL CHANGES IN APPLE

cv. ‘RED DELICIOUS

1. ABSTRACT 87

2. INTRODUCTION 88

3. MATERIALS AND METHODS 90

4. RESULTS 91

5. DISCUSSIONS 116

6. SUMMARY,CONCLUSIONS AND RECOMMENDATIONS 123

CHAPTER No. 6

INFLUENCE OF CaCl2 TREATMENT ON STORAGE

PERFORMANCE OF APPLE CULTIVARS

1. ABSTRACT 125

2. INTRODUCTION 126

3. MATERIALS AND METHODS 127

4. RESULTS 129

5. DISCUSSIONS 149

6. SUMMARY,CONCLUSIONS AND RECOMMENDATIONS 156

OVERALL CONCLUSIONS AND RECOMMENDATIONS 158

LITERATURE CITED 159

APPENDICES 177

INFLUENCE OF STORAGE DURATION, HARVESTING STAGE AND

CALCIUM TREATMENT ON THE STORAGE PERFORMANCE OF APPLE

CULTIVARS

Ibadullah Jan and Abdur Rab

Department of Horticulture, Khyber Pakhtunkhwa Agricultural University, Peshawar

ABSTRACT

The “Influence of storage duration, harvesting stage and calcium treatment on the

storage performance of apple cultivars” was conducted at Department of Horticulture,

Khyber Pakhtunkhwa Agricultural University Peshawar, Pakistan during the years

2007-10 to optimize the storage duration and calcium treatments for apple fruit. The

fruit of apple (Pyrus domestica L.) cultivars: Royal Gala, Mondial Gala, Golden

Delicious and Red Delicious were harvested at optimum maturity and stored at 5±1°C

with 60-70% relative humidity. Physico-chemical changes in fruit were determined at

30 days interval during storage. Significant differences were observed among apple

cultivars. Cultivar Red Delicious had the highest juice content (58.47%), TSS/Acid

ratio (23.12), ascorbic acid (13.12 mg/100g), fruit firmness (5.98 kg/cm2), fruit

density (0.82 g/cm3) as well as the least weight loss (2.22%) but also had the highest

bitter pit (11.86%) and soft rot (13.53%) incidence. Titratable acidity was the highest

(0.55%) in cultivar Mondial Gala and starch score was the maximum (5.22) in

cultivar Golden Delicious.

Storage resulted in significant increased in weight loss, total soluble solids, total

sugar, pH, TSS/Acid ratio, bitter pit incidence and soft rot, while juice content, starch

score, titratable acidity, ascorbic acid, firmness and density of fruit decreased with

increasing storage duration.

Physico-chemical characteristics of apple fruit varied significantly with harvesting

stage and storage duration. The juice content (47.68%), total soluble solids (10.07),

total sugar (9.31%), pH (3.71), TSS/Acid ratio (18.73), ascorbic acid (10.11 mg/100g)

and soft rot (9.52%) recorded with early mature fruit, increased to 59.33%, 12.92,

12.98%, 4.23, 29.29, 12.50% and 15.22% accordingly in late mature fruits, while

weight loss (3.34%), starch score (4.95), titratable acidity (0.59%), fruit firmness

(5.88 kg/cm2), density of fruit (0.82 g/cm

3) and bitter pit incidence (11.69%) recorded

at early maturity stage, declined with delaying the harvesting to 1.93%, 3.21, 0.49%,

4.81 kg/cm2, 4.81 g/cm

3 and 6.63% respectively at late maturity stage.

Dipping in calcium solution declined the storage related changes but the influence

was dependant on concentration as well as dipping duration. The juice content

(60.63%), starch score (5.05), ascorbic acid (12.67 mg/100g), firmness (5.98 kg/cm2)

and density of fruit (0.81 mg/100g) recorded in fruits dipped in 0% CaCl2 solution

(control), increased to 64.34%, 5.68, 13.87 mg/100g, 6.54 kg/cm2 and 0.84 mg/100g

accordingly in fruits dipped in 9% CaCl2 solution. By contrast, weight loss (1.95%),

total soluble solids (12.01), total sugar (10.95%), TSS/Acid ratio (28.09), bitter pit

incidence (15.18%) and soft rot (15.33%) incidence recorded in control, decreased to

1.31%, 11.88, 10.76%, 23.88, 3.80% and 2.10% in fruits treated with 9% CaCl2

solution. The starch score (5.30), firmness (6.13 kg/cm2) and density of fruit (0.82

mg/100g) recorded in fruits dipped for 3 minutes in CaCl2 solution, increased to 5.50,

6.49 kg/cm2 and 0.84 mg/100g accordingly in fruits dipped for 12 minutes in CaCl2

solution, whereas weight loss (1.81%), TSS/Acid ratio (27.21), bitter pit incidence

(11.92%) and soft rot (7.07%) incidence recorded in fruits dipped for 3 minutes in

CaCl2 solution, reduced to 1.41%, 25.27, 5.60% and 6.28% respectively in fruits

treated CaCl2 solution for 12 minutes. It can be concluded that cultivar Red Delicious

had superior quality but more susceptible bitter pit and soft rot with prolong storage.

Harvesting at mid mature stage and calcium chloride (9%) treatment for 9 minutes

resulted in enhanced storage performance.

ACKNOWLEDGEMENT

I have no words to express my deepest sense of gratitude to Almighty Allah,

the Most Merciful, the Beneficent, Who bestowed upon me the courage and will to

complete this project, and contribute to the noble field of knowledge. Cordial

gratitude to the Prophet Muhammad (P.B.U.H) who is forever a torch of guidance and

knowledge for humanity.

I wish to express my deepest gratitude and profound regard to my honorable

supervisor Prof. Dr. Abdur Rab, Department of Horticulture for his constant

encouragement, helpful suggestions and guidance during my scholastic life. His

critical insight, consistent advice, constructive criticism, personal interest and

supervision, generated the vigor for excellence in its pursuits, without which it would

not have been possible to undertake this research project.

I feel pleasure to thank members of my supervisory committee, Prof. Dr.

Amanullah Jan, Department of Agronomy, for their cooperation excellent supervision,

guidance and valuable suggestions. I am also thankful to Prof. Dr. Noor-Ul-Amin,

Chairman Department of Horticulture, Prof. Dr. Farhatullah, Director Advance

Studies and Research (DASAR), Prof. Dr. Zahoor Ahmad Swati, Dean Faculty of

Crop Production Sciences for their cooperation.

I am highly indebted to Dr. Muhammad Arif (Asstt. Prof), Department of

Agronomy for his help in data analysis. I also extend many thanks to Prof. Dr. Nawab

Ali, Prof. Dr. Sher Muhammad, Dr. Muhammad Zubair, Dr. Abdul Mateen and Dr.

Abrar Hussain Shah, Dr. Gohar Ayub and Mr. Mehboob Alam, Department of

Horticulture for their full support during my research work. Thanks are also extended

to Dr. Muhammad Sajid, Assistant Professor and Syed Tanveer Shah, Lecturer,

Department of Horticulture for providing sincere help and cooperation. I gratefully

acknowledge Higher Education Commission, Islamabad for providing full financial

during my studies.

Finally, I would feel incomplete without thanking to my parents, wife,

brothers, sisters and other family members who tolerated me patiently during this

critical period and their prayers enabled me to complete my Ph.D work successfully.

IBADULLAH JAN

LIST OF TABLES

Table No. Description Page No.

Table 3.1 The effect of storage duration on weight loss (%), percent 36

juice (%), starch, TSS (%) and total sugar (%) of apple cultivars

Table 3.2 The effect of storage duration on percent titratable acidity, pH, 39

TSS/Acid ratio and ascorbic acid (mg/100g) of apple cultivars

Table 3.3 The effect of storage duration on firmness (kg/cm2), density 43

of fruit (g/cm3), soft rot (%) and bitter pit (%) of apple cultivars

Table 4.1. Calcium content (mg/kg) of orchard soil at the time of fruit 58

picking

Table 4.2. Calcium content (%) of apple leaves at the time of fruit picking 58

Table 4.3 The effect of harvesting stages and storage on weight lost (%), 63

percent juice, starch, TSS (%) and total sugar (%) of apple

cultivars

Table 4.4 The effect of harvesting stages and storage on percent titratable 69

acidity, pH, TSS/Acid ratio and ascorbic acid (mg/100g) of apple

cultivars

Table 4.5 The effect of harvesting stages and storage on firmness (kg/cm2), 74

fruit density (g/cm3), soft rot (%) and bitter pit (%) of apple cultivars

Table 5.1 The influence of storage, dipping duration and CaCl2 conc- 96

entration on weight lost (%), percent juice, starch, TSS (%)

and total sugar (%) of apple cultivars

Table 5.2 The influence of storage, dipping duration and CaCl2 concen- 109

tration on ascorbic acid (mg/100g), firmness (kg/cm2), fruit

density (g/cm3), bitter pit (%) and soft rot (%) of apple cultivars

Table 5.3 Calcium content (mg/kg) of apple fruit cv Red delicious as affected 115

by CaCl2 concentration and dipping duration

Table 6.1 The effect of cultivars, storage and CaCl2 application on 133

weight lost, percent juice, starch, Titratable acidity (%), Total

sugar (%), TSS (%) and TSS/Acid ratio of apple cultivars

Table 6.2 The effect of calcium application and storage on ascorbic acid 142

(mg/100g), firmness (kg/cm2), fruit density (g/cm

3), soft rot (%)

and bitter pit (%) of apple cultivars

Table 6.3 Effect of CaCl2 dipping on calcium content (mg/kg) of apple cultivars 148

LIST OF FIGURES

Figure No. Description Page No.

Figure 3.1 Interaction effect of storage duration and cultivar on asco- 40

rbic acid (mg/100g) of apple fruit

Figure 3.2 Interaction effect of storage duration and cultivar on bitter pit 44

incidence (%) of apple fruit

Figure 3.3 Interaction effect of storage duration and cultivar on soft rot (%) 44

of apple fruit

Figure 4.1 Variation in percent weight loss among apple cultivars after 64

150 days storage

Figure 4.2 Interaction effect of cultivar and harvesting stage on percent 64

weight loss in apple fruit

Figure 4.3 Influence of harvesting stages on percent weight loss in apple 65

fruits after 150 days storage

Figure 4.4 Interaction effect of cultivar and harvesting stage on percent 65

weight loss of apple fruits stored for 150 days

Figure 4.5 Interaction effect of storage and harvesting stage on total soluble 66

solids of apple

Figure 4.6 Interaction effect of storage and harvesting stage on total 66

sugar of apple

Figure 4.7 Interaction effect of storage and harvesting stage on titratable 70

acidity (%) of apple

Figure 4.8 Interaction effect of cultivar and storage on pH of apple fruits 70

Figure 4.9 Interaction effect of cultivar and storage ascorbic acid 71

(mg/100g) of apple

Figure 4.10 Interaction effect of storage and harvesting stage on ascorbic 71

acid (mg/100g) of apple

Figure 4.11 Interaction effect of cultivar and harvesting stage on bitter 75

pit (%) of apple

Figure 4.12 Influence of harvesting stages on bitter pit (%) of apple fruits 75

after 150 days storage

Figure 4.13 Interaction effect of cultivar and harvesting stage on soft 76

rot (%) of apple

Figure 4.14 Influence of harvesting stages on soft rot (%) of apple fruits 76

stored for 150 days

Figure 5.1 Influence of CaCl2 concentration on percent weight loss in apple 97

fruits stored for 150 days

Figure 5.2 Influence of dipping duration on percent weight loss in apple fruits 97

stored for 150 days

Figure 5.3 Interaction effect of CaCl2 concentration and dipping 98

duration on percent weight loss in apple fruit

Figure 5.4 Interaction effect of CaCl2 concentrations and storage on 98

percent juice of apple fruit

Figure 5.5 Interaction effect of CaCl2 concentration and storage on starch 99

score of apple

Figure 5.6 Interaction effect of dipping duration and storage on starch 99

scores of apple

Figure 5.7 Interaction effect of CaCl2 concentration and dipping duration 100

on starch scores of apple

Figure 5.8 Interaction effect of CaCl2 concentration and storage duration 100

on TSS of apple

Figure 5.9 Interaction effect of dipping duration and storage duration on TSS 101

of apple

Figure 5.10 Interaction effect of CaCl2 concentration and storage duration 101

on total sugar (%) of apple

Figure 5.11 Interaction effect of CaCl2 concentration and storage 102

duration on titratable acidity (%) of apple

Figure 5.12 Interaction effect of dipping duration and storage duration on 102

titratable acidity (%) of apple

Figure 5.13 Interaction effect of CaCl2 concentration and storage duration 103

on TSS/Acid ratio of apple

Figure 5.14 Interaction effect of dipping duration and storage duration 103

on TSS/Acid ratio of apple

Figure 5.15 Interaction effect of CaCl2 concentrations, dipping durations 104

and storage durations on TSS/Acid ratio of apple

Figure 5.16 Interaction effect of CaCl2 concentration and storage duration 110

on ascorbic acid (mg/100g) of apple

Figure 5.17 Interaction effect of CaCl2 concentration and storage duration 110

on fruit flesh firmness (kg/cm2) of apple

Figure 5.18 Interaction effect of dipping duration and storage duration on 111

fruit flesh firmness (kg/cm2) of apple

Figure 5.19 Interaction effect of CaCl2 concentration and storage duration on 111

fruit density (g/cm3) of apple

Figure 5.20 Influence of CaCl2 concentrations on bitter pit (%) of apple fruits 112

after 150 days storage

Figure 5.21 Influence of dipping durations on bitter pit (%) of apple fruits 112

stored for 150 days

Figure 5.22 Interaction effect of CaCl2 concentration and dipping duration on 113

bitter pit (%) of apple

Figure 5.23 Influence of CaCl2 concentration and dipping duration on bitter 113

pit (%) of apple fruits stored for 150 days

Figure 5.24 Effect of CaCl2 concentration on soft rot (%) incidence in apple 114

fruits stored for 150 days

Figure 5.25 Influence of dipping duration on soft rot (%) incidence in apple 114

fruits after 150 days storage

Figure 6.1 Variation in weight loss (%) in apple fruits stored for 150 days 134

of different apple cultivars

Figure 6.2 Effect of CaCl2 concentrations on weight loss (%) in apple fruits 134

stored for 150 days

Figure 6.3 Interaction effect of CaCl2 application and storage duration on 135

starch scores of apple

Figure 6.4 Interaction effect of CaCl2 application and storage duration on 135

TSS of apple

Figure 6.5 Interaction effect of CaCl2 application and storage duration on 136

total sugar (%) of apple Figure 6.6 Interaction effect of cultivar and storage duration on titratable 136

acidity (%) of apple

Figure 6.7 Interaction effect of CaCl2 application and storage duration 137

on titratable acidity (%) of apple

Figure 6.8 Interaction effect of CaCl2 application and storage duration 137

on TSS/Acid ratio of apple

Figure 6.9 Interaction effect of cultivar and storage on ascorbic acid 143

(mg/100g) of apple

Figure 6.10 Interaction effect of CaCl2 application and storage duration on 143

ascorbic acid (mg/100g) of apple

Figure 6.11 Interaction effect of cultivar and storage duration on fruit 144

flesh firmness (kg/cm2) of apple fruit

Figure 6.12 Interaction effect of CaCl2 application and storage duration on 144

fruit flesh firmness (kg/cm2) of apple

Figure 6.13 Variation in bitter pit (%) incidence in apple fruits after 150 145

days storage of different cultivars

Figure 6.14 Interaction effect of cultivar and storage on bitter pit (%) incidence 145

in apple

Figure 6.15 Effect of CaCl2 concentrations on bitter pit (%) incidence in 146

apple fruits after 150 days storage

Figure 6.16 Interaction effect of cultivar and storage on bitter pit (%) 146

of apple cultivar stored for 150 days

Figure 6.17 Influence of 150 days storage on soft rot (%) incidence in 147

apple cultivars

Figure 6.18 Effect of CaCl2 concentrations on soft rot (%) incidence in apple 147

fruits stored for 150 days

LIST OF APPENDICES

Appendix No. Description Page No.

1. ANOVA for weight loss (%) of apple cultivars during storage 177

2. ANOVA for juice content (%) of apple cultivars during storage 177

3. ANOVA for starch (score) of apple cultivars during storage 177

4. ANOVA for total soluble solids of apple cultivars during storage 177

5. ANOVA for total sugar (%) of apple cultivars during storage 178

6. ANOVA for percent acidity of apple cultivars during storage 178

7. ANOVA for pH (%) of apple cultivars during storage 178

8. ANOVA for TSS/Acid ratio of apple cultivars during storage 178

9. ANOVA for ascorbic acid (mg/100g) of apple cultivars during 179 storage

10. ANOVA for firmness (kg/cm2) of apple cultivars during storage 179

11. ANOVA for fruit density (g/cm3) of apple cultivars during storage 179

12. ANOVA for bitter pit (%) of apple cultivars during storage 179

13. ANOVA for percent soft rot of apple cultivars during storage 180

14. ANOVA for weight loss (%) of apple cultivars as affected by 180 storage and harvesting stages

15. ANOVA for juice content (%) of apple cultivars as affected by 180 storage and harvesting stages

16. ANOVA for starch (score) of apple cultivars as affected by 181 storage and harvesting stages

17. ANOVA for percent acidity of apple cultivars as affected by 181 storage and harvesting stages

18. ANOVA for total soluble solids of apple cultivars as affected 181 by storage and harvesting stages

19. ANOVA for total sugar (%) of apple cultivars as affected by 182 storage and harvesting stages

20. ANOVA for pH (%) of apple cultivars as affected by storage 182

and harvesting stages

21. ANOVA for TSS/Acid ratio of apple cultivars as affected by 182 storage and harvesting stages

22. ANOVA for ascorbic acid (mg/100g) of apple cultivars as affected 183 by storage and harvesting stages

23. ANOVA for firmness (kg/cm2) of apple cultivars as affected by 183 storage and harvesting stages

24. ANOVA for fruit density (g/cm3) of apple cultivars as affected by 183 storage and harvesting stages

25. ANOVA for bitter pit (%) of apple cultivars as affected by storage 184 and harvesting stages

26. ANOVA for percent soft rot of apple cultivars as affected by 184 storage and harvesting stages

27. ANOVA for weight loss (%) of apple fruit as affected by 184 storage, CaCl2 concentrations and dipping durations

28. ANOVA for juice content (%) of apple fruit as affected by 185 storage, CaCl2 concentrations and dipping durations

29. ANOVA for starch (score) of apple fruit as affected by storage, 185 CaCl2 concentrations and dipping durations

30. ANOVA for percent acidity of apple fruit as affected by 185 storage, CaCl2 concentrations and dipping durations

31. ANOVA for total soluble solids of apple fruit as affected by 186 storage, CaCl2 concentrations and dipping durations

32. ANOVA for total sugar (%) of apple fruit as affected by storage, 186 CaCl2 concentrations and dipping durations

33. ANOVA for TSS/Acid ratio of apple fruit as affected by storage, 186 CaCl2 concentrations and dipping durations

34. ANOVA for ascorbic acid (mg/100g) of apple fruit as affected by 187 storage, CaCl2 concentrations and dipping durations

35. ANOVA for firmness (kg/cm2) of apple fruit as affected by 187 storage, CaCl2 concentrations and dipping durations

36. ANOVA for fruit density (g/cm3) of apple fruit as affected by 187 storage, CaCl2 concentrations and dipping durations

37. ANOVA for bitter pit (%) of apple fruit as affected by storage, 188 CaCl2 concentrations and dipping durations

38. ANOVA for percent soft rot of apple fruit as affected by storage, 188 CaCl2 concentrations and dipping durations

39. ANOVA for weight loss (%) of apple cultivars as affected by 188 storage and CaCl2

40. ANOVA for juice content (%) of apple cultivars as affected by 189 storage and CaCl2

41. ANOVA for starch (score) of apple cultivars as affected by 189 storage and CaCl2

42. ANOVA for percent acidity of apple cultivars as affected by 189 storage and CaCl2

43. ANOVA for total soluble solids of apple cultivars as affected by 190 storage and CaCl2

44. ANOVA for total sugar (%) of apple cultivars as affected by 190 storage and CaCl2

45. ANOVA for TSS/Acid ratio of apple cultivars as affected by 190 storage and CaCl2

46. ANOVA for ascorbic acid (mg/100g) of apple cultivars as 191 affected by storage and CaCl2

47. ANOVA for firmness (kg/cm2) of apple cultivars as affected 191 by storage and CaCl2

48. ANOVA for fruit density (g/cm3) of apple cultivars as affected 191 by storage and CaCl2

49. ANOVA for bitter pit (%) of apple cultivars as affected by 192 storage and CaCl2

50. ANOVA for percent soft rot of apple cultivars as affected by 192 storage and CaCl2

CHAPTER 1: GENERAL INTRODUCTION

The apple

Apple (Pyrus domestica L) is one of the most important tree fruit of the world. The

apple was cultivated in Greece around 600 BC or earlier. It is a highly nutritive fruit

which is a rich source of sugars 11%, fat 0.4%, protein 0.3%, carbohydrates 14.9%,

vitamins and minerals. A 100 g fresh apple contains, water 84.7%, fibre 0.8 g,

carbohydrates 13.9 g, proteins 0.4 g, lipid 0.3 g, ash 0.3 g, vitamin C 8 mg/100gm,

sodium 0.3 mg/100g, potassium 145 mg/100g, calcium 7 mg/100g, magnesium 6

mg/100gm, iron 480 μg/100g, Phosphorus 12 mg and Iodine 2 μg (Hussain, 2001).

Due to its high nutritional value, it ranks third in consumption after citrus and banana

(Bokhari, 2002).

Status of apple in Pakistan

In Pakistan its cultivation is limited and restricted to the northern hilly tracts of Punjab

and KP, and the Quetta region of Balochistan. Currently, the apple is grown over an

area of 11.13 thousand hectares with a total production of 437.39 thousand tons in

Pakistan (MINFA, 2008-09). In KP, the apple plantation is distributed in Swat, Dir,

Mansehra, Parachinar, Chitral, Hunza, North and South Waziristan Agencies. District

Swat, with an area of approximately 4000 square miles with in the Malakand

Division, is the most important of all the apple producing districts of Khyber

Pakhtunkhwa followed by the districts of Mansehra, Dir, Abbottabad, Chitral and

Hunza (Bokhari, 2002; Ali et al., 2004). Increased production of apple by extending

its cultivation of apple in low altitude areas of Pakistan is limited by its high chilling

requirements (Janick, 1974).

Climatic requirements

Due to its chilling requirements, it grows best in relatively cooler climates than other

deciduous fruits (Westwood and Chestnut, 1964). Apples can endure quite low

temperatures, but temperatures of –30oC and rapid fluctuation in winter from

relatively warm to extremely cold temperatures are harmful (Bokhari, 2002). The

apple gives better yield in relatively long, cool and slow growing season, the type of

climate which usually prevails at altitudes of 1700-2500 m.

Soil requirements

Apple trees grow well in a wide range of soil types. They prefer soils with a texture of

sandy loam to a sandy clay loam. Good soil drainage is also critical for successful

apple production. Ideal soil pH for apple tree is near 6.5 (Gao, 2001). The growth and

development of apple tree is adversely affected by water logged soils, rising water

tables into the root zone even for a short time, soils having hardpan and shallow soils

(Chaudhary, 1994).

Common apple cultivars grown in Pakistan

Various cultivars of apples which are being grown in Pakistan include Top Red, Red

Spur, Red Delicious, Golden Delicious, Super Gold, Red Chief, Apple Elite, Stark

Crimson, Oregon Spur, Red Rom Beauty, Royal Gala, Mondial Gala, Spartan And

Double Red (Chaudhary, 1994).

The need of apple storage

Being in high demand throughout the year, the apple is generally stored in cold

storage. In relatively cold climates, simple warehouses may be effective for short term

storage (Mitropoulos and Lambrinos, 2000) but cold storage is required for long term

storage and quality retention. It is estimated that about 17% of apples produced in

Balochistan are lost during postharvest operations (Shah et al., 2002). In Pakistan,

apples kept under the conditions of cold storage for 22 weeks, losses were found to be

28 percent (Ilyas et al., 2007).

Postharvest losses

Postharvest and storage losses may vary among different cultivars (Golias et al.,

2008), due to internal quality characteristics such as titratable acidity, soluble solids,

fruit flesh firmness, ethylene production and weight loss in cold storage (Golias et al.,

2008), which may in turn influence the texture and storage performance of apple

cultivars (Perring, 1989; Hoehn et al., 2003). Cultivars may also differ in fruit

physiology and anatomy (Saleh et al., 2009), including ethylene production, texture,

fruit flesh firmness (Knee et al., 1983; Larrigaudiere et al., 1997; Stow et al., 2000;

Johnston et al., 2001; Nilsson and Gustavsson, 2007) and water loss during storage

(Khan and Ahmad, 2005).

The physical properties such as fruit flesh firmness (Wilson and Lindsay, 1969;

Hudson, 1975; Zaltzman et al., 1987), density and juice (Wolfe et al., 1974; Zaltzman

et al., 1987) of apple fruit is a measure of dry matter (Jordan et al., 2000) and may

vary with maturity and during storage (Mitropoulos and Lambrinos, 2000).

Significant variations in physical characteristics have been reported for different

cultivars and correlated with storage performance of apple (Karathanos et al., 1995),

gas exchange (Ho et al., 2010) and subsequent storage life (Meisami et al., 2009).

Postharvest losses also depend on production area and market distance and the time of

transportation. It is reported that the total losses in the apples transported from Quetta,

Swat and Murree to Faisalabad market during the months of August, September and

November were found to be 23, 20 and 25 percent respectively (Ilyas et al., 2007).

The postharvest losses may also depend on storage conditions. Among the external

conditions, temperature and relative humidity during postharvest handling operations

are the most important factors influencing the storage performance of apple (LeBlanc

et al., 1996), which affect the fruit flesh firmness, juice content, weight loss, pH,

soluble solids content (SSC), and other quality (Tu et al., 2000).

Extending the storage life of apple

The apple fruit is in high demand throughout the year and hence a considerable

quantity is generally stored in cold storages in Pakistan. Apple being a perishable

commodity is prone to qualitative and quantitative losses after harvest. The losses

may occur during postharvest operations or storage which could be as high as 17%

(Shah et al., 2002) or even greater (Ilyas et al., 2007). The postharvest quality and

losses during storage may depend on cultivar (Watkins, 2003; Saleh et al., 2009),

cultural practices (Tomala, 1999), nutritional status (Hernandez et al., 2005),

harvesting stage (Ferguson and Watkins, 1989) and storage condition (LeBlanc et al.,

1996). Thus, the selection of best adopted cultivars (Ferguson and Watkins, 1989),

optimum pre and postharvest management (Conway et al., 2002) and optimum

storage conditions (Lau, 1992) can be used to minimize postharvest losses as well as

increased the storage life of apple fruit (Mahmud et al., 2008; Gupta and Jawandha,

2010).

Low temperature storage

Apple fruits are kept in cold storage after harvest to preserve their quality. Low

temperature plays main role in slowing the degradation of apple fruit quality during

storage, depending on the sensitivity of particular cultivars to chilling injury. Apples,

like other climacteric fruits, display abrupt increase in ethylene production during

ripening that lead to changes in texture, fruit flesh firmness, color etc. Endogenous

ethylene plays key role in apple softening and rapid fruit softening of several cultivars

is associated with a rapid rise in ethylene production (Knee et al., 1983; Larrigaudiere

et al., 1997; Stow et al., 2000; Johnston et al., 2001; Nilsson and Gustavsson, 2007).

The low storage of apples offers the prospect of preventing or delaying softening and

improving the texture and quality of the fruit available to consumers (Golias and

Letal, 1995).

Harvesting stage and storage life

In Pakistan, the apples are harvested at edible maturity for both fresh market and

storage. Fruit harvested at this stage have advanced in maturity and are more prone to

mechanical injury, have short storage life and greater susceptibility to pathogens and

physiological disorders (Juan et al., 1999). In addition, careless harvesting

characterized by immature and over mature fruit, is another serious cause of post

harvest losses (Ingle et al., 2000). Being a climacteric fruit, the apple can be harvested

at physiological maturity (Roth et al., 2005), stored to catch good price in the market

(Sayin et al., 2010). In general, apple fruit harvested at immature stage have poor

color and flavour and can be more susceptible to physiological disorders such as bitter

pit and superficial scald (Kader and Mitchell, 1989; Kvikliene, 2008). By contrast,

fruit harvested over-mature tend to be soft and easily damaged during post harvest

operations (Ingle et al., 2000). Such fruits are more susceptible to diseases and

physiological disorders as well as quality deterioration during or after storage (Ingle et

al., 2000; Hribar et al., 1996).

Calcium treatment and storage life

Several physiological disorders and diseases of apple fruit during storage are related

to the calcium content of fruit (Huder, 1981; Shear, 1975). Calcium deficiency results

in economic losses in fruit crops, including apples (Dyson and Digby, 1975;

Wilkinson and Fidler, 1973). It helps in regulation of metabolism in apple fruit, and

adequate concentration maintain fruit flesh firmness and minimize the incidence of

physiological disorders like water core, bitter pit, and internal breakdown (Bangerth et

al., 1972; Faust and Shear, 1968). The increase in calcium is generally delayed the

ripening and fruit maintain their quality during prolong storage. The application of

calcium also reduced the incidence of storage decay (Conway, 1982; Sharples and

Johnson, 1977). Thus it is imperative that compositional changes in apple fruit of

different cultivars are evaluated over a range of storage duration to standardize the

storage duration, harvesting time and calcium concentration for each cultivar.

General objectives:

1. Evaluate the quality of different apple cultivars

2. Evaluate the storage performance of apple cultivars

3. Examine the changes in internal quality characteristics during storage of apple

cultivars

4. Determine the influence of harvesting stages on the quality and storage

performance of apple cultivars

5. Evaluate the influence of CaCl2 application on the quality and storage

performance of apple cultivar Red Delicious

6. Optimize the CaCl2 concentration and dipping duration to minimize the

quality losses during storage in apple cultivar Red Delicious

CHAPTER 2: REVIEW OF LITERATURE

The apple

The Apple (Pyrus domestica) is one of principal fruits, grown in temperate region of

the world. It has beautiful and colourful appearance, crispy flesh, pleasant flavour and

sweet taste that attract the consumers and fetch good price. In Pakistan apples are

grown in temperate region of the country such as Murree Hills (Rawalpindi), part of

Peshawar region, Northern areas, Kashmir and Quetta (Ali et al., 2004). Kashmiri,

Kashmir Amri, Kandhari, Kulu, Kalat Special, Red Beauty of Bath, Golden Delicious,

Banki and Sky Spur varieties are grown in temperate regions whereas, Tropical

Beauty, Einsheimer and Enna produce good quality fruit at lower altitudes

(Chaudhary, 1994). About 80% of the total apple production of Pakistan is

contributed by Kalat, Killa Saifullah, Loralai, Mastung, Pishin, Quetta and Ziarat

districts of Balochistan province.

The area under this fruit has increased five times during 80 and 90 decades of 20th

century (MINFAL, 1999). The apple is a rich source of nutrients and contains, water

84.7%, 0.8 g fibre, 13.9 g carbohydrates, 0.4 g proteins, 0.3 g lipid, 0.3 g ash, vitamin

C 8 mg/100gm, sodium 0.3 mg/100g, potassium 145 mg/100g, calcium 7 mg/100g,

magnesium 6 mg/100gm, iron 480 μg/100g, Phosphorus 12 mg and Iodine 2 μg

(Hussain, 2001). Besides fresh consumption of apple fruit, it is used in many products

like, jams, jellies, marmalades, muraba, salads, sandwich, filling, snacks, in many

dishes, puddings, sweet meats, pickles and other preserves include pie filling, slices

and sauces. In foreign countries fermented apple juice is used for alcoholic purposes.

Sour varieties of apple are used for the preparation of fermented apple juice as cider

(Hulme, 1970). Perez et al. (2001) reported that the US per capita consumption of

apples has risen over the past three decades, with consumption of processed apple

products exceeding consumption of fresh apples in the last 20 years. While fresh

apple consumption remained fairly stable, the largest increases in processed per capita

use during the 1990s were for juice, frozen, and dried products.

Physical characteristics of agricultural products are the most important parameters to

determine the proper standards of design of grading, conveying, processing and

packaging systems (Tabatabaeefar and Rajabipour, 2005). Among these physical

characteristics, mass, volume and projected area are the most important ones in

determining sizing systems (Khodabandehloo, 1999). Quality differences in fruits can

often be detected by differences in density. When fruits are transported hydraulically,

the design fluid velocities are related to both density and shape. Postharvest

evaluation gives possibilities for delivering a high quality product and a basic

understanding of apple texture is necessary for the development of technology for

postharvest evaluations (Ioannides et al., 2007). Mechanical properties of the tissue

determine the susceptibility to mechanical damage that can occur during harvest,

transport and storage and that eventually leads to a profound reduction in commercial

value (Oey et al., 2007). Mechanical properties such as failure stress and strain as

well as modulus of elasticity can also be used to evaluate the behavior of the fruits

mechanically under the static loading. Firmness or hardness is another important

attribute of fruits and it is often used for fruit quality assessment (Vursavus et al.,

2006).

Chemical properties

Information regarding chemical properties of fruit is crucial in processing it into

different foods (Vursavus et al., 2006). The sugars content, sucrose, glucose, fructose,

and sorbitol, in fruit flesh contribute to the fruit sweetness, and are one of the major

characteristics of fruit quality and market value. The apple fruit accumulate starch at

the early stages of maturation that is later on hydrolyzed to sugars (Magein and

Leurquin, 2000). Golias et al. (2008) stored the apple five cultivars in cold storage

and studied the chemical attributes for titratable acidity, soluble solids, firmness,

ethylene production and weight loss for 100 days. The changes in titratable acids,

ethylene production and loss of firmness significantly differentiated the cultivars,

although Golden Delicious, Reinders and Resista still could not be completely

separated. Total soluble solids and loss in weight did not contribute to the

discriminant resolution. Khorshidi et al. (2010) studied the postharvest quality of Red

Delicious apple under different temperatures (0, 5 and 12°C) for one month. They

found that the fruit diameter, fruit weight, volume, firmness, total titratable acids

(TTA), total soluble solids (TSS), elements of sodium and potassium, marketable

quality and color surface were significantly affected by different storage temperatures.

However, the Red Delicious apple fruit stored at temperature 0oC maintained the

better quality attributes. Rutkowski et al. (2008) used optical reflectance spectrometry

method for the measurement of chlorophyll and evaluate other quality parameters in

„Golden Delicious‟ apples. They reported that fruit firmness, chlorophyll content and

acidity were decreased during vegetative and postharvest period. Significant

interaction was observed in chlorophyll content, titratable acidity and fruit firmness.

Thammawong and Arakawa (2010) harvested mature and immature apple fruits and

treated them with 1-MCP and ethylene for evaluating their response on sugar

accumulation. Immature fruits treated with ethylene showed decreased amount of

starch while total sugar content was not significantly affected. Ethylene and 1-MCP

did not significantly affect the ripening aspects of immature fruit. They reported

inverse correlation of sugars accumulation with ripening properties and starch

hydrolysis in „Tsugaru‟ fruit during storage.

Physical variations

The physical characteristics of apple fruits are important for their storage as well as

processing properties. Significant variations have been reported in physical

characteristics among apple cultivars (Weibel et al., 2004). Appearance, tastiness and

texture are the main determinants of product‟s quality accepted by consumers.

According to Surmacka-Szczesniak (2002) texture is an indicator of structural and

mechanical properties of food products and determines consumer‟s acceptability.

Fruit firmness is one of the basic criteria of fruit texture estimation and in some

countries a specific degree of firmness is included in primary parameters for

marketing (Hoehn et al., 2003). The fruit firmness depends on fruit density related

with the quality and storage performance of apple fruit (Amarante et al., 2000).

However, the softening rate has also been reported to vary from cultivar to cultivar,

depending on the presence and expression of genes which regulate the activity of

hydrolytic enzymes (Ingle et al., 2000; Konopacka and Plocharski, 2002; Johnston et

al., 2001).

Chang-Hai et al. (2006) evaluate the response of peach fuirt firmness to different

levels of temperature during storage. They recorded the delayed softening of peach

fruit and inhibition of changes in cell wall and pectin materials at low temperature of

5°C. They reported that softening of fruit cell wall was due to increased activities of

cell wall polysaccharide-related enzymes at higher temperature. Sakiyama and

Nakamura (1980) subjected cucumber fruits to different levels of temperature under

dry and wet conditions with maintaining their specific gravity at constant while

volume was at high. The specific gravity and volume of cucumber fruits which were

in wet conditions was changed at 20°C and became similar to fruits stored in dry

conditions. A non-significant change was observed in volume and specific gravity in

fruits stored at 10°C in humid conditions, with a little change in fresh weight. By

removing wet conditions their specific gravity and volume was changed at higher rate.

Meisami et al. (2009) observed the physical characteristics of apples having different

diameters. Average mass and volume were 74.87 g and 104.5 cm3 respectively while

apparent density and density were 0.2401 g/cm3

and 0.7427 respectively. Porosity of

apples having different diameters was 57.24, 54.13 and 50.17 percent and their

Average packaging was 0.45. Kheiralipour et al. (2008) evaluated different physical

and chemical attributes of two apple cultivars. They reported that two apple cultivars

were significantly different in different physical characteristics at the one percent

probability level. Nislihan and Celik (2006) stored the apple cultivars in controlled

environment with 0oC temperature and 85-90% relative humidity. Then heat

treatments were given for 4 days at 38oC to these cultivars. High weight loss was

observed in cultivars with heat treatment which was found effective for firmness

during storage. The heat treatment increased the ripening by accelerating the process

of respiration and starch degradation. Crouch (2003) treated apple cultivars with

Smart Fresh and reported significant changes in fruit firmness and incidence of bitter

pit. Apple cultivar Royal Gala showed highest firmness (5.7 kg/cm2) which was

followed by cultivar Red Delicious (5.6 kg/cm2) while lowest firmness (4.9 kg/cm

2)

was recorded in Golden Delicious. Minimum bitter pit incidence was reported in

cultivar Red Delicious.

The physical properties of the fruit determine the diffusivity of water gases through

the fruits. Thus, influences the availability of oxygen for respiration and water loss.

Ho et al. (2010) used permeation diffusion reaction model to study the gas exchange

of apple fruits. They measured the gas respiration parameters and exchange properties

of the fruit organ tissues. The measurements revealed the existence of metabolic gases

in apple fruit. Large potential for controlled atmosphere (CA) storage was recorded in

Jonagold while Braeburn showed low diffusion properties. Kanzi had less O2 anoxia

at CA storage compared with Braeburn. Karathanos (1995) used different

concentrations of sucrose for determining the air drying kinetics of fresh and

dehydrated apples fruits. The samples that were pre-treated with concentrated

solutions of sugar of 45% significantly decreased the diffusivity. The low diffusivity

helps in storage stability and for better utilization of fruits.

Postharvest problems

The apple fruits are characterized by relatively low rates of respiration 5-10 mg CO2

kg-1

h-1

) and high rates of ethylene production (10-100 µl kg-1

h-1

) as well as sensitivity

to ethylene (Kader, 2002). Therefore, the apple fruits are prone to significant

postharvest losses during postharvest handling and storage. According to (LeBlanc et

al., 1996), the fruit production chain, including harvest, storage and distribution are

generally not perfect with 90% of fresh apples stored under improper conditions,

especially during the summer period. It is found that some cultivars are more

susceptible to decay than the others. Thus the incidence of different pathogens on

apple fruit such as blue mold, gray mold, bull‟s-eye rot, and mucor rot is dependent

on cultivar (Spotts et al., 1999). Hence apple cultivars are generally selected for

resistance to certain postharvest diseases. For example, „Royal Gala‟ is extremely

resistant to wound pathogens, „Granny Smith‟ to skin punctures, and „Braeburn‟ to

infiltration of fungal spores into the core (Spotts et al., 1999). The onset of ripening

and senescence in various fruit and vegetables renders them more susceptible to

infection by pathogens (Kader, 1985). Extended storage of apple fruit may cause

enzymatic browning accompanied by unpleasant colors and flavors and a loss of

nutrients. The browning of apple fruit during storage depends on polyphenol content

and polyphenoloxidase (PPO) activity (Goupy et al., 1995), an enzyme that catalyses

the oxidation of polyphenols to their corresponding quinones (Rocha and Morais,

2001).

Shah et al. (2002) analyzed quality and marketing of apple produced in Balochistan.

There are two cold stores in Balochistan which have the capacity of 700 tones.

Because of tight packaging and wooden crates 17 percent of apples were found

damaged in cold storage, while 12 percent were unconsumed. in Quetta market during

the month March 70% of apples were shin kulu while the rest were Gala, Tore kulu,,

Mashadi and Kashmiri. The apple variety Shin kulu resulted longer shelf life as

compared to other varieties because of firmness in texture. Ilyas et al. (2007)

estimated the losses of apples during transportation in different months. When apples

were kept in cold storages then losses decreased to 28 percent because certain types of

fungus related infections were controlled. The pathogenic fungi in both inoculated and

non inoculated apple fruits were Rhizopus nigricans, Aspergillus niger and Alternaria

tenuis, while the rottening of banana fruits were due to a number of fungi and

fumigates was also pathogenic to both injured and non injured banana fruits. Tu et al.

(2000) examined apple cultivars at different RH conditions keeping in view the

quality of apples. Depending on the cultivar some apples at RH 95% and 20°C

develop mealy texture. The 65% RH is typical and 30% is a low RH for increasing

shelf life. The firmness of apples for both apple cultivars became decreased with a

slower rate at higher RH, while weight loss became higher at low RH. Higher levels

of RH was helpful in maintaining firmness of apples and in decreasing weight losses

but it promote mealy texture at 20°C. Scheper et al. (2007) evaluated the effect of

washing and unwashing treatments on post harvest apples in controlling storage rots

in injured and uninjured fruits. Washing of apples in high fungal populations

significantly affected the punctured fruits as compared the uninjured fruits while no

significant difference was observed in punctured and uninjured fruits when washed

with water containing less population of fungi. Penicillium spp. was the main causal

agent of rots while non significant effect was observed in yeast rot incidence. Pesis et

al. (2009) treated apple fruits with ethylene and then stored at cold storages to observe

the ripening process and superficial scald development of climacteric fruits. The bitter

pit and development of superficial scald was greatly suppressed by cold storage at

0oC. the transformed lines of 103Y, 130Y and 68G a little amount of ethylene in cold

storage at 0oC during the first 3 months and then little increase at 20

oC, while the

untransformed fruits significantly increased the ethylene production at cold storage

which was dramatically increased at 20oC and respiration was not significantly

affected. The line 68G produced greater amount of both (E, E) alpha-farnesene and

(Z, E) alpha-farnesene as compared to yellow and green fruits in all lines after 2

months at 0oC. (E, E) alpha-farnesene produced 100 times more than (Z, E) alpha-

farnesene in all lines. The severity of superficial scald were more in untransformed

GS apples whereas lines 103Y and 68G show less severity while line 103Y was free

from any scald. Green fruits were severely affected from superficial scald as

compared to yellow fruits. The production of 6-methyl-5-hepten-2-one (MHO) was

also higher in these lines which is a major oxidation product of (E, E) alpha-

farnesene. Superficial scald and MHO were absent in line 130Y. they reported that

transgenic apples produce alpha-farnesene which then oxidizes to MHO and free

radicals and develop superficial scald.

Apple cultivars and storage performance

A large number of apple cultivars have been developed and considerable differences

have been reported in their storage performance. Saleh et al., (2009) stored four apple

cultivars in two seasons at 0ºC temperature and 85-90% relative humidity in different

durations. Highest weight loss was recorded in Gala while least weight loss was

observed in Star Cremson. Golden delicious showed highest fruit firmness while

lowest firmness was observed in Star Cremson and Starking Delicious. All apple

cultivars were significantly affected in all parameters during cold storage. Apple

cultivar Star Cremson showed highest fruit storability. Ali et al. (2011) examined

chemical changes in apple pulp during storage. They reported that ascorbic acid

content, pH and sugar acid ratio was decreased while TSS and titratable acidity was

increased in 90 days of storage. Treatments and storage intervals significantly affected

the physico-chemical properties of apples. Omaima et al. (2007) treated pre-harvest

apple cultivar Anna with boric acid and calcium chloride as a foliar spray to decrease

the incidence of Bortytis cinerea, a main causal agent of fruit rot. The combined

treatments of foliar spray significantly increased total soluble solids, fruit firmness,

total anthocyanine and total sugar, while decreased fruit rot decay percentage, weight

losses percentages and total acidity at 5°C and cold storage for 60 days.

Kvikliene et al. (2006) evaluated the pre and post harvest chemical changes in apple

cultivar „Auskis‟. Least weight loss was observed in apple cultivar harvested at

optimum maturity. Fruit firmness was decreased with late harvesting. Positive

correlation was observed between firmness at harvest and post-storage acidity and

negative correlation was observed in firmness at harvest and post-storage sugar/acid

ratio. Post-storage sugar/acid ratio and post-storage soluble solid content were

correlated to soluble solids content at harvest. They reported that optimal harvest time

is in between of 114 and 121 days for apple cultivar „Auskis‟ after full bloom.

Markuszewski and Kopytowski (2008) grafted different apple cultivars on each other

and applied soil cultivation in six manners in rows. After the harvest and storage

period, fruits were contained less ascorbic acid, dry matter and organic acids and

more simple sugars and total sugars. The cultivar „Szampion‟ grafted on MM.106

showed best results for all parameters. The manner of soil cultivation significantly

affected the apple cultivars for most of the parameters while the best results were

obtain with manure and polypropylene fabric. Eugenia et al. (2006) compared the four

apple cultivars in both traditional and refrigerating storages. Refrigerating storage

showed best results as compared to traditional storage. Refrigerated storage resulted

lowest dehydration in Wagener Premiat varieties while highest water loss was

recorded in Jonathan. Wagener Premiat varieties also resulted better qualities

regarding ascorbic and acid total sugar as compared to other varieties. They reported

that apples should be stored in controlled atmosphere (CA) storage to keep the apples

in optimum conditions.

Ali et al. (2004) stored five apple varieties in ordinary storage at room temperature of

25oC. An increase was observed in reducing sugar while a decrease was observed in

non-reducing sugar and total sugars were increased with the prolonged storage

condition. Acidity was non significantly affected while total soluble solids

significantly increased during storage at room temperature. A decrease was observed

in Vitamin C during storage. They recommended Golden Delicious and Amri

cultivars of apple for storage to fetch good market price. Khan and Ahmad (2005)

stored five apple cultivars under ordinary storage conditions at room temperature in

September. The first two weeks of storage did not significantly affected the apple

cultivars while gradual change in weight loss and fruit frimness was observed with

four weeks of storage. Apple cultivar Amri showed highest weight loss during six

weeks of storage while the cultivar Kalakulu resulted least weight loss. Dobrzanski et

al. (2001) established sorting line for sorting and sizing of apples. From outlets of

sorter apples of different sizes were analyzed for their weight, size and colour for

assigning a fruit quality index. For achieving final fruit quality index some nutritional

values of apple like L-ascorbic acid and reducing sugar were also determined. Eisele

and Drake (2005) compared 175 apple varieties collected from several geographical

areas of USA in terms of their pH, Brix, glucose, fructose, sorbitol, citric, calcium and

sodium levels with existing compositional database values. The juices obtained from

apple varieties were highly variable in terms of their phenolic compounds. Some of

the characteristics were highly matched with one another such as the phloridzin and

chlorogenic acid were in same levels in all varieties of apples while arbutin was in not

measurable levels. They reported that the data developed from different apple

cultivars is useful with other databases for the development of apple commercial

varieties in future to meet the consumer requirements.

Harvesting time

To ensure maximum storability, apples should be picked when mature, but not fully

ripe. If apples are picked when they are too ripe, physiological processes are

underway which complicate storage, even under optimal conditions (Ingle et al.,

2000). Apples picked at right stage have the organoleptic qualities which enable them

to survive more than six months of storage. Apples which were harvested the earliest

were firmest both before and after storage, but lost a greater percentage of their

firmness during storage. Apples harvested 100 days after full bloom (DAFB) had a

firmness of 10.2 kg at harvest and 5.0 kg after storage, and lost 51% of their initial

firmness. Apples harvested 128 DAFB had a firmness of 8.2 kg at harvest and 4.7 kg

after storage, and lost 43% of their initial firmness. Apples harvested 114 and 21

DAFB lost only 41% of their initial firmness. This agrees well with an earlier study

on fruit softening in other cultivars (Meresz et al., 1993). Fruits that are picked before

physiological maturity will not ripen satisfactorily (Robertson et al., 1990), while

those harvested at more mature stage have shorter shelf life (Meredith et al., 1989)

and did not ship well because of reduced shelf life (Murray et al., 1998). Peaches, if

harvested too early are small, very firm in texture, with low sugars, reduced flavour

and colour while the later picked fruits are very soft, high in sugar and water content

and all the physiological processes which complicate storage are underway. Once the

fruit ripens, senescence begins; physical and chemical changes continue after

optimum ripeness is reached including further softening, loss of desirable flavor and

complete breakdown (Kader and Mitchell, 1989). Gupta and Jawandha (2010) studied

the response of peach cultivar „Earli Grande‟ to three stages of fruit harvest and

evaluated their physical and chemical characteristics to cold storage of 0-20oC

temperature 85-90% relative humidity for 21 days. The fruit quality parameters were

significantly affected by different stages of fruit harvest. An increase in physiological

loss in weight, acid ratio, spoilage, TSS and anthocyanins was observed with the

delay in harvesting stage and increase in storage time. With the advancement in

maturity and storage duration a linear decline in Vitamin A content was observed. A

gradual decrease of reducing sugars was observed in fruits with the increase in storage

period picked after optimum maturity. They reported that peach fruits harvested at

optimum maturity retained maximum TSS acid ratio and could be stored for three

weeks in cold storage.

Lafer (2006) investigated the response of apples to different harvesting dates while

applying treatments of AVG before harvest and 1-MCP after harvest. Storage in

controlled atmosphere treated with 1-MCP and AVG showed good titratable acidity

and firmness while delayed the fruit softening. Over matured fruits lost more acidity

and firmness as compared to those fruits which were harvested at optimal maturity

stage. AVG and 1-MCP treatments also affected the amount of Total soluble solids.

Storage for more time showed CO2 damages, senescent scald and fungal decay.

Maximum incidence of internal browning was observed in over ripeed apples treated

with 1- MCP. McLellan et al. (1990) harvested apple fruits at three different stages.

The harvested fruits were at cold storages with a 95% RH. The slices of apples were

taken from different treatments for analyzing their Brix/acid ratio. Raw slices of

apples were analyzed though Sensory analysis. Slice firmness was due to CA delay

and harvesting date. With the delay of storing at CA storage the un-blanched raw

slices, showed softening, while late harvest also resulted higher softening. Blanching

of slices greatly increased the softening. A significant increase in apple flesh

browning was recorded at delay in storage at CA and due to later harvest. There was

no significant difference in acceptability rating of raw slices of apples before freezing.

Echeverria et al. (2002) evaluated the response of fruit quality and production of

aroma of apples to influence of storage conditions and harvest date. Fruit firmness,

soluble solids, titratable acidity, physiological disorders, skin color and aroma

production was measured after 3, 5 and 7 months of storage. Controlled atmosphere

maintained good quality of fruits as compared AIR atmospheres. Apples treated with

ULO1 maintained good firmness in storage conditions as compared to other

treatments. AIR atmosphere maintained the more aroma of apple. By passing of more

time, decrease in aroma was recorded. Storage of apples in ultra-less O2 atmospheres

showed less aroma production treated with ULO2. Erkan and Pekmezcu (2004)

studied the effect of harvest dates (15 days interval) on superficial scald development

and postharvest quality in „Granny Smith‟ apples (Malus domestica) stored at 0oC

with 90% relative humidity for 8 months. A significant variation was observed for

weight loss, soluble solids, titratable acidity and flesh firmness among the different

harvest dates. Increased soluble solids were achieved with Delay harvest. Flesh

firmness, titratable acidity and soluble solids remained at acceptable levels regardless

of harvest dates and storage durations. Early harvested fruits were decayed at a lower

rate. The „Granny Smith‟ apples could be stored for 8 months with minimal scald

incidences (0% to 14.2% depending on storage length). Hernandez et al. (2005)

harvested apple (Malus domestica) of the fruit at two or three different maturity stages

stored at 33 ºF in air or in controlled atmosphere (CA). Fruit stored in CA conserved

higher firmness and produced less CO2. Internal browning was not seen in fruit stored

in air, but appeared in fruit after two months storage in CA. The incidence did not

increase after longer storage times. It did not affect the incidence of internal

browning, but DPA inhibited internal browning completely. A mineral analysis of the

apple flesh showed differences among the seasons. Concentrations of calcium (Ca),

boron (B) and magnesium (Mg) were significantly higher, corresponding with a lower

incidence of internal browning.

Tomala (1999) investigated the effect of several renowned factors on the quality of

pome fruits at harvest and following storage. Sensitivity to low calcium and

susceptibility to physiological disorders during storage was observed by the apple

fruits. Calcium content of apple at maturity was influenced by environmental and

cultural factors. Important factors (fertilization, pollination, seed number and fruit set)

played a crucial role in fruit quality after breakage of dormancy and appearance of

bloom. Fruits, which develop from terminal flowers, are richer in calcium than those

developing from lateral ones. The location of fruits in the tree crown is also

influencing calcium concentration, and incidence of physiological disorders; more

fruits are affected in the upper parts of canopy. Calcium treatments reduced the

occurrence of physiological disorders. Apples low in calcium showed an earlier onset

of the endogenous ethylene climacteric as fruits mature on the tree as compared to

early blooming ones. Fruits from late blooming flowers produced less ethylene,

exhibited a lower starch index and developed superficial scald during storage.

Steenkamp et al. (1983) recorded that bitter pit tissue had a higher concentration of

calcium, potassium and magnesium than sound tissue as well as higher concentrations

of oxalic and citric acid but a lower concentration of malic and succinic acid. It

appeared that localized excessive concentrations of oxalic and citric acid could induce

bitter pit. Cocucci (1983) reported the mechanism energy dependent able to secrete

proton, linked to cation influx in plasmalemma of apple fruit (cv. Granny Smith). This

helps in uptake of organic and inorganic compounds by apple cells during ripening.

The pitted fruits had 60% lowered proton secretion as compared to fine ones but

similar transmembrane electric potential at low k+ level. The pitted fruits had lower

Ca2+

content as compared to the fine ones. Calmodulin level was 40% higher in the

pitted apple fruits than in the sound ones. This result indicated an involvement of the

calmodulin- Ca2+

system in the bitter pit. Juan et al. (1999) investigated the effect of

harvest date on storage ability of 'Golden Delicious' apple and cold stored for seven

months. Quality indices (soluble solids content, flesh firmness, acidity and starch

index) were determined weekly for one month before the first harvest date and upon

removal from storage. Fruit susceptibility with increasing maturity was inoculated

with Penecillium expansum, keeping in cold storages for five weeks. After removal

from cold storage, superficial scald and moisture loss incidence were higher on fruit

picked earlier. Bitter pit occurrence was also observed. The percentage of marketable

size fruit and disease severity increased with harvest date. Starch index was

significantly correlated to acidity, soluble solids and firmness, suggesting that it could

be used to predict fruit quality after cold storage. Kvikliene et al. (2008) studied the

effect of fruit maturity on apple fruit cv. „Ligol‟ storage ability and rot development.

Fruits for storage were harvested 5 times at weekly intervals before, during and after

predictable optimum harvest date. The fruits quality parameters changed according to

harvest date. Later harvested fruits were softer. Content of soluble solids did not

depend on harvest time. Fruit storage ability was closely connected to fruit maturity.

The best quality apple fruits one week before climacteric peak were picked after 180

days of storage.

Calcium and postharvest performance

According to Conwey et al. (1982) fruits and vegetables require additional cost in

value addition, when they are moved from the field to the consumer. Thus, it is an

economic necessity to decrease by extending the storage life. While several treatments

e.g. heat, chemicals, and irradiation can be used to reduce incidence of

microorganisms, but injury to fruit and consumer‟s concerns about chemical residues

or ionizing radiation requires the development of alternative methods of protection.

Calcium is an important second category macro-nutrient which is involved in variety

of different function. Calcium helps to regulate the metabolism in apple fruit, and

adequate concentration maintain fruit firmness, delays fruit ripening, lower the

incidence of physiological disorders such as water core, bitter pit, and internal

breakdown (Bangerth et al., 1972; Faust and Shear., 1968; Mason, et al., 1975; Reid

and Padfield., 1975) and suppress Erwinia carotovora (Jones) incidence on apple

fruits (Conway, 1982; Sharples and Johnson., 1977).

Mahmud et al. (2008) treated Papaya (Carica Papaya L.) fruits with 1.5, 2.5 and 3.5%

solutions of calcium chloride by dipping and vacuum infiltration (33 Kpa) or

untreated (0%) as control to study the storage life and postharvest quality

characteristics. The postharvest infiltration of calcium at 2.5% has the potential to

control disease incidence, prolong the storage life and preserve valuable attributes of

postharvest papaya, presumably because of its effects on inhibition of ripening and

senescence process and loss of the fruit firmness of papaya. Kadir (2005) sprayed

„Jonathan' apple trees at three commercial orchards with calcium chloride (CaCl2)

solution containing 3.2 g/L, starting when apple sizes were between 0.9 and 1.6 cm

average diameters. Apples were stored for two and four months in regular atmosphere

storage at 2°C (36°F). Apples stored for two months had better quality than those

stored for four months. Depending on the location, five to eight CaCl2 applications

and two to seven applications were necessary to retain an average of 26% of fruit

firmness and an average of 35% of the SSC/TA, respectively, in the two-month

storage. At least seven applications were required to retain an average of 29% of fruit

firmness of apples stored for four months. Six to seven applications of CaCl2 retained

fruit weight by 22 to 33% more than the non-treated control apple. In general, CaCl2

was beneficial for storage quality of 'Jonathan' apples in Kansas. Trentham (2008)

stored the apple fruits at 0oC after dipping for 2 minutes in 0, 2%, 4%, or 6% solution

of CaCl2 at 0 or 68.95 kPa. He recorded the data for different parameters with the

interval of four months. Paraffin sections were stained with an aqueous mixture of

alcian blue 8GX, Safaranin 0 and Bismark brown Y, or with theperiodic acid-Schiff

(PAS) reaction. No histological difference was observed in fruit treated with 2%

CaCl2 compared with those pressure-infiltrated with greater amounts of Ca. Fruits

pressure-infiltrated with 6% CaCl2 exhibited the greatest amount of flattened

epidermal cells and hypodermal cavities. Cuticles were also affected at the higher

CaCl2 treatment levels (with regard to staining with Bismark brown), becoming more

condensed and uniform. Cuticle and hypodermis were stained differentially with PAS

in the 6% CaCl2 treatment. All tissues, including the cuticle, were stained magenta

red, indicating a possible chemical alteration of the cuticle and the underlying tissue

by calcium. Petersen (1980) reviewed the available information regarding calcium

(Ca) nutrition of apple trees. In spite of a high Ca content in most orchard soils and a

high potential of Ca uptake in apple trees, there is no doubt about Ca deficiency being

a causal factor for many disorders in apple fruits. Translocation acts by ion exchange,

mainly in the xylem, and is very slow. Apical meristems and young growing fruits

with rapid cell division have a high demand for Ca and depend on a continuous

supply. Concurrent with a change in fruit growth from cell division to cell expansion,

the Ca intake in the fruits may cease and fruit Ca content may even decrease, as the

fruits may then serve to some extent as a source of Ca for growing leaves and shoot

tips. Fruits containing Ca at less than 50 mg kg−1

of fresh weight are sensitive to bitter

pit and internal breakdown. As dipping the ripe fruit in a Ca solution after harvest

often gives the same protection as a Ca spray on the trees, permanent damage in the

developing or ripening fruits can be avoided. That means that some of the disorders of

the fruits are caused by lack of Ca in the respiratorial and senescence processes rather

than in the developmental stage. Conway et al. (2002) suggested that calcium, the

most important mineral element determining fruit quality. It seemed to be especially

important in apples where it reduced metabolic disorders. Calcium in adequate

amounts helped to maintain apple fruit firmness and decreases the incidence of

physiological disorders (water core, bitter pit and internal breakdown). Postharvest

decay may also be reduced by increasing the calcium content of apple fruit. Directly

applied calcium increased fruit calcium content. Both pre- and postharvest calcium

treatment methods had inherent problems. Developing a commercially acceptable

method of successfully increasing calcium concentration in fruit is a continuing

challenge.

Freitas et al. (2010) examined that bitter pit, a Ca2+

deficiency disorder of apple fruit

(Malus domestica), is a complex process that involves not only the total input of Ca2+

into the fruit, but also a proper Ca2+

homeostasis at the cellular level. The objective of

this study was to test the hypothesis that Ca2+

accumulation into storage organelles

and binding to the cell wall is associated with BP development in apple fruit. The

experiment was carried out on „Granny Smith‟ apples stored at 0oC for 60 days. After

storage, fruit were segregated into two lots for analysis, apples with the water-soaked

initial visual symptoms of BP and those not showing this symptom. Cytochemical and

ultra structural observations showed an accumulation of Ca2+

in the vacuole of

individual outer cortical cells of pitted fruit. We also observed an increase in the

expression of genes encoding four pectin methyle-sterases, a greater degree of pectin

de-esterification and therefore more Ca2+

binding sites in the cell wall, and a higher

fraction of the total cortical tissue Ca2+

content that was bound to the cell wall in

pitted fruit compared with non-pitted fruit. Cells of the outer cortical tissue of pitted

fruit consistently had higher membrane permeability than outer cortical cells of non-

pitted fruit. The results provide evidence that Ca2+

accumulation into storage

organelles and Ca2+

binding to the cell wall represent important contributors to BP

development in apple fruit. Hayat et al. (2003) investigated the effect of different

concentrations of calcium chloride (1%, 1.5%, 2%), paraffin wax coating and

different wrapping materials (polyethylene, carton paper) to increase the shelf life and

to avoid the postharvest losses of Banky cultivars of apple. All the treatments had a

significant effect on the shelf life of fruits. Calcium chloride (2%) proved very useful

for reducing weight loss and shrivelling and retained consumer acceptability even

after 60 days of storage. Polyethylene packaging stood second position after 2%

calcium chloride treatment. Swiątkiewicz and Błaszczyk (2007) studied the effect of

late spraying with 0.8% Ca(NO3)2 on calcium content as well as nutrient mutual

relations between mineral constituents in „Elise‟ fruit of 5 year old apple tree. In

general, foliar spray with calcium nitrate increased Ca concentration in fruits

determined both after treatments and after harvest however this effect was modified

by weather conditions in particular experimental years. Sprays with calcium nitrate

significantly decreased N/Ca and K/Ca ratio in fruits analyzed after treatments as well

as freshly harvested fruits, however only in 2005. Castro et al. (2008) studied the

biochemical factors associated with a CO2 induced internal flesh browning (FB)

disorder of Pink Lady apples (Malus domestica‟). Pink Lady apples were stored in air

or controlled atmosphere (CA) with 1.5 kPa O2 and 5 kPa CO2 at 0.5oC for 2 and 4

months. Both brown and surrounding healthy tissues in apples with FB showed a

decrease in ascorbic acid and an increase in dehydroascorbic acid during the first 2

months of storage in CA, the time period when FB developed. Undamaged, CA-

stored apples retained a higher concentration of ascorbic acid after 2 months in

storage. The level of hydrogen peroxide (H2O2) increased more in the flesh of CA

stored apples than in air stored apples, an indication of tissue stress. In addition,

concentrations of H2O2 were significantly lower in diphenylamine (DPA) treated

apples. Treatment with DPA also inhibited FB completely compared to untreated

apples. Poly phenol oxidase (PPO) activity was similar for apples kept in air or CA

storage and between undamaged and damaged fruit. The results showed a closer

association between FB and the oxidant antioxidant mechanisms such as ascorbic

acid, H2O2 and DPA, than to the activity of specific browning enzymes like PPO.

Further investigation of the protective effect of ascorbic acid is warranted as is further

research on the underlying causes of apple fruit susceptibility to FB. Biggs et al.,

(1993) treated apple cultivar Nittany by Alternaria spp with the calcium chloride

(CaCl2) for its efficacy in reducing the incidence and severity of infection. CaCl2

reduced the incidence of rot from 61% in the controls to 27 and 33%, respectively.

Dip treatments alone reduced rot incidence to 17 and 12% for the CaCl2 and liquid

CaCl2 treatments, and seasonal sprays followed by dip treatment reduced incidence to

5%. In postharvest tests, fruit treated with CaCl2 alone and in combination with

iprodione exhibited the lowest incidence and severity of Alternaria rot. At harvest,

isolation frequency from surface-disinfested fruit averaged 34%. Martin et al. (1960)

sprayed different treatments to half-trees of Cleopatra apples, it was shown that

magnesium nitrate increased the incidence of pit and calcium nitrate decreased it but

increased the calcium content, borax decreased the effectiveness of the calcium nitrate

treatment. Magnesium or calcium nitrate, with or without borax, did not affect the

potassium, magnesium, phosphorus, or nitrogen content of the fruit cortex.

Petersen (1980) conducted an experiment with apple trees, cultivar „Cox's Orange‟,

Ca was omitted in the nutrient solution for periods of different length. In the bulked

sample, average size of fruits was not considerably affected, but the distribution of

small and large fruits changed toward smaller fruits. Concurrently, bitter pit was

reduced compared to the control. Average fruit size was not significantly changed, but

the distribution was towards larger fruits. Under these circumstances bitter pit was

increased. Ca deficiency, caused either by omission of Ca or competition between K

and Ca, increased fruit rot, russeting and cracks on the fruits. Short term variations in

Ca levels were not seen to produce any measurable response. Perring (1989)

examined the development of physiological disorders in particular zones of apples

that might be allied to changes in the chemical composition in these and other zones.

The flavour and texture of the various zones of the fruit may alter differently during

storage because of changes in the distribution of dry matter, water and organic acids.

Bitter pit and calcium

Bitter pit is a physiological disorder that appears as depressed brown lesions in the

skin of the fruit, located mainly on the calyx end (Ferguson and Watkins, 1989). The

disorder is inversely related to the Ca concentration of the fruit and, in general, is

directly related to Mg, potassium (K), phosphorous (P), and nitrogen (N) levels in

fruit tissues (Fallahi et al., 1997). Summer and root pruning, application of growth

regulators, fruit thinning, Ca fertilization, effect of localized Ca application have

shown that the incidence of bitter pit relates to the Ca distribution within the plant

than to the total Ca supply from the soil. Because Ca moves mainly through the

transpiration stream as the vegetative tissues have less resistance to transpiration, Ca

absorbed from the soil will tend to move toward vegetative tissues and away from the

fruit (Jones and Higgs, 1982).

Reid and Padfield (1975) evaluated the incidence of bitter of apple cultivar „Cox‟s

Orange Pippin‟ after dipping in solution containing 2.5% CaCl2 or Ca(NO3)2. The

incidence of bitter pit was reduced considerably when fruit was dipped in solution

containing lecithin of egg. Lecithin addition also alleviated the damage often

associated with calcium dips and improved control of two other physiological

disorders, breakdown and water core. A dip containing lecithin alone was relatively

effective. It was suggested that lecithin might assist the movement of applied calcium

into apple fruits. Dris and Niskanen (1999) treated five commercial apple (Melba,

Raike, Red Atlas, Akero, Aroma, and Lobo) with preharvest calcium chloride (CaCl2)

sprayed at Ca 2.0 g/l, stored at 2-6 months at 2-4oC and 85-95% RH. Preharvest CaCl2

sprays increased fruit firmness and the titratable acidity but decreased soluble solids,

soluble solids/titratable acidity ratio, and the incidence of physiological storage

disorders of some cultivars.

Physical characters and apple

Jordan et al. (2000) determined the density of unripe kiwifruit (Actinidia deliciosa cv.

Hayward) early in storage as a means to find out the current fruit dry matter (DM) and

total sugar-plus-starch concentrations, and of predicting DM and soluble solid

concentrations later when the fruit fully matured. As fruit taste is related to sugar

concentration, and sugars make up the bulk of the soluble solids in fruit. Density to

both DM and ripe fruit soluble solids in the composition trial had similar parameter

values to those of the survey trial and gave S.E. of prediction of about 0.3% FW. DM

levels were about 3.2% FW above the sum of soluble solids and starch concentrations

in both ripe and unripe fruit, a difference largely independent of DM concentration.

Starch lost during ripening was accounted for by the increase in the glucose and

fructose sugar pools, and these two sugars had near equal concentrations at each DM

level. Sucrose and minor sugar levels were independent of DM and ripeness.

McGlone et al. (2007) measured non-destructive density and Visible-Near Infrared

(VNIR) on yellow-fleshed kiwifruit (Actinidia chinensis) harvested on four occasions

across a commercial harvest period. Density measurements were made by flotation

and the VNIR measurements using a polychromatic spectrometer system operating

over the range 300–1140 nm, although much smaller spectral regions were better for

predicting DM and SSC (both 800–1000 nm), or Hue (500–750 nm). Harvest-time

and post-storage data sets were formed and used to develop models for predicting

harvest-time and/or post-storage quality parameters. The VNIR method proved

superior to the density method in every case, especially for DM and SSC predictions

where the VNIR method was close to twice as accurate. The VNIR method yielded

accuracies (standard errors in prediction) of ± 0.40%, ± 0.71% and ± 1.05° for

predictions of harvest DM, SSC and Hue, respectively. Predictions of post-storage

DM, SSC and Hue, from post-storage spectra, had improved accuracies of ± 0.24%, ±

0.31% and ± 0.98% respectively. The increased accuracy for SSC prediction, from ±

0.71 to ± 0.31%, is theorized to be a consequence of the VNIR method being better at

predicting the total carbohydrate concentration, which comprises starch and soluble

sugars in about equal amounts at harvest but is mainly soluble sugar after the fruit

ripens during cold storage. That theory was supported by the observation that post-

storage SSC predictions based on harvest-time VNIR spectral models were also more

accurate (± 0.38%) than the equivalent harvest-time SSC predictions. In addition,

harvest-time DM predictions were shown to be capable of at least rank ordering (R2 =

0.87) kiwifruit in terms of post-storage SSC.

CHAPTER 3: INFLUENCE OF STORAGE DURATION ON PHYSICO-

CHEMICAL CHANGES IN FRUIT OF APPLE CULTIVARS

Ibadullah Jan and Abdur Rab

Department of Horticulture, Khyber Pakhtunkhwa Agricultural University

Peshawar, Pakistan

Abstract

The experiment on “Influence of storage duration on physico-chemical changes in

fruit of apple cultivars” was conducted at Department of Horticulture, Khyber

Pakhtunkhwa Agricultural University Peshawar, Pakistan during the years 2007-08.

The fruit of apple cultivars: Royal Gala, Mondial Gala, Golden Delicious and Red

Delicious were harvested at optimum maturity and stored at 5±1°C with 60-70%

relative humidity. Physico-chemical changes in fruit were determined at 30 days

interval during storage. Apple cultivar Red Delicious had the highest juice content

(58.47%), TSS/Acid ratio (23.12), ascorbic acid (13.12 mg/100g), fruit flesh firmness

(5.98 kg/cm2), fruit density (0.82 g/cm

3) as well as the least weight loss (2.22%) but

also had the highest bitter pit (11.86%) and soft rot (13.53%) incidence. Titratable

acidity was the highest (0.55%) in cultivar Mondial Gala and starch score was the

maximum (5.22) in cultivar Golden Delicious. The percent weight loss, total soluble

solids, total sugar, pH, TSS/Acid ratio, bitter pit incidence and soft rot increased with

increase in storage duration while juice content, starch score, titratable acidity,

ascorbic acid, fruit flesh firmness and density of fruit declined with increase in storage

duration.

3.1. INTRODUCTION

Apple (Pyrus domestica L) is one of the most important tree fruit of the world. The

apple was cultivated in Greece around 600 BC or earlier. It is a highly nutritive fruit

which is a rich source of sugars 11%, fat 0.4%, protein 0.3%, carbohydrates 14.9%,

vitamins and minerals. A 100 g fresh apple contains, water 84.7 %, fibre 0.8 g,

carbohydrates 13.9 g, proteins 0.4 g, lipid 0.3 g, ash 0.3 g, vitamin C 8 mg/100 gm,

sodium 0.3 mg/100 g, potassium 145 mg/100 g, calcium 7 mg/100 g, magnesium 6

mg/100 gm, iron 480 μg/100 g, phosphorus 12 mg and iodine 2 μg (Hussain, 2001).

Due to its high nutritional value, it ranks third in consumption after citrus and banana

(Bokhari, 2002). In Pakistan its cultivation is limited and restr