Cristiana M. P. Yoshida

Aplicação de filmes proteicos à base de soro de leite

The efficiency of whey protein films packaging was evaluated. The packaging system consisted of whey protein films closing the top extremity of synthetic plastic container. Slices of apple were packed and stored at room temperature (25 °C) and at 10 °C. Modified atmosphere packaging (N2 gas flushing) was studied to verify the oxygen permeability of the films. Whey protein films (6.5% of protein, 3.0% of glycerol, and pH 7.0) were obtained by thermal denaturation, emulsification (0.5% (w/w) with stearic acid), and enzymatic modification (10U/g protein of transglutaminase, ACTIVA-TG). Mechanical properties (tensile strength and elongation at break), water vapor permeability, and coloropacity properties of different films were evaluated. The film integrity was observed during the packaging and storage processing associated to the good mechanical properties. The water vapor permeability was evaluated by weight loss, moisture content, and texture profile of apple slices. The results showed that the whey protein films presented a moderated moisture barrier if compared with systems with no covering. The browning of the apple slices was investigated associated to the polyphenoloxidase action in presence of oxygen.

Electrostatic Self-Assembled Chitosan-Pectin Nano- and Microparticles for Insulin Delivery

A polyelectrolyte complex system of chitosan-pectin nano- and microparticles was developed to encapsulate the hormone insulin. The aim of this work was to obtain small particles for oral insulin delivery without chemical crosslinkers based on natural and biodegradable polysaccharides. The nano- and microparticles were developed using chitosans (with different degrees of acetylation: 15.0% and 28.8%) and pectin solutions at various charge ratios (n+/n− given by the chitosan/pectin mass ratio) and total charge. Nano- and microparticles were characterized regarding particle size, zeta potential, production yield, encapsulation efficiency, stability in different media, transmission electron microscopy and cytotoxicity assays using Caco-2 cells. The insulin release was evaluated in vitro in simulated gastric and intestinal media. Small-sized particles (~240–~1900 nm) with a maximum production yield of ~34.0% were obtained. The highest encapsulation efficiency (~62.0%) of the system was observed at a charge ratio (n+/n−) 5.00. The system was stable in various media, particularly in simulated gastric fluid (pH 1.2). Transmission electron microscopy (TEM) analysis showed spherical shape particles when insulin was added to the system. In simulated intestinal fluid (pH 6.8), controlled insulin release occurred over 2 h. In vitro tests indicated that the proposed system presents potential as a drug delivery for oral administration of bioactive peptides.

Biodegradability Kraft Paper Coated with Films Emulsified Chitosan and Palmitic Acid

The use of natural polymers is an alternative to polymers derived from petroleum that may reduce industrial waste and contribute to the environmental protection. Following the same reasoning, the biodegradability of paper packaging is already known for it being a product originated from cellulosic materials (cellulosic fibers). The aim of this work was to assess the process of degradation from the junction of two different materials; biopolymer and sheets of paper. This paper proposes the study of the biodegradability of chitosan film-coated Kraft paper sheets and emulsified chitosan film-coated Kraft paper sheets added with palmitic acid, both in comparison with uncoated Kraft paper sheets. The biodegradability study was conducted based on analyses of biofilm formation by Scanning Electron Microscopy (SEM), soil respiration, Gravimetry, Microbial Biomass Carbon and enzymatic soil activity and evaluation.