Identification of bioactive properties (Ace-inhibition and antioxidant activities) of protein extracts and fractions from white mulberry (Morus alba L.) and leaves

Bioactive peptides are activated by processes such as enzymatic hydrolysis, fermentation and heat treatment while they are inactive within the proteins in the structure of foods. For this reason, it was aimed to investigate the effects of proteins on Angiotensin converting enzyme (ACE) inhibition activity and antioxidant capacity by applying heat treatment and enzymatic hydrolysis to dry mulberry and dry mulberry leaf samples used in the study. The isoelectric point (pH:9) and alkaline extraction point (pI:5) were determined to obtain the protein extracts with maximum efficiency and the extraction was performed with these parameters. The extracts were hydrolyzed by pepsin, trypsin, chymotrypsin and alkalase enzymes and the highest hydrolysis yield was determined by pepsin. After hydrolysis of proteins, 10 kDa and 3 kDa membranes were used to separate peptides according to their molecular size. The values showing statistically the highest ACE inhibition activity in mulberry samples belong to the extraction and hydrolysates of the sample heated at 50ºC (IC50: 0.061mg /mL). Furthermore, it was determined that the fraction below molecular weight 3kDa showed higher activity than the fraction below 10 kDa. It was determined that ACE inhibition activity decreased as temperature intensity increased compared to other samples and that the lowest activity belonged to the sample heated at 90 ° C. In terms of antioxidant capacity, it was determined that unlike the antihypertensive effect of mulberry samples, the antioxidant capacity increased as the temperature intensity increased and the highest values belonged to the sample hydrolyzed at 90ºC. According to mulberry leaf results, the values showing the highest ACE inhibition activity belong to the extraction and hydrolysates of the sample heated at 50ºC (IC50: 0.107 mg/mL). When compared to other mulberry leaf samples, ACE inhibition activity decreased as the temperature intensity increased and the lowest activity belonged to the sample hydrolyzed at 90ºC. In terms of antioxidant capacity, it was observed that the antioxidant capacity decreased as the temperature intensity increased compared to mulberry leaf samples. At the end of the study, heat treatment and enzymatic hydrolysis applications were found to be beneficial in increasing ACE inhibition and antioxidant activity when compared to dry Mulberry and dry mulberry leaf samples.