Thermal and irradiation resistance of folic acid encapsulated in zein ultrafine fibers or nanocapsules produced by electrospinning and electrospraying.

The objectives of this study were to characterize zein fibers and capsules prepared by electrospinning and electrospraying techniques, respectively, and then use them to encapsulate folic acid. Folic acid containing fibers and capsules (0.5, 1.0, and 1.5%, w/v) were submitted to thermal treatment (100, 140, and 180 °C) and ultraviolet A light (UVA) irradiation to evaluate the resistance of folic acid. Zein fibers and capsules containing folic acid showed high encapsulation efficiency (>80%). Unencapsulated folic acid showed a reduction in folic acid content from 17.17 µg/mL to 5.44 µg/mL (approximately 70%) when exposed to 180 °C. Photodegradation of unencapsulated folic acid lowered its concentration from 17.17 µg/mL to 12.58 µg/mL (~26% of reduction), when exposed for 1 h to UVA irradiation. However, folic acid concentration when encapsulated in fibers (1.5%) was maintained or only slightly reduced from 9.73 µg/mg to 8.88 µg/mg after thermal treatment at 180 °C. The capsules containing 1.5% of folic acid also presented a slight reduction in folic acid concentration from 8.84 µg/mg to 7.88 µg/mg when exposed to 24 h of UVA irradiation. Zein fibers and capsules containing folic acid present promising characteristics for application in foods that require thermal processing or exposure to irradiation.

Ultrafine fibers of zein and anthocyanins as natural pH indicator.

BACKGROUND: pH-sensitive indicator membranes, which are useful for pharmaceutical, food, and packaging applications, can be formed by encapsulating halochromic compounds within various solid supports. Accordingly, electrospinning is a versatile technique for the development of these indicators, by entrapping pH dyes within ultrafine polymer fibers. RESULTS: The ultrafine zein fibers, containing 5% (w/v) anthocyanins, had an average diameter of 510 nm. The pH-sensitive membrane exhibited color changes from pink to green when exposed to acidic and alkaline buffers, respectively. The contact angle was negligible after 10 and 2 s for neat and 5% anthocyanin-loaded zein membranes, respectively. CONCLUSION: The pH membranes exhibited color changes in a board pH range, which can potentially be used in various active packaging applications. © 2017 Society of Chemical Industry.

Acetylated rice starches films with different levels of amylose: Mechanical, water vapor barrier, thermal, and biodegradability properties.

Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films.

Antioxidant activity and enzyme inhibition of phenolic acids from fermented rice bran with fungus Rizhopus oryzae.

The solid-state fermentation (SSF) has been employed as a form making available a higher content of functional compounds from agroindustrial wastes. In this work, the effect of SSF with the Rhizopus oryzae fungus on the phenolic acid content of rice bran was studied. Phenolic extracts derived from rice bran and fermented rice bran were evaluated for their ability to reduce free radical 1,1-diphenyl-2-picrihidrazil (DPPH) and for the ability to inhibit the enzymes peroxidase and polyphenol oxidase. The phenolic compound content increased by more than two times with fermentation. A change in the content of phenolic acids was observed, with ferulic acid presenting the greatest increase with the fermentation, starting from 33µg/g in rice bran and reaching 765µg/g in the fermented bran. [corrected]. The phenolic extracts showed an inhibition potential for DPPH and for the peroxidase enzyme, however did not inhibit the polyphenol oxidase enzyme.

Assessment of the antifungal activity of Spirulina platensis phenolic extract against Aspergillus flavus / Avaliação da atividade antifúngica de extrato fenólico de Spirulina platensis contra Aspergillus flavus

The production of safe food has stimulated the search for natural substances that possess antifungal activity. The indirect methods of estimating fungal biomass are based on the measurement of glucosamine, ergosterol and protein - typical compounds produced during the development of biomass. The aim of the study was to assess the effect of the phenolic extract from Spirulina platensis on the production of structural compounds in Aspergillus flavus, in order to identify its action on fungal inhibition. The Spirulina platensis methanolic extracts presented 1.15 mg phenolic compound/g Spirulina platensis, which showed an antifungal effect against Aspergillus flavus, inhibiting the glucosamine production up to 56 percent. Therefore, it may be employed as natural defense when food protection is necessary.

A produção de alimentos seguros tem estimulado a busca por substâncias naturais que possuem atividade antifúngica. Os métodos indiretos de estimativa de biomassa fúngica são baseados na medição de glucosamina, ergosterol e proteína - compostos típicos produzidos durante o desenvolvimento da biomassa. Neste estudo, objetivou-se avaliar o efeito do extrato fenólico de Spirulina platensis na produção de componentes estruturais em Aspergillus flavus, a fim de identificar seu mecanismo de ação dos fenóis na inibição fúngica. O extrato metanólico de Spirulina platensis apresentou 1,15 mg de compostos fenólicos/g Spirulina platensis, apresentando um efeito antifúngico contra Aspergillus flavus, inibindo a produção de glucosamina em até 56 por cento. Portanto, pode ser empregado como antifúngico natural quando for necessária a proteção de alimentos.