45D-5 |
Protein and cellulose film coatings on tomato color |
N. S. HETTIARACHCHY and S. ESWARANANDAM. Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., N-218 Food Science Bldg., Fayetteville, AR 72704-5690 Coating with antimicrobial edible films to prevent survival of pathogen on the surface of fresh produce should not have any adverse effect in masking the color. The objective of this study was to evaluate the maximum thickness of coating that can be applied on tomato without masking its color. Tomatoes were dipped 6 times into soy (SP) / whey (WP) / wheat gluten (WG) proteins / carboxymethyl cellulose (CMC) film-forming solutions and were dried between coatings. Thickness of coating was evaluated with micrometer after peeling the film. The colors of tomatoes were determined by colorimeter. Color L* (Lightness) a* (redness) b* (yellowness), chroma and hue angle were recorded. Thickness of 1 to 6 SP / WP / WG / CMC coated films on tomato ranged from 10 - 170, 10 – 33, 20 – 168 and 8 – 40 mm, respectively. CMC coatings up to 6 times were not affected color of tomato. Coatings using WP / SP / WG were not as effective as CMC coating. Whey protein coating did not affect the redness of tomato up to 5 coatings (20 mm) but the lightness increased and yellowness decreased after 1 coating (10 mm) compared with control (p<0.05). Soy protein film coated tomatoes were more red, yellow and had higher chroma and hue angle and lower lightness after 1 coating (10 mm). Wheat gluten film coating decreased redness after 2 coatings (30 mm), decreased yellowness, chroma and increased lightness after 1 coating (20 mm). Carboxymethyl cellulose can be used with a very thin coating without having any masking effect on color of tomato. Soy protein coating increased redness, while WP and WG coating increased lightness of tomato. Whey and soy protein and cellulose coatings can be used as carriers of antimicrobial substances without having any adverse effect on the red color of tomato.
Session 45D, Food Packaging: General
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