100B-31 |
Diffusivity of sorbic acid in glucomannan film and the film application as affected by acid concentration, film thickness, and relative humidity |
A. JANGCHUD1, V. Haruthaithanasarn1, T. Hungsaperk1, and W. Prinyawiwatkul2. (1) Department of Product Development, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand, (2) Department of Food Science, Louisiana State University Agricultural Center, Baton Rouge, LA 70803-4200 Konjac flour mainly contains glucomannan and can be used as a raw material to produce biodegradable film. The glucomannan film can be incorporated with antimicrobial agents and functions as an active packaging. Some parameters of the film formation process may affect diffusivity of antimicrobial agents in the glucomannan film and its food applications. Research in this area has not been investigated and is worth investigation. Our objective was to determine effects of sorbic acid concentration, film thickness, and relative humidity (RH) on (1) sorbic acid diffusivity in the glucomannan film and (2) the film application on durian paste during storage. The glucomannan film was prepared from 1% konjac flour (w/v water) and 30% glycerol (w/w of konjac flour). Various levels of sorbic acid concentrations (10, 15 or 20% w/w of konjac flour), film thickness (0.04, 0.07 or 0.10 mm) and RH (65 or 100%) were studied. The film application was tested on durian paste used as a demonstrative model for intermediate moisture foods. The shelf life of durian paste double wrapped with glucomannan film first, then with polypropylene film, was studied. Sorbic acid concentration, film thickness, and RH significantly (p£0.05) affected the sorbic acid diffusivity. The lowest diffusivity of film stored at 65 and 100% RH was, respectively, 0.060x10-12 and 0.3133x10-12 m2/s, both at 10% sorbic acid incorporated. The shelf life of durian paste double wrapped with glucomannan (containing 10% sorbic acid) and polypropylene films was 10 weeks when stored at room temperature, which was longer than that of the samples not inner-wrapped with the glucomannan film. This study showed that konjac flour could be used as a raw material to produce biodegradable film. The film showed potential for use as an active wrapping film that helps extend the shelf life of intermediate moisture food products.
Session 100B, Food Packaging
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