Respiration Rate of Cherry Tomatoes and Gas Permeability of Hydroxypropylmethyl Cellulose-Based Coating

The aim of this study was to measure the gas permeability of edible films using a homemade experimental apparatus and to determine the respiration rate of tomatoes (L. esculentun var. Cerasiforme) without (NC) and with (CC) edible coating at different temperatures. Permeability was determined using an experimental device according to the ASTM D1434 method and the apparatus was validated using permeability data from a synthetic film obtained using an Oxtran equipment. The coating applied to the tomatoes was based on hydroxypropyl methylcellulose (HPMC). Permeability values found to oxygen (O2) for polyethylene/ low-density polyethylene, polyamide/ polyethylene, and polyamide/ ethylene vinyl alcohol-based synthetic film were 2.02x10, 2.09x10, and 4.81x10 mol μm m2 s Pa, respectively. These results were compared with permeability data obtained by the Oxtran equipment and no significant difference (p<0.05) was found. The permeability values of the coating used were 2.11x10 and 2.19x10 mol μm m2 s Pa for O2 and carbon dioxide (CO2), respectively. Regarding the respiration rate, the edible coating showed a significant difference (p<0.05) in O2 consumption at temperatures of 10 °C, 15 °C and 20 °C. However, the difference was not significant (p<0.05) for the production of CO2 at all temperatures studied. The results showed that the homemade experimental unit was efficient to measure the permeability of edible films and the coating used decreased the respiration rate of cherry tomatoes as compared to the control. Keywords— Gas permeability; respiration rate; coating.