引种果桑和叶桑叶片中营养功能成分含量及其抗氧化活性

李珂; 张振军; 杜玉霞; 李彩霞; 张勇; 王恩军; 张东芝

doi:10.13386/j.issn1002-0306.2023100104

引种果桑和叶桑叶片中营养功能成分含量及其抗氧化活性

Analysis of Nutrient Functional Components and Antioxidant Activity in Leaves of Introduced Fruit and Leaf Mulberries

摘要

摘要: 为明确引种桑叶的营养和抗氧化特性，促进桑叶资源在河西地区的开发和利用。本研究以果桑和叶桑的叶片为研究材料，测定其主要营养功能成分的含量，并分析不同活性成分与桑叶提取物抗氧化能力之间的相关性。结果表明，叶桑中粗蛋白、粗脂肪、还原糖、灰分的含量均显著高于果桑（P<0.05），而两者的γ-氨基丁酸和芦丁含量无显著差异（P>0.05）。叶桑中黄酮含量（50.57 mg.g⁻¹）显著高于果桑（46.96 mg.g⁻¹）（P<0.05），两者中的多酚和多糖含量差异不显著。果桑和叶桑叶片中矿质元素的含量大小顺序均为K>Ca>Mg>Na>Fe，且呈现高钾低钠特性，叶桑中K、Mn、Zn、Cu、Ni元素的含量高于果桑，而Ca、Mg、Na、Fe元素含量却呈现相反的趋势。果桑和叶桑叶片中Na元素、粗脂肪和还原糖含量的营养质量指数（index of nutritional quality，INQ）均<1，而K、Mn、Ca、Mg、Zn、Fe、Cu元素、粗蛋白的INQ均>1，营养当量（nutrition equivalent，NEU）显示叶桑高于果桑。果桑中黄酮和多糖对DPPH自由基清除率高于叶桑，但叶桑中黄酮对ABTS⁺自由基清除率高于果桑，而两品种中多糖对ABTS⁺自由基清除率差异不大。相关性表明，叶桑和果桑叶中黄酮、芦丁、多酚、多糖含量与DPPH自由基清除存在极显著正相关（P<0.01），相关系数在0.899~0.991范围内，而与ABTS⁺自由基清除率之间比较差异不显著（P>0.05）。综上，叶桑的营养功能价值及抗氧化活性优于果桑，更适宜于引种至河西地区进行综合开发利用。

Abstract: Clarifying the nutritional and antioxidant characteristics of introduced mulberry leaves aids development and utilization in Hexi region, China. The main nutrients and functional components of fruit and leaf mulberries, and correlations between antioxidant capacities of their leaf extracts, were investigated. Crude protein, crude fat, reduced sugar, and ash contents of leaf mulberry were significantly higher than those of fruit mulberry (P<0.05), while differences in γ-aminobutyric acid and rutin in leaves of these two cultivars were not significant (P>0.05). Flavonoid concentrations in leaf mulberry (50.57 mg.g⁻¹) were significantly higher than in fruit mulberry (46.96 mg.g⁻¹) (P<0.05), but differences in polyphenol and crude polysaccharide concentrations between them were not significant. Mineral contents in fruit and leaf mulberry leaves were high in potassium and low in sodium, and occur in the order K>Ca>Mg>Na>Fe. Leaf mulberry K, Mn, Zn, Cu and Ni contents were higher than those in fruit mulberry, while the opposite holds for Ca, Mg, Na and Fe contents. The Index for Nutritional Quality (INQ) of Na, crude fat, and reduced sugar contents in fruit and leaf mulberry leaves were<1, while K, Mn, Ca, Mg, Zn, Fe, Cu, and crude protein contents were>1. Additionally, nutrition equivalent (NEU) from leaf mulberry exceeds that of fruit mulberry. Flavones and polysaccharides in fruit mulberry have higher DPPH radical clearance activity than leaf mulberry, but flavonoids in leaf mulberry had higher radical clearance of ABTS⁺ than fruit mulberry. There was little difference in polysaccharide clearance of ABTS⁺ between the two cultivars. Highly significant positive correlations (correlation coefficients ranging 0.899~0.991) in flavonoid, rutin, polyphenol and polysaccharide content DPPH radical scavenging exist between the two cultivars. There was no significant difference in the ABTS⁺ free radical scavenging rate. The nutritional function and antioxidant activity of leaf mulberry exceed those of fruit mulberry, which was more suitable for the Hexi region.