Plant protein flavor chemistry fundamentals and techniques to mitigate undesirable flavors

Abstract

Many plant protein ingredients have unpleasant flavor (e.g., green, beany, bitterness) characteristics. Isolation of the protein fraction will reduce the intensity of the undesirable flavors but in most cases the flavor issue is not eliminated. The objective of this review is to provide information about undesirable flavors associated with plant proteins and approaches to mitigate these flavors. The focus of the review will be on flavor associated with plant proteins from pulses, soybean, and oilseeds (e.g., hempseed, flaxseed). While other plant proteins exist, they will not be covered extensively in this limited review. The undesirable flavors are defined as volatile organic compounds (VOCs) and non‐volatile organic compounds (non‐VOCs). Example VOCs include aldehydes, ketones, and isobutyl pyrazines whereas saponins, bitter peptides, and phenolics are among the most common non‐VOCs. The raw material used as the source for the protein dictates the undesirable flavors remaining in the protein ingredient. The intensity of the binding of the VOCs and non‐VOCs to protein serves as the basis for the detection and difficulty in removing these compounds from the protein. A discussion about flavor binding and processing methods to mitigate unwanted flavors in protein ingredients will be provided. Methods presented will focus on extraction and thermal treatment. Although flavor masking is an approach to minimize undesirable, this topic will not be covered. Understanding the compounds responsible for the flavor issues and methods to minimize their impacts on sensory characteristic of protein ingredients can provide manufacturers with solutions to addressing flavor issues inherent to plant proteins.