RESUMO

The effects of edible monolayer and bilayer chitosan-gelatin coatings on the weight loss, lipid oxidation, color preservation (display-life), and shelf-life of beef steaks during 10 days of retail display (at 4 °C; 12 h light/day) were evaluated. The edible coatings had a homogeneous crack-free surface, with the bilayer films being two times thicker than the monolayer coatings. During storage, the control samples had higher pH values and more weight loss (P < .05) than the coated ones. The coatings effectively retarded (P < .05) lipid oxidation and microbial growth (psychrotrophic bacteria, molds, and yeast), extending the shelf-life from 6 to 10 days. The coatings also significantly prevented metmyoglobin accumulation on the beef surface, as reflected in the maintenance of the CIE color indices and sensorial redness perception throughout storage. These effects were similar for both the monolayer and bilayer films, suggesting that chitosan-gelatin coatings could improve the shelf-life and display-life of beef during retail storage.

Assuntos

RESUMO

The effects of different doses of gamma radiation (0-20kGy) on the color and lipid oxidation of mortadella prepared with increasing nitrite levels (0-300ppm) were evaluated using a central composite rotatable design. Higher radiation doses increased the redox potential, promoted the lipid oxidation and elevating the hue color of the mortadellas. Nevertheless, higher addition of sodium nitrite elevated the residual nitrite content, reduced the lipid oxidation and promoted the increase of redness and the reduce of hue color of the mortadellas, regardless of the radiation dose applied. Nitrite addition had a greater effect than irradiation on the quality parameters evaluated, and even at low levels (∼75ppm), its use decreased the deleterious effects of irradiation at doses as high as 20kGy.

Assuntos

RESUMO

Chitosan gelatin-based coating films were applied to beef steaks, and their effects on color preservation and lipid oxidation during retail display were evaluated. Response surface methodology was used to model and describe the effects of different biopolymer concentrations (0 to 6% gelatin; 0.5 to 1.5% chitosan; and 0 to 12% glycerol based on dry gelatin+chitosan weight) in the coating film for optimizing the best combination for meat application. Film application reduced weight loss and lipid oxidation of the steaks after 5 days of storage, and films with higher gelatin concentrations were more effective. The percentage levels of different myoglobin-redox forms were not affected by coating, but myoglobin oxidation during retail display was reduced and the percentage of deoxymyoglobin increased with the gelatin content of the film. Steak color stability during retail display was promoted by film application; the steaks exhibited a darker, more intensely red color when coated in blends with higher gelatin and chitosan contents. Blends containing between 3% and 6% gelatin, between 0.5% and 1.0% chitosan and 6% glycerol exhibited the best results and provide a promising alternative to the preservation of beef in retail display.

Assuntos

RESUMO

Este trabalho teve como objetivo avaliar os efeitos da aplicação de diferentes doses de irradiação (0, 7,5 e 15kGy) e níveis de nitrito (0, 75 e 150ppm) sobre o índice de TBARS, cor objetiva, concentração residual de nitrito e de pigmentos heme totais (PHT) e nitrosos (PHN) em mortadelas armazenadas sob refrigeração (4°C) por 69 dias. A irradiação aumentou (P<0,05) os valores de TBARS e reduziu (P<0,05) os níveis de nitrito residual no primeiro mês de estocagem, mas pouco afetou os níveis de PHN das amostras. A cor dos produtos formulados com 150ppm de nitrito não foi afetada (P>0,05) pela irradiação. Pôde-se concluir que altas doses de irradiação podem ser aplicadas em mortadelas com mais de 75ppm de nitrito, sem que haja grandes alterações na cor e nas características químicas dos produtos.

The present study was undertaken to evaluate the irradiation doses (0, 7,5 and 15kGy) and nitrite levels (0, 7,5 and 15kGy) effects on the TBARS index, objective color (CIELAB), residual nitrite content and total and nitrous heme pigments in bologna-type sausage during storage (4°C) for 69 days. Irradiation increased (P<0.05) TBARs values and decreased (P<0.05) residual nitrite content in the first month of storage, but had little effects on nitrous heme pigments content. The color of products with 150ppm nitrite added was not affected (P>0.05) by irradiation. Results indicated that high doses of gamma radiation can be applied in bologna-type sausages with 75ppm nitrite added without major changes in color and chemical characteristics.

RESUMO

The effects of mechanically deboned poultry meat (MDPM) and levels of collagen fibers on comminuted, cooked sausage quality characteristics were investigated using the central composite rotatable design of response surface methodology (RSM). Use of collagen fiber as an additive affected the sausage characteristics, but the effect depended on the amount of the MDPM used. While MDPM additions resulted in higher cooking loss and darker and redder frankfurters, the addition of collagen fibers improved cooking yields and contributed to the lightness of the final product. Higher collagen fiber content was also accompanied by a significant increase in frankfurter hardness regardless of the MDPM content. Use of collagen fibers countered the negative effects of MDPM on sausage quality attributes, especially on cooking yields and final product color.

Assuntos