Optimizing enzymatic hydrolysis of pumpkin seeds protein (Cucurbita maxima L.) by pancreatin with using microwave pretreatment

The seeds of Cucurbitaceae plants (pumpkin, melon, etc.) are one of the rich sources of protein. Proteins are one of the most important nutritional sources for humans. Enzymatic hydrolysis of pumpkin seed protein by using microwave pretreatment leads to the production of hydrolyzates with bioactive properties, including antioxidant activity. The use of microwave pretreatment causes changes in the 3D structure of proteins, It opens the 3-dimensional structure of the protein and accelerates the access of the enzyme to the peptide bonds. Therefore, the use of microwave pretreatment is a suitable method to save time and enzyme concentration which are used in enzymatic hydrolysis. In this study, The solution of pumpkin seed protein concentrate was exposed to microwave energy with a power of 500-900 W for 30-90 seconds and it was used as a substrate solution in enzymatic hydrolysis experiments. Enzymatic hydrolysis by pancreatin, with the concentration of 0.5 to 2.5% compared to the protein substrate, was performed in the time from 20 to 190 minutes, at the optimum temperature and pH of pancreatin, in order to produce hydrolysates with antioxidant potential. Antioxidant power was measured by using DPPH radical scavenging activity methods, total antioxidant activity (Absorbance at 695 nm) and iron chelating activity. The highest amount of antioxidant activity by using microwave pretreatment was in 105 minutes and the ratio of 1.5% E/S and the optimal conditions that provided by the software to achieve the maximum iron chelating activity (95.5%), DPPH radical scavenging activity (51.5%) and total antioxidant (Absorbance at 695 nm) (0.976), was in 102 minutes and the ratio of 1.5% E/S of which 89.5% corresponded with the obtained results.