Nutritional Value Improvement of Oats by Solid-State Fermentation with Monascus purpureus

Abstract

With increasing research, the nutritional value of oats is gaining recognition. Fermentation is an emerging biotransformation pattern that changes the nutritional structure of whole grains. Currently, research on whole-grain fermentation is relatively focused on phenolic compounds and their antioxidants, but less attention has been given to avenanthramides (Avns) and the glycemic index (GI) in fermented oats. In this study, oats were subjected to solid-state fermentation (SSF) by Monascus purpureus for 21 days, and samples were taken at different time points. Changes in the contents of nutrients, phytochemicals, and antinutritional factors were analyzed using one-way ANOVA. Additionally, a simulated in vitro digestion experiment was conducted to assess the estimated glycemic index (eGI) of SSF oats. The results revealed that the nutritional structure of oats was changed by SSF, and the Avns content significantly increased, with 3.2 times more Avns in SSF oats than in unfermented oats, including 3.05, 3.09, 3.09, and 3.7 times more Avn A, Avn B, Avn C, and Avn D, respectively, and the eGI was reduced from 40.22 to 39.97 with increasing fermentation time. In general, SSF with Monascus purpureus has improved nutritional value, significantly increased the content of active ingredients, and reduced the level of eGI and two antinutritional factors (phytate and oxalate), which provides an effective way to improve the nutritional and digestive characteristics of oats.