Change in oxygen permeability of plastic vacuum bags containing germinated brown and parboiled germinated rice

The study was conducted to investigate changes in oxygen permeability of Nylon/Polyethylene (Nylon/PE) and Low Density Polyethylene (LDPE) films, utilised for vacuumed packages of germinated brown rice and parboiled germinated rice, during 120-day storage at an ambient condition (35 degrees C). Weights of both Nylon/PE and LDPE films, immediately in contact with both types of rice, continuously increased and approached saturation. These were well described by the Langmuir-based model. Film weights of Nylon/PE were relatively higher than those of LDPE films. Absorption of fat from rice to the films was considered the key process attributing to the increase in film weight. Absorbed fat, effectively acting as a plasticiser in polymeric structure, caused an increase in the oxygen transmission rate (OTR) values of the films. Whilst OTR values of Nylon/PE films noticeably increased throughout the storage, those of LDPE films showed inconsistent trends. The present work demonstrates that estimation of oxygen flux across the Nylon/PE film into the package, by assuming constant film permeability to oxygen, would underestimate experimental results during storage, due to the increased film permeability as a result of rice-film interaction. (C) All Rights Reserved