Pork Color Evaluation And Muscle Homogenate Gel Functionalities Of Various Color Grades

As one of crucial parameters in pork quality, pork color determined the consumer's intention of purchase.Pork color has been effected by gene type,raising conditions,different seasons,pre-slaughter handles and other factors.At present,pork color grading has not been widely carried out in slaughter industry.Technical comunication was seldom held between pork producers,slaughter houses and meat processing industrie.Most consumers were not familiar with the relation between pork color and its processing properties.It caused great losses as pork color grading has not been employed by slaughter industries and suggestions have not been made for products processing.The thesis was about pork color standard reseach and color parameters were measured by colorimeter and computer vision system.Various pork color ranging from extremely pale to extremely dark have been employed to prepared muscle homogenate,gels subsequencely made via heat-induce and gel functionality has been observed.This study bridge between pork producers, slaughter houses and meat processing industrie.Chapter 1: In this study,600 m. longissimus dorsi of porcine carcass were employed to measure pH and temperature 45 minutes and 24 hours postmortem,color parameters include L^*,a^*,b^*,AE^*,Chroma,Hue angle,H,S,L and CVS grading output were observed as well.The results indicated that a^* and Hue angle were only two variables which followed normal distribution(P>0.15).Others didn't follow normal distribution(P<0.05).Chaper 2:In this study,120 m. longissimus dorsi samples(20 duplicate for each pork color grading) have been taken from pork carcass 24 hours postmortem.Sensory evaluation,colorimeter and CVS measurement were implemented.The results showed that pH_45min,T_45min,pH_24h,L^*,AE^*,L and output of CVS was significantly different between the grading groups of 1～6(P<0.05).a^* and Chroma showed no significant difference between the grading groups of 1～6(P>0.05).Colorimeter parameter L^* was recognized as the best indicator for instrumental color grading,the value was suggested to be 60,55,51,46,41 and 38 along with 1～6 pork color grading.Chapter 3:In this study,60 pork m. longissimus dorsi samples(10 duplicate for each pork color grading)were injected of extra deioned water with 4 levels (0%, 5%, 10%, 20%). The results demonstrated that no color changes in PSE meat in different moisture content comparing with controled group(0% miosture content).In the second color group, 10% moisture content could been detected by CVS comparing with controled group(0% miosture content).In the third,fourth and fifth color groups and DFD group,20% moisture content could been detected comparing with controled color groups(0% miosture content).It was concluded that the pork moisture content could be effectively detected by CVS comparing with contrled groups.However,PSE could not be distinguished with extra water injected groups.Instrumental L^* value was siginificantly different(P<0.05) vary from 4 moisture levels within each group.Chapter 4:In this study,pork muscle homogenate have been prepared under pH6.5,pH7.0 and certain ionic strength.Total protein solubility was then tested,and after heat-induced gel preparation,gel purge loss,gel WHC,hardness and springness of gel were observed.The lowest total protein solubility,gel WHC and highest gel purge loss has been observed in PSE under pH6.5 in all groups, DFD showed the highest protein solubility,gel WHC and lowest gel purge loss under pH7.0.PSE and the second color grading could not form gel under pH6.5.PSE also could not form any gel under pH7.0.The second color grading could only form weak gel which showed the weakest gel strength include hardness and springness.The DFD gel showed the highest hardness and springness under pH6.5.The muscle homogenate functional properties were extremely significant effected by pork color factor(P<0.01).Total protein solubility was significantly effected by pH factor(0.010.05).