School of Agriculture and Food, Faculty of Science, The University of Melbourne, 3010 Parkville, VIC, Australia.
Centre for Sustainable Bioproducts, School of Life and Environmental Sciences, Deakin University, 3217 Waurn Ponds, VIC, Australia.
Front Biosci (Landmark Ed). 2023 Mar 3;28(3):44. doi: 10.31083/j.fbl2803044.
Lentil ( M.) is a legume widely consumed worldwide. It is rich in bioactive compounds, including polyphenolic compounds that contribute to positive health benefits.
This study aimed to determine the phenolic content and antioxidant activity of black, red, green, and brown whole lentils. Towards this end, the lentils' phenolic compounds were evaluated regarding their total phenolic content (TPC), total flavonoid content (TFC), total tannin content (TTC), total condensed tannin (TCT), total proanthocyanin content (TPAC), total anthocyanin content (TAC). For the antioxidant activity 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), hydroxyl radical scavenging activity (•OH-RSA), ferrous ion chelating activity (FICA), reducing power assay (RPA) and phosphomolybdate (PMA) assay were accessed. To identify individual phenolic compounds, liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS2) was used.
The results showed that green lentils exhibited the highest TPC (0.96 mg gallic acid equivalents (GAE)/g) whereas red lentils presented the highest TFC (0.06 mg quercetin equivalents (QE)/g). Black lentils were noted with the highest TCT (0.03 mg catechin equivalents (CE)/g), TPAC (0.009 mg cyanidin chloride equivalents (CCE)/g), and TAC (3.32 mg/100 g) contents. While the greatest TTC (2.05 mg tannic acid equivalents (TAE)/g) was observed in the brown lentil. Regarding the total antioxidant capacity, red lentils (4.01 mg ascorbic acid equivalents (AAE)/g) presented the greatest activity, whereas the lowest was found in the brown samples (2.31 mg AAE/g). The LC-ESI-QTOF-MS2 tentatively identified a total of 22 phenolic compounds, containing 6 phenolic acids, 13 flavonoids, 2 lignans, and 1 other polyphenol. The relationships among phenolic compounds by Venn Diagram showed a high number of overlapping compounds in brown and red lentils (6.7%), and a low number of overlapping compounds between the green, brown, and black lentils (2.6%). Flavonoids were the most abundant phenolic compound within the studied whole lentils, with the brown lentils being the richest in phenolic compounds, especially flavonoids.
This study emphasized a comprehensive understanding of the antioxidant potential of lentils and disclosed the phenolic distribution across various lentil samples. This may increase interest in the development of functional food products, nutraceutical ingredients, and pharmaceutical applications with lentils.
小扁豆（M.）是一种在全球范围内广泛食用的豆类。它富含生物活性化合物，包括多酚化合物，这些化合物有助于带来积极的健康益处。
本研究旨在确定黑、红、绿、棕全扁豆中的酚类含量和抗氧化活性。为此，评估了小扁豆中的酚类化合物，包括总酚含量（TPC）、总类黄酮含量（TFC）、总单宁含量（TTC）、总缩合单宁（TCT）、总原花青素含量（TPAC）、总花青素含量（TAC）。对于抗氧化活性，使用了 2,2-二苯基-1-苦基肼（DPPH）、铁还原抗氧化能力（FRAP）、2,2'-联氮双-3-乙基苯并噻唑啉-6-磺酸（ABTS）、羟基自由基清除活性（•OH-RSA）、亚铁离子螯合活性（FICA）、还原能力测定（RPA）和磷钼酸盐（PMA）测定法。为了鉴定个体酚类化合物，使用了液相色谱-电喷雾电离四极杆飞行时间质谱联用（LC-ESI-QTOF-MS2）。
结果表明，绿扁豆的 TPC（0.96 毫克没食子酸当量（GAE）/克）最高，而红扁豆的 TFC（0.06 毫克槲皮素当量（QE）/克）最高。黑扁豆的 TCT（0.03 毫克儿茶素当量（CE）/克）、TPAC（0.009 毫克矢车菊素氯化物当量（CCE）/克）和 TAC（3.32 毫克/100 克）含量最高。而在棕扁豆中发现了最大的 TTC（2.05 毫克单宁酸当量（TAE）/克）。关于总抗氧化能力，红扁豆（4.01 毫克抗坏血酸当量（AAE）/克）表现出最大的活性，而棕扁豆的活性最低（2.31 毫克 AAE/g）。LC-ESI-QTOF-MS2 初步鉴定了 22 种酚类化合物，其中包含 6 种酚酸、13 种类黄酮、2 种木脂素和 1 种其他多酚。通过 Venn 图显示的酚类化合物之间的关系表明，棕扁豆和红扁豆之间有大量重叠的化合物（6.7%），而绿扁豆、棕扁豆和黑扁豆之间重叠的化合物数量较少（2.6%）。类黄酮是研究全扁豆中最丰富的酚类化合物，棕扁豆中含有最丰富的酚类化合物，尤其是类黄酮。
本研究强调了对小扁豆抗氧化潜力的全面理解，并揭示了不同小扁豆样品中酚类化合物的分布情况。这可能会增加对开发功能性食品产品、营养保健品成分和药物应用的兴趣。
