Microstructural and physicochemical quality maintenance in green bell pepper infected with Botrytis cinerea and treated with thyme essential oil combined with carnauba wax.

Bell pepper presents rapid weight loss and is highly susceptible to gray mold caused by the fungus Botrytis cinerea. The most employed method to control this disease is the application of synthetic fungicides such as thiabendazole (TBZ); however, its continued use causes resistance in fungi as well as environmental problems. For these reasons, natural alternatives arise as a more striking option. Currently, bell pepper fruits are coated with carnauba wax (CW) to prevent weight loss and improve appearance. Moreover, CW can be used as a carrier to incorporate essential oils, and previous studies have shown that thyme essential oil (TEO) is highly effective against B. cinerea. Therefore, this study aimed to evaluate the effect of CW combined with TEO on the development of gray mold and maintenance of microestructural and postharvest quality in bell pepper stored at 13°C. The minimal inhibitory concentration of TEO was 0.5%. TEO and TBZ provoked the leakage of intracellular components. TEO and CW + TEO treatments were equally effective to inhibit the development of gray mold. On the quality parameters, firmness and weight loss were ameliorated with CW and CW + TEO treatments; whereas lightness increased in these treatments. The structural analysis showed that CW + TEO treatment maintained the cell structure reducing the apparition of deformities. The results suggest that CW + TEO treatment could be used as a natural and effective antifungal retarding the appearance of gray mold and maintaining the postharvest quality of bell pepper. PRACTICAL APPLICATION: CW and TEO are classified as generally recognized as safe (GRAS) by the US Food and Drug Administration (FDA). This combination can be employed on the bell pepper packaging system to extend shelf life and oppose gray mold developments. Bell pepper fruits are normally coated with lipid-base coatings such as CW before commercialization; therefore, TEO addition would represent a small investment without any changes on the packaging system infrastructure.

Chitosan as an Outstanding Polysaccharide Improving Health-Commodities of Humans and Environmental Protection.

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.

Caprylic acid in Vitex mollis fruit and its inhibitory activity against a thiabendazole-resistant Colletotrichum gloeosporioides strain.

BACKGROUND: Colletotrichum gloeosporioides causes anthracnose in a large number of crops. Synthetic fungicides are employed to prevent this disease, even though their effectiveness and safety is questionable. Thus, effective and innocuous antifungal compounds are proposed as natural alternatives against anthracnose. The hexane fraction of Vitex mollis pulp (HF-VM) reduces anthracnose incidence in papaya fruit; however, the active compounds and antifungal mechanism of HF-VM are unknown. The aims of this study were to characterize the activity of HF-VM sub-fractions (sHF1 -sHF7 ) against a thiabendazole-resistant Colletotrichum gloeosporioides strain, identify the chemical components and investigate the mechanism of the most active sub-fraction. RESULTS: The sHF3 showed the highest inhibitory activity against Colletotrichum gloeosporioides with a minimal inhibitory concentration (MIC) of 0.5 mg mL-1 , whereas thiabendazole (TBZ) had a MIC value higher than 2 mg mL-1 . The gas chromatography-mass spectrometry (GC-MS) analysis showed that the compounds in sHF3 were methyl 4-decenoate, caprylic acid, and 24-methylencycloartanol. These compounds are rarely found in fruits and are reported for the first time on Vitex species. The purified 24-methylencycloartanol was inactive (MIC > 0.5 mg mL-1 ). In contrast, the commercial standard of caprylic acid presented an elevated activity (MIC = 0.125 mg mL-1 ), indicating that this compound is the main one responsible for the antifungal properties of sHF3 . Furthermore, the sHF3 inhibited the spore germination and induced membrane disruption in both the spore and mycelium of Colletotrichum gloeosporioides. CONCLUSION: Vitex mollis fruit is a novel source of antifungal caprylic acid that could be employed as a marker to prepare standardized extracts with antifungal properties. © 2022 Society of Chemical Industry.

Cell wall stabilization and calcium absorption on mango fruit treated with a quarantine hot water treatment combined with calcium salts and stored at chilling temperature.

Hot water treatment (HT) induces chilling injury (CI) tolerance in mango, but prolonged exposure to HT causes softening. In this sense, calcium salts stabilize the cell wall. Nevertheless, there is little information on the effect of HT combined with calcium salts (HT-Ca) on calcium absorption and cell wall stability during storage of mango at CI temperature. We evaluated the effect of quarantine HT in combination with calcium chloride (CaCl2 ), calcium citrate (CaCit), or calcium lactate (CaLac) on calcium absorption, CI tolerance, and cell wall stabilization. HT and HT-CaCl2 had the lowest CI development. HT increased firmness loss and electrolyte leakage, and HT-Ca counteracted this effect. Overall, HT-Ca treatments had a similar effect on the cell wall degrading enzymes. HT-CaCl2 was the best treatment and did not present alterations on the epicuticular wax as observed on HT. HT-CaCl2 is a useful technology to stabilize cell wall and preserve mango during chilling storage. PRACTICAL APPLICATIONS: The addition of calcium salts in an established hot water quarantine procedure for mango exportation represents a viable alternative to counteract the negative effects of this thermal treatment upon cell microstructure, maintaining its positive effect of tolerance to chilling injury. In this sense, mango producers and packers can use a HT-CaCl2 treatment to reduce the presence of chilling injury and extent the fruit shelf life and improve its commercialization. Furthermore, technical and infrastructure changes are not necessary for the packaging chain.

Phenolic profile associated with chilling tolerance induced by the application of a hot water treatment in bell pepper fruit.

Hot water treatment (HT) has proved to alleviate chilling injury (CI) in bell pepper and other Solanaceae species, this has been associated with the presence of metabolites such as sugars and polyamines, which protect the plasmatic membrane. However, it is unknown if the phenolic compounds in bell pepper play a role in the CI tolerance induced by the application of a HT. The aim of this study was to identify the specific phenolics associated with induced CI tolerance in bell pepper by HT (53 °C, 1 to 3 min). Fruit treated for 1 min (HT-1 min) exhibited CI tolerance (the lowest symptom development, electrolyte leakage, and vitamin C loss) and was the chosen treatment for further experiments. The phenolic composition was affected by HT-1 min and CI. Phenolics presented a strong correlation with the antioxidant activity. In fruit with CI tolerance, the concentration of seven compounds was increased, being quercetin-O-rhamnoside-O-hexoside and chlorogenic acid the most remarkable. Quercetin-3-O-rhamnoside was accumulated only in fruit with induced tolerance, meanwhile orientin was particularly sensitive to heat and cold exposure. Thus, HT-1 min (53 °C, 1 min) is a useful technology to induce CI tolerance in bell pepper and such tolerance is associated with the phenolic composition that may reduce the prevalence of oxidative stress during the storage under CI conditions. PRACTICAL APPLICATION: Phenolics induced by CI and HT may be useful to detect early stages of heat and chilling injuries in bell pepper and prevent the negative effect of such stresses even before its harvest and during commercial storage. Additionally, the phenolics associated with CI tolerance may be used as markers in breeding programs to create new chilling resistant cultivars.

Effectiveness of hydrothermal-calcium chloride treatment and chitosan on quality retention and microbial growth during storage of fresh-cut papaya.

Rapid degradation of fresh-cut papaya limits its marketability. Hydrothermal treatments in combination with a calcium dip, applied to whole fruit before slicing, and also the application of chitosan as a coating film, have been found to have very good results in maintaining the quality of fresh-cut fruits. Based on these considerations, the aim of this study was to evaluate the effect of hydrothermal treatment (HT; 49 °C, 25 min) containing calcium chloride (Ca; 1%, w/v) followed by dipping in chitosan (Chit; 1%, w/v, 3 min) on the physical, chemical, and microbial qualities of papaya slices stored at 5 °C for 10 d. Pulp color, firmness, ascorbic acid, total phenolics, ß-carotene, and lycopene were evaluated every 2 d while the microbial quality (mesophilics, psychrophilics, molds, and yeasts) was evaluated every 5 d. Fruit treated with HT-Ca and HT-Ca + Chit showed better color and firmness retention than Control and Chit. Papaya slices treated with HT-Ca + Chit had higher nutritional content and lower microbial growth at the end of storage. The application of the HT-Ca + Chit could be used to reduce deterioration processes, maintaining physical, chemical, and microbial qualities and increasing the shelf life of fresh-cut papaya stored at 5 °C.