Application of a Bioactive Compound 2,4-Di-tert-butylphenol in Nanoemulsion Form for Shelf-Life Extension of Cherry Tomatoes: From Microbial Inactivation to Quality and Safety Evaluation

Abstract

Postharvest spoilage of cherry tomatoes caused by pathogenic microorganisms and oxidative browning leads to significant economic losses and food waste. Natural bioactive compounds are gaining increasing attention as alternatives to synthetic pesticides. In this study, a nanoemulsion (NED) formulation of nature-derived 2,4-di-tert-butylphenol was developed and evaluated for its potential to preserve cherry tomato quality during storage. The NED was prepared using high-pressure homogenization, and demonstrated good water solubility and stability. The particles and polydispersity index of NED were an average size of 80–170 nm and 0.2389, respectively. The conductivity and zeta potential of the nanoemulsion were detected as 1.007 mS/cm and 1.611 mV, respectively. Antimicrobial assays showed that the nanoemulsion effectively inhibited the growth of major postharvest pathogens, including human-pathogenic bacterial S. aureus, and phytopathogenic fungal B. cinerea, with minimum inhibitory concentration values of 1.0, 2.0 μL/mL, respectively. Preservation performance tests indicated that the nanoemulsion was effective under both room temperature and refrigerated conditions. When applied to cherry tomatoes, the NED significantly reduced surface bacterial quantity, and preserved fruit quality, as evidenced by a lower weight loss rate, and higher levels of soluble sugars, protein, total phenolics, flavonoids, and ascorbic acid, and total antioxidant capacity (all comparisons were statistically evaluated by one-way ANOVA followed by Tukey’s HSD test, p < 0.05). Importantly, the NED can be completely removed after three times of washing. Collectively, these findings demonstrate that NED is an effective and safe bioactive preservative under laboratory-scale conditions. However, further validation under commercial postharvest handling conditions is necessary prior to practical application. This work provides a fundamental basis for the application of nanoencapsulated natural phenolic compounds in the postharvest preservation of fruits and vegetables.