73D-33 |
The effect enzymatic reaction temperature in the permeability and mechanical properties of gelatin based films |
C. R. F. GROSSO and R. A. Carvalho. Dept. of Food Planning & Nutrition, State Univ. of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Campinas, SP, 13083-970, Brazil Due to the high permeability of water vapor, the application of gelatin based films as packing materials has some limitations. The utilization of the transglutaminase enzyme produces cross-links in the film matrix, what may improve its permeability. The objectives of this work were to evaluate the enzymatic reaction temperature effect on mechanical and barrier characteristics in native films (NF), films modified by the enzyme (FME) and films without the enzyme which had the same thermal treatment as that of the FME (FWE). The films were produced through hydration, solubilization, enzyme addition (Activa-TGS®=10U/g of gelatin) at different temperatures (40, 50, 60, 70 oC ), inactivation at 85 oC (FME and FWE) and drying at room temperature. The tensile strength and elongation of the films were determined by utilizing a texturometer with the films previously equilibrated at RU 50%. The water permeability was determined through gravimetric techniques. The results showed a reduction in tensile strength, elongation and water vapor permeability of FME compared to NF and FWE. A lower permeability and higher mechanical resistance determined the enzymatic reaction temperature (50oC). At this temperature, the permeability and tensile strength values were 14.6N and 0.11g.mm/kPa.h.m2 , respectively. The water vapor permeability was improved by the enzymatic activation. The temperature effect caused mechanical resistance increase and water vapor permeability decrease due to a better orientation of the matrix.
Session 73D, Food Packaging
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