The effect of <i>Bacillus subtilis</i> fermentation of Australian sweet lupin on its mineral composition and in vitro bioaccessibility

Abstract Fermentation may beneficially increase the bioaccessibility of minerals in legumes. In this study, the contents and in vitro bioaccessibilities of Ca, Mg, Fe and Zn were determined in lupin whole seed and dehulled seed during soaking, cooking and then fermentation with Bacillus subtilis into a natto analogue. For total mineral content, a significant loss (P &amp;lt; 0.05) of Mg was observed after cooking for both whole and dehulled seed. During pre-processing, the Ca bioaccessibilities of whole and dehulled were highest (P &amp;lt; 0.05) in the soaked seed and for Mg was highest (P &amp;lt; 0.05) in the cooked samples. At all fermentation times, the bioaccessibility of all minerals was higher (P &amp;lt; 0.05) in the dehulled than the whole seed. Significant increases (P &amp;lt; 0.05) in bioaccessibility during fermentation were observed for Fe at 48 h and Zn 24 h in dehulled seed, providing the first evidence for the beneficial effect of lupin fermentation by B. subtilis in terms of Fe and Zn availability.