Effect of biological processing on the in vitro gastrointestinal digestion and bioaccessibility of whole grain wheat

Abstract In vitro simulation experiments were performed to evaluate the digestion properties of whole grain wheat (WGW), including starch and protein digestibility, mineral bioaccessibility, and polyphenol composition, following different types of biological processing (fermentation, germination and phytase treatment). The results showed that fermented WGW underwent greater starch digestion during the oral stage, whereas germinated WGW displayed the highest starch digestibility in the final stage. Germinated WGW had a lower protein digestibility at the start of the oral phase, whereas WGW fermented with Lactobacillus plantarum had the highest protein digestion in the final stage. An obvious decrease in the molar ratio of phytate to calcium after digestion suggested that residual phytate after biological processing no longer hindered calcium uptake. A slight change in content of bound phenolics after digestion indicated the generation of free phenolics derived from the hydrolysis and release of other conjugated polyphenols rather than bound forms.