73D-38 |
Characteristics of corn zein and methyl cellulose bi-layer edible films as affected by preparation protocol |
M. S. CHINNAN, Department of Food Science and Technology, University of Georgia, 1109,Experiment Street, Griffin, GA 30223 and H. Y. Koh, Department of Food Nutrition and Technology, Woosuk University, Samnae , Wanju, Chonbuk, 565-701, South Korea.
A considerable amount of information is available on protein and cellulose-based films. However, such is not the case with protein and cellulosic-based composite films. It is hypothesized that composite films will have improved characteristics than the individual protein or cellulosic films. Prepare composite films with the different corn-zein (CZ) and methylcellulose (MC) ratios and drying protocols and characterize such films for physical and permeability properties. CZ (16.6%) or MC (3.0%) solutions (3 to 12 g) were poured onto petri dishes and dried overnight under ambient conditions. Following which MC solution was poured onto the dried CZ and CZ solution on MC film to obtain MC/CZ or CZ/MC composite films. Film thickness, water vapor transmission rate (WVTR), puncture force (PF), tensile strength (TS) and percent elongation (E) were measured and surface appearances were pictured. WVTR of CZ and MC films decreased from 25.8 and 53.4 g/h/m2 in 3 g solution to 21.2 and 46.2 g/h/m2 in 12 g solution and decreased to 15.8 - 32.7 g/h/m2 in composite films, respectively. PF of CZ and MC films were 863 and 1485 mN, respectively, prepared from 3 g solutions, the values increased proportionally with the solution weight. Similar trends were observed for TS. PF and TS of composite films were significantly higher than the individual films. E values were 5.1 - 5.2% in CZ single films, 9.1 - 18.5% in MC single films and 5.1 - 12.6% in composite films. MC/CZ were more whitish with uneven surface but opposite trends were noted for CZ/MC films. It is possible to make composite films from proteinaceous and cellulosic materials with significantly improved properties than the single material films.
Session 73D, Food Packaging
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