RESUMO
The packaging nets used for bell peppers act as a form of protection. However, the manufacturing is based on polymers that cause serious environmental problems. The effects of nets made of biodegradable materials, such as poly(lactic) acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), and cactus stem residues, were evaluated on four different colors of 'California Wonder' bell peppers stored over a 25-day storage period under controlled and ambient temperature conditions. Compared to commercial polyethylene nets, the bell peppers kept in the biodegradable nets did not show notable differences with respect to color, weight loss, total soluble solids, and titratable acidity. However, there were significant differences (p < 0.05) in terms of phenol content, carotenoids (orange bell peppers), anthocyanins, and vitamin C, with an overall tendency to show a higher content in those kept in PLA 60%/PBTA 40%/cactus stem flour 3% compared to commercial packaging. In addition, the same net notably reduced the development of bacteria, fungi, and yeasts during the storage of red, orange, and yellow bell peppers. As postharvest packaging for bell peppers, this net could be considered a viable option for the storage of this product.
RESUMO
For sale in the domestic market, Hass avocados are kept in non-biodegradable plastic nets and stored at an ambient temperature. The fungus Colletotrichum gloeosporioides can cause important losses at this stage. Consequently, formulations based on polylactic acid (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) 60/40 biodegradable blends added with pine essential oil (PEO) at 10, 12, 14, and 20% and coated with 1% chitosan (CH) were used for the elaboration of nets, which were evaluated on C. gloeosporioides and Rhizopus stolonifer on nutrient media and fruit and on the ripening behavior of Hass avocados at ambient temperature. The spore germination stage of C. gloeosporioides was the most extensively damaged (78% inhibition). The incidence of anthracnose was notably reduced by almost 80% in the avocados stored in the 60/40 PLA/PBAT nets coated with 1% CH. The overall values regarding weight loss, °Brix, and dry matter were c.a. 23.5%, 7.5, and 24.5%, respectively. The changes in firmness, color, and CO2 production were particularly associated with the initial harvest index and storage temperature rather than with the nets. In future research, essays on nets should include evaluations at the commercial levels.
RESUMO
The fungus Aspergillus flavus causes serious damage to maize grains and its by-products, such as tortilla. Currently, animal and plant derivatives, such as chitosan and propolis, and plant extract residues, respectively, are employed as alternatives of synthetic fungicides. The objective of this research was to evaluate the efficacy of several formulations based on propolis-chitosan-pine resin extract on the in vitro growth of A. flavus, the growth of maize grain plantlets and the quality of stored tortillas at 4 and 28 °C. The most outstanding formulation was that based on 59.7% chitosan + 20% propolis nanoparticles + 20% pine resin extract nanoparticles; since the in vitro conidia germination of A. flavus did not occur, disease incidence on grains was 25-30% and in tortillas, 0% infection was recorded, along with low aflatoxin production (1.0 ppb). The grain germination and seedling growth were markedly reduced by the nanocoating application. The percentage weight loss and color of tortillas were more affected by this coating compared to the control, and the rollability fell within the scale of non-ruptured at 4 °C and partially ruptured at 28 °C. The next step is to evaluate the toxicity of this formulation.
