| Summary: | 碩士 === 實踐大學 === 食品營養與保健生技學系碩士班 === 96 === The aim of this study was to improve the water vapor permeability of LDPE film by incorporating various porous materials (zeolite, silica, carbon, calcium carbonate, active carbon powder, and chitosan) with varying particle sizes. The dispersing agents, including stearic acid, sorbitol and tannic acid, were also employed to improve the uniformity in the distribution of the additives. The films were prepared by using a hot press machine, and their tensile property and water vapor permeability were investigated. Results showed that films containing zeolite, silica and carbon displayed higher water vapor permeability than the films containing other materials. Furthermore, the larger the particle size was, the greater the water vapor permeability obtained. In this study, the films containing silica with a particle size of 125-177 μm exhibited the highest water vapor permeability of 56.84 ± 4.52g/m2 at 38C and 95% RH. The addition of stearic acid to the silica-containing films improved its tensile property but slightly reduced its water vapor permeability (p<0.05). Fresh-cut lettuce was packaged in the silica/stearic acid-containing films, and stored at 4C, 40% RH or at 25C, 60% RH for 11 days. Results showed that the films delayed the reduction of oxygen as well as the production of ethylene and carbon dioxide in the packages. Sensory evaluation indicated that the films with higher water vapor permeability better preserved the quality of fresh-cut lettuce.
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