AQUEOUS EXTRACTION OF CHICKPEA (Cicer arietinum) PROTEIN ASSISTED BY PAPAIN: IMPACTS ON BIOACTIVITY

Chickpea (Cicer arietinum) is a leguminous seed primarily distinguished by its favorable protein profile, the presence of bioactive compounds, and other essential nutrients that contribute to the promotion of human health. Its aqueous extracts represent a promising alternative for the development of protein-rich beverages. However, considering that not all protein fractions are water-soluble, the application of specific processing strategies may be beneficial to enhance extraction yields. Enzymatic extraction is particularly promising, as it not only increases the solubilization of proteins but also facilitates the release of bioactive peptides, which are relevant to health promotion and disease prevention. Therefore, the objective of this study was to evaluate the bioactivity of aqueous chickpea extracts obtained through enzymatic hydrolysis assisted by papain. Desi chickpeas (var. GB Cappuccino) were provided by AgroGarbanzo (Brazil). Whole seeds were ground and passed through an 80-mesh sieve. The resulting flour was suspended in water and treated with papain at an enzyme-to-protein ratio of 1:100, then incubated for 24 hours at 37°C. The degree of hydrolysis was determined using the o-phthaldialdehyde (OPA) method, based on the quantification of free α-amino groups. Antioxidant activity was assessed by the ABTS radical scavenging assay. The data indicated that the antioxidant activity of the extract increased progressively and was directly correlated with the degree of protein hydrolysis. After 1 minute of hydrolysis, the extract presented 96.3 nmol of free α-amino groups per mg of sample and 0.619 nmol Trolox equivalents per mg of sample. After 24 hours, these values increased to 411.93 nmol and 1.895 nmol, respectively. These findings clearly demonstrated that prolonged papain-mediated hydrolysis enhances both the concentration of free α-amino groups and the antioxidant capacity of chickpea extracts. This potential bioactivity was found to be closely associated with the increased degree of protein hydrolysis.