Development of a Halochromic, Antimicrobial, and Antioxidant Starch-Based Film Containing Phenolic Extract from Jaboticaba Peel.

In this study, the antioxidant, antimicrobial, mechanical, optical, and barrier attributes of Solanum lycocarpum starch bio-based edible films incorporated with a phenolic extract from jaboticaba peel were investigated. Aiming to determine the effect of the polymers and the phenolic extract on the properties of the films, a three-factor simplex-lattice design was employed, and the formulation optimization was based on the produced films' antioxidant potential. The optimized formulation of the starch-PEJP film showed a reddish-pink color with no cracks or bubbles and 91% antioxidant activity against DPPH radical. The optimized starch-PEJP film showed good transparency properties and a potent UV-blocking action, presenting color variation as a function of the pH values. The optimized film was also considerably resistant and highly flexible, showing a water vapor permeability of 3.28 × 10-6 g m-1 h-1 Pa-1. The microbial permeation test and antimicrobial evaluation demonstrated that the optimized starch-PEJP film avoided microbial contamination and was potent in reducing the growth of Escherichia coli, Staphylococcus aureus, and Salmonella spp. In summary, the active starch-PEJP film showed great potential as an environmentally friendly and halochromic material, presenting antioxidant and antimicrobial properties and high UV-protecting activity.

Nanofibrillated Cellulose-Based Aerogels Functionalized with Tajuva (Maclura tinctoria) Heartwood Extract.

Aerogels are 3-D nanostructures of non-fluid colloidal interconnected porous networks consisting of loosely packed bonded particles that are expanded throughout their volume by gas and exhibit ultra-low density and high specific surface area. Cellulose-based aerogels can be obtained from hydrogels through a drying process, replacing the solvent (water) with air and keeping the pristine three-dimensional arrangement. In this work, hybrid cellulose-based aerogels were produced and their potential for use as dressings was assessed. Nanofibrilated cellulose (NFC) hydrogels were produced by a co-grinding process in a stone micronizer using a kraft cellulosic pulp and a phenolic extract from Maclura tinctoria (Tajuva) heartwood. NFC-based aerogels were produced by freeze followed by lyophilization, in a way that the Tajuva extract acted as a functionalizing agent. The obtained aerogels showed high porosity (ranging from 97% to 99%) and low density (ranging from 0.025 to 0.040 g·cm-3), as well a typical network and sheet-like structure with 100 to 300 µm pores, which yielded compressive strengths ranging from 60 to 340 kPa. The reached antibacterial and antioxidant activities, percentage of inhibitions and water uptakes suggest that the aerogels can be used as fluid absorbers. Additionally, the immobilization of the Tajuva extract indicates the potential for dentistry applications.

Bioactive compounds in Mexican genotypes of cocoa cotyledon and husk.

A characterization of the phenolic profile of 25 cocoa genotypes established in a Mexican gene bank was carried out. From five different extraction methods commonly used for phenols, extraction with acidified methanol-water was chosen as the best to quantify the concentrations of theobromine and individual phenols in cocoa beans. High concentrations of individual and total phenols were found for genotypes native to Mexico (like RIM105, M031, and M033) or from Peru and Ecuador (INI10), but not the commercial mix (CAF), and were directly associated with their antioxidant activities. Despite the loss of some theobromine and phenols during fermentation, epicatechin remained in the fermented cotyledon in high concentrations. This study could help promote the commercialization of Mexican genotypes of cocoa and reports the possibility of upcycling fermented cocoa husks, which are rich in bioactive compounds and fiber, as novel functional extracts for use in food formulation or for nutraceutical purposes.

Effect of natural compounds on Fusarium graminearum complex.

BACKGROUND: A search is underway for new solutions to counter farm loss caused by fungal contamination of grains, since the active agents of fungicides can remain in the environment and contribute to the development of resistant and toxigenic species. In this study, the antifungal activity of natural compounds (γ-oryzanol, phenolic extract of neem seeds and of rice bran) was assessed on three toxigenic strains of Fusarium graminearum isolated from wheat, rice and barley. Their efficacy was compared to that of synthetic fungicides. The halo diameters were measured and the susceptible pathways were determined by the levels of structural compounds and activities of enzymes involved in the primary metabolism of the microorganisms. Moreover, mycotoxin production and gene expression were examined. RESULTS: Phenolic extracts were more effective at inhibiting F. graminearum than was γ-oryzanol, as evidenced by the minimum inhibitory concentration. This work contributed to the elucidation of the mechanism of action of natural antifungal agents. CONCLUSION: Natural antifungals effectively inhibited fungal growth, especially via the inactivation of the enzymatic systems of F. graminearum. Natural antifungals inhibited mycotoxin production by the fungi. A correlation between the levels of deoxynivalenol and the expression of Tri5 gene was observed, indicating that the natural compounds could be considered alternatives to synthetic antifungals. © 2015 Society of Chemical Industry.

Solid-state fermentation for the enrichment and extraction of proteins and antioxidant compounds in rice bran by Rhizopus oryzae

The objective of this work was to evaluate the solid-state fermentation with Rhizopus oryzae CCT 7560 of rice bran for the enrichment of proteins and the antioxidant compounds in the fermented biomass. Fermentation was performed in tray bioreactors at 30ºC for 120 h. Protein extraction was done at alkaline pH, followed by precipitation with acetone. Phenolic compounds were extracted with cold methanol. The maximum protein was recovered from after 120 h (26.6%). The content of total phenolic compounds increased during the fermentation and was maximum after 96 h, which inhibited the DPPH radical by 87%. The promising characteristics of the protein and phenolic extracts of the biomass suggested the application in the coating composition for vegetal tissues preservation.