Purple Potato and Its Polyphenols Modulate Cecal Fermentation in Rats

This study investigated the effects of the purple potato (PP) cultivar (cv.) 'Shadow-Queen,' rich in polyphenols and resistant starch (RS), on cecal fermentation in rats. It compared such effects with those obtained with a white potato (WP) cv. 'Toyoshiro,' and polyphenol-removed (decolorized purple potato, DPP) 'Shadow-Queen' potatoes. Seven-week-old male Fischer rats were fed diets containing WP, PP, or DPP. Compared to the cecal microbial composition of the control (CON), WP, and DPP groups, the PP group exhibited higher or lower relative abundances of the phyla Firmicutes or Bacteroidetes, respectively. Unclassified Clostridiales and Lactobacillus were more abundant in the PP than in the CON group. Compared to the other three, cecal succinate and immunoglobulin A (IgA) levels were elevated in the PP group. Compared to the CON group, cecal acetate, n-butyrate, and total short-chain fatty acid (SCFA) concentrations were enhanced in the PP, WP, and DPP groups; total SCFAs were higher in PP than in the WP or DPP groups. These results suggest that potato RS altered the cecal microbiota profile and increased SCFA production; the polyphenols in 'Shadow-Queen' potatoes further modulated the microbiota composition, thereby enhancing SCFA and IgA biosynthesis. Therefore, PPs may exert superior physiological effects compared to WPs due to the combined influence of RS and polyphenols.