Establishment Of Predictive Models For The Qualities Of Stewed Chicken Legs

Traditional Chinese stewed meat products originate from Chinese cuisine culture and they are the most representative Chinese traditional meat products.The key technology lies in the control of duration and degree of heating.However,very limited work on the mechanisms of duration and degree of heating has been done because its control was mainly according to the experience.Moreover,the traditional methods of judging heating degree is subjective,arbitrary as well as without standardized parameters,resulting in the uniformity of the heating degree.Therefore,it is hard to ensure the stable quality of the Chinese stewed meat products.In order to study the effects of different heating degree on the qualities of Chinese stewed meat products,mathematical models were introduced to characterize the quantitative relationship between the qualities of the traditional meat products and the heating degree parameters.Taking chicken as the research object and stewed chicken legs product processing as a model,the project starts with the effect of cooking degree on changes of qualities of the stewed chicken legs products,establishes the predictive models reflecting the effect of cooking degree on these qualities,and builds the relationships among cooking degree and the characteristics of the qualities.The project will provide theoretical support for modernization of traditional stewed meat products,and it may be possible for presenting experience and ideas for other traditional stewed meat products.Based on the different quality indexes that have been obtained by our research team under different cooking conditions,the quality indexes were further analyzed.According to the results,it was found that there were not suitable predictive models for the sense and other quality indexes of the stewed chicken legs under the predetermined heating conditions.The possible reasons may be that there are many factors influencing these indexes and the mechanism of the changes of these indexes was complicated.So it is worthy of further study.In this experiment,the qualities of the stewed chicken legs under different cooking conditions such as cooking time and cooking temperature were determined.Five indexes including yield,cooking loss,active thiol group,total mercapto group and non-protein nitrogen of different parts of stewed chicken legs were determined with different temperature-time combinationsunder different firepower to find out the influence of different cooking degree on the qualities of chicken legs.The main findings were as follows:1.Effect of cooking conditions on the yield of stewed chicken legsThe establishment and validation of the predictive yield models were performed out by the Origin 8.5 software,and the results showed that the Polynomial2 D model and the Parabola2 D model could be used to simulate changes of the yields of chicken legs under big fire cooking condition and small fire cooking condition respectively.In summary,the yield of stewed chicken legs was less affected by the firepower.Under both cooking conditions,yields of stewed chicken legs decreased to some extent with the increase of cooking time and temperature.For both kinds of firepower,an optimal yield could be achieved when the cooking time ranged from 10 min to 30 min and the temperature value was between 70 ? to 90 ?.2.Effect of cooking conditions on cooking losses of stewed chicken legsThe establishment and validation of the predictive cooking loss models were performed out by the Origin 8.5 software,and the results showed that the Rational Taylor model could be used to simulate the changes of cooking loss of chicken legs under two firepower.In summary,the cooking loss of stewed chicken legs was less affected by the firepower.Under both firepower,the cooking losses increased with the increase of cooking time and temperature.For both kinds of firepower,a lower cooking loss could be achieved when the cooking time ranged from10 min to 30 min and the temperature value was between 70 ? and 90 ?.3.Effect of cooking conditions on sulfhydryl –group activity content of stewed chicken legsThe establishment and validation of the predictive sulfhydryl –group activity content models were performed out by the Origin 8.5 software,and the results showed that the Rational2 D model could be used to simulate changes of the ulfhydryl –group activity content of stewed chicken legs under different firepower and regions of chicken legs.In summary,not only firepower but also region had no obvious effect on the ulfhydryl –group activity content of stewed chicken legs.Under different cooking temperature in the same firepower,the ulfhydryl –group activity content in the two regions of stewed chicken legs decreased with the increase of the cooking temperature.Under different cooking time in the same firepower,the ulfhydryl –group activity content in the two regions of stewed chicken legs presented earlier increase and later decrease trend with the increase of cooking time.For both kinds of firepower,a higherulfhydryl –group activity content could be achieved when the cooking time ranged from 10 min to 20 min and the temperature value was between 70 ? and 80 ?while that decreased to a lower level when the cooking time ranged from 100 min to120 min and the temperature value was between 100 ? and 110?.4.Effect of cooking conditions on the total thiols of stewed chicken legsThe establishment and validation of the predictive total thiols models were performed out by the Origin 8.5 software,and the results showed that Parabola2 D model and Poly2 D model could be used to simulate changes of total thiols of the interior stewed chicken legs under two firepower.Besides,Poly2 D model could be used to simulate changes of total thiols of the exterior stewed chicken legs under two firepower.In summary,not only firepower but also region had no obvious effect on the total thiols of stewed chicken legs.Under the same firepower with different temperature,total thiols presented decrease trend with the increase of cooking temperature.Moreover,under the same firepower with different cooking time,total thiols also presented decrease trend with the increase of cooking time.For both kinds of firepower,a higher total sulfhydryl content could be achieved when the cooking time ranged from 10 min to 30 min and the temperature value was between 70 ?and 90? while that decreased to a lower level when the cooking time ranged from100 min to 120 min and the temperature value was between 90 ? and 110?.5.Effect of cooking conditions on non-protein nitrogen content of stewed chicken legsThe establishment and validation of predictive non-protein nitrogen content models were performed out by the Origin 8.5 software,and the results showed that the Rational2 D model could be adopted to assess changes of non-protein nitrogen content of the exterior stewed chicken legs under two firepower.Besides,Polynomial2 D model could be used to assess changes of non-protein nitrogen content of the interior stewed chicken legs under two firepower,respectively.In summary,firepower had no obvious effect on non-protein nitrogen content of the stewed chicken legs while the region had obvious effect on them.For exterior region of stewed chicken legs under two cooking firepower,the non-protein nitrogen content presented earlier increase and later decrease trend with the increase of the cooking time and temperature.However,for interior region of stewed chicken legs under two cooking firepower,the non-protein nitrogen content presented earlier increase and later decrease trend with the increase of cooking time while there was no regular trend with the increase oftemperature.For the interior region of stewed chicken legs,a higher non-protein nitrogen content could be achieved when cooking time ranged from 70 min to 80 min and the temperature value was between 90 ? and 100?.A lower level could be got when cooking time ranged from 10 min to 20 min and temperature value was between70 ? and 80?.For the exterior region of stewed chicken legs,a higher non-protein nitrogen content could be achieved when cooking time ranged from 60 min to 70 min and temperature value was between 70 ? and 80?.Meanwhile,a lower content would be achieved when cooking time ranged from 110 min to 120 min and temperature value was between 60 ? and 70?.