The effects of lactic acid bacteria-fermented lemon juice on blood pressure regulation and allergic responses in rodents

Lemon juice contains numerous biologically active substances that have potential health benefits. In this study, we evaluated the biotransformation characteristics and functional properties of lactic acid bacteria-fermented lemon juices and examined their effects on regulating blood pressure. Fermentation of Pingtung Eureka lemon juice with a mixture of five selected strains of lactic acid bacteria was found to be the most effective in enhancing juice gamma aminobutyric acid (GABA) levels, with an increases in yield of up to 7.37 +/- 0.39 g/l. Among the different lemon varieties fermented with Lactobacillus fermentum LF33, Taichung Eureka and Nantou Eureka gave the highest fermentation yields of GABA at 4.19 +/- 0.17 and 5.35 +/- 0.36 g/l, respectively. In spontaneously hypertensive rats that were administered fermented lemon juice to assess to the effects on blood pressure, we observed that diastolic, systolic, and mean blood pressures, as well as heart rate, were significantly lower than those in control rats (p < 0.1). Fermented lemon juice was also found to contribute to a significant increase in serum IgG concentrations (p < 0.05). Finally, we evaluated the efficacy of Taichung Limon and Pingtung Limon juice fermentation broths on the allergic effect of ovalbumin in sensitized BALB/c mice, and found that these fermented juices significantly reduced ovalbumin-induced IgE antibody levels (p < 0.05). In conclusion, we speculate that juice-containing substances, such as GABA, have a calming effect on ganglia, which could contribute to stabilizing heart rate, and that consumption of fermented lemon juice may have the effect of reducing levels of IgE antibodies.