Enhancing Pea Flour Characteristics Through Radio Frequency Heating: Effects on Composition, Flavour, Anti-Nutrients and Functionality

Abstract

Peas and other legume crops are sources of sustainable plant-based proteins. Dry pea seeds can be processed into whole seed flour or dehulled milled flour and used as food ingredients. However, the widespread consumption of plant-based ingredients from peas is limited by their poor sensory properties, limitations in their functionality, nutritional properties and presence of anti-nutritional factors. Many of these negative attributes could potentially be overcome by using novel processing technologies. In this study, radio frequency (RF) pre-treatment of whole dry yellow peas was carried out at two temperatures (85°C and 115°C) and their effects on the macromolecular composition, amino acid profiles, anti-nutritional content, techno-functional properties and flavour chemistry were analysed. Significant reduction in the amounts of 12 out of 18 amino acids were observed in RF-treated samples compared to untreated control, while the other six amino acids showed a slight increase after RF treatment. Upon RF treatment, total phenolic content increased, while saponin content, trypsin inhibitor activity and lipoxygenase enzyme activity showed a reduction. Volatolomics studies revealed the generation of a number of new pyrazine class of volatile flavour compounds in situ, only in the RF treatment at the higher temperature of 115°C. Techno-functional analysis of dehulled milled flours prepared from RF-treated seeds showed an increase in water holding capacity, while the oil absorption capacity, foaming and emulsion properties decreased compared to untreated control. The significant findings of this investigation include the identification of a set of pyrazine compounds that enhance the flavour profile of RF-treated seeds and an improvement in water holding capacity of the flour that can increase its utilization in meat-analogue applications.