30H-13 |
Determination of odor changes in bruised blueberries during storage using an electronic nose |
N. DEMIR1, C. O. Ferraz2, S. A. Sargent3, and M. O. Balaban1. (1) Dept. of Food Science & Human Nutrition, Univ. of Florida, PO Box 110370, 359 FSHN Bldg., Newell Dr., Gainesville, FL 32611-0370, (2) FEAGRI, State Univ. of Campinas, Caixa Postal 6011, Campinas, Sao Paulo, 13089-970, Brazil, (3) Horticultural Sciences Dept., Univ. of Florida, Institute of Food & Agricultural Sciences, Gainesville, FL 32611-0690 Blueberry can be bruised during handling. An electronic nose (EN) can evaluate rapidly and non-destructively bruising-induced changes in volatile flavors of blueberry. Our objectives were to determine changes in aroma of blueberries subjected to various mechanical impacts using an EN, and to determine the correct classification potential of Discriminant Function Analysis (DFA) for these data. Unblemished ¢ Misty ¢ blueberries (Vaccinium corymbosum), 1.5 to 2.5 g each, were subjected to the following mechanical treatments: (control) berries were carefully packed into 4 clamshell containers. T1: 640 g of berries were poured from a plastic bucket onto a plastic surface from a height of 20 cm. Then berries were poured from one bucket to another 6 times. Finally, they were equally distributed in 4 clamshells. T2: was similar to T1 except the fruits were dropped onto a steel surface, and berries were transferred between buckets 10 times. All treatments were stored at 2°C and 95 % RH. An EN with 12 conducting polymer sensors was used to measure odors at days 0, 2, 10, 17, and 24. Five replicates were run for each treatment. DFA was used to classify samples by treatment and storage time. Correct classification rates (CCR) were calculated and cross validation analysis performed. No berries showed skin rupture or leaking during storage. The classification rates and cross-validation results for each storage time (0, 2, 10, 17 and 24 days) were 0%, 100%, 100%, 100% and 100%, respectively. As expected, on day 0, there was no significant difference in the odor of samples. Correct classification rates for all treatments and storage times were between 80% and 100% during storage. Cross validations for different treatments and storage times also ranged from 75% to 100 %. EN is a useful tool in screening bruised blueberries based on their odor.
Session 30H, Quality Assurance
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