Selected probiotic lactic acid bacteria isolated from fermented foods for functional milk production: Lower cholesterol with more beneficial compounds

Two lactic acid bacteria (LAB) were isolated from fermented foods and identified as Pediococcus pentosaceus ENM104 and Lactobacillus plantarum SPS109. ENM104 reduced cholesterol at 7.53 ± 1.78% in basal medium containing 100 μg/ml cholesterol, while SPS109 released γ-aminobutyric acid (GABA) at 1157.01 ± 4.76 μg/ml in MRS containing 5 mg/ml monosodium glutamate (MSG). They hydrolysed skim milk, deconjugated glycocholic acid (GCA), taurocholic acid (TCA) and taurodeoxycholic acid (TDCA) as bile salts and tolerated simulated gastrointestinal juice, including H₂O₂. None performed any haemolysis. ENM104 cultured in MRS reduced cholesterol at 15.34 ± 1.12% (initial content, 100 μg/ml) at 72-h and produced intracellular cholesterol oxidase at 8.73 ± 2.00 mU/mg protein. Milk fermentation using the two strains as starters in single cultures and a co-culture showed that the co-culture (1:1) was the most effective. At 72 h, cholesterol in milk fermented with the co-culture was significantly reduced cholesterol at 10.98 ± 3.80%, while GABA content increased to 4.47 ± 0.04 μg/ml and angiotensin-converting enzyme (ACE) inhibition increased to 57.63 ± 2.97%. Based on 2,2′-azinobiz(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-2-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays, all antioxidant activities significantly increased. Fermented milk using probiotic LAB ENM104 and SPS109 has the potential to be an approved functional dairy product.