No abstract

The aim of this study was to produce ascorbic acid (AA) microcapsules by complex coacervation, characterize them, and evaluate the release profile in simulated gastrointestinal fluids. The microcapsules were made of gelatin and pectin at concentrations of 1.0, 2.0, and 3.0%. The coacervated microcapsules were assessed for morphology (by optical microscopy and scanning electron microscopy), water activity (Aw), hygroscopicity, solubility, encapsulation efficiency (EE), thermal behavior, and AA release profile. The AA microcapsules were characterized by low solubility, low hygroscopicity, high thermal stability, and low diameter (<10 μm), with EE ranging from 23.7 to 94.3%. The release profile was faster in gastric fluid (pH 1.8) than in intestinal fluid (pH 6.8). The sample containing 2.0% of wall material and 50% (w/w) of the simple emulsion (core) had the highest EE and the best in vitro release profile, with release of only 68% of AA in 120 min in the gastric fluid. Practical applications Ascorbic acid (AA) is widely used in the food industry as an antioxidant, but practical use becomes limited due to its high instability. Microencapsulation was proposed as an alternative to increase the stability of this compound. Gelatin and pectin were used as wall materials in the production of ascorbic acid microcapsules by complex coacervation. Both solubility and hygroscopicity were low while the thermal stability of the active material improved with the microencapsulation process. Ascorbic acid release was more pronounced in gastric fluid (pH 1.8) and slower in intestinal fluid (pH 6.8). The results of this study demonstrate that the microcapsules produced represent a feasible method of increasing AA availability in food products, especially for those samples that presented high encapsulation efficiency.

O mel é um alimento muito apreciado, em função do seu sabor característico e do seu considerável valor nutritivo. Sua qualidade nutricional, devida à presença de vitaminas e minerais, seu valor energético elevado, suas propriedades medicinais, como a ação antioxidante e a atividade anti-séptica, e suas propriedades sensoriais têm atraído inúmeros consumidores. Todos os fatores químicos e físicos fazem com que as propriedades terapêuticas do mel sejam únicas, sendo utilizado como um potente agente antimicrobiano. O objetivo deste trabalho foi avaliar a ação antimicrobiana de méis (n=13) comercializados na região dos Campos Gerais - Paraná. A atividade antimicrobiana revelou um comportamento variável, tanto no que se refere à sensibilidade dos microrganismos (Staphylococcus aureus e Escherichia coli), quanto ao poder antimicrobiano das amostras testadas.

Galacto-oligosaccharides are compounds that are synthesized from lactose containing two to five galactose units and a terminal glucose residue. They are formed from lactose by the transgalactosylation activity of the enzyme β-galactosidase. During the galactooligosaccharides synthesis are formed significant amounts of glucose and galactose, products that are considered reaction inhibitors. This work aims to produce and partly purify galacto-oligosaccharides using sequential fermentation. Galacto-oligosaccharides were produced using Aspergillus oryzae ATCC 11488 by solid-state fermentation (first part); Saccharomyces cerevisiae was used for the selective removal of the monosaccharides from the GOS mixture, (second part). The substrate for the solid-state fermentation was moistened wheat bran with a solution of 2% (w/v) lactose whey permeate. For the production of the galacto-oligosaccharides, a solution of 25% (w/v) lactose whey permeate was used. Enzymatic activity of β-galactosidase was determined using o-nitrophenylgalactopyranoside as substrate. β-galactosidase maximum activity was 0.43 U mL-1 , obtained in 96 hours of solid-state fermentation. Galacto-oligosaccharide yield was 13.7%, area percentage of glucose and galactose was 13.76%, and 7.93% respectively, after 24 hours of fermentation at 40 °C and pH 5.9. After sequential fermentation, 85% of glucose was removed in 48 hours of fermentation and a 63% increase in the area percentage of galacto-oligosaccharides after 60 hours of fermentation. It was shown that sequential fermentation can be used in the partial purification of mixtures of carbohydrates, which facilitates the subsequent separation stages.