336: Effect of Thermal and Nonthermal Pasteurization and Glucose Supplementation on the Lactic Fermentation of Pea Protein Concentrate

Introduction

In recent years, there has been significant interest in utilizing pea ingredients for the production of dairy product alternatives. Pea protein concentrate (PPC), which is sustainably produced, has limited commercial use due to unoptimized functional properties and antinutritional factors. Fermentation with lactic acid bacteria can potentially enhance the physicochemical, nutritional, and sensorial properties of PPC. This study investigates the lactic acid fermentation of PPC and the effect of pre-fermentation pasteurization, either thermal and nonthermal (by high pressure processing) and glucose supplementation on the physical characteristics of fermented PPC.

Methods

PPC solutions were pasteurized thermally (65°C, 30 min) or with HPP (600MPa, 4min, 5°C), supplemented with 0/1% (w/w) glucose for a final protein concentration of 10% (w/w), inoculated with starter culture (Lactobacillus plantarum or VEGA™ Premium), incubated at 37°C until pH 4.6, and then stored at 4°C. Negative controls without inoculum were also prepared. The change of pH during fermentation was monitored and cell counts were taken after inoculation (t=0) and at the end of fermentation on MRS and M17 agar. Finished PPC samples were analyzed for texture and water holding capacity.

Results

Both thermal and HPP pasteurization achieved a ≥3-log reduction in the initial microbial load of samples. As PPC has a large starch fraction, thermal pasteurization led to starch gelatinization and a more viscous consistency than HPP. Neither pasteurization method had a negative impact on fermentation. Both L. plantarum and VEGA™ Premium successfully acidified the PPC substrate, with and without glucose supplementation. MRS cell counts of all fermented samples were ≥2-log higher than at t=0. Compared to the negative controls, L. plantarum ferments had higher gel hardness, while the VEGA™ Premium ferments displayed ropiness, increased hardness, and ~10% greater water holding capacity. This demonstrates that a particular combination of culture and the pre-fermentation treatment can result in fermented products with different characteristics.

Significance

This study shows pathways for obtaining fermented PPC products with different textural characteristics. Gelatinization of the starch contained by the PPC can eliminate the need for additional ingredients and facilitate the development of clean label products with desirable textural properties.

Authors: April Huang, Carmen I. Moraru