Abstract:The purpose of this study was to prepare silkworm pupa protein glycopeptides by transglutaminase-induced glycosylation, and explore their umami taste-enhancing effect and hazardous substances. On the basis of single factor experiments, the conditions of TGase enzymatic reaction were optimized by the response surface methodology with sensory score and grafting degree as the evaluation indexes. Then, the differences in taste and hazardous substances between the high temperature Maillard reaction products (HMP) and low-temperature enzymatic glycosylation reaction products (LEP) were compared. The results showed that the optimum conditions for low-temperature enzymatic reaction were as follows: peptide/sugar ratio, 2.2:1; protein peptide mass fraction, 6.5%; initial pH of the reaction, 6.9; reaction temperature, 50 ℃. mass faction of TGase enzyme, 3%; reaction time, 4 h. At the same concentration and degree of glycosylation, the contents of acrylamide, 5-hydroxymethylfurfural and furfural were 113.3 μg/mL, 3.0 μg/mL and 1.76 μg/mL in HMP, respectively. However, in LEP, the contents of acrylamide, 5-hydroxymethylfurfural and furfural were reduced to 64.05 μg/mL, 1.96 μg/mL and 0.01 μg/mL, respectively. The contents of the three major hazards of LEP were significantly lower than those of HMP, indicating that the low-temperature enzymatic reaction was superior to the Maillard reaction. The sensory results showed that there was insignificant difference in the taste between HMP and LEP. Compared with the control group, the sensory score of LEP was significantly increased, indicating that the low-temperature enzymatic reaction can be used as another effective approach for increasing the umaminess of silkworm pupa protein peptide components. The results showed that the lowtemperature enzymatic reaction could enhance the umaminess and reduce the formation of hazard substances in silkworm pupa protein peptide fractions on the basis of the hazard and sensory analyses.
