Optimization of Maillard Reaction Conditions and Changes of Physicochemical Properties of Enzymatic Hydrolysate of Sipunculus nudus

The enzyme hydrolysate(SEH)was used as raw material,on the basis of browning intensity and sensory scores,single-factor experiments and orthogonal experiments were employed to optimize the Maillard reaction conditions,the color parameters,contents of free amino acids and total amino acids and fluorescence intensity before and after Maillard reaction were compared and analyzed. The results showed that the optimized conditions for Maillard reaction were as follows:galactose addition 4%,pH9.0,temperature 130 ℃ and reaction time 60 min,under which the sensory score reached 13.77. Compared with SEH,MRPs-SEH became darker,deeper and fuller in color. The contents of seventeen kinds of amino acids in MRPs-SEH were significantly lower than those in SEH(p<0.05). The contents of total amino acids in MRPs-SEH were 279.729 mg/g,60.27% lower than that in SEH,and the contents of Tyr and Met were 73.84% and 72.98% lower than that in SEH,respectively. This indicated that the two kinds of amino acids participated in Maillard reaction to a greater extent,whereas His(content reduction 44.85%)showed relatively low activity in Maillard reaction. The proportion of delicious amino acids in total free amino acids in MRPs-SEH was 8.26% higher than that in SEH. Maillard reaction changed the structure of peptide chain in SEH. Overall,Maillard reaction improved the color and flavor of SEH,which provided a theoretical reference for the development of new condiments of Sipunculus nudus.