Digestibility of Protein and Iron Availability from Enriched Legume Sprouts

Plant ferritin is suggested as a good source of iron for human. Usually present in trace amounts, it was induced in legumes seeds by their sprouting in FeSO₄ solution. Fortified sprouts were digested in the in vitro model of the human gastrointestinal tract. ~49% of lupine and ~ 45% of soy proteins were extracted into gastric fluid and next ~ 12% and only ~ 1% into intestine fluid from lupine and soybean, respectively. Gastric digestion released mainly ferrous iron (~ 85% from lupine and ~ 95% in soybean sprouts). Complexed iron constituted ~ 43% of total iron in intestine after lupine digestion and ~ 55% after soybean digestion. Intestine digestion doubled the total iron released from lupine sprouts (from ~ 21% up to 38%), while in soybean it increased from ~ 16% up to ~ 23%. Ferritin presence was confirmed by the specific antibodies in digestive fluids, but it is only partially extracted from sprouts during in vitro digestion.