(P19-006-25) Influence of Quinoa Processing on the Human Gut Microbiome Through In Vitro Fermentation Study

Objectives: Quinoa is a nutrient-dense grain, rich in fiber and high-quality proteins. The effects of quinoa processing on the human gut microbiome remain unexplored. Thus, an in vitro fermentation approach was used to analyze changes in the gut microbiome profile.

Methods: A selected quinoa line was tested in raw, boiled, extruded, and baked (cookies) forms. Dietary fiber was analyzed using the AOAC 99.43 method, and total polyphenols were measured using the Folin Ciocalteu assay. Quinoa samples were subjected to in vitro digestion, then freeze-dried for subsequent fermentation. Fecal samples from 10 healthy volunteers were used for 48-hour in vitro fermentation. Microbiome composition was analyzed using 16S rRNA amplicon sequencing on an Illumina MiSeq platform, with data processed through the Mothur bioinformatic pipeline. Short-chain fatty acids (SCFAs) are being quantified in fecal supernatants using standard procedures.

Results: Boiled and extruded quinoa significantly increased total polyphenol content (p < 0.05), while raw and baked quinoa had lower polyphenol concentrations. Dietary fiber levels were consistently lower across all products. Fecal fermentation of pre-digested raw and processed quinoa significantly (p < 0.05) increased beneficial lactic acid-producing bacterial (LAB) genera, including Bifidobacterium, Lactobacillus, Pediococcus, and Weissella. Both raw and cooked quinoa increased Bifidobacterium (15-20% relative abundance) in the first stage of fermentation. In the second stage, LAB relative abundance increased to 20-40%, with raw quinoa promoting greater Pediococcus and Weissella growth, suggesting plant material that may be harder to ferment. The bifidogenic effect was more sustained with boiled quinoa, while baked and extruded quinoa showed higher Lactobacillus. SCFA analysis is ongoing to further explore quinoa's effects on the gut microbiome’s metabolic activity.

Conclusions: These findings highlight quinoa's prebiotic properties, which are largely preserved across various cooking methods. Interestingly, boiling optimizes these beneficial effects. Future studies on quinoa and other grain products should integrate food chemistry and gut microbiota outcomes to identify physicochemical properties that influence microbiota responses.

Funding Sources: Foundation For Food and Agricultural Research