Preparation And Prediction Of Pork Flavor Characteristic Precursors Based On Lard Enzymatic Hydrolysis

Three different lipases were used to enzymatic hydrolysis of lard in this paper firstly. Process conditions of enzymatic hydrolysis on lard were decieded by single-factor, and then lipolysis rate was used to choose the process conditions of different lipase. The optimum process conditions of lipase Yiming was substrate concentration of 55%, lipase loading of 1.55%, pH of 8, reaction temperature of 45 ℃ and reaction time of 4 h. The suitable condition of lipase Novozymes was substrate concentration of 55%, lipase loading of 1.05%, pH of 8, reaction temperature of 55 ℃ and reaction time of 4 h. And the optimal condition of lipase Amano was substrate concentration of 50%, lipase loading of 0.55%, pH of 6, temperature df 45 ℃ and time of 2.5 h.The effect of enzymatic hydrolysis degree on characteristic pork flavor and free fatty acid were analyzed by GC-MS. The results showed that the volatile compounds and free fatty acids in enzymatic hydrolysis lard samples were higher in untreated samples. Then unenzymatic hydrolysis lard, enzymatic hydrolysis lard with lipase Yiming (63.39%), lipase Novozymes (68.15%), lipase Amano (61.37%), were used to prepare pork flavors, and GC-MS, electronic nose and sensory evaluation were used to analyze the products. The results showed that lipase Amano was a suitable lipase for pork flavor. And the different lipolysis rate of lipase Amano enzymatic hydrolysis samples were studied in the same way. The results were that the higher lipolysis rate of lard was more suitable samples.Finally, the analyze method of PLSR was used to investigate the correlation between free fatty acid in lard and volatile compounds, sensory attributes of the PF samples. And the results showed that characteristic pork-like flavor precursors from enzymatic hydrolysis of lard might be 9c-C18:1 oleic acid,9t-C1 8:1 linolelaidic acid, 10c-C17:1 Heptadecenoic acid,9c,12c-C18:2 linoleic, C18.0 stearic and 9c-C16:1 palmitoleic. Then the prediction model of sensory evaluation and oleic acid, linoleic acid and linolenic acid were established and validated, and results showed that the prediction model could fast projections for oleic acid, linoleie acid, while linolenic acid was slightly inferior.