Okra seeds proteins: Amino acid profile, free radical scavenging activities and inhibition of diabetes and hypertensive converting enzymes indices

Abstract

The study was aimed to determine bioactivity of okra seed proteins against oxidative stress, diabetes, and hypertension. Whole okra seed flour (OKPF), protein isolate (OKPI) and hydrolysate (OKPH, using proteolytic Lactic Acid Bacteria) were produced by standard methods. Samples were evaluated for protein contents, amino acids, in-vitro antioxidant, and enzymes (pancreatic lipase, α-amylase, α-glucosidase, and Angiotensin-1 converting) inhibitory properties. Protein content (g/100 g) of OKPH (97.45) was more than OKPI (80.09) and OKPF (26.42). In-vitro protein digestibility indicated that OKPH (87.17%) had the highest value followed by OKPI (77.63%) and OKPF (66.06%), respectively. Amino acid composition (mg/100 g protein), i.e., hydrophobic (32.36), aromatic (7.56), antioxidant (19.15), and branch chain (13.0) in OKPH were higher than in OKPF and OKPI. Functional properties of OKPH showed better attributes than in OKPI and OKPF, respectively. Protein hydrolysate (OKPH) exhibited highest antioxidant and free radical scavenging activity than in OKPI and OKPF. Sample OKPH exhibited highest percentage inhibition against carbohydrate-hydrolyzing and anti-hypertensive enzyme inhibition indices than in OKPF and OKPI. This study established that OKPH exhibited highest antioxidant, pancreatic lipase, angiotensin-1 converting, α-amylase and α-glucosidase enzyme activities. Hence, it may be suitable as nutraceutical agent for antidiabetic and antihypertension.