Lactiplantibacillus plantarum SG053 and SG066 Enhance Nutritional Value of Soy Protein via Improved Essential Amino Acid Bioavailability.

The rising popularity of vegetarian diets, driven by health, aesthetic, and environmental considerations, highlights the limitations of plant-based proteins, particularly their incomplete amino acid profiles. Probiotics have emerged as a promising solution to enhance amino acid availability from plant protein sources. This study focused on the investigation and validation of Lactiplantibacillus plantarum SG053 and SG066 as effective agents to improve amino acid absorption, employing both in vitro assays and in vivo rat models. Estimated protein digestibility showed that these two strains were able to enhance the concentration of essential amino acids (up to 127.6%), non-essential amino acids (up to 107.3%), and total amino acids (up to 117.0%) at 4 h after probiotic addition. In an in vivo experiment, rats were administered probiotics at two doses (1 × 10 CFU/day and 1 × 10 CFU/day) to evaluate the effects of prolonged intake on serum amino acid concentrations under standard chow diet and high-protein diet regimens. The in vivo experiment showed that both low-dose and high-dose probiotics increased serum total amino acid concentrations (28.8-79.7%), with a more prominent elevation (p < 0.05) in essential amino acid levels (56.5-104.3%) presented in high-dose probiotics treatment. In a further postprandial experiment, rats in a high-protein diet group supplemented with 1 × 10 CFU of probiotics showed remarkable increases in essential amino acid concentrations, with SG053 enhancing levels by 82.0% and SG066 by 69.4%. These findings suggest that integrating SG053 with plant-based diets could enhance the nutritional value of plant proteins, offering a practical solution for more balanced and sustainable dietary practices.