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  • Author or Editor: J. Emilio Villarreal x
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The objective of this study was to evaluate kernels of different pecan (Carya illinoinensis) cultivars for their antioxidant capacity and characterize the nature of the antioxidant compounds. Nuts collected from four pecan cultivars `Cheyenne', `Cape Fear', `Desirable', and `Pawnee' were shelled, chopped and analyzed for their antioxidant capacity (AC), and for their phenolic, tannin, and vitamin C content. AC was measured using one spectrophotometrical [DPPH (2,2-diphenyl-1-picrylhydrazyl)] and one fluorescence method [ORAC (Oxygen Radical Absorbance Capacity)]. Total phenolic and tannin content were determined using spectrophotometrical assays. Finally, ascorbic and dehydroascorbic acid were determined using a high performance liquid chromatograph. Both AC methodologies, DPPH and ORAC, gave similar results with marked differences between cultivars. `Desirable' had the highest antioxidant capacity (47,747 μg TEq/g DW with DPPH method) followed closely by `Cheyenne' (36,192 μg TEq/g DW) and, with smaller amounts, by `Cape Fear' and `Pawnee' (16,540 and 13,705 μg TEq/g DW, respectively). Total phenolic content showed a similar trend but `Pawnee' showed a higher phenolic content than `Cape Fear'. `Cheyenne' had the highest amount of tannins, 9,114 μg/g DW, followed by `Cape Fear', `Pawnee' and `Desirable' with 7,764, 6,043 and 5,508 μg/g DW respectively),. `Cheyenne' had also the highest vitamin C content, up to ≈10-fold greater than `Cape Fear' and `Pawnee', the highest difference within the antioxidants analyzed. There is the need to determine the phenolic profile and degree of polymerization of tannins, their contribution to the AC and how they are affected by horticultural practices in order to better understand the nutraceutical potential of each cultivar.

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The objective of this study was to evaluate kernels of different pecan (Carya illinoinensis) cultivars for their antioxidant profile and their contribution to nutritional and quality attributes. Kernels were analyzed for their antioxidant capacity (AC), phenolic, tannin, and vitamin C content. Fatty acid (FA) composition and phenolic profile were determined using, respectively, gas and liquid chromatographic techniques. AC was measured using one spectrophotometrical [2,2-diphenyl-1-picrylhydrazyl (DPPH)] and one fluorescence method [oxygen radical absorbance capacity (ORAC)]. Phenolic and tannin content were determined using spectrophotometrical assays. Ascorbic and dehydroascorbic acid were determined using a HPLC. Both AC methodologies gave similar results with marked differences between cultivars. `Desirable' had an antioxidant capacity of 47,747 μg·g-1 TEq/DW with DPPH method followed closely by `Cheyenne' (36,192 μg·g-1 TEq/DW) and, with smaller amounts, by `Cape Fear' and `Pawnee' (16,540 and 13,705 μg·g-1 TEq/DW, respectively). Total phenolic content showed a similar trend, but `Pawnee' showed a higher phenolic content than `Cape Fear'. The FA composition varied between cultivars. This phenolic profile jointly with FA composition and other compositional characteristics will provide the quality and nutritional attributes of each specific cultivar. Furthermore, the high antioxidant profile of pecans suggests that bioactive and anticancer properties should also be evaluated. Results from the present research can be used as an additional tool to evaluate pecan cultivars and help create new guidelines for breeding programs to select “healthier” pecans.

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