基于游离氨基酸的组分及特征比较四种食用菌与四种果蔬的营养与风味特征

为科学评价食用菌与果蔬两类食材的营养特征与口感风味,本研究选取4种常见食用菌（金针菇、斑玉蕈、香菇、双孢蘑菇）和4种常见果蔬（苹果、香蕉、胡萝卜、番茄）,采用氨基酸自动分析仪测定其游离氨基酸,系统比较了两类食材的游离氨基酸组分比例及呈味特征。主成分和聚类分析表明 4种食用菌和4种果蔬显著分为两类,食用菌类游离氨基酸总量平均是果蔬类的3倍以上,4种食用菌中各游离氨基酸的比例均衡。4种食用菌的必需氨基酸/(必需氨基酸+非必需氨基酸)在40%左右,必需氨基酸/非必需氨基酸接近或大于60%,均接近理想值。4种食用菌所含的呈味氨基酸（鲜味、甜味、芳香族、苦味）均是4种果蔬的2倍以上,TAV值最显著的是：谷氨酸、苯丙氨酸、甘氨酸、苏氨酸、组氨酸、赖氨酸、缬氨酸、精氨酸和丙氨酸。这些氨基酸分属在五大氨基酸家族,在食用菌与果蔬中代谢途径相同;只有赖氨酸在二者中的合成途径不同。结果表明供试的食用菌比果蔬有优质的氨基酸比例和丰富的呈味组分,此差异体现在众多氨基酸的代谢层面,而非个别氨基酸导致。     

珠子参地上部分氨基酸测定及营养评价

对珠子参茎、叶、花的氨基酸组成与含量进行测定和营养评价分析.结果表明,珠子参茎、叶、花中均含有17种常见氨基酸,氨基酸总量分别为3.73％,14.80％和8.72％;珠子参的茎中必需氨基酸与总氨基酸的比值(E/T)为0.39,必需氨基酸与非必需氨基酸的比值(E/N)为0.64,叶中E/T为0.41,E/N为o.71,花中E/T为0.39,E/N为0.63,氨基酸配比较为合理;珠子参茎、叶、花中蛋氨酸+胱氨酸均为第一限制氨基酸;珠子参茎、叶、花中均含有γ-氨基丁酸,含量分别为0.12％,0.26％和0.16％,叶片中γ-氨基丁酸的含量最高.     

饲养中国大鲵氨基酸组成分析

实验对饲养中国大鲵氨基酸组成成分进行了比较全面的测定与分析,结果表明:饲养中国大鲵肌肉的蛋白质质量分数为164.3 g.kg-1,水解氨基酸总量为160.6 g.kg-1,各种氨基酸组成相当全面,必需氨基酸(EAA)为75.2 g.kg-1,占氨基酸总量的46.82%,符合人体需要量模式的程度相当高,为优质食物蛋白,可与做为参考蛋白的鸡蛋蛋白相媲美。研究同时发现呈味氨基酸总量70.5 g.kg-1,占氨基酸总量的43.90%,为研发味道鲜美的大鲵食品提供了有力的数据。     

冬虫夏草口服液游离氨基酸和微量元素的分析比较

目的：为了研究冬虫夏草口服液的有效成分和药用价值,测定冬虫夏草口服液中的游离氨基酸和微量元素的不同种类和含量。方法：采用安捷伦1200高效液相色谱仪,C18反相柱梯度分离,邻苯二甲醛一芴甲酯柱前自动衍生化,利用已知浓度氨基酸标准品进行外标法定量,根据已知浓度氨基酸标准品的峰面积与样品峰面积之比计算游离氨基酸的含量。结果：冬虫夏草口服液中含有23种游离氨基酸和18种微量元素,氨基酸总量在口服液中占0．892％,必需氨基酸在游离氨基酸总量中占53．1％;含量最高的游离氨基酸依次是赖氨酸、亮氨酸、精氨酸。结论：游离氨基酸是冬虫夏草口服液中重要的生物有效成分,为冬虫夏草口服液的药效提供了基础数据。     

小碎斑鱼蛉幼虫资源成分分析及价值评价

针对小碎斑鱼蛉Neochauliodes sparsus(Liu et Yang)幼虫,进行了资源成分测定,分析。结果表明:小碎斑鱼蛉幼虫干物质中蛋白质、氨基酸、脂肪、糖类及灰分含量分别为67.69%、56.02%、10.4%、1.59%、7.05%,含有18种氨基酸,包括8种人体必需氨基酸,其必需氨基酸占总氨基酸含量的45.32%,必需氨基酸与非必需氨基酸含量的比值为82.89%,第一限制性氨基酸为色氨酸;此外,还含有Ca、P、Fe、Zn等多种矿物质和微量元素。在分析了小碎斑鱼蛉幼虫资源成分的基础上,对其开发利用价值进行了评价。     

商品鹿鞭中氨基酸含量比较

采用氨基酸自动分析仪测定不同品种与产地的9份鹿鞭药材中氨基酸成分的种类及含量。这9份样品中均含17种氨基酸,其中人体必需氨基酸6种。17种氨基酸中以甘氨酸含量最高,必需氨基酸中亮氨酸含量最高;比较不同样品的含量,以辽宁西丰的梅花鹿鞭的总氨基酸含量最高,黑龙江梅花鹿鞭的必需氨基酸含量最高。结论为不同产地鹿鞭中氨基酸含量有一定差异,该方法可用于鹿鞭药材的质量评价。     

大杯香菇辐射新株系各类氨基酸的遗传主成分分析

对大杯香菇辐射选育新株系的各类氨基酸总量进行了遗传主成分分析。结果表明,变异系数最大的为硫氨基酸总量,达到13．39％;其次为儿童氨基酸总量,变异系数为7．00％;其它变异系数较小分别为甜味氨基酸总量、芳香族氨基酸总量、必需氨基酸总量、支链氨基酸总量和鲜味氨基酸总量为5．69％、5．64％、5．19％、5．24％和5．06％;在相关性上,鲜味氨基酸总量与甜味氨基酸总量、支链氨基酸总量、芳香族氨基酸总量、儿童氨基酸总量和必需氨基酸总量是呈极显著和显著的正相关,甜味氨基酸总量与支链氨基酸总量、儿童氨基酸总量和芳香族氨基酸总量呈极显著和显著的正相关,硫氨基酸总量与儿童氨基酸总量呈极显著负相关,与必需氨基酸总量是呈极显著正相关;支链氨基酸总量与芳香族氨基酸总量、必需氨基酸总量是呈极显著,与儿童氨基酸总量呈显著正相关;芳香族氨基酸总量与儿童氨基酸总量和必需氨基酸总量是呈极显著和显著的正相关;主成分分析结果表明,前4个特征根在7个特征根中累计贡献率达97．14％,也就是前4个主成分对变异的贡献率达96．07％。在各类氨基酸总量指标选择上,首先对变异大的各类氨基酸总量进行选择是及其重要的。在辐射选育新株系选择时,应注意选择大杯香菇中硫氨基酸总量高的新株系。     

Rates of exchange of free amino acids between plasma and brain in mice

The rate of appearance of label in the brain in mice following the intraperitoneal or intravenous injection of tracer doses of amino acids was measured in short time periods (1–8 min). Amino acid flux varied between 2 and 10 nmol/min per g brain for the amino acids used. Defining half-life as the uptake of labeled amino acid amounting to 50% of endogenous levels, a short half-life (between 3 and 30 min) was found for the essential amino acids. The half-life of the nonessential amino acids varied between 2 and 24 h, depending on their level in brain. Flux (exchange) of an amino acid was increased when the level of amino acids belonging to the same transport class was increased by intracerebral injection. Protein-free diet resulted in decrease in some amino acids, increase in others; flux was altered parallel to changes in brain levels in animals on this diet. The stercospecificity of exchange and the substrate specificity of effects of altered brain amino acids indicate that exchange occurs via mediated transport. Mediated exchange was present in immature brain. Heteroexchange (flow of one amino acid causing the counterflow of a related amino acid) may play an important part in cerebral homeostasis.     

洞庭青鲫肌肉营养成分分析及营养价值评定

对2002年在湖南澧县澧水尾闾、洞庭湖区边缘化的封闭型湖泊——北民湖发现的洞庭青鲫(Carassius auratus var.dongtingking)(n=15)的含肉率和肌肉中的生化成分、比能值及氨基酸测定分析。结果表明,洞庭青鲫的含肉率为52.18%;其肌肉生化成分(鲜重百分比)为:水分78.14%,蛋白质18.63%,脂肪1.51%,灰分1.22%,比能值5.09kJ/g及E/P值27.32kJ/g。肌肉中含有17种氨基酸,总量为866.12mg/g(干重比);其中9种人体必需氨基酸含量占氨基酸总量的48.21%(盐酸水解法);支/芳值达2.81,接近人体正常所需;4种鲜味氨基酸占氨基酸总量的50.39%。根据氨基酸评分(AAS)和化学评分(CS)标准,洞庭青鲫的第一限制因子是甲硫氨酸和胱氨酸,其次是缬氨酸、苯丙氨酸和酪氨酸。即洞庭青鲫氨基酸含量与组成与彭泽鲫(C.a.var.pengze)、异育银鲫(C.a.var.allogynogeneticrp)、萍乡肉红鲫(C.a.var.pingxing red)相比,均存在差异。     

羊胎素中氨基酸测定与评价

用日立L-8800型氨基酸自动分析仪测定了羊胎素中的氨基酸含量。结果表明羊胎素中18种氨基酸总量、必需氨基酸及药效氨基酸含量较高,提示羊胎素在营养学和医学上都有很高的研究价值。     

Influence of amino acid supply on ribosomes and protein synthesis of perfused rat liver

1. The livers of rats were perfused in situ with medium containing mixtures of amino acids in multiples of their concentration in normal rat plasma. The incorporation of labelled amino acid into protein of the liver and of the perfusing medium increased with increasing amino acid concentration. During 60min. perfusions, labelling of liver protein reached a plateau, and labelling of medium protein was inhibited when the initial concentration of the amino acid mixture was more than ten times the normal plasma value. 2. Examination of polysome profiles derived from livers perfused without amino acids in the medium showed that the number of large aggregates was decreased and the number of small aggregates, particularly monomers and dimers, was increased with time of perfusion. The addition of amino acids to the perfusion medium reversed this polysome shift to an extent that was dependent on the initial concentration of amino acids. Polysome profiles derived from livers perfused for 60min. with ten times the normal plasma concentration of amino acids were essentially the same as the polysome profiles of normal non-perfused livers. 3. The ability of ribosome preparations from perfused livers to incorporate amino acids into protein in vitro decreased with increasing time of perfusion when no amino acids were added to the medium, but increased as the concentration of amino acids in the perfusion medium was increased. 4. The ability of cell sap from perfused livers to support protein synthesis in vitro was not influenced by the amino acid concentration of the perfusion medium. 5. Livers were perfused for 60min. with medium containing amino acid mixtures at ten times the normal plasma concentration but deficient in one amino acid. Maximal incorporation of labelled amino acid into liver protein, the stability of the polysome profile and the ability of ribosome preparations to incorporate amino acids into protein were found to depend on the presence of 11 amino acids: arginine, asparagine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, threonine, tryptophan and valine. A mixture of these 11 amino acids, at ten times their normal plasma concentration, stimulated the incorporation of labelled amino acid into liver protein, stabilized the polysome profile and increased the ability of ribosome preparations to incorporate amino acids into protein to the same extent as the complete mixture. 6. It is concluded that the availability of certain amino acids plays an important role in the control of protein synthesis, possibly by stimulating the ability of ribosomes to become, and to remain, attached to messenger RNA.     

蓬蘽果实与叶片氨基酸成分分析

通过对蓬蘽氨基酸成分分析,蓬蘽果实与叶片均含有17种氨基酸,其中7种为人体必需氨基酸。其果实不同类型氨基酸之间的配比及含量达到或接近FAO/WHO提出的理想蛋白质模式谱标准[1]。谷氨酸含量最高,蛋氨酸含量最低,其中谷氨酸、天冬氨酸、亮氨酸居前三位。蓬蘽叶片氨基酸总含量显著高于鲜果,谷氨酸含量最高,丙氨酸含量最低,谷氨酸、赖氨酸、苏氨酸居前三位,均衡度稍逊于果实。作为对照,测定了草莓果叶、茶叶的相关数据。     

麦苗中氨基酸测定与评价

用日立L-8800型氨基酸自动分析仪测定了麦苗中的氨基酸含量.结果表明麦苗中18种氨基酸总量、必需氨基酸及药效氨基酸含量较高,提示麦苗在营养学和医学上都有很高的研究价值.     

Amino acid transport and metabolism in nitrogen-starved cells of Saccharomyces cerevisiae.

Nitrogen-starved yeast derepress a general amino acid permease which transports basic and hydrophobic amino acids. Although both groups of amino acids are metabolized, the derivatives of the basic amino acids are retained by the cells, whereas those of the hydrophobic amino acids are released as acidic and neutral deaminated derivatives. The release of the deaminated derivatives of the hydrophobic amino acids only occurs in the presence of glucose, which presumably produces amino acceptors. The accumulation of intracellular amino acids results in trans-inhibition of the uptake of exogenous amino acids whether the intracellular amino acid is a basic amino acid or the product of intracellular transamination from a hydrophobic amino acid. Variation of permease and transaminase activity was measured during growth under repressed (ammonia-grown) and derepressed (proline-grown) conditions. Maximum levels for both activities occurs at the mid-exponential phase.     

Extra- and intracellular amino acids in the hippocampus during development of hepatic encephalopathy

Fulminant hepatic failure was induced in rabbits by intravenous administration of galactosamine hydrochloride. The animals were sacrified after 45 h and the hippocampus analyzed for free amino acids. In addition, free amino acids were measured in plasma and in the extracellular fluid of the hippocampus 20, 30 and 45 h after galactosamine injection. The extracellular fluid compartment was analyzed by slow perfusion of a thin dialysis tube which was implanted in the hippocampus one day prior to galactosamine administration. The amino acid concentration in the extracellular fluid agreed fairly well with that of the cerebrospinal fluid in the control situation. During development of hepatic failure, the plasma concentrations of all amino acids increased. The changes in extracellular amino acids were smaller, except for phosphoethanolamine and glutamate. The concentration ratio intra/extracellular amino acids decreased in the hippocampus for amino acids with a normally high concentration gradient.     

Infusion of amino acids decreases the hyperglycaemic effect of per- and postoperative glucose infusion: an experimental study in the rabbit

The effects on blood glucose concentration of 10% glucose with amino acid solution at low (18%) and high (25%) concentration of branched chain amino acids were studied, two days after laparotomy in fasted rabbits. During the whole study period, saline infusion was associated with normoglycaemia. Among the other infusion combinations peroperative infusion of amino acid solution high in branched chain amino acids with 10% glucose was the least hyperglycaemic. An amino acid solution low in branched chain amino acids with 10% glucose had the lowest hyperglycaemic effect 24 hours postoperatively. After 48 hours an infusion of 10% glucose produced the weakest hyperglycaemia. In preoperatively and 24 hours postoperatively 10% glucose was more hyperglycaemic than 10% glucose with the two amino acid solutions. After 24 and 48 hours, infusion of 10% glucose with amino acids high in branched chain amino acids was more hyperglycaemic than 10% glucose with amino acids low in branched chain amino acids.     

白斑狗鱼含肉率及其营养价值的分析

测定了6尾白斑狗鱼(Esox lucius)的含肉率和营养成分,并与部分淡水优质经济鱼类进行了比较.结果表明:白斑狗鱼含肉率为64.8%,粗蛋白含量和脂肪含量分别为19.1%和1.4%,17种氨基酸总量为17.38%,其中7种必需氨基酸总量为8.14%,鲜味氨基酸总量为6.36%.必需氨基酸总量占氨基酸总量的45.73%,低于鸡蛋蛋白模式,但明显高于WHO/FAO模式.必需氨基酸指数为76.35,根据化学评分计算结果,得出第一限制性氨基酸为缬氨酸,第二限制性氨基酸为蛋氨酸,第三限制性氨基酸为异亮氨酸.结果提示,白斑狗鱼是一种营养价值较高的鱼类.     

冬虫夏草及人工虫草菌丝体的氨基酸营养

本文研究了天然虫草菌与人工虫草菌的氨基酸含量。结果表明,天然虫草菌、人工虫草菌的总氨基酸含量稍有差异,但中性、酸性、碱性氨基酸和必需氨基酸在总氨基酸中所占百分比的高低基本一致。     

Gustatory responses of eel palatine receptors to amino acids and carboxylic acids

The gustatory receptors of the eel palate were found to be extremely sensitive to amino acids and carboxylic acids. The results obtained are as follows: (a) 11 amino acids which are among naturally occurring amino acids elicited responses in the palatine nerve, but 9 amino acids did not elicit a response even at a high concentration. The effect of D-amino acids was always much less than that of their corresponding L-isomers. There was no appreciable difference in the effectiveness of an alpha-amino acid (alpha-alanine) and beta-amino acid (beta-alanine). (b) The threshold concentrations of the most potent amino acids (arginine, glycine) were between 10(-8) and 10(-9) M. A linear relation between the magnitude of the response and log stimulus concentration held for a wide concentration range for all the amino acids examined. (c) The palatine receptors responded sensitively to various carboxylic acid solutions whose pH was adjusted to neutral. The threshold concentrations varied between 10(-4) and 10(-7) M. The magnitude of the response at 10(-2) M increased with an increase of carbon chain length. (d) The extent of cross-adaptation was examined with various combinations of amino acids. A variety of the response patterns showing complete cross-adaptation, no cross-adaptation, or synergetic interaction was observed. The synergetic interaction was also observed when one amino acid below its threshold concentration was added to the other amino acid below its threshold concentration was added to the other amino acid. No cross-adaptation was observed between amino acids and fatty acids. (e) The treatment of the palate with papain led to loss of the responses to arginine, glycine, and histidine without affecting those to proline and acetic acid. The treatment with pronase E eliminated selectively the response to proline. The possibility that the eel gustatory receptors are responsible for sensing food at a distance was discussed.     

Formation of molecules of biological interest from formaldehyde and hydroxylamine in a modified sea medium

As reported previously, glycine, serine, aspartic acid, and beta-alanine are the predominant amino acids produced from equimolecular formaldehyde and hydroxylamine in a modified sea medium enriched with essential transition metal ions. The time course of formation of the amino acids, and related substances was studied. Among the amino acids, glycine was produced earlier. Urea was produced initially and disappeared rapidly. Formation of cyanide, glycinenitrile, and glycinamide preceded the formation of amino acids. Probable pathways for the formation of amino acids and urea are suggested.