Gliadin proteins in the developing wheat seed

In extracts of developing seeds of wheat (Triticum aestivum L., cultivars Scout 66, Cheyenne, Nugaines and INIA 66R) examined by polyacrylamide gel electrophoresis, gliadin proteins appeared at 12-15 days post-anthesis with mobilities covering nearly the whole range found with mature seeds. Some differences among extractants [2M dimethylformamide (DMF); 2M urea; 60% ethanol; the aluminium lactate-lactic acid electrophoresis buffer, pH 3.2] in both intensity and occurrence of specific bands were observed. With immature seeds, 60% ethanol extracts produced a maximum number of bands and least background colour, but DMF and urea extracts showed bands from 12- to 15-day seeds at least as well as 60% ethanol extracts despite more background colour. Aluminium lactate buffer extracts occasionally yielded bands not found with other extractants, but gave poor extraction from immature seeds and relatively heavy background staining with mature seeds, especially in the w-gliadin (lowest mobility) region. A quantitative sodium dodecyl sulphate-electrophoresis procedure¹ was used to follow the formation of proteins in various molecular weight ranges (cv. Scout 66 only). At 12-18 days post-anthesis, synthesis of protein of molecular weight 30 000-37 000 accelerated, consistent with the onset and acceleration of formation of α-, β-, and some y-gliadins. Protein in a band of 44 000 molecular weight formed in similar fashion. In other molecular weight ranges, gliadin bands could not be positively identified because of the complexity of the banding pattern of the total protein.     

Changes in chemical composition during soybean seed development

This study examined the compositional change of five specialty soybean genotypes, which are low in oligosaccharides, high in oil, high in protein, large seeded or small seeded, along with two commercial cultivars, Jack and Ozark, during seed development and maturation. Seeds were sampled at 7-day intervals from initial seed formation to full maturity for approximately 8 weeks, and analysed for oil, protein, soluble saccharides, and starch. Although there were significant differences among the seven soybean genotypes in their chemical compositions, some compositional changes followed similar trends. Protein content decreased during the first 3–5 weeks after flowering and then gradually increased. Oil was accumulated rapidly during the early stages. The percentage of starch ranged from 6 to 15% in developing seeds, but declined sharply to 0.2–1% at maturity. Sucrose decreased during seed development and maturation, while non-digestible oligosaccharides (raffinose, stachyose, and verbascose) remained at low levels during early stage until 3 weeks before harvest and increased towards maturity. These findings provide valuable information for developing and selecting specialty soybean varieties for specific applications.     

复羽叶栾树种仁的脂肪酸及氨基酸组成分析

采用国标方法对复羽叶栾树种仁的脂肪酸以及氨基酸组成进行分析测定。结果表明:复羽叶栾树种仁的粗脂肪含量为11. 4%,种仁油中含有15种脂肪酸,主要为花生一烯酸(45. 4%)、油酸(23. 7%)、亚油酸(9. 2%)、棕榈酸(6. 1%)、芥酸(5. 6%),不饱和脂肪酸含量达87. 20%,单不饱和脂肪酸含量为74. 95%;种仁粗蛋白质含量为26. 2%,种仁蛋白中氨基酸含量为19. 29%;在种仁蛋白中至少有16种氨基酸,其中必需氨基酸含量占氨基酸总量的33. 59%,药效氨基酸占70%。研究表明,复羽叶栾树种仁既可作为生产生物柴油、药物和化妆品的原料,也是良好的蛋白质和食用油资源,具有广阔的开发前景。     

Biochemical changes in developing wheat grains. Changes in nitrogen fractions,amino acids and nutritional quality

Two spring wheat cultivars (Triticum aestivum L. em Thell.), one tall (Chris) and the other semi-dwarf (Era), with different yields and grain protein potentials, were grown in controlled environment chambers to compare the nitrogen fractions, amino acids and nutritional quality in developing grains at 12, 22, 29 and 36 days after heading. The proportions of gliadin I, gliadin II and glutenin II increased and those of albumin and globulin decreased as the wheat cultivars matured. The amount of lysine, methionine, threonine, valine, tyrosine, alanine, aspartic acid and glycine was lower and that of glutamic acid and proline was higher with grain development in both cultivars. At 12 days after heading Era had a higher content of amino acids (16 g^?1 N) than Chris. Isoleucine was the first limiting amino acid in Era and Chris at the first collection period whereas at later stages lysine was the limiting amino acid in both cultivars. Chemical score, essential amino acid index, requirement index and calculated biological value all decreased as the grain matured and, except for the 12-days collection period, the data were almost similar for both the cultivars.     

大豆氨基酸粉的生理功能与开发应用

本文综述了大豆氨基酸粉的生理功能、生产工艺及良好的开发应用前景。     

不同品种芡实种仁蛋白质亚基组成及氨基酸分析

本实验选择3个不同品种、2种不同成熟度的5个芡实种仁样品,通过SDS-PAGE法及氨基酸分析仪法对其蛋白质亚基结构和氨基酸组成进行了初步分析。结果表明,刺芡（成熟）种仁蛋白质含量显著高于苏芡（成熟）（p≤0.05）,且刺芡（成熟）种仁蛋白质中必需氨基酸、甜味和鲜味氨基酸含量也高于苏芡（成熟）,说明刺芡在营养和口感上要优于苏芡。SDS-PAGE的分析结果显示,芡种仁总蛋白中分离出约20条谱带,相对分子质量在16.24⁸2.04 k Da之间。其中分子量35.9 k Da左右基含量最高,是芡实总蛋白中最主要亚基。芡实蛋白质中的水溶性蛋白含量很少,且不同成熟度样品间差异很大,苏芡（嫩）和淮芡（嫩）中均未检出水溶性蛋白。品种间醇溶性蛋白质亚基组成差异较大,碱溶性蛋白质亚基及分子量分布品种间和成熟度间差异不大。      

4种胡桃科坚果中氨基酸和脂肪酸组成分析与营养评价

为对我国不同种类胡桃科坚果的高阶营养(氨基酸和脂肪酸组成)进行比较和评价,选取产自浙江、安徽、甘肃、陕西、四川、新疆6省的4种胡桃科坚果(普通核桃(Juglans regia Linn.)、泡核桃(Juglans sigillata Dode)、山核桃(Carya cathayensis Sarg.)、薄壳山核桃(Carya illinoensis (Wangenh.) K. Koch)),参照国标方法对其氨基酸与脂肪酸组成进行分析,利用必需氨基酸指数、氨基酸匹配度与平衡度评价、氨基酸比值系数评价法和脂肪酸指数评价法分别对氨基酸与脂肪酸组成进行营养评价。结果表明,泡核桃与普通核桃总氨基酸含量较高,4种坚果中必需氨基酸含量占总氨基酸含量的1/3左右,总氨基酸与必需氨基酸含量呈正相关关系。非必需氨基酸中天冬氨酸、谷氨酸、精氨酸含量较高。新疆阿克苏泡核桃在必需氨基酸指数与氨基酸匹配度的评价结果中为最优,4种胡桃科坚果氨基酸平衡度较为相近。氨基酸比值系数评价法显示浙江临安山核桃最优,新疆阿克苏泡核桃次之。4种胡桃科坚果中山核桃和薄壳山核桃中油酸含量较高;泡核桃和普通核桃中亚油酸含量较高。研究结...     

Magnesium nutrition on accumulation and transport of amino acids in tea plants

BACKGROUND: Free amino acids in young tea shoots are important chemical constituents, remarkably influencing the quality of green teas. Nutrient solution, soil pot and field experiments were conducted to investigate the effect of magnesium nutritional status on accumulation and transport of free amino acids in tea plants ( Camellia sinensis (L.) O. Kuntze). RESULTS: A sufficient supply of Mg in nutrient solution increased biomass production and concentrations of free amino acids, notably theanine in young shoots and roots, without affecting total N in the leaves, absorption rates of inorganic N and glutamine synthetase activity. Amino acids in xylem saps and phloem exudates or total sugars in phloem exudates of tea plants from pot and field experiments showed their highest levels in bud breaking and shoot extension in early spring (March and early April). Application of Mg increased the amounts of amino acids and total sugars in the xylem saps and phloem exudates. CONCLUSION: Adequate supply of Mg nutrient promoted the synthesis of theanine in roots and its accumulation in the young shoots of tea plants. Magnesium nutritional status was an important factor influencing the mobility of amino acids and sugars via xylem and phloem especially when N and C reserves remobilized to support spring growth of young shoots. Copyright © 2011 Society of Chemical Industry     

葡萄酒酿造过程中氨基酸含量变化的研究

应用HPLC对我国4个产区多个品种葡萄酒酿造过程样品中氨基酸含量变化趋势进行了研究,结果表明,L-脯氨酸是所有葡萄汁中氨基酸的主体,也是各样品含量差异最大的氨基酸;红葡萄酒中含脯氨酸、苏氨酸、赖氨酸等20种氨基酸,其中以脯氨酸含量最高,发现不同葡萄品种之间游离氨基酸种类和含量有差别,这与葡萄品种、气候、发酵工艺有关。     

Protein nutrition of dairy cows receiving grass silage diets. The effects of post-ruminal supplements of proteins and amino acids

Milk production and food intake responses to abomasal infusion of proteins were examined in dairy cows receiving a basal diet of high-quality grass silage ad libitum plus a barley-soya supplement at 5 kg day^?1 Four cows received each of the following five treatments: (i) basal diet, (ii) basal diet plus 230 g casein days^?1 infused into the abomasum, (iv) basal diet plus 273 g soya-protein isolate (SPI) day^?1 infused into the abomasum, (iv) basal diet plus 273 g SPI day^?1 plus methionine (MT) and tryptophan infused into the abomasum (SPI + MT), and (v) basal diet plus 273 g SPI day^?1 plus a mixture of essential amino acids (AAs) infused into the abomasum (SPI + AA). The SPI + MT and SPI + AA were designed to be equivalent to the casein treatment with regard to the supply of methionine and tryptophan and all essential AAs, respectively. The cows were allocated to four columns of a 5 × 5 latin square design with 7-day periods. All infusions increased (P < 0.01) the yields of milk and milk protein relative to the basal treatment, the values being 20.2, 22.4, 21.5, 21.9 and 21.7 kg day^?1 for milk yield and 626, 725, 673, 689 and 691 g day^?1 for protein yield for the basal, casein, SPI, SPI + MT and SPI + AA treatments, respectively. Casein infusion produced a higher (P <0.05) yield of milk protein than all other treatments. It is concluded that the nutritional value of a protein supplied post-ruminally cannot be assessed solely in terms of its AA composition. The possible roles of factors such as the rate of absorption of AAs and the release of biologically active peptides during digestion are discussed.     

Changes in carbohydrates and amino acids during baking of Vicia faba

Chemical changes in carbohydrates, proteins and amino acids of the broad bean Vicia faba which occur during the production of the baked beans “foul midamis” were studied. During baking part of the sugars and amino acids of the beans were involved in discolouration reactions with subsequent decrease of the components studied.     

四川麸醋发酵过程中有机酸及游离氨基酸含量变化分析

为了解四川麸醋发酵过程中有机酸及游离氨基酸含量的变化规律,采用高效液相色谱和氨基酸自动分析仪对发酵过程中7种有机酸及17种游离氨基酸含量进行测定。结果表明,四川麸醋发酵过程中含量最高的2种有机酸为乙酸和乳酸,随着发酵的进行,其含量显著增加;草酸、柠檬酸、酒石酸、苹果酸、琥珀酸含量较低,在发酵过程中含量略有变化。游离氨基酸含量随着发酵的进行呈增加趋势,从发酵初期668mg/100g增至1 470 mg/100g,其中天门冬氨酸、丝氨酸、谷氨酸、甘氨酸、丙氨酸、缬氨酸、组氨酸、异亮氨酸、酪氨酸、脯氨酸对四川麸醋风味形成具有较大的贡献。     

辣木籽种仁氨基酸组成、矿质元素及油脂脂肪酸成分分析

采用国标方法对辣木籽种仁的氨基酸组成、矿质元素及油脂脂肪酸成分进行分析。结果表明：辣木籽种仁粗脂肪含量为25.5%,粗蛋白质含量为37.11%;辣木籽种仁中17种氨基酸的总含量为3348%,7种人体必需氨基酸占氨基酸总含量的29.63%;辣木籽种仁中含有丰富的常量元素,属于高钾低钠食品;微量元素中Zn元素含量较高,为41.970 μg/g;重金属元素含量符合国家限量标准;辣木籽油主要含有油酸（70.85%）、棕榈酸（5.43%）、山嵛酸（8.38%）等10种脂肪酸,不饱和脂肪酸含量为79.86%。辣木籽具有较高的食用和药用价值,具有很好的市场开发前景。     

氨基酸口服营养品的现状与展望

氨基酸的功能一直为人们所关注,可广泛应用于医药、食品、农牧渔业、农药、化妆品、保健品等领域。氨基酸向来是国际医药市场的大宗产品。近年来国外出现了一种新趋向,即原本作为药用的氨基酸开始向保健品方向发展。简要综述了发达国家如美国、日本以及国内氨基酸口服保健品的现状,并初步探讨我国氨基酸保健品市场进一步的发展方向。