Monitoring the Aroma Profile During the Manufacturing of Pea Protein Isolates

Abstract

In recent years, there has been rapid growth in the use of plant proteins in food products. Among the different plant protein options, peas have gained popularity as they are high in protein, non-GMO, have low occurrence of allergenicity and are viewed as more healthy and environmentally friendly than animal proteins. However, challenges persist in producing a high-quality protein with a bland flavor profile that can be used in a wide variety of food products. Little work has been published on the impact of processing conditions on the aroma profile of pea protein isolates (PPIs) during manufacturing. This project focused on characterizing the aroma compounds present in PPIs and determining whether these compounds were inherent to the plant or formed during manufacturing by optimized salt- and pH- extractions. The first part of this study developed a protocol for the isolation and analysis of aroma compounds in pea flour (PF). That protocol was then used to monitor the aroma profile during manufacturing of PPIs by using both salt- and pH-methods. The analytical data showed that 12 aroma compounds detected during the salt-extraction and 13 aroma compounds during the pH-extraction are likely significant contributors to the aroma profile of the examined samples. These initial findings were supported by a sensory evaluation of both PF and PPI (produced by salt- and pH-extractions) aqueous solutions. A majority of the aroma descriptors used in the sensory analysis of the PF and PPI were also used to describe individual odors eluting from the sniffing port of the GC-MS-O during the olfactory analysis. While no new aroma compounds appear to be produced via the protein isolation process, no existing compounds were completely removed from making a sensory contribution. The majority of the compounds were present from the first step of the process, which indicates that they are likely derived from the peas as plant metabolites or are formed at some point before or during the production of PF. This study will provide ingredient manufacturers with insights on the compounds that are likely to contribute to the unpleasant aroma of PPI, their potential precursors and source, and suggest approaches that can be explored in the future to reduce or prevent their formation.