14A-28

V. GHOSH, Department of Food Science, Pennsylvania State University, 111 Borland Lab., University Park, PA 16802 and R. C. Anantheswaran.

Micro-perforated films are increasingly being used in modified atmosphere packaging (MAP) of fruits and vegetables with high respiration rates. In the design of MAP of fruits and vegetables, the knowledge of film permeability is essential. The goal of this work was to design a setup to measure the oxygen permeability of micro-perforated films, and to use the results obtained to evaluate the different mathematical models available for predicting the gas transport through micro-perforated films.

Static and dynamic (flow through) methods were used to study the oxygen transmission rate (OTR) through micro-perforations. The static method simulated the real package situation but was very time consuming. The flow through method was relatively simple and took less time to give results, but it gave higher values than that obtained by the static method. The OTR data from the static method was correlated with the OTR data from the flow-through method by a regression equation:OTR_static=1.02 OTR_flow^0.964 , R²=95.7%.

Published models for predicting gas exchange through micro-perforations were evaluated using experimental data obtained using the static method for six different films. The model proposed by Fishman et al. (1996) (J=-D(C - C_A)/L_h; L_h=thickness of the film + radius of the perforation) had a very good agreement with the results obtained through experiments.