Papaya is susceptible to fungal deterioration and the use of essential oils (EOs) emerges as a promising alternative to fungicides, which causes environmental and human health problems. To evaluate the antifungal activity of essential oils and their major constituents in controlling papaya pathogens, the following in vitro assessments were conducted: I) screening of seven EOs regarding the antifungal activity; II) determination of the minimum inhibitory concentration (MIC) of the most promising EOs; III) analysis of chemical composition of the most effective oils; and IV) evaluation of the antifungal potential of the major constituents both individually or in combination. The results showed that the EOs of cinnamon bark, oregano, clove basil, and rosemary pepper exhibited high antifungal activity against all studied fungi, with MIC values from 0.50 to 2.00 μL mL^-1. The major constituents found in oregano EO were carvacrol, ρ-cymene, and thymol; in cinnamon bark EO, cinnamaldehyde, o-methoxy, and cinnamyl; in rosemary pepper EO, thymol, ρ-cymene, and caryophyllene; and in clove basil EO, eugenol, ρ-cymene, and caryophyllene. Regarding the antifungal activity of the EO constituents, the mixture of the three major demonstrated greater efficiency against the studied fungi. Using constituents represents an alternative for controlling postharvest diseases in papaya.

Anthracnose, caused by the Colletotrichum sp. gloeosporioides complex, severely affects guava quality, highlighting the need for sustainable alternatives to synthetic postharvest fungicides. This study is the first to evaluate modulated UV-C radiation as an innovative approach to controlling postharvest diseases and extending guava shelf-life. The modulation frequency significantly influenced mycelial growth and conidial germination, following a quadratic model (R² = 0.98), with maximum efficacy at ~30 Hz, reducing germination to 5.3 × 10⁴ CFU per plate. In vivo, the combinations of 0.99 kJ m⁻²/30 Hz and 0.66 kJ m⁻²/45 Hz inhibited anthracnose incidence and severity. Most physicochemical parameters remained unaffected after seven days of storage. However, treated fruits showed a higher hue angle (h) and lower a*, indicating the maintenance of shades closer to green due to slower chlorophyll degradation, and firmness was preserved, suggesting delayed ripening. Modulated UV-C also significantly reduced the respiration rate, lowering the climacteric peak. These findings demonstrate that anthracnose control depends on the modulation frequency, with 0.99 kJ m⁻²/30 Hz being particularly effective. Modulated UV-C radiation represents a promising, sustainable, and effective strategy for improving guava postharvest quality and shelf-life.

Sour rot caused by Geotrichum citri-aurantii is one of the most destructive postharvest diseases affecting citrus fruits, mainly the ‘Lima’ variety, leading to severe economic losses. Beyond its economic impact, the management of postharvest diseases is linked to global efforts to reduce food losses and decrease reliance on synthetic agrochemicals, aligning with the Sustainable Development Goals related to responsible production. In this context, active coating-based strategies have emerged as promising alternatives to conventional fungicides. In this study, in vitro and in vivo experiments were conducted to evaluate the antifungal capabilities of an emulsion produced by mixing a chitosan solution with the major constituents of oregano ( Origanum vulgare) essential oil - carvacrol, thymol, and p-cymene . We also treated postharvest oranges with this emulsion to evaluate. The physicochemical quality and defense enzyme activity. The formulated emulsion exhibited a broad oil droplet size distribution in the micrometric range and a good film-forming capacity. In vitro experiments demonstrated complete inhibition of colony formation at 0.25 µL mL⁻¹ and inhibition of mycelial growth at 3.00 µL mL⁻¹, whereas lower antifungal efficacy was observed in the vapor phase. When applied to orange fruit, the emulsion at 7.5 µL mL⁻¹ reduced disease severity. The treatment also maintained higher firmness values and more stable pH and color attributes at the evaluated sampling times. Changes in the activity of enzymes were also observed at specific sampling times following treatment. Overall, the results indicate that the emulsion is a promising alternative for controlling sour rot while preserving the postharvest quality of citrus fruits.