Varietal differences in amino acid composition of wheat (Triticum aestivum L) grain

The differences in the amino acid composition of the developing grain between the three winter wheat (Triticum aestivum L) varieties Splendeur, Hobbit and Maris Huntsman were analysed in a growth-room experiment. At 15 days after anthesis, Maris Huntsman, the variety with the fastest leaf senescence, had a larger proportion of glutamate and smaller levels of threonine, glycine, alanine, valine, methionine and isoleucine in the total amino acid fraction; at later dates these differences were in general less pronounced, particularly compared with Splendeur. This suggests that, in the variety with the fastest leaf senescence, rapid gliadin synthesis in the grain occurs earlier. At any given percentage of nitrogen in the mature grain, Hobbit had a smaller proportion of glutamate and greater proportions of lysine, arginine and alanine; Splendeur, the only bread-making variety, had smaller levels of aspartate and lysine; and Maris Huntsman had the greatest relative amount of phenylalanine. The possible differences among the varieties in the relative proportion of some protein fractions are discussed. Until 25 days after anthesis Maris Huntsman had smaller relative proportions of free alanine, valine, leucine, isoleocine and threonine, in particular when compared with Splendeur. In Maris Huntsman, the relative amount of aspartate increased from 15 days after anthesis onwards, whereas in Hobbit it only did so in mature grains.     

海南茶叶与茶树花氨基酸含量对比分析

主要对比分析了海南五指山、白沙、保亭、琼中、定安5个主要茶产区的茶叶与茶树花中氨基酸总量及氨基酸组成。结果表明:各茶产区茶叶中氨基酸总量均明显高于茶树花,各产区茶叶与茶树花在氨基酸总量上差值接近;不同产区茶叶中的16种氨基酸的组成比例非常接近,不同产区茶树花中的16种氨基酸组成比例也非常接近,组成比例中占比最高的氨基酸是谷氨酸,占比最低的氨基酸是蛋氨酸;茶叶中谷氨酸、酪氨酸、赖氨酸、精氨酸4种氨基酸占比高于茶树花;茶叶中丝氨酸、脯氨酸、丙氨酸、缬氨酸4种氨基酸占比低于茶树花,其余氨基酸在茶叶和茶树花中的占比较为接近。     

硬骨鱼纲鮟鱇鱼与其他鱼皮基本成分对比及分析

对鮟鱇鱼鱼皮、金鳟鱼鱼皮和大马哈鱼鱼皮的基本成分、氨基酸含量、脂肪酸含量及矿物质含量进行比较和分析。3种鱼皮的粗蛋白质含量是大马哈鱼鱼皮(31.1%)>金鳟鱼鱼皮(30.41%)>鮟鱇鱼鱼皮(20.46%),氨基酸组成相似,3种鱼皮中氨基酸含量最高的均为甘氨酸,分别为26.83,180.00和71.78 mg/g,3种鱼皮的EAAI值均为1.29,均可作为开发蛋白质类产品的优质蛋白源;3种鱼皮饱和脂肪酸占脂肪酸总量比例分别为23.03%,33.37%和26.18%,占比最大的是金鳟鱼鱼皮,单不饱和脂肪酸占比最大的是大马哈鱼鱼皮,多不饱和脂肪酸占比最大的是鮟鱇鱼鱼皮;鮟鱇鱼鱼皮和金鳟鱼鱼皮含有丰富的矿物质元素,含量最丰富的均为钙,含量分别为1537.15和9199.03 mg/kg;大马哈鱼皮中的矿物质元素较少。鮟鱇鱼鱼皮与其他2种鱼皮氨基酸组成相似,脂肪酸相差较大,矿物质元素较其他2种更丰富。     

Proline and arginine accumulation in developing berries of Vitis vinifera L. in Australian vineyards: Influence of vine cultivar, berry maturity and tissue type

Using HPLC analysis, free amino acid profiles were obtained for ripe berries of six grapevine cultivars (Cabernet Sauvignon, Grenache, Muscat Gordo, Pinot Noir, Riesling and Sangiovese) grown under comparable conditions and harvested at similar maturities. Compositional differences were observed between cultivars, however proline and arginine were always the major amino acids. Mature berries of Cabernet Sauvignon contained a very high concentration of proline, but a much lower concentration of arginine. Those of other cultivars contained moderate levels of both arginine and proline.
Changes in free amino acid profiles during grape berry development were further investigated in four cultivars (Cabernet Sauvignon, Chardonnay, Gewurztraminer and Muscat Gordo). In all cases, most of the proline accumulation occurred late in ripening, around four weeks post-veraison. In contrast, arginine accumulation began before veraison and continued to full maturity, except for those cultivars in which a high concentration of proline accumulated, in which case the concentration of arginine reached a plateau relatively early in development. Accumulation of both proline and arginine appears to be develop-mentally regulated. These observations are discussed with reference to proline and arginine metabolism and possible links between them.
The distribution of free proline, arginine and other amino acids amongst pulp, skin and seed was examined using mature fruit of Cabernet Sauvignon and Riesling. Amino acid profiles were found to vary considerably between the berry components. The skin contained a greater ratio of arginine:proline compared with the pulp. This suggests that the yeast-assimilable nitrogen content of juices, and therefore their fermentability, could be enhanced in the presence of skins.     

Free amino acids in botanicals and botanical preparations

ABSTRACT:  Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia , and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and γ-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown.     

AMINO ACID ANALYSIS OF BEER POLYPEPTIDES

The principles of amino acid analysis of proteins and polypeptides are reviewed. Analysis of the amino acid composition of dialysed beer material prepared from a wide variety of commercial and pilot brewery beers showed that the principal amino acids comprised glutamic acid/glutamine, proline, glycine and aspartic acid/asparagine. The results from the analysis of a series of pilot brewery beers brewed under standardised conditions showed that the composition of the grist may influence the amino acid composition of beer polypeptide fractions. Dialysed beer material prepared from beer brewed from grists containing torrified wheat, wheat flour and malted wheat contained greater proportions of glutamic acid/glutamine compared to material prepared from all malt beers. Further fractionation and analysis of dialysed beer material prepared from pilot brewery beers suggested that fractions MW>60000 contained polypeptide material derived from yeast mannan-protein. In addition fractions MW>60000 prepared from beer brewed from grists containing torrified wheat, wheat flour or all malted wheat may contain high molecular weight polypeptide material derived from wheat proteins. The results from the analysis of fraction MW 40,000–60000 prepared from beers brewed from grists containing all malt, 80% malt and 20% torrified wheat and 50% malt and 50% malted wheat are consistent with the presence of polypeptide material derived from cereal albumins and globulins whereas fractions MW 40,000–60000 prepared from beers brewed from 80% malt and 20% wheat flour and 100% malted wheat may contain polypeptide material derived from wheat prolamins and glutelins. The amino acid composition of fraction MW 20,000–40,000 from all pilot brewery beers investigated is consistent with the presence of polypeptide material derived from cereal prolamins and glutelins. The amino acid composition of beer polypeptide fractions may be used to detect the use of wheat adjuncts in beer brewing.     

发酵牛肉干加工中理化特性与风味品质分析

为探究发酵牛肉干不同加工阶段理化性质和风味品质的变化,以牛臀肉为原料,接种木糖葡萄球菌和清酒乳杆菌制作发酵牛肉干,并对牛肉干在发酵前后及成品的营养成分、质构、色泽等理化特性及游离氨基酸、脂肪酸组成和挥发性风味物质对比分析。结果表明,与发酵前相比,接种复合发酵剂的牛肉干pH值、水分活度、亚硝酸盐残留量、硬度、咀嚼性均显著降低（P＜0.05）;红度值和游离氨基酸含量显著增加,且鲜味氨基酸占比最高;游离脂肪酸以棕榈酸、硬脂酸、油酸、亚油酸为主,其中油酸占比最大;发酵后牛肉检出47 种挥发性化合物,高于发酵前42 种,提高了牛肉干中醛、醇、酚、酯、酸、含氮及其他化合物的种类和相对含量。发酵牛肉干质构及色泽明显改善,游离氨基酸和脂肪酸含量增加,产品营养价值、风味品质及质量安全显著提高。     

Effects of nitrogen catabolite repression‐related amino acids on the flavour of rice wine

The quality of rice wine is highly dependent on the content of the flavour compounds produced by the budding yeast Saccharomyces cerevisiae. In this study, the effects of three amino acids (arginine, glutamate and glutamine) related to nitrogen catabolite repression on the formation of flavour compounds were investigated. Each of these amino acids could promote the growth of S. cerevisiae, and a total of 83 flavour compounds were found in a model system of rice wine production. The effects of arginine, glutamate and glutamine on the content of the higher alcohols, amino acids and esters were significant, whereas the effects on the aldehydes and organic acids were slight. The results of this study could facilitate the development of new strategies to control the flavour pattern and improve the quality of rice wine. Copyright © 2015 The Institute of Brewing & Distilling     

电渗析脱盐对鱼露氨基酸和挥发性风味物质组成的影响

本文采用电渗析(ED)技术对传统鱼露发酵液进行脱盐处理,结果表明,在电压为9 V,流速4 cm/s的条件下,目标盐含量为22%、20%、15%、10%、5%和2%(m/m)的鱼露的氨基态氮、氨基酸以及挥发性风味物质含量随脱盐程度的升高而呈非线性降低趋势。当盐含量降低为20%时,氨基态氮损失率为8%,损失率相对较低;游离氨基酸中几种苦味氨基酸如酪氨酸、精氨酸、组氨酸和赖氨酸损失的比例较大,鱼露中所有氨基酸的质量随着脱盐程度增加而降低,尤其是苦味氨基酸如酪氨酸、精氨酸、组氨酸和赖氨酸的损失率较大,当电渗析脱盐至盐含量为2%时,其质量损失率分别为51.60%、49.41%、42.41%和31.12%;挥发性风味物质种类不变,除2-甲基丁醛、3-甲基丁醛和苯甲醛相对百分含量增加外,酸类、酮类、含氮类和含硫类化合物的相对百分含量随着脱盐程度的增加而有所降低,但未低于其呈味阈值;感官评定结果显示当盐含量降低为20%时,电渗析脱盐对鱼露整体风味影响不大,同时利于鱼露的防腐保存,可为低盐鱼露的生产提供参考。     

Tissue degradation,amino acid liberation and bacterial decomposition of bulk stored capelin

Bulk stored capelin with high contents of feed in the gut is easily solubilised because of high proteolytic activity. The amino acids most quickly liberated are arginine, serine, histidine, leucine, lysine and tyrosine; glycine, aspartic acid and glutamic acid are liberated at a slower rate. Bacterial activity results in a rapid and considerable decrease in total amounts of tyrosine, lysine, serine, arginine and histidine. The main products formed by bacterial decomposition of lysine, histidine and arginine are cadaverine, histamine and putrescine, respectively. Storage of capelin in the presence of antibiotics increased the amounts of free amino acids and total amino acids. After 10 days' storage at 6°C, about 30% of the total amino acid content in fish treated with antibiotics were fee amino acids.     

全自动氨基酸分析仪法测定4种贝类肌肉中谷胱甘肽和游离氨基酸含量

建立一种测定贝类肌肉中谷胱甘肽和游离氨基酸的全自动氨基酸分析仪法,以4种常见贝类为研究对象,采用0.02 mol/L盐酸溶液作为提取剂,体积分数5%磺基水杨酸溶液为蛋白沉淀剂,同时优化了缓冲溶液的组成及洗脱程序,并对该方法的线性范围、检出限、精密度以及回收率进行测定。结果表明:贝类肌肉中的谷胱甘肽和游离氨基酸有着较好的分离效果,线性关系良好,相关系数为0.999 1~0.999 9,检出限(RSN=3)为0.07~0.27μmol/L,加标平均回收率为86.40%~102.42%,日内和日间相对标准偏差分别为0.31%~0.73%和1.14%~2.60%。4种贝类肌肉组织中的游离氨基酸含量比较丰富,总游离氨基酸含量分别为1 396.39、1 016.04、911.15、287.01 mg/100 g,文蛤青蛤缢蛏牡蛎,主要的游离氨基酸为牛磺酸(Tau)、谷氨酸(Glu)、丙氨酸(Ala)、精氨酸(Arg);谷胱甘肽含量分别为103.20、82.53、61.77、33.37 mg/100 g,青蛤文蛤缢蛏牡蛎。该方法适用于贝类肌肉中谷胱甘肽和游离氨基酸含量的测定与分析。     

Effects of nitrogen,phosphorus and potassium on amino acid composition and on relationships between nitrogen and amino acids in wheat and oat grain

During two seasons, pot experiments in which increasing applications of nitrogen, phosphorus and potassium were given to wheat and oats produced grain with widely varying N contents. The total amino acid composition of the grain was mainly dependent on N content of grain. Phosphorus and potassium affected the amino acid composition of wheat and oat grain only indirectly through their effects on nitrogen concentration. In wheat increasing grain N% was accompanied by a decrease in the amount (as g per 16 g N) of lysine, threonine, methionine, cystine and an increase in glutamic acid, proline, phenylalanine, and serine contents. Lysine, methionine, and cystine in oats decreased with increasing grain N content, but arginine, aspartic acid, glutamic acid and phenylalanine increased. Changes were less pronounced with oats than with wheat, and concentrations of most essential amino acids were higher in oats. When expressed as % dry matter all amino acids increased with increasing N concentration. Linear regression equations were calculated and significant correlations were found in both crops between concentrations of most amino acids and N content in grain. Some correlations between amino acids in the grain are also given. Correlations between amino acids and nitrogen within a variety were similar despite widely differing yields.     

Characterisation of pseudocereal and cereal proteins by protein and amino acid analyses

Maize, wheat, amaranth, rice and soybean were screened for protein content. Alcohol‐soluble (A1 and A2) and glutelin (G1 and G2) fractions were isolated and compared in terms of their amino acid and protein compositions. The average proportions of nitrogen content between total alcohol‐soluble proteins (TASP) and total glutelins (TGlu) in the pseudocereals amaranth and soybean were about 1.8:26.9 and 14.9:12.3 respectively. In the cereals maize and wheat these proportions were 47.8:33.2 and 44.7:31.2 respectively. The sum of essential amino acids was 47.6 and 60.3 g per 100 g protein in amaranth and soybean respectively. The highest contents of methionine, lysine and arginine were found in the pseudocereals. The relatively high content of essential amino acids shows that pseudocereals could be used as a nutrient substitute for cereals. © 2002 Society of Chemical Industry     

热应激时奶牛血液中游离氨基酸流向与乳蛋白下降的关系研究

目的:探讨热应激时奶牛血液中氨基酸与乳蛋白的相互关系。方法:选取6头相同泌乳期奶牛,正常饲喂和饮水,实验期35 d(6月29日—8月5日)。每日10:00和18:00记录气温,统计产奶量,每周取全天奶样,Foss乳成分分析仪检测乳蛋白含量。于实验开始第1周和最后1周采集颈静脉血液,反相高效液相色谱法检测血液中游离氨基酸含量。结果:随着气温的升高(由26℃升高至最高38℃),实验奶牛日均产奶量由15.2 kg/d下降至10 kg/d,乳蛋白产量由0.47 kg/d下降至0.31 kg/d。血液中Glu、Asp、Gly和Val等主要的生糖氨基酸(参与糖异生作用)以及Leu、Ile等生酮氨基酸均升高或显著升高(0.01P0.05);总支链氨基酸(Val、Ile、Leu,主要参加免疫反应)含量显著增加(P0.05),在必需氨基酸中所占的比例由54.75%增至67.89%。结论:在夏季高温高湿条件下,奶牛可发生热应激,产奶量和乳蛋白含量均降低,但血液中游离氨基酸,特别是支链氨基酸含量显著升高。提示热应激时奶牛血液中高水平的游离氨基酸并未完全用于乳蛋白的合成,还发挥了除此之外的其他作用,而后者的作用优先于参与乳蛋白的合成,即可能优先作为功能性氨基酸参与了机体的其他活动。     

Postharvest changes in ammonium,amino acids and enzymes of amino acid metabolism in asparagus spear tips

Harvested asparagus (Asparagus officinalis L) spears accumulate ammonium and amino acids in their tips during storage at ambient temperatures. To further investigate these phenomena the authors held spears at 20°C in the dark after harvest and examined several parameters of amino acid metabolism in the tips. Soluble protein content declined faster than total protein over the 5-day storage period. Protein loss was accompanied by an increase in total free amino acids with asparagine showing the most dramatic increase. A pronounced accumulation of ammonium occurred, starting after 3 days. The activities of glutamine synthetase (EC 6.3.1.2) and aspartate and alanine aminotransferases (EC 2.6.1.1 and EC 2.6.1.2, respectively) declined slightly whereas glutamate dehydrogenase (EC 1.4.1.2) activity almost doubled over 5 days. Phenylalanine ammonia lyase (EC 4.3.1.5) activity declined rapidly during the first 2 days and then partially recovered. Asparagine synthetase (EC 6.3.1.1), asparagine aminotransferase (EC 2.6.1.14), asparaginase (EC 3.5.1.1) and glutaminase (EC 3.5.1.2) activities were not detectable at any time during the storage period. Ammonium accumulation could be caused by increased glutamate dehydrogenase activity coupled with a shortage of aspartate.     

市售黑猪和白猪营养成分分析及评价

对比市售2 款黑猪（吉神黑猪（BP1）和太湖黑猪（BP2））和2 款白猪（均为大三元杂交猪种（WP1,WP2））背最长肌的一般营养成分、脂肪酸组成和氨基酸组成。结果表明：白猪WP2和黑猪BP2脂肪含量显著高于白猪WP1和黑猪BP1,分别为2.88、2.98 g/100 g,WP1水分含量显著高于WP2,为74.3 g/100 g,所有样品蛋白质含量无显著差异;WP2棕榈油酸和油酸含量较高,单不饱和脂肪酸相对含量最高,为52.72%,多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）相对含量最低,为5.28%;BP2 PUFA相对含量最高,为12.30%,Σn-6PUFA/Σn-3 PUFA比值最低,为8.5;WP2和BP1的必需氨基酸（essential amino acid,EAA）占比显著高于BP2,分别为41.35%和41.38%,各样品氨基酸总量、EAA、非必需氨基酸和鲜味氨基酸含量均无显著差异;经蛋白质营养价值评价,赖氨酸氨基酸比值系数最高,为1.44,缬氨酸（除蛋氨酸＋胱氨酸外）是限制性氨基酸,其他氨基酸均接近于1,说明所有猪肉样品氨基酸构成比例较合理,蛋白质营养价值较高。     

燕麦分离蛋白消化特性和消化产物对STC-1细胞分泌胆囊收缩素的影响

为研究燕麦分离蛋白的消化特性及其消化产物对肠内分泌细胞分泌胆囊收缩素(CCK)的影响,以燕麦为原料,采用碱提酸沉法得到燕麦分离蛋白,分析燕麦分离蛋白在模拟胃肠道消化过程中的分子质量变化、氮释放规律、消化产物的氨基酸组成,计算氨基酸评分、化学评分和必需氨基酸指数,并以STC-1细胞为肠内分泌细胞模型评价消化产物对STC-1细胞分泌CCK的影响。实验结果表明:燕麦分离蛋白经胃肠消化后,消化产物的分子质量小于10kDa,释放的可溶性氮的比例为90.11%,消化产物可溶性部分中游离氨基酸的比例为22.8%,肽的比例为67.31%,并且肽的分子质量主要在1000Da以下(约74%)；燕麦分离蛋白消化产物中必需氨基酸总量占38.75%,必需氨基酸与非必需氨基酸的比值为0.63,且必需氨基酸指数(0.95)大于0.90。燕麦分离蛋白消化产物对STC-1细胞影响的实验结果表明,燕麦分离蛋白消化产物对STC-1细胞生长具有显著的促进作用,且能够增加CCK的合成和分泌。研究结果表明,燕麦分离蛋白作为一种优质的蛋白质原料,不仅具有优良的营养功能,而且具有促进肠内分泌细胞分泌CCK的生物活性,在食品领域具有较大的应用潜力。     

Nucleation of amino acid‐rich crystals on the surface of dried scallop (Chlamys farreri) during storage: formation mechanism and influence of environmental relative humidity

Formation of crystals on the surface of dried scallop (Chlamys farreri) adductor muscle is often observed during storage. The composition of these white crystals was determined, and the effect of relative humidity (RH) during storage on their formation was also studied. The white crystals were determined as the crystal of free amino acids, mainly composed of taurine (Tau) and glycine (Gly). The main polymorphic form of glycine in the crystals was further confirmed as the γ‐form. Besides free amino acids, another major part of the crystal composition was ions, such as Na⁺, NH₄⁺, K⁺, PO₄^3? and Cl^?. The presence of various free amino acids and Na⁺ and K⁺ might contribute to the crystallisation of γ‐glycine. RH particularly at 65% and above significantly increased the amount of crystals. RH of 43% and below was recommended to prevent the formation of amino acid‐rich crystals on dried scallops during storage.     

Free amino acid profiles from ‘Pinot noir’ grapes are influenced by vine N-status and sample preparation method

This study examined the impact of extraction method on ammonia, free amino acids, and yeast assimilable nitrogen (YAN) concentrations in ‘Pinot noir’ berries obtained from a vine nutrition study (altered supply of N, P, or K). Berries were either juiced or exhaustively extracted as whole berries prior to analysis. Extracts, compared to juice samples, had a significantly higher level of ammonia–N, assimilable amino acid–N, and YAN. For example, juice YAN values were approximately 50% of extract YAN values, when both were expressed in the same units. Free amino acid profiles and relative concentrations of individual amino acids were different in juice versus extracts, depending on how well the skin fraction was extracted prior to analysis. Lowering N supply reduced free amino acids, with arginine being reduced more than the other 20 free amino acids identified in ‘Pinot noir’ berries. This was true in both juice and extracts. Since berry skin contributed to actual YAN, wineries that determine YAN from mainly the pulp fraction (juice) may underestimate YAN and as a result add more (artificial) N supplement than is required for the healthy fermentation of red winemaking (whole berry fermentations). Extraction procedure should be taken into consideration when comparing grape YAN.     

Changes in the amino acid compounds of the wholecrop wheat during ensiling and after fermentation

Changes in amino acid fractions of chopped low-to-medium protein whole-crop wheat were studied at four stages of maturation and at two stages after a 24 h wilting period. Tests were carried out after an ensiling period of 90 days, and after a further 7-day post-fermentation aerobic exposure. Total amino acids contents in the dry matter during the fermentation period remained stable. Quantities of essential amino acids decreased during maturation and fermentation and remained stable during post fermentation aerobic exposure. The highest amino acid concentrations recorded in the fresh material were those of arginine, lysine, glutamic acid, alanine, leucine, glycine and aspartic acid. Free amino acids varied from a low level in the fresh material < 10% of the total amino acids to ca 65% after the aerobic process. Ammonia-N content increased in the silage and remained relatively stable on post fermentation aerobic exposure. The concentration of all free amino acids increased except arginine and glutamine during the ensiling period and post fermentation aerobic exposure. After wilting, an increase in free amino acids and a decrease in insoluble amino acids was recorded. The changes in concentration of 18 amino acids during ensilage and following post fermentation aerobic exposure are given.