Bioaccessibility of thiamin, riboflavin, niacin, and folate in legume matrices

Legumes are potential sources of B vitamins. Knowledge regarding the liberation of vitamins from legumes and their stability in digestion is scarce. Hence, we examined the thiamin, riboflavin, niacin, and folate contents and their in vitro bioaccessibility in dry, soaked, boiled, and germinated legume seeds. The contents in faba bean, lupin, and pea mainly retained in soaking (18 h, 8 °C) but decreased by 13-62 % in boiling (45 min). Germination (5 days, 15 °C) retained or increased the contents in faba bean and lupin seeds, and vitamins were synthesised in sprouts. The bioaccessibility of thiamin, riboflavin, and niacin was generally good (64-128 %), whereas the bioaccessibility of folate was lower (19-68 %) likely due to instability in digestion. Processing did not consistently enhance or diminish the bioaccessibility. The bioaccessible B vitamin contents varied among differently processed seeds, being the lowest in boiled seeds and the highest in dry seeds.