Effect of Biodegradable Coatings on the Growth of Aspergillus flavus In Vitro, on Maize Grains, and on the Quality of Tortillas during Storage.

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.

Monitoring the infection process of Rhizopus stolonifer on strawberry fruit during storage using films based on chitosan/polyvinyl alcohol/polyvinylpyrrolidone and plant extracts.

Different formulations based on nanoparticles of chitosan-plant extracts were evaluated to detect the infection process from the earliest stage of the fungus Rhizopus stolonifer on strawberry fruit during storage. Chitosan/polyvinyl alcohol (Ch/PVA) and chitosan/polyvinylpyrrolidone (Ch/PVP) films enriched with nanoparticles (NPs) of chitosan blended with plant extracts were prepared. They were placed inside a plastic package containing inoculated fruits and stored at 25 °C for 72 h. The thickness values of the films were in the range of 0.10 to 0.25 mm. All samples showed a maximum absorbance peak of about 300-320 nm; however, the Ch/PVP films enriched with NPs of chitosan and 10% of radish extract had an evident decrease in the optical absorbance as the fungal infection progressed. Additionally, as observed by scanning electron microscopy, the cross-section and surface morphology of films were not modified during storage, and the growth of R. stolonifer was evident after 48 h. Therefore, the Ch/PVP films enriched with chitosan NPs blended with 10% radish extract could be a reliable indicator of this fungus's growth.

Physical-Chemical Evaluation of Active Food Packaging Material Based on Thermoplastic Starch Loaded with Grape cane Extract.

The aim of this paper is to evaluate the physicochemical and microbiological properties of active thermoplastic starch-based materials. The extract obtained from grape cane waste was used as a source of stilbene bioactive components to enhance the functional properties of thermoplastic starch (TPS). The biomaterials were prepared by the compression molding technique and subjected to mechanical, thermal, antioxidant, and microbiological tests. The results showed that the addition of grape cane extract up to 15 wt% (TPS/WE15) did not significantly influence the thermal stability of obtained biomaterials, whereas mechanical resistance decreased. On the other side, among all tested pathogens, thermoplastic starch based materials showed antifungal activity toward Botrytis cinerea and antimicrobial activity toward Staphylococcus aureus, suggesting potential application in food packaging as an active biomaterial layer.

Cactus stem (Opuntia ficus-indica Mill): anatomy, physiology and chemical composition with emphasis on its biofunctional properties.

Cactus stem (Opuntia ficus-indica Mill) is native to Mesoamerica and marketed in different forms such as fresh, frozen or pre-cooked. Worldwide, this vegetable is recognized for its pharmaceutical actions, including its antioxidant, diuretic, anticarcinogenic, anti-inflammatory, anti-diabetic, and anti-hypercholesterolemic properties, as well as their antiviral and antispermatogenic effects. However, not all of these properties have been associated with its chemical composition; therefore, this review aims to present and integrate information available on the physiology and anatomy of cactus stem and its chemical composition, focusing on some of the many factors that determine its biofunctionality. © 2017 Society of Chemical Industry.