IDENTIFICATION AND QUANTIFICATION OF PHENOLIC COMPOUNDS AND ANTIOXIDANT ACTIVITY IN COWPEAS OF BRS XIQUEXIQUE CULTIVAR

ABSTRACT Cowpea (Vigna unguiculata [L.] Walp.) is one of the most important legumes produced in tropical and subtropical regions throughout the world, especially in the developing countries in Africa, Latin America, and Asia. It is the main source of protein, calories, dietary fiber, minerals, and vitamins for a large segment of the world population. Cowpea is also a potential functional food with a range of bioactive compounds, including phenolic compounds. This legume is grown mainly in the North and Northeast regions of Brazil, but is also consumed in other regions, and is thus important for the farmers who depend on this crop for income. This study identified and quantified phenolic compounds in the cowpea cultivar BRS Xiquexique. Such quantification reveals the functional characteristics of cowpeas, mainly as a source of antioxidants, which will be essential to add value to this food and to expand its forms of consumption. The extracts were analyzed using an HPLC model LC-20AT, equipped with a manual injector. For the HPLC analysis, standard solutions were prepared with pure phenolic acids such as gallic acid, quercetin, caffeic acid, chlorogenic acid, ferulic acid, p-coumaric acid, catechin, and epicatechin. The major phenolic compounds identified were catechin (2.07± 0.329 mg 100 g-1), epicatechin (0.48 ± 0.130 mg 100 g-1), gallic acid (67.19 ± 6.200 mg 100 g-1), ferulic acid (32.07 ± 0.753 mg 100 g-1), and chlorogenic acid (3.08 ± 0.489 mg 100 g-1). We observed that the BRS Xiquexique cultivar contains functional phenolic compounds, especially gallic acid and ferulic acid, demonstrating the antioxidant potential of cowpea.

摘要 豇豆（Vigna unguiculata [L.] Walp.）是全球热带与亚热带地区种植的核心豆科作物之一，在非洲、拉丁美洲及亚洲的发展中国家尤为重要。它是全球大量人口获取蛋白质、热量、膳食纤维、矿物质与维生素的主要膳食来源。豇豆同时也是一类具备开发潜力的功能性食品，含有包括酚类物质在内的多种生物活性化合物。该豆科作物主要栽培于巴西北部与东北部地区，同时在其他区域亦有广泛消费，因此对于依赖该作物创收的农户而言具有极高的经济价值。本研究对豇豆品种BRS Xiquexique中的酚类化合物开展了鉴定与定量分析。此类定量分析可揭示豇豆的功能特性，尤其是其作为抗氧化剂来源的潜力，这对提升该食品的附加值、拓展其消费形式具有关键意义。本研究采用配备手动进样器的LC-20AT型高效液相色谱（High Performance Liquid Chromatography，HPLC）对提取物进行分析。在高效液相色谱分析流程中，我们以没食子酸、槲皮素、咖啡酸、绿原酸、阿魏酸、对香豆酸、儿茶素及表儿茶素等纯酚酸配制了系列标准溶液。本次研究鉴定出的主要酚类化合物包括：儿茶素（2.07±0.329 mg·100g⁻¹）、表儿茶素（0.48±0.130 mg·100g⁻¹）、没食子酸（67.19±6.200 mg·100g⁻¹）、阿魏酸（32.07±0.753 mg·100g⁻¹）及绿原酸（3.08±0.489 mg·100g⁻¹）。研究结果表明，BRS Xiquexique品种含有具备功能活性的酚类化合物，尤其是没食子酸与阿魏酸，证实了豇豆的抗氧化应用潜力。