| Oyster is one of the most important economic shellfish species. The flavor of oyster sauce and other traditional condiments is very good, and speculated that the taste peptide is an important flavor component. However, the traditional processing method is complicated and inefficient; and it is improtent to update technology and maintain its good flavor for the deep processing of oyster and the taste peptide of oyster. In this paper, the oyster protein was controlled enzymatic hydrolysis with the modern biology and simulation optimization technology, to get the oyster hydrolysis with the good taste and peptide-rich. Further purify the peptides and analyse them flavor characteristics, in order to provide the theoretical basis for the taste mechanism of the oysters and the development of high-end seafood seasonings.The main contents and conclutions are as follows:1. Under the same conditions, pepsin, Alcalase 2.4L, and trypsin, animal proteolytic enzymes, flavor enzymes were used to hydrolyze the oyster protein respectively. The results showed that: trypsin enzyme solution was not only the highest protein utilization of 83.33%, also riched small peptide compounds; And compared several other enzymes hydrolyzate , the flavor of trypsin hydrolyzate were sweeter , glutamate-like taste and a strong flavor characteristics.2, On the basis of the orthogonal experimental design and randomized trials data, the hydrolysis time, hydrolysis temperature, enzyme dosage and the water ratio as the input value, the proportion of peptide and the sensory scores as the output value, establish a three-layer BP neural network with four-input and single-output, its topology photo 4-13-1, Very strong correlations were found between calculated values obtained from the ANN and those experimentally determined(±5%). The results so obtained will be useful to controll enzymatic reactions involving food proteins.3. The optimized operation conditions obtained by the neutral network method and genetic algorithm was: enzymatic time 5.4h, enzymatic temperature 58.6℃, enzyme concentration 1.03%, ratio of oyster muscle to water 1:2.8.And the result of confirmatory experiment and sensory scores were 78.35%, 6.39 respectively, which was better than the orthogonal. 4. Prepara oyster enzyme solution to the optimal process, and ultrafiltra. Through the Sephadex G-25, the ultra filtrate was separated into T1, T2, T3, T4, T5 and T6 six fractions. The sensory evaluation, determination of molecular weight and amino acid composition were analysised. The results showed that: T2 fraction have shown a strong flavor taste either in solution or a saline solution or sodium glutamate solution. While the other five fractions didn't give any clearly taste in the solution. And the molecular weight of T2 fraction is mainly distributed in 5Kda, in which the molecular weight of 3~5 KDa paragraph contains about 24.71%. The T2 fraction contains large amounts of free amino acids, but the peptide also was relatively high, and the ratio of peptide- amino acids was 45.28%.5. When the T2 fraction from the Sephadex G-25 was chromatographed on 201×7 Strong basic anion resin (acetate type), be further separated into component T2 T2-W and T2-S in two parts. Sensory analysis showed that: T2-S fraction was strong glutamate-like taste, but the T2-W no significant glutamate-like taste.6. Through the amino acid determination, the content of free glutamic acid and aspartic acid in the T2-S fraction were very high, and it was 81.53 percent in totle amino acids. But the proportion of free amino acids in T2-W was only 50.17%, in which the content of free glutamic acid and aspartic acid were 0.44 percent in totle amino acids. The results showed that: the flavor taste compounds in T2-S fraction were glutamate and aspartate, and the peptides in T2-W didn't find any taste activity. |
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