Abstract:

Grass carp (Ctenopharyngodon idellus) proteins were hydrolyzed sequentially by pepsin and pancreatin in an in
vitro digestion model system after microwave pretreatment. The degree of hydrolysis, amino acid composition, molecular
weight distribution and antioxidant activity were studied. The results demonstrated that the degree of hydrolysis was
significantly decreased at 800 W microwave power with an increase in microwave treatment time. Accordingly, we observed
an increase in the contents of hydrophobic amino acids and short chain peptides with molecular weight lower than 500 D.
Enzymatic breakdown in the simulated gastrointestinal environment caused a 3.35-fold increase in DPPH radical scavenging
activity and a 7.23-fold increase in reducing power but a 44.77% reduction in 2,2’-azino-bis (3-ethylbenzothiazoline-6-
sulfonic acid) diammonium salt (ABTS+·) scavenging activity compared to the blank samples. In conclusion, high microwave
power can decrease the digestibility of the proteins and affectthe antioxidant activity of the digested products.

Key words: grass carp (Ctenopharyngodon idellus) protein, microwave, hydrolysate, antioxidant activity