76C-19 |
Objective quality assessment of modified atmosphere stored zucchini (Cucurbita pepo L. cv. Elite) slices using electronic nose, machine vision and instron |
N. DEMIR1, M. O. Balaban1, J. K. Brecht2, C. A. Sims3, and M. S. Gulay4. (1) Food Science and Human Nutrition, University of Florida, P.O. Box 110370, 359 FSHN Bldg, Newell Drive, Gainesville, FL 32611-0370, (2) Horticultural Sciences, University of Florida, Institute of Food and Agricultural Services, PO Box 110690, Gainesville, FL 32611-0690, (3) Food Science & Human Nutrition, University of Florida, P. O. Box 110370, 359 FSHN Bldg, Newell Drive, Gainesville, FL 32611-0370, (4) Animal Sciences, University of Florida, P.O. Box 110910, Gainesville, FL 32611-0910 In fresh-cut products, biochemical changes, microbial spoilage, and degeneration can occur over time, resulting in changes in color, texture and flavor. Modified atmosphere packaging (MAP) is an important method to extend shelf life. Using electronic nose (EN), machine vision (MV) and Instron provides objective quality evaluation of foods. The objective was to measure quality changes of MAP stored sliced zucchini using EN, MV and Instron, and to correlate these data with sensory parameters and microbial counts. Zucchini were washed (100 ppm chlorinated water, 2 min), sliced (5mm),and slices dipped in 100ppm chlorinated water for 2 min. Slices were spin-dried and put into two different plastic bags (~280g/ bag). Bags were flushed with gas (2%O2+15%CO2 balance N2, or air as control) and sealed. Samples were stored (5°C, RH=95%) up to 24 days, and evaluated every other day using EN, MV and Instron, and organoleptic quality parameters determined by a sensory panel. Aerobic microbial counts were performed. EN and MV data were evaluated by Discriminant Function Analysis (DFA). Treatments and storage times were used as grouping variables. Correct classification rates (CCR) were calculated. Cross validation analysis was performed. Average L a b values and % color changes showed that the best color preservation was with 15%CO2 treatment. CCR for color data was 96%, 94%, 97%, 98% for air and 15%CO2 in first and second bag, respectively. DFA of EN data for storage time gave CCR of 93% for all treatments. DFA of storage time by combined treatments gave CCR of 91%.Cross-validation results for different treatments and storage times showed that MAP significantly reduced microbial growth, discoloration and off-odor, while maintaining, hardness, crispness and zucchini aroma (p>0.0001). DFA was successfully used to correlate EN and color data with microbial levels, storage time, and sensory results.
Session 76C, Fruit & Vegetable Product: Fresh Fruits and Vegetables
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