Characteristics of lacto-fermented whey, milk, hemp and lupine proteins

Lacto-fermentation of proteins not only improves their biological and functional value but also causes nutritional and biochemical alteration as well as the formation of undesirable compounds, which needs to be monitored. The aim of this study was to evaluate the changes in whey, milk, hemp and lupine protein characteristics (acidity, microbiological parameters, color characteristics, free amino acid (AA) profile, biogenic amine (BA) and gamma-aminobutyric acid (GABA) concentrations) during lacto-fermentation with Pediococcus acidilactici LUHS29 and Pediococcus pentosaceus LUHS183 strains. Greater lactic acid bacteria growth and drop in pH was found in fermented plant proteins than in the animal ones. The contents of free essential and non-essential AAs were increased in all proteins fermented with the LUHS29 strain. This strain also possessed a greater GABA-producing ability in all fermented proteins. Compared to plant proteins, fermented animal proteins exhibited less GABA and total BA contents. Fermented hemp proteins had the highest BA content (on average, 215.8 mg/kg), while milk proteins fermented with LUHS183 for 48 h had the lowest value. P. acidilactici LUHS29 strain could be beneficial for a notable enhancement of AA and GABA in proteins, while the monitoring of BA synthesis in fermented hemp proteins needs specific attention.