The effect of microwave pretreatment on degree of hydrolysis and antioxidant activity of Beluga (Huso huso) viscera protein hydrolysate

The purpose of this study was to investigate the effect of microwave pretreatment on the degree of hydrolysis and antioxidant activity of Beluga (Huso huso) viscera protein hydrolysate. For this purpose, the samples were hydrolyzed after two conditions of pretreatment including no treatment with microwave or after ten minutes treatment with microwave (frequency 2450 Hz and temperature 90 °C), by alkalase enzyme with a concentration of 2%, temperature of 55°C and pH 8, and then the degree of hydrolysis and antioxidant activity of the produced samples were evaluated. According to the results, the degree of hydrolysis after microwave treatment was significantly higher than the sample without microwave treatment (p<0.05). Also, the sample produced after microwave treatment showed higher antioxidant activity (DPPH and ABTS radicals scavenging activity and Fe reduction capacity) compared to the control treatment (p<0.05). The IC50 values ​​of this treatment in inhibiting DPPH and ABTS radicals scavenging activity were obtained as 1.25 mg/ml and 1.63 mg/ml, respectively, which was significantly lower than the control treatment (p<0.05). Also, in both samples, antioxidant activity increased significantly with increasing concentration (p<0.05). In general, it can be stated that 10 minutes of microwave pretreatment at 90 °C has a favorable effect on the properties of Beluga viscera protein hydrolysate which can indicate the applicability of this technology in the production process of fish protein hydrolysate.