Location: Healthy Processed Foods Research
Title: Effect of UV-B light and different cutting styles on antioxidant enhancement of commercial fresh-cut carrot products Authors
Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: February 10, 2011
Publication Date: N/A
Technical Abstract: Carrots are a rich source of antioxidants. Fresh-cut processing provides a convenient way to consume this nutritious root crop. Cutting operations induce wounding stress activation of phenylalanine ammonia-lyase (PAL) and chalcone synthase, and enhance the nutrient content of carrots by increasing the synthesis of secondary metabolites, including phenolic compounds. Ultraviolet-B (UV-B) light exposure further promotes the formation of soluble phenolic compounds and significantly increases the antioxidant capacity of fresh-cut carrots. In this study four commercial fresh-cut carrot products (sticks, crinkle cut coins, oblong chips, and baby carrots) with different area/weight ratios were exposed on both the top and bottom surfaces to a total energy dose of 141.4 mJ/cm2 in 14 s with a bimodal peak irradiance UV-B light of 20.2 mW/cm2. The final temperature increased to 12.1°C, from an initial temperature of 4.2°C on carrot surfaces. After incubation at 15°C for 72 h to allow enzyme activation, the responses of carrot products to the treatment conditions were assessed in terms of total soluble phenolic contents (TSP), chlorogenic acid (CA), total carotenoids, antioxidant capacity (AC), and PAL activity. TSP, AC and CA showed a significant linear correlation increase corresponding to the increasing in area/weight ratio of the different carrot products exposed to UV-B. The largest increase in TSP, AC and CA (3.2, 3.3 and 7.3 times, respectively), with a corresponding increase of 2.6 times in PAL activity due to the sole effect of UV-B exposure, was observed in oblong carrot chips with the largest area/weight ratio (6.9 cm2/g). Otherwise total carotenoids of the carrot products were unchanged after UV-B exposure. PAL activity increased significantly after the UV-B exposure, but was not affected by the extent of cutting. Optimization of the nutritional beneficial effects of UV-B exposure is correlated to increasing exposure area of fresh-cut carrots.