Abstract:[Objective] This study aims to prepare γ-aminobutyric acid (GABA)-enriched milk fermented with lactic acid bacteria and evaluate its anti-exercise fatigue effect.[Method] High GABA-producing lactic acid bacteria were selected and used to ferment milk with a commercial starter culture. A mouse model of exercise fatigue was established by four weeks of exhaustive swimming training. After four weeks, the exhaustive swimming time, serum biochemical indicators, antioxidant indicators, and energy storage substance levels were measured and analyzed.[Result] Lactobacillus plantarum (L. plantarum) LP-5 was selected as the strain for fermentation, and its GABA yield reached (1.340±0.003) g/L. The fermented milk showed the titratable acidity of (46.29±2.01) oT, the colony count of 2.18×109 CFU/mL, and the GABA mass concentration of (1.780±0.011) g/L. Compared with that at the initial fermentation, the fermented milk showed increased content of various free amino acids (P<0.05). Differences were observed in the fatigue-related indicators between the control and model groups (P<0.01). Compared with the model group, the commercial starter culture group and the commercial starter culture + L. plantarum LP-5 group exhibited increases in swimming exhaustion time (P<0.01) and decreases in activities of creatine kinase and lactate dehydrogenase in the serum, mass concentration of blood lactate, and concentration of blood urea nitrogen (P<0.01). In addition, the two groups showcased increased activity of superoxide dismutase (P<0.01), decreased concentration of malondialdehyde (P<0.01), and increased mass fractions of glycogen in the liver and muscle (P<0.01). Moreover, the commercial starter culture + L. plantarum LP-5 group showed better anti-fatigue effects.[Conclusion] The GABA-enriched milk fermented with lactic acid bacteria has significant anti-exercise fatigue effects in mice, with the commercial starter culture + L. plantarum LP-5 group showing the most significant effect.
