氨基酸是参与人体蛋白质合成和各种代谢和免疫反应的一组重要化合物。中国大枣(ZiziphusjumbaMill。)是一种重要的水果和药用植物,原产于中国,已被引入约50个国家。然而,对大枣中氨基酸组成和含量多样性的系统研究尚缺乏。在这个实验中,采用高效液相色谱法测定了161个大枣品种果实的氨基酸组成和主要氨基酸含量。在检测到的二十一种氨基酸中,共检测到14种氨基酸,其中八种氨基酸含量相对较高,包括五种必需氨基酸(苏氨酸,缬氨酸,异亮氨酸,亮氨酸,和苯丙氨酸)和三种非必需氨基酸(甘氨酸,丙氨酸,和脯氨酸)。然而,其余六种氨基酸的含量相对较低(天冬氨酸,谷氨酸,组氨酸,丝氨酸,精氨酸和色氨酸)。因此,以8种伯氨基酸为指标,对161个枣品种的氨基酸进行评价。在8种氨基酸中,脯氨酸占总氨基酸含量的56.8%。大多数枣品种中8种伯氨基酸的总含量为1-1.5g/100g,“枣强马连枣”的最高含量为2.356g/100g。脯氨酸的平均含量是其他7种氨基酸的6.01-14.84倍。根据世界卫生组织/粮农组织修订的人类理想必需氨基酸模型谱,19个品种符合E/T(必需氨基酸/总氨基酸)标准,其值在35%至45%之间;12个品种符合E/NE(非必需氨基酸)≥60%。所有品种均达到BC(支链氨基酸)/E≥40%的要求,其中15个品种超过68%。一百五十七个品种达到BC/A(芳香族氨基酸)≈3.0〜3.5的标准。氨基酸比系数分析表明,苯丙氨酸是所有枣品种的第一限制性氨基酸。134个品种的氨基酸比例系数(SRC)值在50%~70%之间,有12个品种超过70%,表明枣果在氨基酸方面具有很高的营养价值。基于主成分分析和氨基酸营养价值综合排序,从161个测试品种中筛选出排名前五位的品种,即,\'滕州昌洪灶\',\'新郑小园早\',\'Hanguowudeng\',\'徐蒲田素灶\',和\'李成小灶\'。这项研究建立,首先,完整的枣果氨基酸含量基础数据分析,可用于筛选适合开发功能性氨基酸食品的种质资源,为大枣氨基酸的高值化利用提供理论支持。
Amino acids are an essential group of compounds involved in protein synthesis and various metabolic and immune reactions in the human body. Chinese jujubes (Ziziphus jujuba Mill.) are an important fruit and medicinal plant which are native to
China and have been introduced into around 50 countries. However, systematic research on the composition and content diversity of amino acids in the jujube is still lacking. In this experiment, the amino acid composition and the contents of the dominant amino acids in the fruit of 161 cultivars of jujube were determined by HPLC. Of the twenty-one kinds of amino acids detected, a total of fourteen kinds of amino acids were detected, of which eight kinds of amino acids were relatively high, including five essential amino acids (threonine, valine, isoleucine, leucine, and phenylalanine) and three nonessential amino acids (glycine, alanine, and proline). However, the contents of the remaining six amino acids were relatively low (aspartic acid, glutamic acid, histidine, serine, arginine, and tryptophan). Therefore, the eight primary amino acids were used as the index to evaluate the amino acids of 161 jujube varieties. Proline accounts for 56.8% of the total amino acid content among the eight amino acids. The total content of the eight primary amino acids in most jujube varieties was 1-1.5 g/100 g, and the highest content of \'Zaoqiangmalianzao\' was 2.356 g/100 g. The average content of proline was 6.01-14.84 times that of the other seven amino acids. According to the WHO/FAO revised model spectrum of ideal essential amino acids for humans, 19 cultivars met the E/T (essential amino acids/total amino acids) standard, and their values ranged from 35% to 45%; 12 cultivars meet E/NE (non-essential amino acids) ≥ 60%. All cultivars reached the requirement of BC (branched-chain amino acids)/E ≥ 40% with 15 cultivars over 68%. One hundred and fifty-seven cultivars reach the standard of BC/A (aromatic amino acids) ≈ 3.0~3.5. The amino acid ratio coefficient analysis showed that phenylalanine was the first limiting amino acid of all the jujube cultivars. The SRC (the score of amino acid ratio coefficient) values of 134 cultivars were between 50% and 70%, with 12 cultivars over 70%, indicating that jujube fruits are of high nutritional value in terms of amino acids. Based on the principal component analysis and comprehensive ranking of amino acid nutritional value, the top five cultivars were screened from the 161 ones tested, i.e., \'Tengzhouchanghongzao\', \'Xinzhengxiaoyuanzao\', \'Hanguowudeng\', \'Xuputiansuanzao\', and \'Lichengxiaozao\'. This study established, firstly, a complete basic data analysis of amino acid content in jujube fruit which could be used to select germplasm resources suitable for developing functional amino acid food, and provide theoretical support for the high value utilization of amino acids in jujubes.