Evaluation of sapodilla pulp as a matrix for probiotic fermentation: Physicochemical changes, antioxidant potential, and in vitro digestibility during storage

Abstract

This study investigated the influence of three probiotic strains (Lacticaseibacillus paracasei subsp. paracasei, Bifidobacterium animalis subsp. lactis, and Lacticaseibacillus rhamnosus) on the fermentation of sapodilla pulp, assessing its bioactive and antioxidant potential, in vitro digestibility, and stability during 28 days of storage. The sapodilla pulp, with high moisture (72.13 %), fiber (6.27 %), and sugars (14.70 % total, 8.96 % reducing), provided a protective matrix for probiotics. Fermentation at 35 °C for 24 h resulted in significant microbial growth, with L. rhamnosus exhibiting the highest viable cell count (8.90 log CFU/g), followed by B. animalis (8.70 log CFU/g) and L. paracasei (8.49 log CFU/g). HPLC analysis revealed substantial glucose and fructose depletion, particularly in L. rhamnosus-fermented samples. Throughout storage, pH (5.10–5.90) and total soluble solids (19.60–19.9°Brix) decreased, while cell viability remained stable (8–9 CFU/g). Fermentation enhanced bioactive compounds, with increased total phenolic content (TPC), β-carotene, and lycopene, the latter peaking at 14 days in B. animalis (45.72 μg/100 g). Antioxidant capacity improved across assays (ABTS, FRAP, and DPPH), with DPPH showing the highest values (2.19–2.85 μM TE/g). Simulated digestion revealed viability loss in oral and gastric phases but a marked recovery in the intestinal phase, where L. rhamnosus demonstrated superior resistance and regrowth. These findings emphasize the role of sapodilla pulp in enhancing probiotic stability and functionality, positioning it as a promising matrix for functional food development with potential health and economic benefits.