Bioactive and chemical properties of Kersting's groundnut proteins

Abstract

Dried seeds of Kersting's groundnut were processed into whole flour, defatted flour, protein concentrate, protein isolate, and protein hydrolysates. The samples were evaluated for proximate composition, in-vitro protein digestibility (IVPD), amino acid profiles, antioxidant and antidiabetic properties using standard protocols. The protein ranged between 27.00% (whole flour) and 90.48% (protein isolate).The IVPD of the whole flour had the lowest value of 52.71% and the hydrolysates (from 3 proteolytic enzymes) had the highest values of 98.21% (pepsin), 98.95% (pancreatin) and 98.06% (trypsin) respectively. The trypsin-hydrolysed protein showed the highest DPPH radical-scavenging ability (92.41%), metal chelating abilities (41.64%) and total antioxidant activity (0.25 mmAAE/g). The samples exhibited average in-vitro ability to inhibit the activities of α-amylase (14.83 to 20.53%) and α-glucosidase (16.66 to 25.11%) enzymes. Kersting's groundnut protein products can find useful applications in protein fortification and enrichment of food as well as the management of oxidation-related ailments or food deterioration.

Keywords

• Amino acids
• Bioactive compounds
• In-vitro protein digestibility
• Pancreatin-hydrolysed protein
• Total antioxidant activity