Study On The Thermal Reaction Shirmp Flavoring With Enzymolysis Method

Penaeus vannamei boone is one of the highest yields of the three types of theworld’s farmed shrimp. About200,000tons of prawn head’s by-products will begenerated annually in the whole nation. Most of these wastes were used for processingfeed and a small of them were discarded, which not only caused tremendous waste ofresources, but also environmental pollution. This paper takes Penaeus vannamei booneheads as raw material, which is generated during the frozen shrimp’s productionprocess. With the purpose of development and utilization of the shrimp head provides anew way, this paper use the methods of enzyme and Maillard reaction to prepare shrimpflavor. The main contents and conclusions are as follows:1. During the Penaeus vannamei boone head’s nutrients, moisture, crude protein,crude fat, ash, total sugar are accounted for68.56%,20.13%,4.62%,3.38%,0.90%respectively.2. Though single factor test and L₉（3⁴） orthogonal test, the paper determines thatthe composite enzymatic hydrolysis’ enzymatic process are as follows, hydrolysis timeis4.5h, hydrolysis temperature50℃, initial pH7.5, the solid-liquid ratio1:4.Analysison the amino acid composition of the shrimp head in the endogenous enzymatichydrolyzate showed that the total content of amino acid is695.6mg/100mL. Amongthem necessary amino acids content is372.6mg/100mL and is flavor amino acidscontent is215mg/100mL. Use ultrafiltration method to divide enzymatic hydrolyzateinto five components, and by Q value rule to do bitterness analysis on the molecularweight of5000-8000Da,3000-5000and1000-3000Da’s polypeptides. Results showedthat the three polypeptides will not render a bitter taste in theory. Using pairedcomparison sensory evaluation method to analyze hydrolysis’s bitterness and the resultsof sensory evaluation and the law of the Q value are the same. So we can determine thehead of the prawn has no bitterness in enzymatic hydrolyzes.3. Using the four kinds of protease do enzymatic hydrolysis to shrimp head andchoose the flavorzyme and protamex as the final composite enzymes choice. Aftersingle factor test and L₉（3⁴） orthogonal test, the paper determines that the compositeenzymatic hydrolysis’ enzymatic process are as follows, hydrolysis time is4h,hydrolysis temperature55℃, initial pH7, the solid-liquid ratio1:4and the additionflavourzyme and composite protease enzyme order is the synchronous hydrolysis, the two protease enzyme is480U/g and720U/g, respectively. Do hydrolysis on thePenaeus vannamei boone shrimp head with the best hydrolysis technology.Thehydrolysates obtained sensory score is50points and the degree of hydrolysis is16.55%.Analysing on the hydrolyzate by Q value rule, results showed that thehydrolyzate will not render a bitter taste in theory.4. Use flavourzyme and composite protease do composite enzymatic hydrolysis onPenaeus vannamei boone shrimp’s head and compare its results with shrimp head’sautolysis. Results showed that when compared with shrimp head’s autolysis, the degreeof hydrolysis, protein utilization, enzymatic hydrolyzate’s flavor and its amino acidcontent have been improved. Among them, the improvement of the flavor is mostobvious.5. Added shrimp heads enzymes’ reducing sugars and amino acids for the Maillardreaction study. This experiment takes Maillard reaction extent and sensory scores as anindicator to study the ratio of xylose and glucose, together with the types of aminoacids’ effect to Maillard reactions. Results showed that the amount of plus xylose andglucose ration is0:5and Maillard reaction choose cysteine as the plus amino acids.After study on the amount of reducing sugar, amino acid addition and Maillard reactionconditions, this study obtained Maillard reaction’s best technology: glucose addition3%, cysteine2%, reaction time30min, the initial pH8, enzymatic hydrolyzate’s watercontent60%.6. Add salt, white sugar and I+G into the shrimp flavor, which is prepared for theMaillard reaction, for the deployment. The experiment use fuzzy comprehensiveevaluation method and set shrimp flavor’s sensory fuzzy comprehensive evaluationmodel.After the three deployment substances’ addition univariate and L₉（3³） orthogonalexperiment, this study ultimately determines the best deployment is: white sugar’saddition8%, salt’s14%and I+G’s0.09%.