JOURNAL OF FRUIT AND ORNAMENTAL PLANT RESEARCH

DETERMINATION OF PHENOLIC

COMPOUNDS IN APPLES AND

PROCESSED APPLE PRODUCTS

MSc Part ISeat No : 14027

INTRODUCTION Fruits and vegetables are the major source of

phenolic compounds in diet. Dietary intake of phenolics is estimated

1gram/day. Many different phenolic compounds have

been identified in apples . The two main subtypes include :

1. Flavonoids (quercetins glycosides and catechin and epicatechin).

2. Phenolic Compounds (caffeic acid and p-coumaric acid).

3. Dihydrochalcones are also present.

Quercetins glycosides are present in the skin of apple.

Dihydrochalcones are present in the core and seeds of apple.

Phenolic acids are present in the cortex of apple.

MATERIAL AND METHODMATERIAL : Phenolics content was measured in four

cultivars of apple : ‘Jonagold’ , ‘Sampion’ , ‘Idared’ and ‘Topaz’.

Replicate batches of these cultivars were processed into clear juice, cloudy juice and applesauce by industrial procedures.

Clear apple juices were digested with Panzym MK at 50°C or Rohapect MA Plus at 20°C and ascorbic acid was added to the cloud juice.

METHOD:HPLC method was used to separate and quantify

phenolic compounds in apples and processed apple products.

The apples were divided into octants and were frozen to -25°C and then grounded up.

o 10g of grounded apples were homogenized for 1 minute with 70% methanol. The slurry was transferred to a 50ml volumetric flask, which was then filled to the mark with 70% methanol.

o The mixture was filtered through Whatman No. 1 filter paper. The filtrate was stored at −18°C prior to analysis.

Samples of sauces and juices were filtered, diluted and extracted with 70% methanol in an ultrasonic bath for 10 minutes before injection.

o All the samples before HPLC were diluted 1:3 (v/v) with sodium acetate buffer (Solvent A)

HPLC HPLC was carried out using an Agilent 1100

Series HPLC System equipped with a DAD detector.

Phenolic compounds were separated using a Phenomenex Fusion RP column with a guard column.

The mobile phase used consisted of 10.2% acetic acid in 2mM of sodium acetate (solvent A) and Acetonitrite (solvent B).

The flow rate was kept constant at 0.5 ml/min for a total run time of 72 min at 25°C.

The system was run with a gradient pattern. The injection volume of the sample was 20 μl.

RESULT The concentration of phenolic compounds in

the cultivars evaluated was 857 mg/kg. The concentration of different groups of

phenolic compounds varied widely from cultivar to cultivar.

The cultivar with the highest level of flavonols was ‘Sampion’ (477 mg/kg).

The cultivar with the highest level of phenolic acids was ‘Idared’.

The cultivar with highest level of quercetin glycosides were ‘Jonagold’ and ‘Topaz’.

During the production of applesauce, phenolics content did not essentially change.

During the production of cloudy juices, phenolics content dropped by 47%.

During the production of clear juices with Panzym MK, phenolics content dropped by 65%.

During the production of clear juices with Rohapect MA Plus, phenolics content dropped by 81%.

CONCLUSION Even though the cultivars differed significantly

in terms of morphology , they all contained about the same amount of phenolics, the most abundant of which were flavonols.

Apple sauces contained more phenolics than juices.

Natural cloudy juices contained more phenolic compounds than clear juices.

In the production of clear juice, phenolic compounds were more effectively extracted when the temperature during enzyme treatment is higher.

BIBLIOGRAPHY Journal Of Fruit And Ornamental Plant

Research ; Vol. 14 (Suppl. 2),2006. Dietary intake and availability of

polyphenols, J NUTR. 130; Saclbert A., Wilska-Jeszka J., Markowski J., 2000.

Flavonoids and chlorogeneic acid levels in apple fruit: characterization of variation, Awad M.A., De Jagger A., Van Westing L.M; 2000.

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