Differential and Cultivar-Dependent Antioxidant Response of Whole and Fresh-Cut Carrots of Different Root Colors to Postharvest UV-C Radiation

Abstract

Fresh-cut produce have become widely popular, increasing vegetable consumption in many parts of the word. However, they are more perishable than unprocessed fresh vegetables, requiring cold storage to preserve their quality and palatability. In addition to cold storage, UV radiation has been used experimentally to try to increase nutritional quality and postharvest shelf life, revealing increased antioxidant levels in some fruits and vegetables, including orange carrots. Carrot is one of the main whole and fresh-cut vegetables worldwide. In addition to orange carrots, other root color phenotypes (e.g., purple, yellow, red) are becoming increasingly popular in some markets. The effect of the UV radiation and cold storage has not been explored in these root phenotypes. This study investigated the effect of postharvest UV-C radiation in whole and fresh-cut (sliced and shredded) roots of two purple, one yellow, and one orange-rooted cultivar, with regard to changes in concentration of total phenolics (TP) and hydroxycinnamic acids (HA), chlorogenic acid (CGA), total and individual anthocyanins, antioxidant capacity (by DPPH and ABTS), and superficial color appearance, monitoring such changes during cold storage. Results revealed that the UV-C radiation, the fresh-cut processing, and the cold storage influenced the content of antioxidant compounds and activities to varying extents, depending on the carrot cultivar, the degree of processing, and the phytochemical compound analyzed. UV-C radiation increased antioxidant capacity up to 2.1, 3.8, 2.5-folds; TP up to 2.0, 2.2, and 2.1-folds; and CGA up to 3.2, 6.6, and 2.5-folds, relative to UV-C untreated controls, for orange, yellow, and purple carrots, respectively. Anthocyanin levels were not significantly modified by the UV-C in both purple carrots evaluated. A moderate increase in tissue browning was found in some fresh-cut processed UV-C treated samples of yellow and purple but not orange roots. These data suggest variable potential for increasing functional value by UV-C radiation in different carrot root colors.

Tea Polyphenols Inhibit the Occurrence of Enzymatic Browning in Fresh-Cut Potatoes by Regulating Phenylpropanoid and ROS Metabolism

“…As shown in Figure 3 a, fresh-cut treatment significantly increases phenolic compound accumulation in potatoes, a finding echoed in studies on fresh-cut broccoli [ 31 ], fresh-cut celery [ 32 ], fresh-cut onion [ 33 ], and fresh-cut carrot [ 34 ]. This indicates that fresh fruits and vegetables initiate secondary metabolic processes and synthesize phenolic compounds to counteract mechanical damage, thereby rapidly restoring metabolic balance [ 35 ].…”

UV-C Treatment Impact on the Availability of Water-Soluble Carbohydrates, Polyphenols, and Antioxidant Capacity of an Algerian Underutilized Date Fruit (Phoenix dactylifera L.)

“…The presence of bioactive compounds in dates has attracted considerable attention from researchers, positioning this fruit as a promising natural source of antioxidants and functional food ingredients [ 76 ]. Additionally, studies have explored the effectiveness of UV-C irradiation in improving the quality and extending the shelf life of fruits and vegetables [ 2 , 77 , 78 , 79 ]. However, there is currently little information on the potential application of UV-C rays in the processing of second-grade dates.…”