Public health, production and preservation of food, development of environmentally friendly (cosmeto-)textiles and plastics, synthesis processes using green technology, and improvement of water quality, among other domains, can be controlled with the help of chitosan. It has been demonstrated that this biopolymer exhibits advantageous properties, such as biocompatibility, biodegradability, antimicrobial effect, mucoadhesive properties, film-forming capacity, elicitor of plant defenses, coagulant-flocculant ability, synergistic effect and adjuvant along with other substances and materials. In part, its versatility is attributed to the presence of ionizable and reactive primary amino groups that provide strong chemical interactions with small inorganic and organic substances, macromolecules, ions, and cell membranes/walls. Hence, chitosan has been used either to create new materials or to modify the properties of conventional materials applied on an industrial scale. Considering the relevance of strategic topics around the world, this review integrates recent studies and key background information constructed by different researchers designing chitosan-based materials with potential applications in the aforementioned concerns.

Fresh-cut mango is in high demand in developed countries; however, it deteriorates quickly and represents a suitable medium for microbial growth during storage. Chitosan coatings and other natural materials, such as essential oils, have been used to lessen these issues. The aim of this study was to evaluate the effect of chitosan (CH), mint essential oil (MEO) and their combination (CH+MEO) on the microbiological incidence, content of bioactive compounds, and antioxidant capacity of fresh-cut mango stored during 15 d at 5 °C. Microbiological analyses (mesophilics, psychrophilics, molds, and yeasts) were evaluated after 0, 7 and 15 d of storage. Physical (color and firmness) and chemical (total soluble solids, titratable acidity, ascorbic acid, phenols, β-carotene, and antioxidant capacity) analyses were performed every 3 d. The applied treatments successfully reduced microbial growth with the same intensity, furthermore, none of them caused significantly negative effects on color, firmness, total soluble solids, titratable acidity, and ascorbic acid. However, the highest total phenolics and β-carotene contents were obtained by CH+MEO, while fruit treated with CH and CH+MEO had the highest antioxidant capacity. The application of CH+MEO could be used to reduce its microbial load while increasing bioactive compounds and antioxidant capacity of fresh-cut mango.

The susceptibility to chilling injury and its relationship with changes in the phenolic compounds content and antioxidant capacity were evaluated in five mango cultivars (Ataulfo, Haden, Keitt, Kent, and Tommy Atkins) with export quality. The chilling injury index (CII), postharvest quality (color, firmness, and total soluble solids (TSS)), bioactive compounds (total phenolic, and total flavonoids), and antioxidant capacity (ABTS, DPPH, and ORAC) were determined during storage at chilling (5 ºC) and non-chilling temperature (13 °C) plus 7 days at ripening (21 °C). Ataulfo cultivar showed the lowest CII, and the best color retention and higher TSS content, but the lowest firmness and the highest accumulation of phenolics, flavonoids, and antioxidant capacity during the ripening period, in both storage temperature. In contrast, Keitt cultivar presented the highest CII, especially to 21 °C, showing the highest firmness and the lowest TSS. The bioactive compounds and antioxidant capacity were low. Kent showed the lowest content of bioactive compounds and antioxidant capacity. Tommy Atkins presented the lowest luminosity and Hue angle values but similar behavior to Haden in the rest of parameters. This indicates that the increase in bioactive compounds, especially flavonoids, improves antioxidant capacity and could generate greater tolerance to CI. Therefore, Ataulfo could be stored at low temperatures, extending its commercial life and regular ripening, while Keitt should not be stored at low temperatures due to susceptibility and irregular ripening.

Papaya fruits have a high content of bioactive compounds that provide them high antioxidant capacity; however, these fruits undergo rapid deterioration processes once harvested, which implies a decrease in antioxidant activity. In order to reduce the oxidative stress that causes deterioration in the fruit, it is important to use technologies to increase the antioxidant system of the fruit. In that sense, the aim of this work was to evaluate the effect of a hydrothermal treatment (HT), calcium chloride (CaCl ₂ ), and their combination (HT‐CaCl ₂ ) on the physicochemical quality and the enzymatic and nonenzymatic antioxidant systems of papaya fruits. Harvested papaya was treated with HT (48°C, 25 min), CaCl ₂ (1% w/v), and the combination HT‐CaCl ₂ followed by storage at 12°C for 20 days. Physicochemical quality (weight loss, external color, and firmness), bioactive compounds (ascorbic acid [AA], total phenolics, and carotenoid content), antioxidant capacity (ABTS and DPPH), and the activity of antioxidant system enzymes (peroxidase [POD] and ascorbate peroxidase [APX]) were evaluated. In this regard, HT‐CaCl ₂ was the most effective treatment in controlling weight loss, preserving the external fruit color, and maintaining the firmness. Furthermore, HT‐CaCl ₂ boosted the fruit antioxidant properties by maintaining the amount of ascorbic acid and increasing total phenolics and carotenoids. Thus, fruits treated with HT‐CaCl ₂ showed a higher antioxidant capacity as well as increased activity of the enzymes of the antioxidant system. In general, HT‐CaCl ₂ can be used as an effective treatment to enhance antioxidant properties by maintaining bioactive compounds and increasing antioxidant enzymes, as well as maintaining the physicochemical quality of papaya fruits.