Effect Of Cooking Egree On Texture Profile Analysis And Colour Of Stewed Chicken Legs

Traditional pot-stewed meat product is an important heritage of Chinese profound dietetic culture, which has rich variety, diversified tastes and welcome by customs. For years, the processing craft of pot-stewed meat product is mainly based on experiences and the threshold is low. Also, most small businesses and food workshops still rely on experience control, lacking of quantitative and standard management. Moreover, processing craft parameters fuzzy and product varies with different individuals. All the above factors cause the product quantity unsteady, which seriously obstructs the development of pot-stewed meat industry. Therefore, the modern industrial Production transformation on traditional pot-stewed meat industry is necessary.This study will explore the effect of cooking degree on changes of texture and colour of stewed chicken legs, providing theoretical support for modernization of traditional pot-stewed meat products, and it maybe possible for presenting experiences for other traditional pot-stewed meat products.In order to study the effect of cooking degree on changes of texture and colour of stwed chicken legs, the cooking loss, TPA, color and sensory evaluation will be tested under three different heat power(under each heat power there will set different cooking temperatures and times) in this experiment.The results showed that:1. With the rising of temperature and prolonging of time, the cooking loss of stewed chicken legs showed a rising trend in general.When chicken legs were hearted under hard fire whose key temperature of the cooking loss was 80℃, 90℃ and 95℃. In the meantime, the cooking loss also had significant changes at 90℃ or 95℃ under both moderate fire and soft fire. Before 40 min, on the overall cooking process, the cooking loss was greatly affected by the firepower.2. All the TPA parameters of sample rised at first, went down latter, then rised again and decreased at last during the whole stewing process, but the changes of TPA parameters under different cooking conditions happened at different times. Compared with different heat power, stewing temperature and duration had more significant effects on the parameters(P<0.05).Under all the three different heat power, 90℃ and 95℃ were the key temperatures of the texture of stewed.3. Stewing at the same temperature, as the heat of different portions of chicken legs obtained were uneven, the degree of protein denaturation were different in each portion. Thereby the following results were caused directly: for the values of L* and b* of the samples, surface>centre>inside; for the value of a*, inside> centre> surface. Based on heat transfer is from the outside in, with the rising of temperature and prolonging of time, the hearting degree of the different portions were toward equality, so the values of their colour were closer and closer. But comparing samples with the raw muscle, the values of L* and b* were significantly increased. Although the changes of heat power and stewing time made the values of L* and b* fluctuate in a definitive range, the temperature had more significant influence on them. However, firepower, temperature and time all had obvious effect on a*, and the value of a* decreased with the increasing of hearting degree. Under the three heat power, 95℃ was the key temperature of the colour of stewed chicken legs.4. The amounts of Mb in different portions of chicken legs were different:inside> centre> surface. Meanwhile, the Mb denatured completely at about 30 min after timing. At the beginning of stewing, the ratio of Met Mb increased significantly(P<0.05), but the trend of Mb O2 was opposite. With the prolonging of stewing time, the ratio of three forms of Mb came into stable state gradually. Stewing chicken legs with three different heat powers, 80℃ was always the key temperature where the states of Mb started changing, and 95℃ was the key temperature where the states of Mb changed completely.5. Whether using hard fire, moderate fire or soft fire, the products stewing 60 min under 90 ℃ were more popular with their excellence in color, aroma and taste. Besides, the products stewing at 95℃ or 100℃ under hard fire and moderate fire were also got high scores. In addition, from the results of TPA we also could come to the conclusion that: there were definite relations between the results of sensory evaluation and TPA—when the value of hardness fell to about 3500 g with the protein degradation, the scores of taste and tenderness of the stewed chicken legs were relatively high.6. Generally speaking, because of the high firepower and short heating up time, all the indexes changed markedly at the beginning of hearting under hard fire. Besides, heat transfer needed time, and the hearting degree to the different portions of chicken legs from inside to outside had some differences, so the indexes of different portions were very different. Instead, using moderate fire or soft fire to stewing chicken legs made these indexes changed gently.Above all, 90℃ and 95℃ were the key temperatures of the texture and colour of stewed chicken legs.Advice: In order to get the popular products, we suggest the businesses stew chicken legs 60 min ~90min at 90℃~95℃ under hard fire or moderate fire. This has low energy consumption and the production ratio is not low.