Controlling Off-Odors in Plant Proteins Using Sequential Fermentation.

Area of Science:

• Food Science and Technology
• Microbiology
• Sensory Science

Background:

• Off-odors in plant-based proteins deter consumer acceptance.
• Volatile compounds are responsible for these undesirable flavors and aromas.

Purpose of the Study:

• To develop and evaluate a two-stage fermentation strategy for reducing volatile off-odors in various plant proteins.
• To assess the efficacy of sequential fermentation using specific bacterial cultures.

Main Methods:

• A two-stage fermentation process was employed, utilizing *Lactobacillus plantarum* in Stage 1 and a traditional yogurt culture (*Streptococcus thermophilus*, *Lactobacillus delbrueckii* subsp. *Bulgaricus*, *Lactobacillus acidophilus*) in Stage 2.
• The method was applied to eight different plant protein solutions (soy, pea, chickpea, mung bean, faba bean, rice, barley-rice, hemp).
• Volatile compounds were analyzed using Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), complemented by sensory evaluation.

Main Results:

• The two-stage fermentation achieved a 95-99% reduction in key odorants like hexanal, 2-pentylfuran, methoxypyrazines, and sulfur compounds across all tested proteins.
• This sequential fermentation approach significantly outperformed a one-stage fermentation process.
• Allulose positively impacted *L. plantarum* activity, while strawberry preserves supported the yogurt culture's performance.

Conclusions:

• The developed two-stage fermentation is an effective, scalable, and clean-label solution for mitigating off-odors in plant-based proteins.
• This strategy enhances the palatability of plant proteins, paving the way for improved plant-based dairy alternatives.
• Microbial metabolism and formulation synergies are key to this deodorization process.