Selection of folate-producing lactic acid bacteria for improving fermented goat milk

Goat milk is a complete food but its low level of folic acid diminisches its nutritional efficacy. In this study,Streptococcus thermophilus, Lactobacillus delbrueckiisubsp.bulgaricus, Lb. delbrueckiisubsp.lactisandLb. helveticusstrains were selected for folate production in goat milk to improve its quality. A suitable HPLC method was developed to directly determine both total folate and its biologically active derivatives such as 5-methyl-tetrahydrofolate (5- CH3-H4-PteGlu), tetrahydrofolate (H4-PteGlu) and 5 formyl-tetrahydrofolate (5-CHO-H4-PteGlu). Results showed thatS. thermophilus, Lb. delbrueckiisubsp.lactisandLb. helveticusstrains produced higher amounts of total folate thanLb. delbrueckiisubsp.bulgaricus, especially 5-CH3-H4-PteGlu and H4-PteGlu. Moreover the use of selectedS. thermophilusstrains in association withLb. delbrueckiisubsp.bulgaricusresulted in yoghurt with a significant quantity of folate and good organoleptic features.