Improving the Shelf Life of Avocado Fruit against Clonostachys rosea with Chitosan Hybrid Films Containing Thyme Essential Oil

Abstract

Hass avocadoes are one of the most popular fruits consumed worldwide because of their nutritional and nutraceutical content. Nevertheless, these fruits are susceptible to phytopathogen attacks that decrease fruit quality during the postharvest period. Herein we present the results of the in situ fungistatic activity of four hybrid films (FT1–FT4) manufactured with chitosan and different concentrations of the essential oil of thyme (TvEO). The films were evaluated as biodegradable materials to prevent fruit decay triggered by Clonostachys rosea which is considered an emergent phytopathogen of this crop. The in situ fungistatic strength, spectroscopic properties (FT-IR), optical features (transmittance/opacity), and consistency obtained by microscopic analysis (SEM), indicated that the films FT3 and FT4 possessed the best physicochemical properties to protect Hass avocadoes against the soft rot produced by C. rosea. Avocadoes treated with the films FT3 and FT4 significantly (p < 0.01) conserved fruit firmness and nutritional composition (protein, fat, fiber, and reducing sugars) as well as the nutraceutical content (oleic, palmitoleic, linoleic, and palmitic acids) of infected avocados for 21 days. Our results validate the potential use of the films FT3 and FT4 to prevent the soft rot caused by C. rosea and to improve the shelf life of Hass avocadoes.

Fungistatic Films Containing Cinnamon Essential Oil: New Coatings to Preserve the Nutraceutical Content of Avocado Fruit against Fusariosis

“…These results were similar to those recently reported for antifungal films made with chitosan and the essential oil of thymus in avocado fruit. [3] Then, the films generated in the present investigation could prevent oxidative damage induced by light. [21] In Situ Antifungal Activity of CvEO Hybrid Films Hybrid films have shown high effectiveness as physical barriers to avoid fungal proliferation.…”

“…The generation of the four hybrid films (FC1 -FC4) was basically performed using the method described in a previous work. [3] For this purpose, CvEO was added at 0.4 % (FC1), 0.7 % (FC2), 1.0 % (FC3), and 1.3 % (FC4) w/ w to the acidic solution of chitosan (1 % w/v). Pure chitosan films (Ch) were used as a reference for physicochemical and fungistatic assays.…”

“…Pure chitosan films (Ch) were used as a reference for physicochemical and fungistatic assays. Fourier-transform-infrared spectroscopy and scanning electronic microscopy were performed using the equipment and conditions reported by Morales-Rabanales et al [9] and Coyotl-Pérez et al [3] For physicochemical tests, each material was analyzed three times (n = 3).…”

“…The films were incubated at 28 °C for 7 d as reported by Morales-Rabanales et al [9] To perform in situ tests, immature avocados were sanitized under sterile conditions to be inoculated with the same number of viable cells (1000 conidia) previously counted using an hemocytometer. The viable cells were inserted into the pericarp of avocadoes as described by Coyotl-Pérez et al [3] The inoculated avocados (n = 100) were grouped in sets of 25 samples to be protected with the four hybrid films (FC1, FC2, FC3, and FC4) and films made with pure chitosan (Ch). Non-treated asymptomatic fruits were used as controls of viability.…”

Cationic Chitooligosaccharide Derivatives Bearing Pyridinium and Trialkyl Ammonium: Preparation, Characterization and Antimicrobial Activities

“…The antifungal activities of the COS and COS derivatives against B. cinerea , G. cingulate and F. oxysporum were tested via the mycelium growth rate method [ 18 ]. In short, compounds were dissolved in deionized water at 10 mg/mL.…”