Various fatty acids, tocopherols, carotenoids, and their respective antioxidant contributions in 7 amaranth seed and 11 quinoa seed samples along with a new evaluation method are reported. The lipid yield was 6.98-7.22% in amaranth seeds and 6.03-6.74% in quinoa seeds, with unsaturated fatty acids (UFAs) being the predominant fatty acids, 71.58-72.44% in amaranth seeds and 81.44-84.49% in quinoa seeds, respectively. Carotenoids, mainly lutein and zeaxanthin, are confirmed for the first time in amaranth seeds, while β-carotene is reported first in quinoa seeds. The predominant tocopherols in amaranth seeds are δ- and α-tocopherol, whereas γ- and α-tocopherol are the primary tocopherols in quinoa seeds. UFAs, carotenoids, and tocopherols showed good correlation with antioxidant activity. All of the amaranth seeds demonstrated lower overall lipophilic quality than quinoa seeds, with the AS1 and QS10 cultivars providing the highest scores for amaranth and quinoa seeds, respectively. Results from this study will contribute to developing quinoa seeds and related functional foods with increased benefits.

Hydrophilic extracts from different parts including leaves, stalks, seeds, flowers and sprouts of 3 Amaranthus species (Amaranthus hypochondriacus, Amaranthus caudatus and Amaranthus cruentus) were characterized for their phytochemical profiles including the phenolics and betacyanins by UHPLC and LC-ESI-MS, and their antioxidant activities by FRAP and ORAC assays. The main betacyanins in Amaranthus samples were identified to be amaranthine and isoamaranthine. Eleven phenolic compounds (gallic acid, protocatechuic acid, chlorogenic acid, gentistic acid, 2,4-dihydroxybenzoic acid, ferulic acid, salicylic acid, rutin, ellagic acid, kaempferol-3-rutinoside and quercetin) were identified in the extracts of different parts of Amaranthus. The total phenolic content (TPC) ranged from 1.04 to 14.94 mg GAE/g DW; the total flavonoid content (TFC) ranged from 0.27 to 11.40 mg CAE/g DW; while the total betalain content (TBC) ranged from 0.07 to 20.93 mg/100 g DW. FRAP values ranged from 0.63 to 62.21 mu mol AAE/g DW and ORAC ranged from 30.67 to 451.37 mu mol TE/g DW. The leaves of Amaranthus showed the highest TPC, TFC, TBC, FRAP and ORAC values; while the seeds and stalks the lowest. There was a strong correlation between TPC, TBC, TFC and the antioxidant activity. The result suggests that all parts of the Amaranthus plant can be a good source of antioxidants. Crown Copyright (C) 2014 Published by Elsevier Inc. All rights reserved.