Effects of Dietary Fibers Obtained from Cold-Press By-products on the in vitro Digestion of Spirulina

This study aimed to investigate the effects of dietary fibers obtained from cold-pressing by-products on the bioactivity of Spirulina (SP) during in vitro digestion. For this purpose, insoluble dietary fibers (CCDL and KCDL) were extracted from cold-pressing by-products of flaxseed and black cumin. SP was combined with CCDL and KCDL, and subjected to an in vitro digestion protocol (INFOGEST). The results showed that the total phenolic content of SP decreased after oral and gastric digestion with the addition of dietary fiber. After small intestinal digestion, the total phenolic content increased. Antioxidant activity values (DPPH and ABTS) decreased in the presence of dietary fiber, while chlorophyll values increased after small intestinal digestion. In particular, in the presence of CCDL, the chlorophyll content increased from 1.61 mg g(-1) to 4.48 mg 2 g(-1) after small intestinal digestion. Furthermore, the bioactivity values of SP after in vitro digestion varied depending on the type of dietary fiber. While KCDL was effective in increasing phenolic compound content, CCDL was more effective in increasing chlorophyll content. Considering the bioactivity values of SP after oral, gastric, and small intestinal digestion, it was determined that the values increased especially in the small intestine. This highlights the possibility that the bioaccessibility and therefore the bioavailability, of SP can be increased through the incorporation of dietary fiber. The addition of bioactive compounds to the development of functional foods rich in dietary fiber has advantages for the food industry in terms of designing and improving healthy foods. This study emphasizes that the in vitro digestion of Spirulina is regulated in the presence of CCDL and KCDL, and that the addition of dietary fibers may contribute to the potential health benefits of Spirulina.