In vitro antioxidant activity of protein fractions extracted from seinat (Cucumis melo var. tibish) seeds

The aim of this study was to assess antioxidant activity of glutelin, albumin, and globulin seinat seed protein hydrolysate (SSPH) fractions. The SSPH fractions were prepared using two food-grade proteases; trypsin and pepsin. The total amino acid composition, molecular weight distribution, and total phenolic contents were evaluated. The antioxidant activity, hydroxyl radical scavenging assay, DPPH radical-scavenging activity, metal chelating activity, and reducing power were also tested. The protein content of the glutelin, albumin, and globulin SSPH fractions was 81.80%, 73.09%, and 50.95%, respectively. The SSPH fractions showed high reducing power. Their molecular weights were in the range of 300 to 5000 Da. The glutelin fraction hydrolysate showed the highest content of the total phenolic (43.53 μg/mL GAE) and the strongest antioxidant activity. The inhibitory concentration of 50% of DPPH and hydroxyl radical scavenging assays and metal chelating was lower (p < 0.05) in the glutelin compared with that in albumin and globulin fractions. The results indicated that hydrolysates derived from seinat seed protein can be considered to be antioxidant sources.