Development of plant-based infant complementary food from Cucumeropsis mannii, Dioscorea dumetorum, Musa paradiasica, and Malus domestica fermented with lactic acid bacteria

Abstract Plant-based complementary foods offer a promising alternative to conventional infant formulas; however, their nutritional limitations, anti-nutritional factors, and functional properties require optimization to ensure suitability for infant nutrition. In this study, a novel ready-to-eat plant-based infant food in paste form was developed from Cucumeropsis mannii (Melon seeds) , Dioscorea dumetorum (sweet Yellow Yam tubers), banana, and apple through fermentation with lactic acid bacteria (LAB) to enhance its nutritional properties. After starter screening and fermentation optimization, the formulation was individually inoculated with 6 Log CFU/g of Lacticaseibacillus paracasei (SK8), Leuconostoc mesenteroides (GSL7), and Lactiplantibacillus plantarum (AFI5), and incubated at 30 °C for 24 h. Subsequently, the effect of fermentation on chemical composition, peptide profile, and antioxidant capacity was investigated. Compared to the control formulation (RAW-F3), fermentation induced distinct changes in sugar consumption, free amino acids content, peptides profiles, along with reductions in key anti-nutritional factors (particularly phytic acid and saponins). Proteolysis driven by enzymes produced by LAB contributed to a modified free amino acid profile, with the formulation inoculated with L. paracasei (SK8-F3) having the highest amounts of free amino acids (401.8 mg/100 g). Likewise, a notable change in peptide profile was observed, and the formulation was inoculated with L. mesenteroides (GSL7-F3) recorded the highest diverse number of peptides (3352), followed by the formulation inoculated with L. plantarum (3417), and SK8-F3 (2697). In SK8-F3, phytic acid and saponins were significantly reduced by 75% and 50%, respectively, compared to RAW-F3 ( P < 0.05). Generally, fermentation enhanced total phenolic content and antioxidant activity, with the highest phenolics in GSL7-F3 (267 mg/L) and the strongest DPPH scavenging in AFI5-F3 (61.3%). Procyanidin B2 and caffeic acid peaked in SK8-F3, while ferulic acid and phloridzin remained consistently high across all formulations. Metabolism by LAB also contributed to improved sensory properties, with the SK8-F3 and AFI5-F3 formulations receiving the highest sensory scores. Overall, our findings affirm the role of LAB in enhancing the nutritional quality, safety, and sensory characteristics of foods, supporting their application in infant food formulations.