49F-5 |
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B. B. SURJADINATA and L. Cisneros-Zevallos. Dept. of Horticultural Sciences, Texas A&M Univ., 202 Horticulture & Forestry Science Bldg., 2133 TAMU, College Station, TX 77843-2133 In previous work, we have shown that wounding stress increases the phenolic content and antioxidant capacity (AOX) of fresh fruits and vegetables. However, it is unclear how different wounding intensities (A/W) affect this increase in AOX during storage. The objective of this study was to determine the effect of different A/W on total phenolics, AOX, and phenylalanine ammonia-lyase (PAL) activity in carrot tissue. Additionally, we characterized the effect of different carrot varieties and storage time. Carrots were washed with 100-ppm chlorine water, cut, stored in 4-L closed glass jars at 15oC, and ventilated every 6-8 h to avoid CO2 accumulation. In a first experiment, Apache carrots were cut into slices, pies, and shreds (A/W of 4.2 to 23.5 cm2/g) and stored for 4 d before measurements. In a second experiment, Navajo, Legend, and Choctaw carrots were shredded (A/W=23.5 cm2/g) and stored for 8 d with measurements done periodically. Phenolics, AOX, and PAL activity were quantified using a spectrophotometer. Results indicated that phenolics, AOX, and PAL activity increased with increasing A/W. The increase was only significant in carrot pies and shreds (A/W of 6.0 and 23.5 cm2/g), however, not in slices (A/W=4.2 cm2/g). In the second experiment, phenolics, AOX, and PAL activity increased during storage for all shredded carrot varieties with PAL reaching a maximum activity on day 2. There was no significant difference in increased phenolics between carrot varieties, and only slight differences in increased AOX and PAL activity. These phenolic compounds showed a high correlation with AOX for all carrot varieties (R2 > 0.9). If wounding stress can be used as a tool to enhance the nutraceutical content without jeopardizing other quality factors, then the fresh-cut industry can claim that fresh-cut produce will not only provide convenience but also a healthier food to the consumers.
Session 49F, Fruit & Vegetable Products: Fresh vegetables
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