Explore the growth-promoting effects of rice peptides on Acidophilic Lactobacillus. Discover the power of low molecular weight peptides for digestive health.

Utilizing alkaline protease to hydrolyze rice protein and subsequent ultrafiltration to separate the hydrolysates, the study aimed to identify how different molecular weight segments of rice peptides influence the growth of this bacteria, which plays a crucial role in the digestive systems of humans, pigs, chickens, and rodents.

Keywords: rice peptide; enzymatic hydrolysis; ultrafiltration; Lactobacillus acidophilus; growth promotion

Acidophilic Lactobacillus, due to its lack of certain biosynthetic pathways and an incomplete protease system, has strict nitrogen source requirements and can only utilize protein hydrolysates such as peptides and amino acids. Peptides, compounds of two or more amino acids linked by peptide bonds, can participate in physiological activities and exert various biological effects, including fermentation promotion, blood pressure reduction, and antioxidation, and are more readily absorbed by the intestine than the equivalent concentration of amino acids. Given the wide availability and cost-effectiveness of rice protein in China, this research contributes to understanding the functional properties of rice peptides and provides a theoretical basis for their further development.

The study methodology involved hydrolyzing rice protein with alkaline protease, separating the hydrolysates by ultrafiltration based on molecular weight, and analyzing the growth-promoting effects on Acidophilic Lactobacillus. The results indicated that peptides with a molecular weight below 1 kilodalton (ku) exhibited a superior growth-promoting effect on Acidophilic Lactobacillus compared to peptides of higher molecular weights. These low molecular weight peptides contained higher proportions of amino acids, particularly glutamic acid, isoleucine, and leucine, which likely contributes to their effectiveness in promoting bacterial growth.

The research further analyzed the amino acid composition of rice peptides, finding that peptides in the <1 ku segment not only had a higher overall amino acid content but also contained essential amino acids required for the growth of Acidophilic Lactobacillus. The presence of high levels of glutamic acid, isoleucine, and leucine in these peptides facilitates their utilization by the bacteria, leading to enhanced growth.

This study contributes valuable insights into the utilization of rice peptides as a nitrogen source for beneficial gut bacteria, highlighting the potential of specific peptide segments to promote bacterial growth. These findings have implications for the development of functional foods and supplements aimed at supporting digestive health and enhancing the symbiotic relationship between host organisms and their beneficial microbial inhabitants.

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Original research by Cai Luyang, Zhang Beilei
(School of Food and Bioengineering, Shaanxi University of Science and Technology, Xi’an 710021) Article ID: 1005-9989(2017)03-0010-05