Study On The Effect Of Cooking Conditions On Protein Degradation Of Stewed Chicken

As one of the traditional Chinese meat product, soy-sauce stewed meat product is very popular among customers for its special taste and flavor. Cooking is an important process in the production of soy-sauce stewed meat, which is significant to the formation of its nutrient and flavor. With the development of modern technology, the industrialization and modernization of soy-sauce stewed meat production is very imperative, and researches on the influence of production process to main nutrient facts is also becoming more and more important. This experiment chooses broiler chicken-- the most popular raw material in the production of soy-sauce stewed meat, adds spicy seasonings of “daokou carbonados”, sets two cooking temperature and time under different heat power, and discusses the influences of cooking condition to the degradation of protein in soy-sauce stewed chicken drumsticks by SDS-PAGE and High Performance Liquid Chromatography(HPLC), and attempts to provide theoretical basis for the application of cooking process to the industrialization of traditional soy-sauce stewed meat product.This experiment includes two different heat power: hard fire and soft fire. We set different cooking temperature and time in each heat power condition, measure and analyze relative index on the degradation of protein in the surface specimens, central specimens and broth of soy-sauce stewed chicken drumsticks separately. Main conclusions as followings.1.The contents of TN in meat samples generally are different under the two fire conditions,but show the same trend.There is relatively large difference under the early and late cooking fire at 75℃,80℃,85℃,90℃between two fire conditions, while a smaller difference on the mid-cooking, especially cooking 40 min and 50 min. Also a smaller difference is found at the beginning of cooking at 90℃.But there is almost no difference of the TN content between two fire conditions at 100℃.The TN content under hard fire is higher than soft fire,at the beginning of six cooking temperatures, especially before 40 min.2.With the rising of temperature and prolonging of time, the non-protein nitrogen contents generally show an increasing trend under hard fire and soft fire in meat samples,and a significant upward trend in the soup specimens. The non-protein nitrogen contents under hard fire is higher than soft fire at the beginning of different cooking conditions,and with prolonging of time, the differences get smaller.3.With the rising of cooking temperature and prolonging of time under two heat power conditions, the myosinogen degrades obviously, and degrade completely when kept warm 10 min under hard fire and 20 min under soft fire at 75℃. Myofibrillar proteins’ thermal stability is relatively well but most of them also degrade, and myosin of 190~200k D firstly precipitate and exists only when cooking 10 min at 75℃ under two heat power condition.There is a big difference in degradation of 24 k D and 44~66k D protein components between hard fire and soft fire,the disappearance of protein lines under soft fire is later than hard fire. The thermal stability of 34 k D and 37 k D connectin are first-rate, and connectin of 24 k D takes the second place.4.With the cooking time extending,the total contents of FAA in meat samples has a tendency to increase in chicken broth,and first increase then decrease in meat samples in different temperatures and fires.Arg,Cys and Ala are the higher levels of free amino acid in the samples.The content of Arg is higher than the other free amino acids and it’s change tendency and content change are similar with the whole free amino acids.The content increases then decrease in the surface meat samples,it is higher under hard fire than soft fire;and show different trends in central specimens because of different fires,but it is higher under hard fire than soft fire,and is later getting its maximum.Ala content is the most highest in the sweet amino acids and has tendency to increase with the prolonging of cooking time. The concent of Glu increase significantly in the soup specimens,and it is higher under soft fire than hard fire.