Antimicrobial Activity and In Vitro Bioaccessibility of Antioxidant Compounds in Chestnut Honeys from Yalova (Türkiye) Region

Abstract

This study evaluated the antimicrobial, antioxidant, and total phenolic profiles of nine chestnut honey samples from Yalova, Türkiye, and the bioaccessibility of these compounds using a simulated in vitro gastrointestinal digestion model. Agar well diffusion and broth microdilution methods were used to evaluate antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis, Staphylococcus epidermidis, Listeria monocytogenes, Salmonella Typhi, Bacillus cereus, Enterococcus faecalis, and Candida albicans. Honey samples (100% and 50% v/v) were effective against all microorganisms except C. albicans. The most sensitive strains were S. aureus and S. epidermidis while E. coli and E. faecalis were less susceptible, respectively. The total phenolic content of honey samples was between 59.9 and 77.5 mg GAE/100 g honey. The DPPH radical scavenging activity ranged from 8.46 to 13.27 μmol TE/g, while the ABTS radical scavenging activity was determined to be between 15.40 and 30.47 μmol TE/g. The CUPRAC reduced capacity ranged from 17.68 to 26.79 μmol TE/g. The antioxidant capacity of honey samples underwent significant fluctuations during in vitro gastrointestinal digestion (p < 0.05). While certain parameters declined during the gastric phase, samples H4 and H6 demonstrated remarkable resilience, achieving the highest post-digestive recovery with superior TPC stability and antioxidant retention.