Pork Ribs Thermoplastic Processing And Dry Product Quality Control Technology Research

A large number of pork bone will be produced in each year in China.The pork bone is a valuable food resource and has good nutrition.If these pig bones are not being used,it's not only a waste of bone resources,but also brings the burden for the environment.People can not use the nutrition of pork bone effectively by the methods of conventional cooking.In order to utilize the nutrition of pork and bone simultaneously.In this experiment,the pork ribs were soften by a special process.The changes of hardness and chemical composition of cooked pork bone were studied,then combining with the hot air drying and oxidation technology to develop an edibled and high value-added pork ribs product.The main research contents and results are as follows:?1?Studying the changes of hardness of bone after cooking in different conditions.The protein content,calcium,phosphorus content and dissolution rate of calcium and phosphorus of pork bone which cooked in different conditions are determined.The differences of microstructure of pork bones were studied by scanning electron microscope.The differences of mid infrared absorption spectrum of pork bones were studied.Results are as follows:High temperature cooking makes pork bone's hardness decreased significantly?p<0.05?,and cooking in acetic acid solution,the effect is better.The relationship between primary and secondary effects of various factors on bone softening is boiling temperature>boiling time>acetic acid concentration.The optimum conditions for bone softening is:Cooking temperature 120?,Cooking time60 min,Acetic acid concentration 0.2%.After cooking,the protein content of pork bone decreased significantly?p<0.05?,the apparent calcium and phosphorus content of pork bone increased significantly and the calcium and phosphorus dissolution rate increased significantly?P<0.05?.Boiling in acetic acid solution,the protein content of pork bone decreased more,the apparent calcium and phosphorus content increased and the calcium and phosphorus dissolution rate are higher.Boiling made pork bone composition change,boiling in water and acid,the composition of pork bones are similar.The mid infrared absorption spectrum of pork bones after cooking in water and acetic acid solution were simpler than the untreated pork bones and similar with synthesized hydroxyapatite.?2?To explore the effect of high temperature water boiling and acid cooking on pork protein degradation,The total nitrogen?TN?,water soluble nitrogen?WSN?,non protein nitrogen?NPN?,free amino acid?FAA?of pork are determined.Results are as follows:After Cooking,the total nitrogen content of meat and soup is lower than the total nitrogen content of fresh meat.The total water soluble nitrogen,total non protein nitrogen and total free amino acid content of meat and soup are all higher than fresh meat's.As a result of a large amount of water soluble nitrogen produced by the degradation of proteins,the total soluble nitrogen,total non protein nitrogen and total free amino of meat and soup cooked in acid were higher than those boiled in water.The degradation degree of pork proteins which cooked in acid was higher than that cooked in water.?3?Different temperatures?50?,60?,70??hot air drying was used to dry the cooked pork ribs products.The mathematical models were established to analyze the influence of temperature on the drying kinetics parameters.Results are as follows:Pork ribs hot air drying process only experienced slow drying stage.During the drying process,the moisture diffusion plays a leading role,and the drying rate increases with the increase of temperature.Modified Henderong and Pabis model is best suited to describe the characteristics of hot air drying of pork ribs.In this experiment,the effective moisture diffusion coefficient(D_eff)of pork ribs was distributed in the range of6.0703×10^-11—2.2264×10^-10m²/s,And increases with the increase of temperature.According to the effective water diffusion coefficient(D_eff),the activation energy?E_d?of the hot air drying of the pork ribs was obtained,and the value was 60.05kJ/mol.?4?The method of fuzzy mathematics comprehensive evaluation was used to optimize the hot air drying process of pork ribs.Effects of different antioxidants?TBHQ,Ascorbyl palmitate,Tea polyphenols?on pork ribs'thiobarbituric acid?TBA?,acid value?AV?and peroxide value?POV?were researched,the most suitable antioxidant was selected.Results are as follows:The evaluation weights of five quality evaluation factors?the color,shape,texture,taste,smell and taste?of the pork ribs,were determined by the sensory evaluation.The result of comprehensive evaluation is the pork ribs have the best sensory quality when the drying temperature is 60?.Three kinds of antioxidants can effectively inhibit fat oxidation of pork ribs,and TBHQ is the best antioxidant.?5?The dried pork ribs were stored at 25?,37?and 45?,The sensory evaluation,pH,total numbers of colony and total volatile basic nitrogen of pork ribs were determined every 15d.The key factor is determined by the Pearson correlation coefficient,the first-order reaction kinetic model and Arrhenius equation were used to predict the shelf life of pork ribs in different storage temperature.Results are as follows:At the same temperature,with the increase of storage time,the sensory scores of samples decreased and pH,the total number of colonies,TVB-N value increased.In the same storage time,storage with the temperature increased the sensory scores of samples decreased and pH,the total number of colonies,TVB-N value increased.Pearson correlation coefficient between sensory evaluation and pH,Total number of colonies,TVB-N are all greater than 0.94,having good correlation with sensory evaluation scores.The Pearson correlation coefficient of TVB-N and sensory evaluation is the largest one,so selecting TVB-N as the key factor.The rate constants of different storage temperatures?25?,37?,45??were obtained by linear regression.Sensory evaluation obtained the TVB-N is 24.95mg/100g in end shelf life of pork ribs.The predicted shelf life of pork ribs at different temperatures?25?,37?,45??is 404d,153d,87d respectively?The activation energy?E_A?of the reaction is 60.72 kJ/mol,and the pre exponential factor(k₀)is 1.36×10⁸.