Optimization of Tiliacora triandra Leaf Extraction and Probiotic Fermentation for Developing a Functional Freeze-Dried Feed Supplements

Tiliacora triandra (Yanang) leaf contains polyphenols, flavonoids, and mucilage polysaccharides with antioxidant and prebiotic functions, making it a promising substrate for probiotic fermentation. This study aimed to optimize Yanang extraction and sterilization to preserve bioactive mucilage and support probiotic survivability during freeze-drying–based encapsulation, and evaluate antimicrobial activity against poultry pathogens. Yanang extract was prepared under different leaf processing conditions and used as a substrate for Pediococcus acidilactici V202, Lactiplantibacillus plantarum TISTR 926, Streptococcus thermophilus TISTR 894, Bacillus subtilis RP4-18, and Bacillus licheniformis 46-2. Fermentation at 37 °C for 24 h revealed that lactic acid bacteria (P. acidilactici V202, L. plantarum TISTR 926, S. thermophilus TISTR 894) reduced pH (<4.10, p < 0.001) while maintaining high viable counts (>8.67 log CFU/mL, p < 0.01), whereas Bacillus strains (B. subtilis RP4-18, B. licheniformis 46-2) retained a higher pH (>5.00) and lower viability (<8.50 log CFU/mL). Total soluble solids decreased across treatments, with the lowest observed for B. subtilis RP4-18 (1.97 °Brix, p = 0.007). Freeze-dried probiotics encapsulated in enzyme-extracted rice bran carriers had comparable physicochemical properties (p > 0.05), while compared with Bacillus strains (p < 0.01), lactic acid bacteria had superior tolerance to simulated gastrointestinal and thermal stress. Supernatant from Yanang extract inhibited B. cereus WU22001, S. aureus ATCC25923, Escherichia coli ATCC25922, and Salmonella typhimurium WU241001 (MIC/MBC 25–50% v/v). These results indicate that Yanang extract supports effective probiotic fermentation, and rice bran encapsulation enhances survivability and antimicrobial functionality for potential functional feed applications.