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- Author or Editor: Malkeet S. Padda x
- HortScience x
Three different style fresh-cut (shredded, French fry, and sliced) sweetpotatoes [Ipomoea batatas (L.) Lam.] were stored at 0 and 5 °C for 4 and 8 days. At specified storage intervals, the fresh-cut sweetpotatoes were analyzed for total phenolics, individual phenolic acids, and antioxidant activity. Sweetpotato tissue analyzed immediately after cutting was considered the control. Storage at 5 °C resulted in an increase in total phenolics in all types of fresh-cut sweetpotatoes, except in shredded tissue analyzed after 4 days of storage. However, at 0 °C, only sliced tissue accumulated higher total phenolics than the control. In general, antioxidant activity in all fresh-cut sweetpotatoes held at 5 °C was higher than in the control. No significant increase in antioxidant activity was observed in shredded sweetpotatoes stored at 0 °C. Chlorogenic acid followed by 3,5-dicaffeoylquinic acid were the predominant phenolic acids present in fresh-cut sweetpotatoes. The highest content of chlorogenic acid (539.9 μg·g−1 dry weight) in sliced tissue stored for 8 days at 5 °C was ≈6-fold higher than in the control (88.3 μg·g−1 dry weight). No significant development of tissue browning, off-odors, or off-flavors were observed after 8 days of storage and the products were considered to be marketable.
Three different style cuts of minimally processed sweetpotatoes (shredded, French-fry, and sliced) were stored at 0 °C and 5 °C for 4 and 8 days. Total phenolic content, individual phenolic acids, and free radical scavenging activity were determined using Folin-Denis reagent, reversed-phase HPLC, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, respectively. Total phenolic content in sliced cut sweetpotatoes held at 5 °C was higher than in the shredded cut. Both sliced and French-fry cut sweetpotatoes held at 5 °C had significantly higher antioxidant activity than shredded cut sweetpotatoes. All treatments, except shredded sweetpotatoes held at 0 °C, had significantly higher total phenolic content and antioxidant activity after 4 and 8 days of storage. Minimally processed sweetpotatoes held at 5 °C accumulated more phenolic compounds and had a higher antioxidant activity than sweetpotatoes held at 0 °C. Chlorogenic acid followed by 3,5-dicaffeoylquinic acid were the predominant phenolic acids present in sweetpotatoes. The rate of increase in individual phenolic acid content with storage time was higher at 5 °C than at 0 °C. No tissue browning was observed in any of the cuts after 8 days of storage and the products were considered to be marketable.
Phenolic compounds and antioxidant activity were quantified in the principal sweetpotato cultivars marketed in the European Union. Total phenolic content, individual phenolic acids, and antioxidant activity in each cultivar were determined using Folin-Denis reagent, reversed-phase HPLC, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, respectively. Significant differences in phenolic composition and antioxidant activity were found between cultivars. A Jamaican-grown, white-fleshed cultivar had the highest total phenolic content [4.11 mg·g-1 chlorogenic acid (dry tissue weight)], while the highest antioxidant activity [3.60 mg·g-1 Trolox (dry tissue weight)] was observed in the orange-fleshed California-grown cultivar Diane. Chlorogenic acid and 3,5-dicaffeoylquinic acid were the predominant phenolic acids, while caffeic acid was the least abundant in most cultivars. The highest content of chlorogenic acid (0.42 mg·g-1 dry tissue weight); 3,5-dicaffeoylquinic acid (0.43 mg·g-1 dry tissue weight); and 3,4-dicaffeoylquinic acid (0.25 mg·g-1 dry tissue weight) was present in the white-fleshed Jamaican cultivar. The orange-fleshed cultivars Diane and Beauregard had the highest content of caffeic acid (0.13 mg·g-1 dry tissue weight) and 4,5-dicaffeoylquinic acid (0.32 mg·g-1 dry tissue weight), respectively.