Metabolomic profiling of sweet potato snacks enriched with agave fructans: Effects of vacuum impregnation on in vitro gut-associated metabolites.

Abstract

White-fleshed sweet potato 'blanco cubano' is an underutilized crop with promising nutritional and functional properties. Enhancement through vacuum impregnation (VI) with agave fructans may improve its prebiotic potential and influence gut microbiota activity. This study evaluated the effects of VI on the nutritional composition, carbohydrate bioaccessibility, in vitro colonic fermentation dynamics, and metabolomic profile of sweet potato slices. Three treatments were applied: untreated control, vacuum impregnation (T1), and immersion impregnation (T2). Samples were analyzed for proximate composition, phenolic content, and antioxidant capacity. In vitro gastrointestinal digestion and colonic fermentation were simulated to assess bioaccessibility and microbial metabolic output. Volatile metabolites from fermentation supernatants were identified using GC-MS, and enrichment analysis used disease-associated fecal metabolite profiles. Results showed that the peel had greater insoluble fiber (9.25 g/100 g dry basis), lipids (1.69 g/100 g), ash (6.12 g/100 g), and phenolics (9.89 mg GAE/g) than the pulp. T1 significantly increased bioaccessible carbohydrates (53.21 g/100 g DB) and soluble indigestible carbohydrates (39.90 g/100 g DB) compared to control and T2. During colonic fermentation, T1 exhibited a pH shift from 5.98 at 3 h to 6.57 at 24 h and higher short-chain fatty acids (SCFA) production, notably butyric and propionic acid. Among 37 identified volatile metabolites, several were linked to health conditions such as autism spectrum disorder, intestinal infections, and colorectal cancer. A reduction in p-cresol levels in T1 by 24 h suggested a healthier fermentation profile. VI with agave fructans improved sweet potato's functional quality by enhancing prebiotic carbohydrates and promoting beneficial metabolite production, supporting its use in developing functional foods targeting gut health and