Abstract: In this study, the changes in the nutritional components and in vitro fermentation characteristics of quinoa were measured after extrusion treatment. Results showed that extrusion could significantly reduce the contents of amylose, fat, total dietary fiber and insoluble dietary fiber in quinoa (P < 0.05), and increase the content of soluble dietary fiber (P < 0.05). During in vitro fermentation, the gas production increased with fermentation time, and the pH decreased significantly at the early stage of fermentation (P < 0.05). Compared with the control group, extruded quinoa could significantly increase the relative abundances of Prevotella, Megamonas, Megasphaera, Phascolarctobacterium, Bifidobacterium and Bacteroides (P < 0.05), but significantly reduce the relative abundance of Ruminobacteriaceae and Enterobacteriaceae (P < 0.05) during the fermentation. At the same time, the level of short chain fatty acids in the fermented broth of all groups increased and was higher in the extruded quinoa group than in the control group after 48 h of fermentation. Therefore, extrusion treatment can affect the nutritional composition of quinoa, and use of extruded quinoa as fermentation substrates can improve the fecal microbiota, which in turn may be beneficial for human gut health. The findings of this study can provide data support for obtaining quinoa products by extrusion and promoting the development of intestinal health products.

Key words: quinoa; extrusion; nutritional composition; in vitro fermentation; microbiota; short-chain fatty acids