Study On The Key Processing Technology Of Crystal Pork Shoulder

A new kind of meat product-jelly crystal pork shoulder is to be developed by using theprocessing procedure and characteristics of Pork Trotter Aspic Jiangsu Style as reference. Toovercome the deficiencies and shortcomings, establish a new process flow of jelly crystalpork shoulder, several critical points including brining, chromogenic reagent, cooking andsterilization were studied respectively. The results were as follows:1. Vacuum pressure and brining concentration had a significant influence on salt osmoticregulation of pork. With the extension of curing time, salt content was gained with anexponential growth pattern, while water content and salt penetration rate decreased, andreached the dynamic equilibrium at6h, the permeation rate constants first increased thendecreased when vacuum pressure increasing, while kept straight up with the increase of saltconcentration. The weight of pork was kept gain during vacuum brining process, and the massgain rate enhanced significantly with vacuum pressure and salt concentration increasing.2. Different vacuum conditions had a significant effect on the quality change of pork invacuum osmotic curing. With the increase of the vacuum pressure, pork sensory scoreincreased and reached the maximum value under0.08MPa; pH did not change significantly;the soluble protein content in solution kept rising; pork tenderness was improved greatly,hardness, elasticity and chewiness gradually increased, while restorative kept decreasing, andcohesiveness decreased after the initial increase. When salt concentration increased, porcinesensory evaluation achieved the maximum score at salt concentration of6%, and it wasaccepted by most of people; soluble protein content reduced after the initial increase;significant improvement was showed in tenderness, hardness and chewiness of pork, but thevalue of elasticity decreased after the initial increase, while no significant variation was foundin cohesiveness and restorative with brine concentration and curing time changing.3. Through the experimental design of responding surface methodology, a mathematicalmodel of salt gain and sensory evaluation of pork shoulder with various factors wasestablished, and the optimum conditions of vacuum impregnation were determined based onthe model. The best brining parameters were: salt concentration of8%, vacuum pressure of0.09MPa, and curing time of6h. 4. Different amount of nitrate had a significant effect on the color of pork. With anincreasing content of sodium nitrite, the value of L*and a*was gradually enhanced, with b*value increased slightly. Chromogenic rate and nitrite residual content exhibited a remarkableincrease as well, but the amount of residual nitrite was always lower than30mg/kg and keptin a safe range. The proportion of metmyoglobin and deoxymyoglobin reduced whileoxymyoglobin content increased significantly.5. Ascorbic acid sodium, niacinamide, and tea polyphenols could greatly promote thecoloration of pork. Orthogonal interactive optimization experiment showed that ascorbicacid sodium, tea polyphenols, and niacinamide had a significant effect on a*value andchromogenic rate (p<0.05). There were prominent interaction between ascorbic acid sodiumand nicotinamide, nicotinamide and tea polyphenols (p<0.05). The optimum chromogeniccombination of crystal pork shoulder was determined at sodium ascorbic acid sodium400mg/kg, niacinamide500mg/kg, and polyphenols300mg/kg. Under this condition, theporcine chromogenic rate of pork could increase in178.3%,60%separately than thoseadded100,150mg/kg sodium nitrite alone in pork, which indicated that the chromogeniccombination was efficient, practical and reliable.6. Using three factors and three levels orthogonal optimization experiments, the bestcombination of spices were obtained: A2B2C3, which meant that the addition of the firstcategory spices (ginger, onion), the second category spices (pepper, star anise, cinnamon,cumin), and the third category spices (cloves, tsaoko) was3%,0.3%and0.04%respectively.Likewise, the optimal condiment combination was D2E2F2that was salt of3%, sugar of1.5%and MSG of0.3%. The optimum conditions of cooking process were90～95℃,60min.7. The best preservative composition could be achieved based on quadratic regressionequation by response surface methodology:0.50%Nisin,0.26%lysozyme,2.90%sodiumlactate, and0.05%potassium sorbate, and the order of inhibitory effect was: lysozyme> Nisin>lactate> potassium sorbate. There were highly significant interaction (p<0.01) between Nisinand potassium sorbate, lysozyme and potassium sorbate. There was also a significantinteraction (p<0.05) between Nisin and sodium lactate.8. Different sterilization methods had a remarkable effect on the number of microbialcolonies and sensory quality of the jelly crystal pork shoulder (p<0.05). Pasteurization (82℃,30min) was selected after comprehensive consideration. According to the hurdle theory,using comprehensive preservation technology that combined complex preservative coatingwith Pasteurization and refrigeration could extend the shelf life of crystal pork shoulder up to90d.