Effects of Chinese wolfberry (Lycium chinense P. Mill.) leaf hydrolysates on the growth of Pediococcus acidilactici

Growth stimulating effects of LYCH leaf hydrolysates on Pediococcus acidilactici IMT101 cells were observed when MRS broth was supplemented with 20% (v/v) H1 + H2, the mixture of hydrolysates prepared by a traditional tea-making process. Cells grown on MRS containing H1 + H2 showed a shortened lag phase while yielding a cell concentration (Xs) significantly higher than other conditions investigated entering stationary phase. The maximal specific growth rate (μmax) was also the highest among all. Microwave-assisted extraction (MAE) at 80 °C for 2 h (M802h) released more amino acids but less sugar (fructose, glucose, and sucrose) than in H1 + H2. Both Xs and μmax reached in M802h-supplemented MRS broth were lower than those in MRS containing H1 + H2. No correlations between amino acids and cell growth were found. P. acidilactici cells grown in MRS broth in general showed higher consumption of carbohydrate in comparison with those in M17 broth containing the same carbohydrate. In the absence of FOS, the increased glucose concentration in MRS when supplemented by H1 + H2 hydrolysates appeared to be responsible for the stimulatory effects on P. acidilactici growth. The growth-enhancing effects of LYCH leaf hydrolysates indicate the potential of developing new applications for LYCH leaves in promoting the growth of other probiotic cells using a simple process.