Location: Processed Foods Research
2012 Annual Report
1)the synergistic response resulting from the combination of wounding and UV-B treatment,.
2)the influence of genotype on responsiveness, and.
3)processing conditions that yielded maximal enhancement of antioxidant activity without reducing product quality.
Research efforts consisted of nearly 900 samples, including whole and precut root crops and vegetables evaluated under multiple conditions, and confirmed that among the crops tested, carrot is the most responsive to UV-B treatment. Samples of whole sweet potatoes, colored potatoes, and white sweet corn, and sliced sweet potatoes, radish and daikon did not show a measurable response to UV-B treatment.
We evaluated five commercial pre-cut carrot products possessing increasingly greater area/weight ratios and found that UV-B responsiveness, as measured in terms of TSP, antioxidant content, chlorogenic acid content, and PAL activity, increased directly as the area/weight ratio increased. We also found that UV-B light exposure only slightly increased the surface temperature of the carrot samples and did not stimulate the accumulation of carotenoids. Analysis of the 21 varieties of UV treated carrots revealed that response and the level of responsiveness was dependent upon the color of the carrot, suggesting that genotype and phenotype plays a role in determining responsiveness. The effect of post-UV treatment conditions and cold storage on the synthesis and stability of phenolic compounds in carrots with and without UV-B treatment was examined. We found that increases in the TSP content of UV treated carrot products were dose and temperature dependent. We were able to identify optimal treatment, handling, and packaging conditions that produced a 2-fold increase in antioxidant content in baby carrots while maintaining product quality that was shelf-stable for 21 days. Bench sensory tests indicated that there were no differences in flavor, odor, appearance and texture between UV-treated and control baby carrots. This project relates to objectives 1 though 3 from the parent project, in which the objectives were addressed.