Methodological inconsistencies in novel plant protein functional properties, and improvements for water absorption capacity determinations

Abstract

As consumer interest and demand for new plant-based proteins increases, novel protein sources and extraction methods are developed, and property comparisons are made with existing data. Proteins are deemed suitable for food product use based on their functional properties: water solubility (WSI), oil and water absorption (OAC and WAC), foaming capacity and stability (FC and FS), and emulsifying and gelling properties. These empirical properties can be compared with previous studies if methodology is consistent. However, methodology for analyzing protein functionality is not standardized, which reduces effectiveness of publication communication. This presentation will identify significant differences among protein functionality methodologies to highlight the need for standardization. It will then dive deeper into the common and standardized methods for determining water absorption capacities (WAC) of plant proteins. Forty articles published in the last twenty years on the various functional properties of novel plant proteins were analyzed, and a total of 190 procedures were evaluated for inconsistencies and variations. Differences in methodology included centrifuge or homogenizer rotation speed, oil type used, time allotted for a given step, pH of the test, protein concentration, and specific formulas used to quantify the functional property. Additionally, four methods for WAC determination were compared using various plant proteins. Specific aspects of methods that can lead to incongruous results were identified and potential improvements were proposed. As consumer demand for novel plant proteins grows, product development will benefit from standardized methods for their functional properties, allowing more meaningful comparisons across studies and unique food applications.