Exploring the Cholesterol-Modifying Abilities of Lactobacilli Cells in Digestive Models and Dairy Products

Abstract

This study aimed to investigate the ability of lactic acid bacteria to remove cholesterol in simulated gastric and intestinal fluids. The findings showed that the amount of cholesterol removed was dependent on the biomass, viability, and bacterial strain. Some cholesterol binding was stable and not released during gastrointestinal transit. The presence of cholesterol affected the fatty acid profile of bacterial cells, potentially influencing their metabolism and functioning. However, adding cholesterol did not significantly impact the survival of lactic acid bacteria during gastrointestinal transit. Storage time, passage, and bacterial culture type did not show significant effects on cholesterol content in fermented dairy products. Variations in cell survival were observed among lactic acid bacteria strains in simulated gastric and intestinal fluids, depending on the environment. Higher milk protein content was found to be more protective for bacterial cells during gastrointestinal transit than fat content. Future research should aim to better understand the impact of cholesterol on lactic acid bacteria metabolism and identify potential health benefits.

Keywords: cell survival; fatty acid profile; gastric juice; gastrointestinal transit; health benefits; intestinal juice; lactic acid bacteria.

Figure 1

(a,c,e,g) Cholesterol removal using biomass samples with different concentrations of live and dead cells of lactobacilli strains under the gastric juice condition after 3 h or under the intestinal juice condition after 5 h. (b,d,f,h) Cholesterol removal or release using biomass samples with different concentrations of live and dead cells of lactic acid bacterial strains under the digestive juice condition after 8 h or in MRS broth after 24 h (mean values and SD values); ^a–j means with different letters in the same figure are significantly different (p < 0.05).

Figure 1

(a,c,e,g) Cholesterol removal using biomass samples with different concentrations of live and dead cells of lactobacilli strains under the gastric juice condition after 3 h or under the intestinal juice condition after 5 h. (b,d,f,h) Cholesterol removal or release using biomass samples with different concentrations of live and dead cells of lactic acid bacterial strains under the digestive juice condition after 8 h or in MRS broth after 24 h (mean values and SD values); ^a–j means with different letters in the same figure are significantly different (p < 0.05).

Figure 2

(a) L. delbrueckii subsp. bulgaricus ATCC 11842; (b) L. helveticus LH-B01; (c) L. delbrueckii subsp. lactis ATCC 4797; (d) L. acidophilus La-5. Survival of lactobacilli strains under digestive juice conditions (log(CFU/mL)); nd, not detected; ^a–f means with different lowercase letters in the same figure are significantly different (p < 0.05).

Figure 2

(a) L. delbrueckii subsp. bulgaricus ATCC 11842; (b) L. helveticus LH-B01; (c) L. delbrueckii subsp. lactis ATCC 4797; (d) L. acidophilus La-5. Survival of lactobacilli strains under digestive juice conditions (log(CFU/mL)); nd, not detected; ^a–f means with different lowercase letters in the same figure are significantly different (p < 0.05).

Figure 3

(a) gastric juice 3 h; (b) intestinal juice 5 h. Graphs of correlation matrix showing the relationship between pH, fat content, dry-matter content, and the viability of tested lactobacilli strains (L. delbrueckii subsp. bulgaricus ATCC 11842, L. helveticus LH-B01, L. delbrueckii subsp. lactis ATCC 4797, and L. acidophilus La-5) (a) after 3 h of incubation under gastric juice conditions, and (b) after 5 h under intestinal juice conditions (with a confidence level of 95.0%); x, not significant at 0.05.