Changes in the Bioaccessibility of Antioxidants after Simulated In Vitro Digestion of Bioprocessed Spelt-Enhanced Wheat Bread

The aim of the study was to determine whether the partial replacement of wheat flour with bioprocessed spelt flour contributes to a higher bioaccessibility of the antioxidants in bread. The results showed that the type and amount of bioprocessed spelt flour in a bread recipe has a major impact on the extractable and bound TPC, the content of individual phenolics, their antioxidant activity, and their bioaccessibility as determined by in vitro digestion. Extractable p-coumaric and trans-ferulic acids in breads decreased after digestion, while extractable cis-ferulic and p-hydroxybenzoic acids increased. The bioaccessibility of TPC in the control bread (100% wheat flour), and in bread enriched with 5% germinated + fermented spelt flour (GFB5), did not differ. However, the digested GFB5 bread contained 5.2-times more extractable, and 1.3-times more bound, trans-ferulic acid than the digested control bread. trans-Ferulic acid showed the lowest bioaccessibility, up to 2.8%. In GFB2.5 and GFB5 breads, the bioaccessibility of p-coumaric, trans-ferulic, and cis-ferulic acids was higher than in other digested breads. PCA visualized the difference between the undigested and digested breads. The incorporation of germinated and fermented, or germinated and enzymatic, treated spelt flour in a white bread recipe could be an attractive way of providing consumers with nutritionally interesting foods.

Automated summary

The study aimed to investigate whether replacing wheat flour with bioprocessed spelt flour enhances the bioaccessibility of antioxidants in bread. The results demonstrated that the type and amount of bioprocessed spelt flour significantly influenced the extractable and bound total phenolic content, individual phenolics, antioxidant activity, and bioaccessibility after in vitro digestion. While certain phenolic acids decreased after digestion, others increased. Notably, the digested bread made with 5% germinated + fermented spelt flour contained significantly higher levels of trans-ferulic acid compared to the control bread. Overall, incorporating germinated and fermented or enzymatically treated spelt flour in white bread recipes could be a promising way to offer nutritionally valuable foods to consumers.