Impact of Autoclaving on Functional Properties of Pigeon Pea Protein Isolates

Abstract

Pigeon pea (Cajanus cajan) is a protein-rich legume crop widely cultivated in tropical and subtropical regions, serving as a vital dietary protein source, particularly where protein malnutrition is a concern. The protein fractions in pigeon pea seeds are primarily composed of albumin, globulin, glutelin, and prolamin, with globulins accounting for nearly 60% of the total protein. Despite its nutritional value, pigeon pea protein remains underutilized in plant protein market. This study investigated the impact of autoclaving treatment on the functional properties of protein isolates obtained from two pigeon pea genotypes, Pusa Arhar 2018-4 and ICP 1452. Key functional properties, including protein solubility, surface hydrophobicity, water holding capacity (WHC), oil holding capacity (OHC), emulsifying properties, and foaming properties, were analysed. Autoclaving significantly reduced protein solubility across all pH levels in the range of 35.85-75.28% due to thermal denaturation and aggregation. Surface hydrophobicity increased by 10.68% and 16.18% for Pusa Arhar 2018-4 and ICP 1452, respectively. WHC decreased to 210.28% for Pusa Arhar 2018-4 and 209.8% for ICP 1452, while OHC increased to 186.44% for Pusa Arhar 2018-4 and 189.25% for ICP 1452. Emulsifying activity index (EAI) and stability index (ESI) decreased after autoclaving, EAI decreasing to 16.39 m2/g for Pusa Arhar 2018-4 and 16.34 m2/g for ICP 1452 and ESI decreasing to 29 min for Pusa Arhar 2018-4 and 30.33 min for ICP 1452. Conversely, autoclaving significantly improved foaming capacity by 22.90% and 34.31% for Pusa Arhar 2018-4 and ICP 1452, respectively, with greater foaming stability, at 60 minutes, it increased to 15.92% for Pusa Arhar 2018-4 and 16.91% for ICP 1452. These findings highlight the potential of autoclaving to modulate the functional properties of pigeon pea protein isolates, enhancing their suitability for diverse food applications like inclusion in development of protein rich functional foods.