A method for the measurement of the oxygen permeability and the development of edible films to reduce the rate of oxidative reactions in fresh foods

A method involving the flow of O2 and N2 gasses from the two sides of an edible film coupled with a simple wet chemical analysis at the end, was developed to measure the oxygen permeability of edible films. The proposed method was employed to determine the oxygen permeability of methyl cellulose (MC)-based edible films of various composition with the aim of finding the optimum composition for minimising oxidative degradation of foods. The effects of the presence of stearic acid (SA), ascorbic acid (AA) and citric acid (CA), in varying amounts in the film composition, on the oxygen permeability (OP) of MC based edible films were examined. The OP increased with increasing SA content of the film and decreased with the inclusion of AA or CA in the film composition. The films, with various compositions and with the measured oxygen permeabilities, were then applied to mushrooms (Agaricus bisporus) and cauliflower (Brassica botrytis). It was found, from the analysis of these coated foods, that the coatings containing antioxidants slowed the browning reactions and reduced the vitamin C loss in both foods, the effects being greater in cauliflower. Moreover, the moisture loss of coated foods was less than that of uncoated.