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Fresh and sun-dried dates of three native varieties from Oman, namely, Fard, Khasab, and Khalas, were examined for their antioxidant activity and total contents of anthocyanins, carotenoids, and phenolics, as well as free and bound phenolic acids. All results are expressed as mean value +/- standard deviation (n = 3) on a fresh weight basis. Fresh date varieties were found to be a good source of antioxidants (11687-20604 micromol of Trolox equiv/g), total contents of anthocyanins (0.24-1.52 mg of cyanidin 3-glucoside equiv/100 g), carotenoids (1.31-3.03 mg/100 g), phenolics (134-280 mg of ferulic acid equiv/100 g), free phenolic acids (2.61-12.27 mg/100 g), and bound phenolic acids (6.84-30.25 mg/100 g). A significant (p < 0.05) amount of antioxidants and carotenoids was lost after sun-drying of dates, whereas the total content of phenolics and free and bound phenolic acids increased significantly (p < 0.05). Anthocyanins were detected only in fresh dates. Date varieties had different levels and patterns of phenolic acids. Four free phenolic acids (protocatechuic acid, vanillic acid, syringic acid, and ferulic acid) and nine bound phenolic acids (gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, and o-coumaric acid) were tentatively identified. Of the date varieties studied, Khalas, which is considered to be premium quality, had higher antioxidant activity, total carotenoids, and bound phenolic acids than other varieties. These results suggest that all date varieties serve as a good source of natural antioxidants and could potentially be considered as a functional food or functional food ingredient, although some of their antioxidant constituents are lost during sun-drying.

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Four different colored carrots, orange, purple with orange core, yellow, and white, were examined for their content of phenolics, antioxidant vitamins, and sugars as well as their volatiles and sensory responses. A total of 35 volatiles were identified in all carrots, 27 positively. White carrot contained the highest content of volatiles, followed by orange, purple, and yellow. In total, 11, 16, 10, and 9 phenolic compounds were determined for the first time in orange, purple, yellow, and white carrots, respectively. Of these, chlorogenic acid was the most predominant phenolic compound in all carrot varieties. Differences (p < 0.05) in relative sweetness, the contents of vitamin C and alpha- and beta-carotenes, and certain flavor characteristics were observed among the colored carrot varieties examined. Purple carrots contained 2.2 and 2.3 times more alpha- and beta-carotenes (trace in yellow; not detected in white) than orange carrots, respectively. Purple carrot may be used in place of other carrot varieties to take advantage of its nutraceutical components.

UM clustering suggests a personalized effect of ellagitannin-containing foods and could explain the controversial pomegranate benefits. Research on the specific role of urolithins and the microbiota associated with each UM is warranted.