Fungal growth in table grapes (Vitis vinifera cv. beauty seedless) is triggered by Botrytis cinerea, Penicillium sp., Aspergillus sp., and Rhizopus stolonifera during post-harvest storage. Due to the safety aspects, this research aimed to develop antifungal packaging embedded with essential oils (EOs) to alleviate the fungal decay of table grapes (TG). The various levels of EOs (0.5–5%, v/v) from clove, cinnamon, thyme, peppermint, lemon, bergamot, ginger, spearmint, and lemongrass were tested against Aspergillus sp. The results attained in radial growth, disk diffusion method, minimal inhibitory concentration, and minimal fungicidal concentration revealed that 1% clove essential oil (CEO) showed higher efficacy against Aspergillus sp. compared to the untreated control and other treatments. CEO at the 1% level exhibited a pleasant odor intensity in TG than the other EOs. The active polyvinyl alcohol (7% PVA) film with 1% CEO resulted in lower weight loss, disease severity, and TG berry drop than the control and other treated samples. Additionally, the acceptance score in the TG sample wrapped with a PVA film containing 1% CEO was augmented. Therefore, the PVA film with 1% CEO retarded the fungal growth and prolonged the shelf life of TG during storage of 21 days at 13 °C and 75% relative humidity (RH).

Importance of the work: Macadamia nutshell (MNS) can be used as a bio-based fungicide, offering a natural alternative to synthetic chemicals and reducing waste. Objectives: Determine physicochemical properties and antifungal activities of pyroligneous acid (PA) from MNS, compare refinement methods and assess mango preservation efficacy. Materials and Methods: Macadamia nutshells were pyrolyzed at 600700°C to extract pyroligneous acid PA, which was then distilled, purified, and analyzed for yield, specific gravity, tar, solids, color, volatile compounds, and antioxidant activity. PA’s antifungal activity was assessed in vitro and on mangoes to evaluate its effectiveness in disease control and fruit quality. Results: Distillation-refined PA from macadamia nutshell demonstrated superior properties over naturally-refined PA, with an 87.55% yield, lower tar content (0.16%), and higher antioxidant activity. It had a lower pH (2.33), higher phenolic content (138.7 g GAE/L), and reduced total soluble solids (3.70% Brix). In-vitro analysis showed an effective antifungal activity against tested fungi with complete inhibition of Colletotrichum gloeosporioides and Colletotrichum musae at 1.5%. Combining 1.5% PA with 1% chitosan significantly enhanced the postharvest quality of Nam Dok Mai Sithong mangoes, reducing decay and weight loss while maintaining firmness, indicating a synergistic effect in preserving fruit quality. Main finding: Our study shows that distillation-refined MNS PA, exhibited a strong antioxidant and antimicrobial properties. PA at 1.5% conc. effectively inhibited Colletotrichum spp., and improved postharvest quality of ‘Nam Dok Mai Sithong’ mangoes, highlighting its potential use as an eco-friendly biocide.

The ability of salicylic acid (SA) to control post-harvest fungal disease mango anthracnose caused by plant pathogen Colletotrichum gloeosporioides and the accompanying biochemical and metabolomic changes were studied. In vitro, C. gloeosporioides mycelial growth at 25 °C for 7 days was inhibited by SA at 2 and 5 mM concentrations. In vivo, mango fruits were treated with 2 mM SA for 10 min, then inoculated with C. gloeosporioides. The fruits were then stored at 25 °C and sampled every 2 days after inoculation. The anthracnose severity, infection index, malondialdehyde (MDA), antioxidant capacity (DPPH and FRAP), total phenolics (TPC), total flavonoids (TFC), ascorbic acid, and metabolomic changes in the peel were studied. Six days post inoculation, the SA-treated fruits showed reduced anthracnose severity, and the infection index was significantly reduced by SA (57%) compared to the control (67%). The SA-treated fruits exhibited decreased MDA, enhanced antioxidant capacity, and increased levels of TPC, TFC, and vitamin C in the peel. Compared with the control, SA treatment reduced MDA content by approximately 50% and increased TPC, TFC, and FRAP antioxidant capacity by 77%, 31%, and 29%, respectively. Vitamin C content and DPPH antioxidant activity were also significantly higher in SA-treated fruits. Untargeted metabolomics and a principal component analysis revealed a separation group between the SA-treated and control fruit. The SA treatment induced D-amino acids, phenylalanine pathways, and the biosynthesis of secondary metabolites such as phenolic acid. Together, these findings demonstrate that SA enhances mangoes’ resistance to post-harvest anthracnose through direct antifungal action and the activation of host defense by improving the antioxidant systems and stimulating the accumulation of secondary defense metabolites in mango fruit.