The patterns of changes in the physicochemical properties and volatile flavors of abalone muscle during drying at 50 ℃ and 65% relative humidity were investigated in this study. With an increase in drying time, the browning intensity and fluorescence intensity of both surface and internal muscles of abalone increased gradually, which started to decrease after reaching a peak on the 90th day. The contents of reducing sugar and lysine in the surface muscle were 3.11 mg/g and 2.60% after pretreatment, and decreased to 1.95 mg/g and 1.61% after 120 days of drying, respectively. High molecular mass polymers were observed in the electrophoretic pattern of abalone muscle after 30 days of drying. Fourier transform infrared spectra showed that the intensity of the characteristic absorption peaks (1403 and 1026 cm^-1) of glycoproteins gradually enhanced with increasing drying time. The response values of the electronic nose sensors W1W (sulfides) andW2S (alcohols, aldehydes and ketones) increased, and the content of 1-octen-3-ol decreased while the contents of linalool and (E,E)-2,4-decadienal increased after 30 days of drying, as determined by gas chromatography-mass spectrometry (GC-MS). At the same drying time, the intensity of Maillard reaction in the surface muscle was weaker than that in the internal muscle.

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 1034.62 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.