Flavor substances of low-valued red swamp crayfish (Procambarus clarkii) hydrolysates derived from double enzymatic systems

To make better use of low-valued crayfish (Procambarus clarkii), double enzymatic systems containing endopeptidase and Flavourzyme® were applied to investigate their effect on the physicochemical properties and volatile substances of low-valued crayfish. The results demonstrated that the double enzymatic hydrolysis had a positive effect on reduced bitterness and increased umami. Among them, the highest degree of hydrolysis (31.67 %) was obtained using trypsin and Flavourzyme® (TF), which showed 96.32 % of peptides with molecular weight < 0.5 kDa and 101.99 mg/g of free amino acids. The quality and quantity analysis showed that the types and relative contents of volatile compounds especially benzaldehyde, 1-octen-3-ol, nonanal, hexanal, 2-nonanone, 2-undecanonewere increased in the double enzymatic hydrolysis. In addition, the increase of esters and pyrazines was also found in gas chromatography-ion mobility spectrometry (GC-IMS). The results indicated that different enzymatic systems could be performed to enhance the flavor substances of low-valued crayfish. In conclusion, double enzymatic hydrolysis may be used as an advisable technique to promote the high-value utilization of low-valued crayfish and provides valuable information for the shrimp products requiring enzymatic hydrolysis.