Impact of lactic acid bacterial fermentation on the chemical composition, antioxidant capacities and flavor properties of dandelion

Dandelion is a medicinal and food plant with a long history of medicinal use, but its application as a functional food has been limited. In this study, the fermentation characteristics of four lactic acid bacteria (LAB) in dandelion were investigated and aimed to screen out the LAB that can improve the nutrition and flavor of dandelion. The results showed that all strains grew well, with L. plantarum having the lowest pH and highest total acidity after fermentation. Fermented dandelions (FDs) showed significantly higher total phenolic and flavonoid contents. The antioxidant and hypoglycaemic activities were also enhanced. Lactic and tartaric acids contents increased significantly after fermentation. The three characteristic phenolic acids were differently changed by different LAB strains. L. plantarum-FD had the highest content of chlorogenic acid (17.22 mg/g), and L. casei-FD had the highest content of caffeic and chicoric acids (0.77 mg/g and 14.90 mg/g, respectively). LAB improved the herbal flavor of dandelion by reducing alcohols, increasing acids and altering the concentrations of other volatiles. Aldehydes and esters increased more in the L. plantarum- and L. fermentum-FDs than in the other groups. L. fermentum added pyrazines in particular but also produced unpleasant butanoic acid and methylpyrazine. Overall, L. plantarum fermentation has shown great potential in improving the flavor and enhancing the biological functions of dandelion. It will be beneficial for enriching dandelion products and increasing added value.