The quality of blueberry fruit is easily altered after harvest. We investigated the regulatory mechanism of heat-shock (postharvest treatment) and edible coating (preharvest treatment) on the post-harvest physiological quality of blueberry from the perspective of physiological, biochemical and organoleptic characteristics. In our research, the optimal TKL concentration and the appropriate range of heat-shock temperatures were first screened based on actual application results, and then a combination of heat-shock temperature and TKL coating with significant differences in preservation effects was selected to investigate the effects of different heat-shock temperatures and TKL60 composite coating on post-harvest quality and volatile compound concentration of blueberries under refrigerated conditions. Our results showed that TKL with 60 mg/L thymol can retard the development of the degree of membrane lipid peroxidation and effectively reduce the incidence of fruit decay and the severity of blueberries infected with major pathogens at 25 °C. Meanwhile, heat-shock treatments were effective in maintaining the quality of blueberries, with a certain advantage from 45 °C to 65 °C after 8 d of storage at ambient temperature, but these treated groups were slightly inferior to TKL60 groups for fresh-keeping effect. Remarkably, the combination of heat-shock treatment and edible coating application could extend the shelf life of blueberries by 7–14 d compared to the results obtained with coating alone under low temperature storage. Specifically, heat treatment at 45 °C for 60 min after TKL60 coating (HT2) retarded the decrease in the levels of ascorbic acid, total anthocyanin, total acid and soluble solids. Gas chromatography–mass spectrometry hierarchical clustering analysis showed that this treatment also improved the aroma of the fruit, which maintained a certain similarity with that of fresh blueberries after 14 d. Principal component analysis (PCA) of the results of the evaluations carried out using an electronic nose (E-nose) and electronic tongue (E-tongue) showed that blueberries of the HT2 treated group did not show a large placement change of the PC1 distribution area from that of the fresh and blank control group. Accordingly, the combination of coating with heat-shock treatment can effectively improve the post-harvest quality and aroma compound concentration of blueberries, showing good application potential in storage and preservation of fresh fruits such as blueberries.

In this study, we isolated and identified pathogenic fungi from the naturally occurring fruits of red grapes, studied their biological characteristics, screened fifteen essential oil components to find the best natural antibacterial agent with the strongest inhibitory effect, and then compared the incidence of postharvest diseases and storage potential of red grapes treated with two concentrations (0.5 EC₅₀/EC₅₀) of essential oil components (inoculated with pathogenic fungi) during storage for 12 d at room temperature. In our research, Alternaria alternata was the primary pathogenic fungus of red grapes. Specifically, red grapes became infected which caused diseases, regardless of whether they were inoculated with Alternaria alternata in an injured or uninjured state. Our findings demonstrated that the following conditions were ideal for Alternaria alternata mycelial development and spore germination: BSA medium, D-maltose, ammonium nitrate, 28 °C, pH 6, and exposure to light. For the best Alternaria alternata spore production, OA medium, mannitol, urea, 34 °C, pH 9, and dark conditions were advised. Furthermore, with an EC₅₀ value of 36.71 μg/mL, carvacrol demonstrated the highest inhibitory impact on Alternaria alternata among the 15 components of essential oils. In the meantime, treatment with EC₅₀ concentration of carvacrol was found to be more effective than 0.5 EC₅₀ concentration for controlling Alternaria alternata-induced decay disease of red grapes. The fruits exhibited remarkable improvements in the activity of defense-related enzymes, preservation of the greatest hardness and total soluble solids content, reduction in membrane lipid peroxidation in the peel, and preservation of the structural integrity of peel cells. Consequently, carvacrol was able to prevent the Alternaria alternata infestation disease that affects red grapes, and its EC₅₀ concentration produced the greatest outcomes.

Edible composite coatings represent an alternative approach to reducing postharvest losses and extending the shelf life of perishable fruits. This study developed a nano-biopolymer coating by integrating pullulan (PUL), nano-silica (Nano-SiO₂), and tea polyphenols (TP) to retard deterioration in cherry tomatoes (Solanum lycopersicum var. cerasiforme). Optimized through response surface methodology (0.06% Nano-SiO₂, 0.1% TP, 1.8% PUL, 0.77% glycerol), the resulting Nano-SiO₂/PUL/TP composite film showed improved barrier properties (water vapor permeability, WVP: 0.2063 g·mm·m⁻²·h⁻¹·kPa⁻¹) and increased mechanical strength (tensile strength, TS: 2.62 MPa; elongation at break, EB: 67.67%), which may be attributed to a homogeneous microstructure stabilized via intermolecular hydrogen bonding. The composite coating exhibited significant (p < 0.05) antioxidant activity (59.04% DPPH·scavenging) compared to the PUL film (1.17%) and showed efficacy against S. aureus. When applied to cherry tomatoes stored at 4 °C for 15 days, the coating contributed to improved postharvest quality by reducing weight loss (−27.6%) and decay incidence (−32.3%), delaying firmness loss (2.40 vs. 0.54 N in uncoated group, CK), suppressing respiration rate (−38.8%), and enhancing the retention of total acidity (+9.7%), vitamin C (+49.6%), and total soluble solids (+48.6%) compared to the CK (p < 0.05). Principal component analysis supported sensory evaluation results, indicating the coating helped maintain sensory quality (scores > 6.0) and commercial value while extending shelf life from 9 to 15 days. These results suggest that the Nano-SiO₂/TP/PUL composite coating may serve as a preservative for extending the shelf-life of cherry tomatoes by effectively reducing decay and mitigating quality degradation.

The escalating environmental burden of conventional plastic food packaging has intensified the search for sustainable, biodegradable alternatives. However, single-component polysaccharide edible films often exhibit suboptimal mechanical and barrier properties, which limits their practical applicability. In this study, pullulan (PUL), konjac glucomannan (KGM) and low-acyl gellan gum (LGG) were blended as film-forming substrates with glycerol as a plasticiser. Single-factor experiments combined with Box–Behnken response surface methodology (RSM) were employed to optimise the formulation of ternary edible composite films. The effects of PUL, KGM and LGG concentrations on mechanical properties and water vapour permeability (WVP) were systematically investigated. The optimised film was comprehensively characterised for microstructure, physical barrier performance, antioxidant activity, soil disintegration, bacteriostatic capacity and plum preservation efficiency. The optimal formulation comprised 1.43 g/100 mL PUL, 0.24 g/100 mL KGM and 0.48 g/100 mL LGG. Under these conditions, the composite film exhibited a transparent and smooth appearance, with a continuous and dense internal microstructure. The comprehensive performance score (K) reached 0.805 ± 0.013, with a WVP of 2.75 ± 0.17 g·μm/(m²·h·kPa), light transmittance of 89.93% ± 1.26%, tensile strength (TS) of 3.05 ± 0.14 N/cm², elongation at break (EB) of 64.57% ± 0.58% and DPPH radical scavenging activity of 34.12% ± 0.96%. Storage trials on two plum varieties demonstrated that the composite coating effectively mitigated fruit weight loss, retarded peel browning and pulp softening, and maintained superior sensory quality throughout storage. Overall, the PUL/KGM/LGG ternary edible composite film exhibited favourable mechanical strength, promising water vapour barrier properties and moderate antioxidant activity, suggesting its potential as a useful reference for the further development and industrial adoption of biodegradable edible films in fruit and vegetable preservation.