Biotransformation of seriguela (Spondias purpurea L.) pulp by Saccharomyces boulardii: modulation of phenolic and volatile profiles, antioxidant capacity and gastrointestinal stability.

The aim of this study was to evaluate the effects of biotransformation by Saccharomyces boulardii on the phenolic and volatile composition, bioactive properties, and probiotic carrier potential of seriguela (Spondias purpurea L.) pulp. To this end, the pulp was fermented with the probiotic yeast and the resulting product was assessed for cell viability, antioxidant activity, phenolic composition (HPLC), volatile profile (GC-MS), and survival during simulated in vitro digestion. Submerged fermentation (37 °C, 175 rpm, inoculum of 108 cells mL-1) resulted in maximum yeast growth between 8 and 10 h, with a 49.04% increase in total phenolic compound content and increased antioxidant activity by ABTS (10.6%) and DPPH (1.45%) methods after 10 h. Gallic and protocatechuic acids showed increases of 26% and 22%, respectively, while rutin showed increases of 170%. The predominant class of volatile compounds identified in the fermented pulp was terpenes. S. boulardii maintained high viability in seriguela pulp under simulated gastrointestinal conditions, with counts above 7 log CFU mL-1 in all samples. Digestion reduced the phenolic compound content by 70% in non-fermented pulp, while in fermented pulp there was an 18% increase. Overall, the results demonstrated that fermentation of seriguela pulp by S. boulardii positively influenced its phenolic and volatile profiles, improved the gastrointestinal stability of bioactive compounds during simulated digestion, and maintained probiotic viability at functional levels. These findings support the use of fermented seriguela pulp as a promising probiotic carrier matrix and functional food ingredient.