36E-17 |
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M. SIDDIQ1, A. Khan1, J. B. Harte1, K. D. Dolan2, and J. K. Collins3. (1) Dept. of Food Science and Human Nutrition, Michigan State Univ., 111 G. Malcolm Trout FSHN Bldg., East Lansing, MI 48824-1224, (2) Dept. of Food Science and Human Nutrition/Dept. of Agricultural Engineering, Michigan State Univ., 208 G. Malcolm Trout FSHN Bldg., East Lansing, MI 48824-1224, (3) Genetics and Production Research Unit, USDA,-ARS-South Central Agricultural Research Laboratory, P.O. Box 159, Lane, OK 74555 Watermelon is rich in lycopene, a carotenoid that is thought to have a protective effect against certain cancers and cardiovascular disease. The consumption of watermelon has risen steadily in recent years; it increased about 60% between 1980 and 2000. However, currently it is consumed mainly in its whole or fresh-cut form. There is a need to develop processing methods for watermelon juice/concentrate that have minimal effect on lycopene degradation, physico-chemical characteristics, and sensory quality. Our objective was to develop a method of processing watermelon juice that maintains a palatable product while optimizing lycopene content, and obtaining favorable consumer acceptance. Whole seedless watermelons were purchased from a local source, washed and sanitized in160 ppm chlorine dip. Fruit was manually peeled and cut into approx. 2-inch chunks and mashed using a propeller-type blender. Juice was pressed from cold macerate (I), hot macerate--50o C for 30 minutes (II), and hot macerate as above treated with 0.01% commercial pectinase (III). Juice was evaluated for lycopene contents, TSS, pH, titratable acidity, juice clarity and Hunter color “L” “a” and “b” values. A small trained panel evaluated juice based on sensory attributes of color, aroma, flavor, mouth feel, and taste. Highest juice yield (86%) was obtained with process III, followed by II and I. Heating of macerate resulted in 18% lower lycopene contents in the juice. Method of juice extraction had little or no effect on pH, titratable acidity and Hunter color “L” or “b” values. However, juice from process I had higher “a” values, i.e. more red in color. Pasteurization of juice resulted in a slight decrease in lycopene contents. Addition of 0.15% gum acacia improved juice stability. Based on the physico-chemical analysis and sensory scores, it is concluded that juice pressed from cold macerate (I) was better in quality than from the other methods used.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |