Purification and Identification of EPS Produced by Five Lactic Acid Bacteria and Evaluation of Their Effects on the Texture of Fermented Goat Milk

Abstract

Extracellular polysaccharide (EPS) produced by five lactic acid bacteria (Limosilactobacillus fermentum B55, Limosilactobacillus fermentum B62, Lactiplantibacillus plantarum 7830, Pediococcus acidilactici B30, and Lactobacillus helveticus K2) were purified and identified, and their effects on the texture of fermented goat milk were evaluated. The purified EPS fractions EPS 1a, EPS 2b, EPS 3c, EPS 4d, and EPS 5e of strains B62, 7830, K2, B55, and B30 were obtained with ion exchange chromatography, and their molecular weights were 2.41 × 104, 1.62 × 104, 6.42 × 103, 6.45 × 103, and 1.26 × 104 Da, found using gel permeation chromatography. The infrared spectrum results showed that these substances all contained polysaccharide characteristic absorption peaks, most of which contained O-H bonds, C-H bonds, hydroxyl and carboxyl bonds, and groups. The analysis of monosaccharide composition presented that EPS1a was composed of guluronic acid, rhamnose, and galactose, with a molar ratio of 2.7:1:2.4; EPS2b and EPS3c were composed of guluronic acid; EPS4d was composed of guluronic acid, glucose, and galactose, with a molar ratio of 1:1.1:1.2; and EPS5e was composed of glucose and galactose, with a molar ratio of 1.6:1, indicating the differences in the composition and structure of EPS produced by various strains. Compared with the control group that only had the starter added, adding EPS-producing strains could promote acid production and improve the texture of fermented goat milk, and its acidity, hardness, consistency, viscosity, and viscosity index were higher.

A novel exopolysaccharide-producing bacterium, Pseudescherichia liriopis sp. nov. isolated from Liriope platyphylla, enhances the growth of Daucus carota subsp. sativus under drought and salinity stress

“…It was confirmed that the EPS from strain L3 T consists mainly of glucose and some mannose, which may be heteropolysaccharides. It is similar to EPSe5 produced by lactic acid bacteria but has a slightly different monosaccharide composition ( Liu et al., 2023 ). Additionally, the monosaccharide composition of EPS produced by strain L3 T suggests that it is different from EPS produced by other strains ( Kim et al., 2022 ; Liu et al., 2023 ).…”

“…It is similar to EPSe5 produced by lactic acid bacteria but has a slightly different monosaccharide composition ( Liu et al., 2023 ). Additionally, the monosaccharide composition of EPS produced by strain L3 T suggests that it is different from EPS produced by other strains ( Kim et al., 2022 ; Liu et al., 2023 ). EPS produced by microorganisms is regulated by several genetic factors, carbon sources, and environmental variables and may differ in composition from EPS produced by other strains, even of the same species ( Pachekrepapol et al., 2017 ).…”

New Insights into the Application of Lactic Acid Bacterial Strains in Fermentation 2.0

“…The use of different nutrients as culture media for lactic acid bacteria may yield exopolysaccharides with different molecular weights, different chemical structures, and different biological properties. Liu et al (2023) isolated different exopolysaccharides produced from goat milk through fermentation with five lactic acid bacteria (Limosilactobacillus fermentum B55, Limosilactobacillus fermentum B62, Lactiplantibacillus plantarum 7830, Pediococcus acidilactici B30, and Lactobacillus helveticus K2). Their results demonstrate that lactic acid bacteria can promote acid production and improve the texture of fermented goat milk, as well as increase the acidity, hardness, consistency, and viscosity of the product [4].…”

“…Liu et al (2023) isolated different exopolysaccharides produced from goat milk through fermentation with five lactic acid bacteria (Limosilactobacillus fermentum B55, Limosilactobacillus fermentum B62, Lactiplantibacillus plantarum 7830, Pediococcus acidilactici B30, and Lactobacillus helveticus K2). Their results demonstrate that lactic acid bacteria can promote acid production and improve the texture of fermented goat milk, as well as increase the acidity, hardness, consistency, and viscosity of the product [4]. In addition to pure plants and pure dairy products, products that are mixed with plants and dairy products and then fermented with lactic acid bacteria have also been developed, such as mixed barley and milk fermented with lactic acid bacteria.…”