Marali Vilela Dias

Use of allyl isothiocyanate and carbon nanotubes in an antimicrobial film to package shredded, cooked chicken meat

We developed antimicrobial packaging incorporated with allyl isothiocyanate (AIT) and carbon nanotube (CNT), and this packaging was used for shredded cooked chicken meat inoculated with Salmonella Choleraesuis. The following parameters were analysed during the 40 days of storage: microbial counts, colour characteristics and changes in the oxidation of the meat as well as changes in the mechanical properties of the film, the structure of the antimicrobial film and the diffusion of the antimicrobial agent into the food. The incorporation of AIT into the films increased the elongation at the break (E) value of the films and decreased the tensile strength (TS) value of the films. The CNT was important to retain the AIT which is a volatile substance in the film. The diffusion of the AIT from the film into the chicken reduced the microbial contamination, controlled oxidation and reduced the colour changes. Thus, these packages were effective for the 40 days of storage.

Development of chitosan/montmorillonite nanocomposites with encapsulated α-tocopherol.

Nanocomposites of chitosan (CS) were developed and characterized in a full factorial design with varying levels of montmorillonite (MMTNa) and encapsulated tocopherol (toc-encap). The structural properties (XRD, FTIR), morphology (TEM), hygroscopic properties (water vapour permeability, hydrophobicity, sorption isotherms) and optical properties (haze, CIELab parameters) of the resulting materials were evaluated. Toc-encap contents up to 10% influenced the intercalation of MMTNa in the CS matrix, resulting in films with reduced water vapour permeability (3.48×10(-11)(g/msPa)), increased hydrophobicity (ΔGHydroph |7.93-59.54|mJm(-2)) and lower equilibrium moisture content (EMC), thus showing potential for active food packaging materials. At levels above 10%, toc-encap agglomerates occurred, which deteriorated the properties of the resulting films, as shown with the TEM. As the toc-encap content increased, the films became slightly more yellow, more irregular and less transparent, with a higher haze index.

Estudo de variáveis de processamento para produção de doce em massa da casca do maracujá (Passiflora edulis f. flavicarpa)

The use of passion fruit peel as raw material for the preparation of preserves represents a good economic alternative for the use of this residue. The objective of this work was to select the best maceration method for the peel and determine the influence of the variables of juice concentration and soluble solids on the physicochemical, physical, and sensory characteristics of the different formulations. The results indicated that the best formulation was the one obtained using skinless albedo macerated for 24 hours with the addition of 150 mL of passion fruit juice and concentrated to 68oBrix , which presented the yellower color and firmer texture.

Quality evaluation of banana skin extract jellies

Due to the great volume of banana skin resulting from the industrialization of banana and to their high pectin content, the objectives of the present study were to evaluate the effect of the following factors: extract/sugar, pectin and citric acid on the chemical, physical and sensory qualities of the jellies obtained. A complete factorial experimental design was used (23) with 3 central points to evaluate the influence of the factors on the dependent variables, testing the linear models. The chemical properties underwent few alterations and the instrumental and sensory texture attributes were mainly affected by the extract/sugar ratio and the pectin level. The brittleness, elasticity and gumminess increased with increases in the extract/ sugar ratio and pectin level. According to the sensory analysis and the purchasing intention, the best formulations were those obtained using a higher extract/sugar ratio (60/40) and lower pectin level (0.5 g/ 100), combined with the highest (20 mL) or lowest volumes of citric acid (15 mL), with scores for all the attributes in the range from ‘I liked slightly’ to ‘I liked moderately’.

Efeito da adição de suco de maracujá e tempo de cozimento sobre a qualidade de doces do albedo de maracujá em calda

Brazil produces tons of yellow passion fruit skin and seed residues that could be used for human consumption. The objective of this work was to determine the effects of the process parameters (volume of passion fruit juice used and cooking time of the albedos), on the physicochemical properties (pH, soluble solids, titratable acidity and total sugars) of compote prepared with passion fruit skin, and the sensory acceptance by consumers aiming to use the residues produced by food industries. A complete 22 factorial design was used to evaluate the parameters and responses. The sensory acceptance of the preserves was evaluated using a 9-point hedonic scale and buying intention using a 5-point scale. Lower pH values were obtained using larger volumes of juice and longer cooking times, both for the albedo and the preserves. For the albedo, higher values for soluble solids were found with longer cooking times and smaller volumes of juice. The overall results indicated a cooking time longer than 10 minutes and a larger volume of passion fruit juice as the most adequate processing conditions.

Water vapor permeability and tensile properties of poly(l-lactic acid)/synthetic mica nanocomposites prepared by melt blending

Poly(L-lactic acid)/synthetic mica (Somasif) nanocomposites were obtained by melt blending in a mixing chamber according to a factorial experimental design and considering the following variables: temperature, rotor speed, nanofiller concentration and residence time. Relatively high degree of dispersion was attained by the melt processing which generates poly(L-lactic acid)/synthetic mica nanocomposites with particle size even in the order of 40 nm. The tensile properties and the water vapor permeability of these nanocomposites were evaluated. The introduction of synthetic mica into neat poly(L-lactic acid) decreased the water vapor permeability by about 50%. The variables which most affected the tensile properties were the mixing time and clay concentration, but the levels studied or the degree of intercalation/exfoliation were insufficient to significantly improve the tensile properties of poly(L-lactic acid)/somasif mica nanocomposites.

Spraying Cellulose Nanofibrils for Improvement of Tensile and Barrier Properties of Writing & Printing (W&P) Paper

An experimental spray coater was used to coat writing and printing (W&P) paper substrate with cellulose nanofibrils (CNFs) suspensions. The effects of spraying variables (i.e. concentration of suspension, spray pressure, distance and time of spray) on the coated sheets were analyzed in terms of the tensile strength, water vapor transmission rate (WVTR), and oxygen transmission rate (OTR). Basis weight and the thickness of coated layers in the different treatments were measured. In addition, image analysis of the microstructure examined the coating adhesion. The WVTR of the papers decreased, while tensile strength increased with one layer of CNF coating. The OTR was not changed with the CNF coating. The tensile strength and microstructure images of the coated papers indicate good adhesion between the CNF coating and the paper substrate when using the spray coater.

Effect of whey protein isolate films incorporated with montmorillonite and citric acid on the preservation of fresh-cut apples

The objective of this paper was to evaluate the effect of bioactive whey protein isolate/montmorillonite films containing citric acid on the inhibition of enzymatic browning and physicochemical properties in minimally processed apples. Whey protein isolate films incorporated with montmorillonite (3 g/100 g) and citric acid (5 and 10 g/100 g) were applied to the apples slices. All samples were packaged in polypropylene trays (14.6 cm × 11.4 cm × 6.5 cm) and stored at 5 ± 2 °C and 85 ± 3% RH for eight days. Every two days, the apples samples were evaluated for color, acidity, pH, soluble solids, water activity and polyphenol oxidase and peroxidase enzyme activity. The enzymatic browning of the apples slices was reduced for all films during storage. However, the films containing citric acid maintained the color characteristics, reducing the loss of quality associated the maintenance of acidity, soluble solids, water activity, reduction of polyphenol oxidase and peroxidase activity, thus prolonging the shelf life of the apples.

Optical and structural properties of biodegradable whey protein isolate nanocomposite films for active packaging

ABSTRACT Films of whey protein isolate/sodium montmorillonite/citric acid nanocomposites were developed by casting. The objective of this study was to evaluate the effect of the sodium montmorillonite clay (MMT) and citric acid (CA) content on the water vapor barrier, optical, morphological and structural properties of whey protein isolate (WPI) films. The interaction between MMT (3 g/100 g of WPI) and CA (5 g/100 g of WPI) showed lower water vapor permeability (WVP). The addition of CA and MMT caused small alterations in the optical properties without affecting appearance, in more opaque films, in relation to the WPI. The scanning electron microscopy (SEM) showed possible dispersion results for films with 1% MMT, and 5 and 10% CA. Infrared Spectroscopic peaks (FTIR) showed interaction between CA, MMT and WPI.

Processability, morphology and thermal behavior of poly(lactic acid)/synthetic mica nanocomposites obtained by melt blending

Poly(lactic acid)/synthetic mica nanocomposites were obtained by melt blending in an internal mixer in an investigation designed by experimental factorial planning. The results indicated that low speeds and temperatures favoured intercalation. In the range of concentrations tested (3–7 wt%), the added mica did not act as a nucleating agent, and it produced no significant change in the thermal properties of the poly(lactic acid). The thermogravimetric analyses suggested that temperatures below 190℃ and short mixing times (<10 min) promoted better dispersion of the synthetic mica in the matrix nanocomposite.