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International Journal of Food Properties

ISSN: 1094-2912 (Print) 1532-2386 (Online) Journal homepage: https://www.tandfonline.com/loi/ljfp20

Effect of Heat-Induced Changes of ConnectiveTissue and Collagen on Meat Texture Properties ofBeef Semitendinosus Muscle

Haijun Chang , Qiang Wang , Xinglian Xu , Chunbao Li , Ming Huang ,Guanghong Zhou & Yan Dai

To cite this article: Haijun Chang , Qiang Wang , Xinglian Xu , Chunbao Li , Ming Huang ,Guanghong Zhou & Yan Dai (2011) Effect of Heat-Induced Changes of Connective Tissue andCollagen on Meat Texture Properties of Beef Semitendinosus Muscle, International Journal of FoodProperties, 14:2, 381-396, DOI: 10.1080/10942910903207728

To link to this article: https://doi.org/10.1080/10942910903207728

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Published online: 25 Feb 2011.

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International Journal of Food Properties, 14:381–396, 2011Copyright © Taylor & Francis Group, LLCISSN: 1094-2912 print / 1532-2386 onlineDOI: 10.1080/10942910903207728

EFFECT OF HEAT-INDUCED CHANGES OF CONNECTIVETISSUE AND COLLAGEN ON MEAT TEXTUREPROPERTIES OF BEEF SEMITENDINOSUS MUSCLE

Haijun Chang1,2, Qiang Wang3, Xinglian Xu1, Chunbao Li1,Ming Huang1, Guanghong Zhou1, and Yan Dai11National Center of Meat Quality and Safety Control, Key Laboratory of MeatProcessing and Quality Control, Ministry of Education, College of Food Scienceand Technology, Nanjing Agricultural University, Nanjing, P.R. China2College of Environmental and Biological Engineering, Chongqing Technology andBusiness university, Chongqing, P.R. China3Department of Biological and Chemical Engineering, Chongqing EducationCollege, Chongqing, P.R. China

The effects of heat-induced changes of intramuscular connective tissue (IMCT) and colla-gen on meat texture properties of beef Semitendinosus (ST) muscle were investigated in thisstudy. ST muscle was heated to core temperature from 40 to 90◦C with an increment of 5◦Cin a water bath and microwave oven, respectively. Characteristics changes of IMCT colla-gen and meat texture were estimated. The results indicated that: cooking loss, total collagenand soluble collagen content increased with the increase in heating temperature and time.Collagen solubility of thermally treated meat was relatively high at 65◦C irrespective of heattreatment mode. The granulation changes of connective tissue collagen occurred at 60◦Cand increased during heating to higher core temperatures. The instrumental texture profileanalysis (TPA) data of heated meat showed also significant differences between two heatingmodes and studied temperatures. Results indicated that heating internal core temperatureof 60◦C and 65◦C were critical for affecting meat texture properties owing to the thermaleffects of collagen in water bath and microwave heating, respectively.

Keywords: Beef Semitendinosus muscle, Connective tissue, Collagen, Texture, Heating.

INTRODUCTION

Acceptability of meat is a common concerned attribute both by meat producers andconsumers; it was also called eating quality of meat, mainly included tenderness, juiciness,and flavor.[1] Thermal treatment is an important step for the conversion of inedible (raw)meat to edible meat, and can affect on the eating and sensory quality of meat, especiallyon the meat texture.[2] The texture of meat is one of the most important quality attributes,which has been studied for many years in different aspects.[3–5] The effects of thermaltreatment on the meat texture mainly resulting from the denaturation and dissociation

Received 4 May 2009; accepted 19 July 2009.Address correspondence to Guanghong Zhou (G. H. Zhou), College of Food Science and Technology,

Nanjing Agricultural University, Weigang 1#, 210095, Nanjing City, Jiangsu Province, P. R. China. E-mail:ghzhou@njau.edu.cn

381

382 CHANG ET AL.

of myofibrillar proteins, transversal and longitudinal shrinkage of meat fibers, aggrega-tion and gel formation of sarcoplasmic proteins and solubilization of connective tissuecollagen.[6–10] The texture of heated meat was related to the characteristics changes ofconnective tissue and collagen to a certain extent due to the thermal effects. In addition, itwas also depended on the mode of heating, heating temperature and time.

Heating modes can affect on the palatability of meat, therefore, in scientificresearches, thermal treatment modes should be selected that either can simulate the prac-tices of common consumer, or can be subjected to experimental controlling, and can notaffect palatability and overshadow treatment effects significantly.[11] Numerous heatingmethods have been studied for use in palatability researches including ultrasound,[12]

roasting,[13] various methods of grilling and broiling,[14,15] and conveyor-belt grilling.[16]

Furthermore, water bath heating was applied widely both in the practical production andscientific researches. Recently, microwave heating has become very popular with con-sumers wanting a quick, convenient, clean and nutritious way for heating in the home.However, there were conflicting results on microwave heating. Some researches havedemonstrated that meat heated by microwave can compare favorably in palatability withmeat heated conventionally.[17] Contrarily, Starrak and Johnson[18] reported that many peo-ple were dissatisfied with the results for meat was heated by microwave ovens. Deethardtet al.[19] reported that acceptability of meat heated by microwave has been low because ofcolor, aroma or flavor problems.

To the best of our knowledge, few data are available on the comparative study on theeffects of heat-induced changes of connective tissue and collagen on meat textural proper-ties of Chinese yellow bulls using water bath and microwave heating. Therefore, the objec-tives of the present study were to: (1) characterize IMCT collagen properties (collagen con-tent and solubility), and connective tissue microstructure of beef ST muscle during waterbath and microwave heating; (2) evaluate the textural properties by means of texture profileanalysis (TPA) parameters (hardness, adhesiveness, springiness, cohesiveness, gumminess,chewiness and resilience) of beef ST muscle, whether the textural properties of heated meatwere related to the characteristics of connective tissue and collagen were examined.

MATERIALS AND METHODS

Materials

Beef ST muscle was collected from 15 Chinese yellow bulls (Simmental × Nanyangcrossbreed ), carcasses were slaughtered humanely at the corporation slaughterhouse (LvQiMeat Co. Ltd, Henan, China) followed by the Halal method. The bulls were 30-month-oldand weighed between 500 ± 30 kg. Muscle samples were collected within 48 h postmortemafter aging in a 4◦C chiller. pH value of all muscle was about 5.6–5.8. The visible subcu-taneous fat and connective tissue were trimmed off and samples were sliced into cubes2.54-cm thick, perpendicular to the direction of the fiber. The steaks were individuallyweighed and vacuum-packed. L-4-hydroxyproline (C5H9NO3, m.w:131.13) standard sam-ple was obtained from Sigma-Aldrich (France). All other chemicals used in this work werealso from commercial sources and of analytical grade.

Heating Treatment

Beef ST muscle steaks (2.5 × 5.0 × 5.0 cm) were packed in polypropylene bags,sealed and heated in a 95◦C water bath (Guohua HH-42, Changzhou, China) to internal

PROPERTIES OF BEEF SEMITENDINOSUS MUSCLE 383

core temperature from 40 to 90◦C with an increment of 5◦C. Four slices at each temper-ature, the internal temperature was measured in one of the slices using a digital needle-tipped thermometer (HI145, HANNA Instruments, Italy). Temperature changes weremonitored constantly until the designed internal core temperature was reached. Meat steakswere also heated in a laboratory microwave oven (600W, 2450MHz) (EM-2008MS1,Shanghai, China) at low power level[20] to the internal core temperatures mentioned above.During microwave heating, the changes of temperature at the center of sample were mea-sured periodically by a temperature probe.[21] The probe was inserted immediately intothe geometric center of steaks, after sample was taken out from the oven at interval of10 s of heating.[22] Care has been taken to measure the product temperature as much asclose to the set temperature although it is extremely difficult to measure the temperatureby common temperature probe. After heating, the steaks were then chilled with cold run-ning water to about room temperature, surface-dried with filter paper, and re-weighed. Rawmeat (unheated) was used as the control group at room temperature (20◦C). The heatingtime for steaks with different core temperatures during heating were listed in Table 1.

Cooking Loss

Cooking losses of samples were assessed as outlined by Vasanthi et al.[23] Everymeat steaks samples were blotted with blotting paper and weighed accurately just beforeheating (Wb). After heating, the samples were cooled to about room temperature and wipedwith blotting paper and re-weighed immediately (Wa). The cooking losses of samples werecalculated according to the following equation:

Cooking loss = Wb − Wa

Wb× 100%

Collagen Content

Total collagen, as measured by hydroxyproline concentration was determinedaccording to the procedures of Bergman and Loxley,[24] Hill,[25] and Vasanthi et al.[23] withsome modifications. Approximately five grams of meat was weighed accurately and 50 mlof 6 M HCl solution was added in a sealed tube, and then hydrolyzed in an oven (FOSSCorporation, Denmark) at 110◦C for 18 h. After hydrolyzed completely, the hydrolysateswere filtered using filter paper and were decolorized with active carbon. The filter paperand active carbon were washed with deionized water for three times until the volume of fil-trate reached 200 ml, then 20 ml of the filtered hydrolysate was taken and neutralized with10 M and 1 M NaOH solution until the pH value up to 7.9–8.0. The neutralized hydrolysatewas again diluted with deionized water to 250 ml in a volumetric flask. Four-milliliterof the neutralized hydrolysate was used to determine the hydroxyproline content.[26] Aconversion factor of 7.25[27] was used to estimate the collagen content and expressed aspercentage of the initial sample wet weight.

The method for soluble collagen determination was adopted from Fang et al.[28] andHill[25] with minor modifications. Five grams of homogenized meat was put in a 50-ml cen-trifuge tube and 12 ml 1/4 Ringer’s solution (1.8 g NaCl, 0.25 g KCl, 0.06 g CaCl2.6H2O,0.05 g NaHCO3, 0.186 g iodacetic acid were dissolved into 1 L distilled water) was addedand the whole mixed (Ultra-Turrax T25 basic blender, IKA-WERKE, Germany). The mix-ture was maintained in a water bath at 77◦C for 60 min, after cooling to room temperature,

Tabl

e1

Para

met

ers

for

wat

erba

than

dm

icro

wav

ehe

atin

gex

peri

men

ts.∗

Cor

ete

mpe

ratu

re(◦

C)

Raw

a40

5055

6065

7075

8085

90

Wat

erba

thhe

atin

gtim

e(m

in)b

–5.

0±

0.5

8.0

±0.

510

.0±

0.5

12.0

±0.

514

.0±

0.5

16.0

±0.

519

.0±

0.5

22.0

±0.

525

.0±

0.5

28.0

±0.

5M

icro

wav

ehe

atin

gtim

e(m

in)b

–3.

0±

0.5

6.0

±0.

58.

0±

0.5

9.0

±0.

510

.0±

0.5

11.0

±0.

512

.0±

0.5

14.0

±0.

516

.0±

0.5

19.0

±0.

5N

44

44

44

44

44

4∗ T

hesi

zeof

sam

ples

for

wat

erba

than

dm

icro

wav

eov

enhe

atin

gex

peri

men

tsw

ere

alla

bout

2.5

×5.

0×

5.0

cman

d10

0±

5g

inw

eigh

t,th

ein

itial

core

tem

pera

ture

ofsa

mpl

esw

ere

all2

0◦C

.a T

hera

wm

eata

sco

ntro

l(un

heat

ed)

(in

the

follo

win

gex

pres

sed

inth

efo

rmof

20◦ C

).bA

vera

gehe

atin

gtim

ew

asre

cord

eddu

ring

heat

ing.

384

PROPERTIES OF BEEF SEMITENDINOSUS MUSCLE 385

centrifuged for 15 min at 3300 × g (Beckman Allegra 64R, Beckman-Coulter Company,USA). The supernatant was collected and 8 ml of 1/4 Ringer’s solution was mixed with theprecipitate and centrifuged again for 10 min at 3300 × g. After rinsing the precipitate, thesupernatants from the two centrifugations were combined and were hydrolyzed accordingto the procedures of total collagen hydrolyzed mentioned above. The percentage of solublecollagen was calculated from the hydroxyproline concentration in the supernatants.

Collagen Solubility

Collagen solubility of meat was calculated and expressed as the percentage of solublecollagen account for total collagen, followed the method of Naewbanij et al.[29]

Instrumental Texture Profile Analysis (TPA)

TPA tests for meat samples were carried out as described by Palka and Daun[30] andPalka[31] with some modifications. Samples of 15-mm diameter and 20-mm length werecut out lengthwise to fibers from the raw and heated meat slices. TPA tests were performedwith a Texture Analyzer TA-XT2i (Stable Micro Systems Ltd., Godalming, U.K.) at roomtemperature (20◦C) using a 25-kg load cell, and the application program provided withthe apparatus (Texture Expert for Windows, Version 1.0). A cylindrical 5-mm-diameterstainless plunger (P/50) was used in the TPA tests. The following experimental conditionswere selected for all measurements: pre-test speed 2.0 mm/s, test-speed 1.0 mm/s andpost-test speed 1.0 mm/s; compressions ratio 50%; penetration distance 4 mm and a restperiod of 5 s between two cycles; trigger force 0.98 N, and data acquisition rate 200 PPS(pulses per s). The probe always returned to the trigger point before beginning the secondcycle. After the second cycle, the probe returned to its initial position. TPA parameterswere calculated by the User Guide Software (Version 1.0).

The data obtained from TPA curve were used for the calculation of textural param-eters. Among the TPA parameters, hardness is expressed as maximum force for the firstcompression. Adhesiveness is expressed as negative force area for the first bite or the worknecessary to pull the compressing plunger away from the sample. Springiness is calculatedas the ratio of the time from the start of the second area up to the second probe reversalover the time between the start of the first area and the first probe reversal. Cohesivenessis a measure of the degree of difficulty in breaking down the samples internal structure.Gumminess and chewiness have been reported as products of hardness, cohesiveness.Chewiness is calculated as hardness × cohesiveness × springiness. Resilience reflects theredeformation capacity of samples tissue after penetration.[32]

Scanning Electron Microscopy (SEM)

The microstructural changes of samples were evaluated using a SEM after preparingthe samples by a method of Nishimura et al.[33] reported and made some modifications. ForSEM procedures, pieces 5 × 5 × 3 mm were excised from raw and heated meat steaks per-pendicular to the orientation of muscles fiber, and fixed in 2.5% glutaraldehyde in 0.1 Mphosphate buffer solution (PBS) (pH 7.4) for 3 days at 4◦C. The specimens were thenrinsed with PBS for three times and 30 min for each time. Subsequently were dehydratedby gradient ethanol series (50, 70, 80, and 90%) for 15 min in each solution at room temper-ature, and in absolute ethanol for three times, 30 min for each time. The samples were then

386 CHANG ET AL.

cementated with t-butanol for three times (30 min for each time); after freeze-dried andsputter-coated with gold film (10 nm), the specimens were examined and photographed ina SEM (S-3000N, Hitachi High-Technologies Corporation, Japan) at an accelerating volt-age of 15.0 kV. Micrographs were taken at the magnification of ×500 for perimysia andendomysia observation.

Perimysium Thickness Determination

Primary and secondary perimysia thickness of raw and heated ST muscle were esti-mated according to the method of Flint et al.[34] modified by Li et al.[35] Briefly, the0.5 × 0.5 × 0.5 cm cubes were removed from raw and heated steak, then were rapidlyfrozen in nitrogen for 5 to 6 h, and cut into sections of 10 μm thick, perpendicular tothe orientation of muscle fibers, using a freezing microtome (CM1900, Leica, Germany).The sections were stained as following procedures: slides were placed in acetone for atleast 12 h, transferred into saturated picro-formalin for 5 min, and then washed by runningwater for 10 min. The samples were stained in saturated pirco-sirius red solutions for 1 h,washed for 2 min in 0.01 M HCl solution, and then dehydrated in 100% ethanol for 5 min.Finally, they were cleared in xylene and mounted in a resinous medium.

After stained, slides were examined under bright-field illumination using a lightmicroscope (BX41, Olympus, Japan), photographs were taken with a digital camera(Olympus, Japan) affixed to the microscope from different visual fields of each slide. Thethickness of the primary and secondary perimysia was measured by the Image-Pro Plus5.1 software (Media Cybernetics, Bethesda, MD). Measurement points were randomlyselected from each photograph and the perimysial thickness was designated as the shortestdistance between the two edges of the membrane.

Statistical Analysis

All measurements in this study were done in triplicate; the results reported here werethe means of the three trials. Statistical analyses were carried out using SPSS 16.0 (SPSSInc., Chicago, IL). One-way analysis of variance (ANOVA) and Duncan’s multiple-rangetest were carried out to determine significant differences of cooking loss, total and solublecollagen content, collagen solubility, TPA parameters and perimysia thickness betweenwater bath and microwave heating, and effects were considered significant at p < 0.05 (∗)levels.

RESULTS AND DISCUSSION

Cooking Loss

Cooking losses of beef ST muscle for Chinese yellow bulls during water bath andmicrowave heating were presented in Table 2. Cooking loss manifested significant differ-ences (p < 0.05) between water bath and microwave treated sample at the core temperatureof 55◦C and 80◦C. On the whole, there was a gradual increase in cooking loss with increasein internal core temperature and heating time for water bath and microwave treatments(Tables 1 and 2). The results were consistent with the reports of Palka and Daun[30]

and Palka.[31] An increase in cooking loss with increase in heating time for salmon andchicken breast muscle was also found by Kong et al.,[6] and the conclusions were similar

Tabl

e2

Coo

king

loss

and

colla

gen

cont

ents

ofbe

efST

mus

cle

duri

ngw

ater

bath

and

mic

row

ave

heat

ing.

Tota

lcol

lage

nSo

lubl

eco

llage

nC

ooki

nglo

ss(%

)a(%

wet

wei

ght)

(%w

etw

eigh

t)C

olla

gen

solu

bilit

y(%

)

Tem

pera

ture

(◦C

)W

b-H

Mo-

HW

b-H

Mo-

HW

b-H

Mo-

HW

b-H

Mo-

H

20–

–0.

66±

0.09

0.66

±0.

090.

16±

0.12

0.16

±0.

1222

.48

±15

.51

22.4

8±

15.5

140

13.7

8±

0.21

10.4

0±

2.14

0.74

±0.

110.

80±

0.07

0.21

±0.

080.

16±

0.07

28.1

8±

5.51

∗20

.62

±10

.60

5015

.95

±0.

0813

.81

±2.

050.

76±

0.08

0.80

±0.

050.

16±

0.20

0.18

±0.

0319

.50

±23

.61

22.7

2±

5.18

5523

.34

±0.

69∗

14.5

4±

0.88

0.86

±0.

070.

98±

0.04

0.16

±0.

020.

18±

0.05

19.0

0±

2.34

18.2

5±

4.36

6023

.93

±0.

8124

.38

±1.

180.

84±

0.10

1.01

±0.

04∗

0.17

±0.

130.

19±

0.03

19.0

3±

12.6

218

.75

±2.

2365

25.1

6±

0.39

27.8

1±

1.72

0.83

±0.

130.

97±

0.14

0.25

±0.

120.

24±

0.05

28.8

2±

11.2

225

.60

±8.

9470

23.7

5±

0.86

22.3

9±

2.16

0.89

±0.

061.

11±

0.04

∗0.

18±

0.06

0.22

±0.

0220

.48

±6.

2719

.79

±1.

0975

31.4

3±

0.87

27.1

2±

2.93

0.90

±0.

171.

21±

0.04

∗0.

28±

0.17

0.25

±0.

0229

.56

±14

.62∗

20.7

1±

2.34

8029

.36

±0.

5836

.14

±2.

69∗

0.83

±0.

091.

10±

0.12

∗0.

20±

0.07

0.26

±0.

0224

.05

±7.

0723

.96

±4.

4685

34.9

7±

1.03

32.8

5±

1.87

1.15

±0.

171.

10±

0.02

0.25

±0.

160.

29±

0.08

20.8

6±

11.8

326

.28

±6.

80∗

9038

.51

±0.

9939

.41

±1.

471.

43±

0.13

1.20

±0.

100.

38±

0.12

0.35

±0.

0526

.39

±6.

2529

.07

±1.

75

Wb-

Hm

eans

wat

erba

thhe

atin

gan

dM

o-H

mea

nsm

icro

wav

eov

enhe

atin

g.A

llda

tain

tabl

ew

ere

Mea

ns±

Std.

Dev

iatio

n,∗ m

eans

sign

ifica

ntdi

ffer

ence

(p<

0.05

)be

twee

ntw

odi

ffer

enth

eatin

gm

etho

ds.

a Coo

king

loss

ofra

wm

eat(

20◦ C

)w

asno

tmea

sure

d.

387

388 CHANG ET AL.

to the present paper. This could be due to a greater degree of transversal and longitudinalshrinkage of the muscle fibers and protein denaturation and coagulation during heating.[23]

Furthermore, it was likely owing to the aggregation and gel formation of sarcoplasmicproteins and solubilization of connective tissue collagen during heating.

Collagen Content

As shown in Table 2. The mean content for total collagen of the raw meat was0.66 ± 0.09 % (wet basis) and was within the normal rage (lower than 1% wet weight).[36]

Total collagen content of microwave treated sample was higher compared to water bathtreatment before heating temperature up to 80◦C, and showed significant differences(p < 0.05) at 60◦C, 70◦C, 75◦C and 80◦C. There was a gradual increase in the total col-lagen content with increase in the temperature during water bath and microwave heating;it was probably attributed to the increasing in cooking loss and the conversion of colla-gen to gelatin during heating. Palka[31] also reported the same conclusions by ST musclewere roasted in an electric oven, but those were different from the researches of Vasanthiet al.[23] This may be due to the differences in the species and anatomic portions of sam-ples, heating methods, temperature and time and so on. However, no statistical differences(p > 0.05) were found for soluble collagen content between water bath and microwavetreated samples, and the same changes tendency were presented as total collagen contentwith increase in the temperature during water bath and microwave heating (Table 2).

Collagen Solubility

Changes of collagen solubility of water bath and microwave treated samples wereirregular (Table 2). There was an unaccountable variation in collagen solubility with amaximum at 75◦C for water bath heated meat. Collagen solubility changed unaccountablythroughout heating due to juice loss and collagen solubilization.[35] For microwave heat-ing, the highest collagen solubility was found when heated to 90◦C, and could be attributedto the conversion of collagen to gelatin occurs at this temperature range. At 65◦C, collagensolubility of water bath and microwave treated samples were relatively higher simultane-ously, partly because of the shrinkage effect of perimysial and endomysial collagen at about65◦C (proved in DSC analysis, data not shown). According to the reports of Li et al.,[35]

low correlations were found between meat Warner-Bratzler shear force (WBSF) values andtotal collagen and collagen solubility, although previous data indicated a high relationshipbetween peak shear force and collagen content for beef.[37]

Instrumental Texture Profile Analysis (TPA)

TPA provides textural change of meat during thermal treatment. TPA parameters ofraw and heated ST meat were shown in Fig. 1. It was found that the thermal conditions(internal temperature) and heating modes had significant effects on all the TPA parametersof meat except for resilience (Fig. 1G). Hardness, as a measure of force necessary to attaina given deformation, gave a different response to the different heating methods and temper-atures applied. Hardness (Fig. 1A) of microwave treated sample was higher compared towater bath treatment at 65◦C, and showed significant differences (p < 0.05) in the temper-ature range from 75◦C to 90◦C. Hardness of water bath heated meat showed a maximumat 60◦C. Changes of adhesiveness (Fig. 1B) for water bath and microwave treated sample

PROPERTIES OF BEEF SEMITENDINOSUS MUSCLE 389

A

***

0

1000

2000

3000

4000

5000

6000

7000

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °C

Temperature (°C)

Har

dnes

s (g

)

Water bath heating Microwave heating

Temperature (°C)

B

*

–200

–150

–100

–50

0

50

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °C

Adh

esiv

enes

s

Water bath heating Microwave heating

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °C

Temperature (°C)

C*

***

0.20.30.4

0.50.60.7

0.80.9

1

Spri

ngin

ess

Water bath heating Microwave heating

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °C

Temperature (°C)

D

**

00.10.20.30.40.50.60.70.80.9

Coh

esiv

enes

s

Water bath heating Microwave heating

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °C

Temperature (°C)

E

*

0

500

1000

1500

2000

2500

3000

Gum

min

ess

Water bath heating Microwave heating

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °C

Temperature (°C)

F

*

*

*

0

500

1000

1500

2000

2500

Che

win

ess

Water bath heating Microwave heating

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °C

Temperature (°C)

G

0

0.05

0.1

0.15

0.2

0.25

Res

ilien

ce

Water bath heating Microwave heating

Figure 1 Effects of heating temperature and methods on TPA: hardness (A), adhesiveness (B), springiness (C),cohesiveness (D), gumminess (E), chewiness (F) and resilience (G) of beef ST muscle. ∗Means significant differ-ence (p < 0.05) between two different heating methods. Error bars indicate mean ± standard deviations of threereplicates.

were irregular with increase in internal core temperatures, and there were no significantdifferences except for 75◦C between both thermal treatments.

Springiness is an important TPA parameter and the date on springiness (Fig. 1C) formicrowave heated meat had a changing point at 65◦C, and the meat springiness of waterbath heated was higher compared to microwave treatment after 65◦C. This parameter seemsto be affected by myosin and α-actinin denaturation, which occurs in this temperaturerange.[38] Springiness of meat is likely related to the degree of fiber swelling which inturn should be reflected in the fiber diameter. As discussed above, the main changes ofspringiness during heating were consistent with the thermal shrinkage of intramuscularcollagen at around 65◦C.

390 CHANG ET AL.

Cohesiveness contributes to the comprehensive understanding of viscoelastic prop-erties including tensile strength. Chewiness is the energy required to masticate a solidfood product to a state ready for swallowing. Therefore, it is considered as an importantparameter since the final phase of mouth feels and the ease in swallowing depends on thechewiness of meat. Cohesiveness (Fig. 1D), gumminess (Fig. 1E), chewiness (Fig. 1F),and resilience (Fig. 1G) were all showed a maximum at 65◦C in microwave treated sam-ple, however, gumminess and chewiness of water bath treatment reached the maximum at60◦C. Changes of cohesiveness and resilience for water bath treated sample were irregularwith the increase in heating temperature, it was may be result from the intercorrelationeffects among TPA parameters during the long time heating for water bath comparedwith the microwave. Resilience was the only TPA parameter that presented no significantdifferences between two thermal treatments.

Changes of TPA parameters in this study suggested that internal core temperature of60◦C and 65◦C were the critical heating temperatures which affect meat texture for waterbath and microwave heating respectively. Furthermore, according to our previous studies,the maximal shrinkage temperature of IMCT collagen was within this range, this can givea full relationship of heat-induced change of collagen to meat quality, especially the meattexture; the results were also clearly showed in the SEM photographs.

Microstructure Observation

The microstructural changes (on the transverse sections) of raw and heated meat fortwo thermal treatments were shown on the SEM micrographs presented in Fig. 2. For theraw samples (Fig. 2, Control), perimysium and endomysium were arranged clearly andclosely, and no gaps and cavities between muscles fibers. When samples were heated to40◦C (Fig. 2A,B) no significant changes were found in the structure of the IMCT com-pared to the unheated samples (control), perimysium and endomysium were well visible.After heated to 50◦C (Fig. 2C,D), granulation changes of the perimysium and endomysiumbegan, it was probably as an effect of thermal denaturation of myofibrillar proteins and col-lagen shrinkage. The granulation phenomena of water bath treated sample (Fig. 2C) weremore obvious than microwave treatment (Fig. 2D). Heated to an internal core temperatureof 50◦C by microwave slightly affected the structure of meat (Fig. 2D), similar results wereobtained during the retorting of the bovine ST muscle to the same temperature by Palkaand Daun.[30]

When heating temperature up to 60◦C (Fig. 2E,F), granulation became more remark-able and perimysium and endomysium were less distinct. Gaps between muscles fiberswere occurred (Fig. 2E). After heating to 70◦C (Fig. 2G,H), for water bath treatment,perimysium and endomysium were solubilized and bigger gaps between muscle fiberswere visible, and was consistent with the reports of Li et al.[35] Whereas, the changes formicrowave heated meat at 70◦C (Fig. 2H) were similar to the samples that heated to 60◦C(Fig. 2F), it was likely owing to the short heating time in microwave treatment (Table 1). Atthe core temperature of 80◦C (Fig. 2I,J) and 90◦C (Fig. 2K,L), collagenous tissue denaturedand melted, histological structure became loose, gaps between muscle fibers were visible,this was because of the solubilization and gelation of IMCT collagen, mainly contributedby perimysial and endomysial collagen. On the whole, microstructure of meat samplesheated by microwave were less changes than water bath heated samples at the same inter-nal core temperature, this was contributed to the non-uniform heat ed in the microwave,and also due to the short heating time (Table 1).

PROPERTIES OF BEEF SEMITENDINOSUS MUSCLE 391

Microwave oven heatingWater bath heating

20 °C

40 °C

60 °C

50 °C

Figure 2 Microstructure of perimysium and endomysium of beef ST muscle raw (control) and heated to coretemperature: 40◦C (A, B); 50◦C (C, D); 60◦C (E, F); 70◦C (G, H); 80◦C (I, J), and 90◦C (K, L). Magnificationwas × 500. A, C, E, G, I, K were water bath heating; B, D, F, H, J, L were microwave heating. P: perimysium,E: endomysium.

392 CHANG ET AL.

70 °C

80 °C

90 °C

Figure 2 (Continued).

After thermal treatments, the collagenous tissue denatured and melted, muscle cellsruptured, the sarcomere shrunk and the extracellular space and intracellular cavities andcanals increased, Granulates of protein aggregation appeared in the extracellular space.[6]

The stability of heated meat relies on the gel network formed with the melted IMCT colla-gen, denatured and aggregated myofibrillar proteins and sarcoplasmic proteins.[10] Resultsfrom SEM evaluation of the present paper can be further confirmed that the textural prop-erties of heated meat was mostly depended on the changes of muscle proteins, includingmyofibrillar protein and connective tissue collagen.

Perimysial Thickness Analysis

The primary perimysial thickness (PPT) of meat steak showed significant difference(p < 0.05) at the internal core temperature of 60◦C between water bath and microwaveheated meat (Fig. 3A), and decreased during hating compared with the control samples.

PROPERTIES OF BEEF SEMITENDINOSUS MUSCLE 393

*

A

0

5

10

15

20

25

30

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °CTemperature (°C)

PPT

(um

)

Water bath heating Microwave heating

20 °C 40 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C 90 °CTemperature (°C)

B

**

0

10

20

30

40

50

60

SPT

(um

)

Water bath heating Microwave heating

Figure 3 Variation in perimysial thickness of beef semitendinosus muscle during water bath and microwave heat-ing. (A): primary perimysium thickness (PPT), (B): secondary perimysium thickness (SPT). ∗ Means significantdifference (p < 0.05) between two different heating methods. Error bars indicate mean ± standard deviations ofthree replicates.

And the secondary perimysial thickness (SPT) showed significant differences (p < 0.05)at the temperature of 60◦C and 65◦C as well as decreased during heating (Fig. 3B).

The changes of perimysial thickness during heating were similar to the results ofSEM observation (Fig. 2). The occurrences of gaps and cavities between muscle fiberslead to the decreasing in the thickness of primary and secondary perimysium during heat-ing. This thermal effects phenemenon for decrease in perimysial thickness were mostlyresulted from the solubilization and gelation of collagen. In addition, it was due to theweakening in the cross-linking degree of collagen fiber during heating. Moreover, accord-ing to Nishimura et al.,[39] proteoglycans was likely to be the main factor in maintainingthe structure of IMCT, in other words, the decreasing in perimysial thickness was probablyowing to the dissolution of proteoglycans during heating, which resulted in the weakeningof the IMCT structure.

CONCLUSIONS

From the results of the research, heat-induced changes of connective tissue colla-gen and meat quality took place during water bath and microwave thermal treatments.

394 CHANG ET AL.

These changes contributed to an increase in cooking loss with increase in heating temper-ature. During heating, the content of total and soluble collagen were all increased with theincreasing of heating temperature from 40◦C to 90◦C, but no statistical differences werefound for soluble collagen content between two kinds of heating methods. Collagen solu-bility of water bath and microwave heated meat were relatively high at 65◦C. Meat texturalproperties can be reflected by TPA estimation largely, and those TPA parameters for heatedmeat changed significantly during heating. The structural changes of IMCT collagen werecorresponding with the textural properties of meat, and perimysial thickness was decreasedduring heating. Heating internal core temperature of 60◦C and 65◦C were critical for affect-ing meat texture during water bath and microwave heating respectively. According to theresults of the study, we can get the conclusion that water bath heating was better for heatingprocess and be recommended to the further study for beef thermal treatment.

ACKNOWLEDGMENT

This study was funded by the project grants 2010-56-12 (Doctoral Research Funds of ChongqingTechnology and Business University), 2006G35 (2) (“948” Project of Chinese Ministry ofAgriculture) and 30972133 (National Natural Science Foundation). We thank Mr. Ziyi He of LifeScience College for his assistance in SEM equipment provision and observation. The authors wouldlike to express special thanks to Mr Lei Du and Jinping Li for their assistance in sampling of thiswork.

REFERENCES

1. Lawrie, R.A. The eating quality of meat. In Lawrie’s Meat Science, 7th English ed.; Lawrie,R.A., Ed. Woodhead Publishing Limited and CRC Press LLC, 2006; 279–341.

2. Zhou, G.H.; Xu, X.L. Eating quality and evaluation of meat. In Meat Science; China’sAgricultural Science and Technology, Beijing, China, 1999; 221–262.

3. Bailey, A.J. The basis of meat texture. Journal of the Science of Food and Agriculture 1972, 23,995–1007.

4. Purslow, P.P. The physical basis of meat texture: observation the fracture behavior of cookedbovine M. semitendinosus. Meat Science 1985, 12, 39–60.

5. Bertola, N.C.; Bevilacqua, A.E.; Zaritzky, N.E. Heat treatment effect on texture changes andthermal denaturation of proteins in beef muscle. Journal of Food Processing and Preservation1994, 18, 31–46.

6. Kong, F.B.; Tang, J.M.; Lin, M.S.; Rasco, B. Thermal effects on chicken and salmon mus-cles: Tenderness, cook loss, area shrinkage, collagen solubility and microstructure. LWT-FoodScience and Technology 2008, 41, 1210–1222.

7. Murphy, R.Y.; Marks, B.P. Effect of meat temperature on proteins, texture, and cook loss forground chicken breast patties. Poultry Science 2000, 79, 99–104.

8. Tornberg, E. Effects of heat on meat proteins-Implications on structure and quality of meatproducts. Meat Science 2005, 70, 493–508.

9. Wattanachant, S.; Benjakul, S.; Ledward, D.A. Microstructure and thermal characteristics ofThai indigenous and broiler chicken muscles. Poultry Science 2005, 84, 328–336.

10. Wattanachant, S.; Benjakul, S.; Ledward, D.A. Effect of heat treatment on changes in texture,structure and properties of Thai indigenous chicken muscle. Food Chemistry 2005, 93, 337–348.

11. Kerth, C.R.; Blair-Kerth, L.K.; Jones, W.R. Warner-bratzler shear force repeatability in beeflongissimus steaks cooked with a convection oven, broiler, or clam-shell grill. Journal of FoodScience 2003, 68, 668–670.

PROPERTIES OF BEEF SEMITENDINOSUS MUSCLE 395

12. Pohlman, F.W.; Dikeman, M.E.; Zayas, J.F.; Unruh, J.A. Effects of ultrasound and con-vection cooking to different end point temperatures on cooking characteristics, shear forceand sensory properties, composition, and microscopic morphology of beef longissimus andpectoralis muscles. Journal of Animal Science 1997, 75, 386–401.

13. Cross, H.R.; Stanfield, M.S.; Elder, R.S.; Smith, G.C. A comparison of roasting versus broilingon the sensory characteristics of beef longissimus steaks. Journal of Food Science 1979, 44,310–311.

14. Berry, B.W.; Leddy, K.F. Comparison of restaurant vs research-type broiling with beef loinsteaks differing in marbling. Journal of Animal Science 1990, 68, 666–672.

15. Berry, B.W.; Bigner, M.E. Use of grilling and combination broiler-grilling at various tem-peratures for beef loin steaks differing in marbling. Journal of Food Serve System 1995, 8,65–74.

16. Wheeler, T.L.; Shackelford, S.D.; Koohmaraie, M. Cooking and palatability traits of beef longis-simus steaks cooked with a belt grill or an open hearth electric broiler. Journal of Animal Science1998, 76, 2805–2810.

17. Korschgen, B.M.; Baldwin, R.E.; Snider, S. Quality factors in beef, pork, and lamb cooked bymicrowaves. Journal of the American Dietetic Association 1976, 69, 635–639.

18. Starrak, G.; Johnson, H.K. New approaches and methods for microwave cooking of meat.Proceedings of the Reciprocal for Meat Conference 1982, 35, 66–69.

19. Deethardt, D.; Costello, W.; Schneider, K.C. Effect of electronic, convection and conventionaloven roasting on the acceptability of pork loin roasts. Journal of Food Science 1973, 38,1076–1078.

20. Sahin, S.; Sumnu, G. Effects of microwave cooking on fish quality. International Journal of FoodProperties 2001, 3, 501–512.

21. Kumar, P.; Coronel, P.; Simunovic, J.; Sandeep, K.P. Thermophysical and dielectric properties ofSalsa Con Queso and its vegetable ingredients at sterilization temperatures. International Journalof Food Properties 2008, 11, 112–126.

22. Yang, H.W.; Gunasekaran, S. Comparison of temperature distribution in model food cylindersbased on Maxwell’s equations and Lambert’s law during pulsed microwave heating. Journal ofFood Engineering 2004, 64, 445–453.

23. Vasanthi, C.; Venkataramanujam, V.; Dushyanthan, K. Effect of cooking temperature and timeon the physico-chemical, histological and sensory properties of female carabeef (buffalo) meat.Meat Science 2007, 76, 274–280.

24. Bergman, I.; Loxley, R. Two improved and simplified methods for spectrophotometric determi-nation of hydroxyproline. Analytical Chemistry 1963, 35, 1961–1965.

25. Hill, F. The solubility of intramuscular collagen in meat animals of various ages. Journal of FoodScience 1966, 31, 161–166.

26. Neuman, R.E.; Logan, M.A. The determination of hydroxyproline. Journal of BiologicalChemistry 1950, 184, 299–306.

27. Goll, D.E.; Bray, R.W.; Hoekstra, W.G. Age-associated changes in muscle composition. Theisolation and properties of a collagenous residue from bovine muscle. Journal of Food Science1963, 28, 503–505.

28. Fang, S.H.; Nishimura, T.; Takahashi, K. Relationship between development of intramuscularconnective tissue and toughness of pork during growth of pigs. Journal of Animal Science 1999,77, 120–130.

29. Naewbanij, J.O.; Dorothy, L.H.; Stone, M.B. Roasting vs cooking in a model system: tendernessof bull adductor muscle conventionally chilled or electrically stimulated-Hot boned. Journal ofFood Science 1983, 48, 337–342.

30. Palka, K.; Daun, H. Changes in texture, cooking losses, and myofibrillar structure of bovineM. semitendinosus during heating. Meat Science 1999, 51, 237–243.

31. Palka, K. The influence of post-mortem ageing and roasting on the microstructure, texture andcollagen solubility of bovine semitendinosus muscle. Meat Science 2003, 64, 191–198.

396 CHANG ET AL.

32. Caner, C.; Aday, M.S.; Demir, M. Extending the quality of fresh strawberries by equilibriummodifiedatmospherepackaging.EuropeanFoodResearchandTechnology2008,227, 1575–1583.

33. Nishimura, T.; Hattori, A.; Takahashi, K. Structural changes in intramuscular connective tissueduring the fattening of Japanese Black Cattle, effect of marbling on beef tenderization. Journalof Animal Science 1999, 77, 93–104.

34. Flint, F.O.; Pickering, K. Demonstration of collagen in meat products by an improved picro-sirius red polarization method. Analyst 1984, 109, 1505–1508.

35. Li, C.B.; Zhou, G.H.; Xu, X.L. Dynamical changes of beef intramuscular connective tissue andmuscle fiber during heating and their effects on beef shear force. Food Bioprocess Technology2008, 3, 521–527.

36. Lawrie, R.A. Chemical and biochemical constitution of muscle. In Lawrie’s Meat Science(Seventh English edition). Press: Woodhead Publishing Limited and CRC Press LLC, 2006;75–76.

37. Powell, T.H.; Dikeman, M.E.; Hunt, M.C. Tenderness and collagen composition of beefsemitendinosus roasts cooked by conventional convective cooking and modeled, multistageconvective cooking. Meat Science 2000, 55, 421–425.

38. Cheng, C.S.; Parrish, Jr. F.C. Heat-induced changes in myofibrillar proteins of bovine longis-simus muscle. Journal of Food Science 1979, 44, 22–24.

39. Nishimura, T.; Hattori, A.; Takahashi, K. Relationship between degradation of proteoglycansand weakening of the intramuscular connective tissue during postmortem aging of beef. MeatScience 1996, 42, 251–260.