Study On Flavor And Antioxidant Properties Changes Of Maillard Reaction In Enzymatic Hydrolysate Of Shiitake Stalk

Maillard reaction is the reaction between carbonyl compounds?aldehydes,ketones or reducing sugars?and amino compounds?proteins,peptide ammonia or amino acids?in the process of food processing.Under the condition of heating,they can generate brownish polymer pigment,produce flavor substances and antioxidant substances,which have the functions of increasing color,producing fragrance,reducing bad flavor and enhancing oxidation resistance.If the by-product of mushroom processing is hydrolyzed with enzyme and added with reducing sugar,and Maillard reaction is carried out under certain conditions,it is expected to remove the bad flavor in mushroom and produce the flavor substance with certain color and flavor and oxidation resistance,so as to achieve the efficient processing and utilization of mushroom.In this study,the Maillard reaction technology of the enzymatic hydrolysate of Lentinus edodes was optimized.The influence of flavor substance and antioxidant activity in the hydrolysate was detected by high performance liquid chromatography and gas-phase ion transfer spectrum,which provided a theoretical basis for the comprehensive application of processing by-products of Lentinus edodes and further development of Lentinus edodes seasoning.The main results are as follows:?1?Optimization of Maillard reaction process for enzymatic hydrolysate of Lentinus edodes stalk.Taking sensory evaluation and absorbance value as evaluation index,the compound reducing sugar of Maillard reaction was determined as sucrose and fructose by single factor test,and the compound ratio was 2:1.The Maillard reaction of enzymatic hydrolysate of lentinan stalk was optimized by orthogonal test,and the optimal condition was obtained:the amount of reducing sugar is 10.0%,the pH of the reaction system is 5.5,the reaction temperature is 100?,and the reaction time is 110 min.The absorbance A₄₂₀20 of Maillard reaction product in the enzymatic hydrolysate of Mushroom Stalk reached 0.3476,and the sensory score reached 21.33.?2?The effect of Maillard reaction on the flavor compounds in the enzymatic hydrolysate of Lentinus edodes stalk.The amino acids and organic acids in the enzymatic hydrolysate of Lentinus edodes before and after Maillard reaction were determined.The results showed that after Maillard reaction,the total amount of amino acids and organic acids in the hydrolysate decreased,and the species also changed significantly.The main amino acids involved in Maillard reaction are aspartic acid,isoleucine,phenylalanine,leucine,proline,histidine,methionine,cystine,etc.The concentration of histidine,methionine,isoleucine,phenylalanine,leucine and other bitter amino acids decreased,and the flavor of enzymatic hydrolysate was improved.The activity of isoleucine in Maillard reaction was the highest,97.08%of isoleucine in hydrolysate participated in Maillard reaction.After Maillard reaction,the total content of organic acids in enzymatic hydrolysate decreased,but the content of tartaric acid,citric acid,succinic acid,maleic acid and other organic acids increased significantly.After Maillard reaction,the contents of heptanaldehyde,dimethyldisulfide,dimethyltrisulfide,3-octanone and isoamyl alcohol with bad flavor in the enzymatic hydrolysate were significantly reduced or even disappeared,and the characteristic flavor substances of MRPs in the enzymatic hydrolysate of Lentinus edodes were formed,mainly ethanol,cyclohexanone,acetone,2-methylpyrazine and2-acetyl Based on pyrrole,the special sweet flavor and roasted flavor of enzymatic hydrolysate were given,and the flavor of enzymatic hydrolysate of Lentinus edodes stalk was obviously improved.?3?Antioxidant analysis of Maillard reaction products.By measuring the scavenging rate of DPPH·free radical before and after Maillard reaction,it was found that the scavenging ability of DPPH·free radical after Maillard reaction was significantly higher than that before Maillard reaction.Maillard reaction not only improved the color and flavor of the enzymatic hydrolysate of Lentinus edodes,but also increased its antioxidant activity,which provided a theoretical basis for the comprehensive application of the by-products of Lentinus edodes processing.