36E-71 |
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K. I. MATSOS, U. V. Lay, and J. D. Floros. Dept. of Food Science, The Pennsylvania State Univ., 111 Borland Lab, University Park, PA 16802-2504 The limited shelf-life of fresh-cut fruits is the main barrier of the wide commercialization of such products. Chemical treatments and the use of whey protein edible coatings have been shown to delay rapid quality deterioration of minimally processed fruits. However, the combined effect of different active compounds, carried by whey protein coatings, on fresh-cut product quality (color and texture) and microbial decay has not been studied in depth. Our objective was to study the effect of ascorbic acid (AA), citric acid (CA), calcium chloride (CaCl2), and potassium sorbate (PS) in whey protein coatings on the quality (color and texture) and microbial decay of fresh-cut apples. Apple slices (var. red delicious) were dipped in whey protein coating solutions of various AA, CA, CaCl2, and PS concentrations, according to a central composite experimental design. The slices were punctured and inoculated with Penicillium expansum. The samples were stored for 4 weeks in plastic bags at 5° C. The color, texture and microbial growth were evaluated over time. The presence of the coating reduced surface browning of apple slices. Addition of PS in the coating appeared to have a dramatic negative effect on both the color and texture of the product. The effect of PS on product quality was so severe that masked any possible positive effects from other compounds (e.g. AA). CA also appeared to have a negative effect on the color of the product. Regarding microbial growth, PS concentrations above 1.1% inhibited microbial growth for at least 21 days. The above results suggest that whey protein coatings delay color changes of fresh-cut apples. Addition of PS inhibits microbial growth on contaminated surfaces. However, due to its severe negative effect on product quality, PS should be replaced by another antimicrobial agent.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |