Revestimento comestível para comercialização de carne bovina refrigerada

Abstract

The aim of this work was study and evaluate the effects of applying edible coatings based on gelatin and chitosan in mono and double layers for maintaining the quality of beef stored under refrigeration (4 ± 1 ºC for 8 days) to simulate the storage conditions in the counter service. In every two days throughout the duration of storage, tests were carried out in weight loss, PH, peroxide value, thiobarbituric acid reactive substances (TBARS), relative myoglobin pigments (O2Mb, Mb+ and MMb), oxygen consumption rate (OCR), metmyoglobin reductase activity (MRA), microbiological analysis and scanning electron microscopy (SEM/EDS). For sensorial characterization, Profile Description Optimized (PDO) was used to evaluate the red and brown color. It can be observed that the coating had a homogeneous, dense, crack-free surface, without pores. The coated beef had less weight loss when compared to the control. The medium pH for the control (5.96) was greater (P < 0.05) than the samples treated with mono (5.67) and bilayer (5.6). It was observed that the application of the coatings was effective in reducing lipid oxidation (evaluated by PV and TBARS). It was verified a largest decrease of O2Mb (%) for control and higher conversion of this pigment to Mb+ an MMb with storage time. The color of the meat was favored by applying coatings both mono and double layers. The control presented (P >0.05) greater OCR (26.9 %) and lower MRA (15.7 %) when compared to mono treatments (15.8 and 25.1 %) and double layers (11.8 and 22.8 %), respectively. For psychotropic microorganisms, coatings mono (average 3.6 log10 CFU / g ) and bilayer (3.4 log10 CFU / g) exerted similar antimicrobial effect during the storage time , and the scores of the coated samples were lower (p < 0.05) than the control (4.2 log10 CFU / g). The bilayer coating decreased to 3.4 log10 CFU / g of mesophilic microorganisms when compared with the control. In the PDO, the samples differed in red and brown tons. The mono and bilayers samples showed the highest values of red, while the control showed higher brown color from the sixth day of storage. It was concluded that the use of edible coatings for beef conservation is a viable alternative to maintaining quality parameters of the meat stored in plain packaging systems with high oxygen permeability and stored under refrigeration.