Abstract: During oven drying of abalone muscle, microwave treatment was conducted at regular time intervals (0, 30, 60, 90 and 120 days). Abalone muscle digestion products (AMDP) were prepared by subjecting dried abalone to in vitro simulated digestion. Our aim was to investigate the effect of microwave treatment during the drying of abalone muscle on the in vitro and in vivo antioxidant activities of AMDP. The results showed that the half maximal inhibitory concentration (IC50) values of AMDP from fresh abalone muscle for scavenging capacity against hydroxyl (·OH) radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) and 1,1-diphenyl-2-phenylhydrazine (DPPH) radical were 3.04, 15.18 and 21.12 mg/mL, respectively. The IC50 values for the scavenging of these three radical species decreased gradually with increasing the drying time of abalone muscle. After being fed AMDP from abalone muscle dried for 120 days, the body length of Caenorhabditis elegans increased from 768.90 to 1 034.62 μm, the head swing frequency increased from 206 to 281 times/min, and the life span was extended by 36.16% under normal conditions and by 59.41% and 38.48% under heat stress and oxidative stress conditions, respectively compared with the control group. Meanwhile, with prolonging the drying time of abalone muscle, the antioxidant enzyme activities, reduced glutathione (GSH) content and total antioxidant capacity of C. elegans fed AMDP increased, and the reactive oxygen species (ROS) content decreased. In summary, prolonging the drying time and using microwave treatment during the drying process could improve the antioxidant capacity of AMDP.

Key words: abalone; drying; microwave treatment; in vitro simulated digestion products; antioxidant activities