Studies On Frozen Storage And Repeated Freeze-thaw Influenced Chicken Quality

This article includes two experiments:Effects of frozen time on meat quality of different varieties (Hyline Chicken, BaichengFatty Chicken-Native Chiken, SanHuang Chiken) were studied;effects of different thawing methods and the number of thaw cycles on chicken quality were also analyzed.Results were as follows:Experiment I Influences of frozen times on chicken quality1With the extension of storage time, the a*value of chest muscle of different varieties decreased, but the A*Value of chest and Leg muscle of different varieties increased. The b*value of Chest and Lgg muscle on the330day were extremely significant difference (p<O.01), compared with the0day.2With the extension of storage time, drip loss, pH, TVB-N, total bacterial count decreased first and increased later. Total bacterial count and pH of Leg muscle was higher than chest muscle,but drip loss of leg muscle was lower than chest muscle.On the300d, the TVB-N of leg muscle of SanHuang Chiken and Native Chiken were more than15mg/g, there were already bad meat. On the330d, the leg muscle of three varieties chicken and the chest muscle of SanHuang Chiken have gone bad.3Warner-bratzler shear and TBARS increased with the extension of storage time and leg muscle was higher than chest muscle. The warner-bratzler shear of Hyline Chicken and TBARS of SanHuang Chicken were the highest than others. Compared with the0day,warner-bratzler shear and TBARS of chest and leg muscle of different varieties on the330day were extremely significant difference (p<0.01).4The acidity-oxidizing ability coefficient measurement of chest and leg muscle of different varieties increased frist and decreased later with the extension of storage time.In the same varieties, the acidity-oxid--izing ability coefficient measurement of chest muscle was higher than leg muscle.5Intramuscular fat and crude protein of chest and leg muscle of different varieties decreased with the extension of storage time and the content of chest and leg muscle of Hyline Chicken was higher than others. Compared with the0day, TAA, EAA and sweet amino acid of different varieties decreased while DTAA increased on the330day.6By theoretical analysis and experimental verification, it was found that the storage time of Hyline Chicken and the chest of different varieties were longest. The qualitative indicators can only as the auxilia-ry indexes for determination of the freshness of meatExperiment II Effect of different thawing methods and the number of thaw cycles on chicken quality.1Compared with the rang of the variance of meat colour L*,a*and b*values of different thawing methods and the number of thaw cycles, the cold water thawing method had a small variation while the hot water thawing method a big variation.2The result of drip loss showed that the later five times thaw of cool water thawing method were no significant difference(p>0.05),the first five times thaw of refrigeration thawing method were no significant difference(p>0.05),drip loss value of hot water thawing method was the largest.The result of warner-bratzler shear showed that compared with the first time, the later four times of cool water thawing were no significant difference(p>0.05)and the six times of ordinary temperature thawing method were no significant difference(p>0.05);the average of warner-bratzler shear of cool water thawing was the smallest while hot water thawing was the largest. 3The result of acidity-oxidizing ability coefficient measurement showed that the first three and the later three times of cool water thawing were no significant difference (p>0.05)but the average of hot water thawing was the largest.The result of TVB-N showed that the later fives times of cool water thawing were no significant difference (p>0.05)and the first thawing of TVB-N was the smallest.The later four times of TVB-N of ordinary temperature thawing were no significant difference (p>0.05) and the average of ordinary temperature thawing was the smallest while the refrigeration thawing was the largest.4The result of intramuscular fat showed that the cool water thawing and refrigeration thawing were no significant difference (p>0.05).The result of crude protein showed that the cool water thawing and ordinary temperature thawing were no significant difference (p>0.05). The result of water content showed that the cool water thawing, refrigeration thawing and ordinary temperature thawing were no significant difference (p>0.05).5Compared of the four thawing methods, meat quality of use the cool water thawing was the best while hot water thawing was the worst.