bioactive peptides from cowpea: characterization and in-vitro assessment of antioxidant, antimicrobial, and antidiabetic activities

This study evaluated the physicochemical, functional, and bioactive properties of cowpea
milk, its protein fractions, and cowpea milk powder, along with its application in a valueadded
product. Fresh cowpea milk showed high moisture content (95.01%), which decreased
to 3.59% after dehydration, ensuring improved shelf stability. The powder exhibited higher
ash content (9.33%) and low fat (1.8%), indicating a mineral-rich, low-fat profile.
Protein behavior was strongly influenced by pH and temperature, with maximum aggregation
near the isoelectric point (pH 4.5–5.0) and increased solubility at extreme pH levels. Thermal
treatment caused progressive protein denaturation, as confirmed by SDS-PAGE. Antioxidant
activity was highest under acidic conditions and enhanced at moderate temperatures, while
flavonoid and phenolic contents increased under alkaline conditions. Protein fractions,
particularly glutelins and globulins, showed significant antioxidant and enzyme inhibitory
activities, indicating potential antidiabetic properties.
Functional analysis revealed improved water absorption after thermal processing, while
particle size and zeta potential indicated aggregation and low colloidal stability near
isoelectric conditions. Application in gulab jamun demonstrated that 70% substitution of
cowpea milk powder provided better color and texture. Overall, cowpea milk shows strong
potential as a functional plant-based ingredient for food and nutraceutical applications.