Amino acid composition of wheat grain. 1: Changes during development

The changes in the composition of free and total amino acids in wheat grain during development are described: the experiment was performed in a growth chamber with three varieties of winter wheat (Triticum aestivum L.): Splendeur, Hobbit and Maris Huntsman. The changes in the total composition of amino acids of the grain as development progressed were consistent with an increase in the proportion of storage proteins. At 15 days after anthesis, the relative amount of glycine increased, suggesting that at this moment the proportion of gliadins was relatively low. The relative amount of arginine increased in mature grain, showing that at times close to maturity the relative proportion of synthesis of a protein fraction rich in this amino acid increased. Free glutamate, proline and arginine decreased at 15 days to a greater extent than the other amino acids and was present in low relative amounts during the period of maximum protein synthesis in the grain; these three amino acids could be the most limiting for protein synthesis in grain. In the free fraction the following showed a similar pattern of change during grain development: aspartate, arginine and histidine on the one hand, and on the other alanine, valine, leucine, isoleucine, threonine, phenylalanine and tyrosine; moreover both groups were inversely correlated. Glycine and lysine were directly related to each other and inversely to glutamate.     

Supplementary effect of aestivum wheat (Triticum aestivum L), bengal gram (Cicer arietinum L) and soya bean (Glycine max L) on protein quality of durum wheat (Triticum durum Desf)

Chapatis and parathas were made from different combinations of durum (Triticum durum Desf) and aestivum (Triticum aestivum L) wheat to test for their organoleptic acceptability. The best accepted durum/aestivum (40:60) combination was supplemented at 10, 20, 30 and 40% levels with Bengal gram (Cicer arietinum L) flour and soya protein (Glycine max L) concentrate. Raw and cooked samples were analysed for some amino acids and trypsin inhibitor activity. The most acceptable cooked products were fed to growing rats for estimation of protein efficiency ratio, apparent digestibility and plasma proteins. Cooking resulted in considerable losses in cystine, available lysine and trypsin inhibitor activity. The losses were greater in paratha than in chapati. Protein efficiency ratio and apparent N digestibility of chapatis were significantly higher than those of parathas. However, protein quality of soya-supplemented parathas was better than that of chapatis.     

Isolation and partial characterisation of two low molecular weight durum wheat (Triticum durum) glutenins

Two low molecular weight durum wheat (Triticum durum Desf) glutenins, DSG-1 and DSG-2 (durum-wheat sulphur-rich glutenin fractions) were isolated from two cultivars, Mondur of good technological quality and Kidur of poor technological quality. The glutenin fraction, composed mostly of DSG protein, was extracted using a low concentration of NA-tetradecanoate and then fractionted by by using molecular sieve chromatography (Bio-Gel P 30). The amino acid compositions and the N-terminal sequences of the pure DSG proteins were determined, and their hydrophobic characteristics, calculated on the basis of these data, showed that DSG-2 is more hydrophobic than DSG-1. The amino acid compositions of DSG-1 and DSG-2 were different. The N-terminal amino acids of DSG-1 and DSG-2 were also different but were identical for each of the two cultivars. In the case of DSG-1, in addition to the main chain a minor chain was found in which the first three amino acids of the main chain were missing. The minor chain represented about 30% int he DSG-1 of mondur and almost 50% in Kidur.     

酸奶中游离氨基酸含量及乳清蛋白组成分析

用反相高效液相色谱法（RP-HPLC）测定了5种原味发酵型酸奶中游离氨基酸含量，并用十二烷基硫酸钠-聚丙稀酰胺凝胶电泳（SDS-PAGE）分析了酸奶乳清蛋白组成。结果表明：被测酸奶中乳清蛋白含量的范围在5.66-10．45g／L，其主要成分为α-乳清蛋白、β-乳球蛋白及少量酪蛋白。用HPLC在酸奶中检测到17种氨基酸，总游离氨基酸质量浓度范围285．90-1116．21mg／L，其中4个品牌酸奶中精氨酸（她）质量浓度最高，1个品牌酸奶中天冬氨酸（Asp）质量浓度最高。     

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.     

A quantitative analysis of amino acid accumulation in developing grain of normal and Opaque-2 maizes

From previous observations concerned with the qualitative and quantitative evolution of protein groups in developing maize (Zea mays L.) grain, it may be deduced that the amount per grain of any amino acid incorporated into the proteins is linearly related to the amount of true protein in the grain. In this study, such a linear relationship is characterised quantitatively from experimental data by regressing the individual amino acid against the total protein accumulated in the developing grain of both normal (+) and opaque-2 (o2) maize. The linear least squares regression on total nitrogen content in the grain is also used for specifying the quantitative variations of any free and protein-incorporated amino acid in the grain. The slope B_j of the regression line represents the relative rate of accumulation of amino acid (j) in grain protein (or nitrogen) and its limiting content in protein (or nitrogen) of a grain which accumulates a large amount of it. B_j, which is compared to the amount of amino acid (j) present in the protein of immature grains, or of mature endosperm, or germ, is close to the amount of amino acid (j) present in the protein of mature endosperm. The same holds for the B_j value determined from opaque-2 maize and which differs from the amount of B_j determined using the normal variety for many amino acids. Using experimental data reported in the literature, a linear relationship has also been found in describing quantitative variations of amino acid in the developing grain of normal and Hiproly barley.     

Protein,amino acid and fatty acid contents in raw and canned sea urchin (Paracentrotus lividus) harvested in Galicia (NW Spain)

Moisture, protein, amino acid and fatty acid contents of raw and canned sea urchin (Paracentrotus lividus) gonads were determined. Sea urchin showed a high moisture content (73%) and a high level of proteins (56% dry matter). The canning process, evaluated at 112 °C for 50 min, did not lead to significant changes in protein, amino acid and fatty acid contents relative to the raw sample. © 2000 Society of Chemical Industry     

Relationships between amino acid composition and nitrogen of foxtail (Italian) millet (Setaria italica) grain of different varieties

The amino acid composition of 13 samples of foxtail millet (Setaria italica L) from six Chinese and one French varieties was determined as a function of their N content (N), which ranged from 1·82 to 3·65 g per 100 g of grain DM. The levels of amino acids in grain DM increased linearly with N with correlation coefficients close to 1 for most of them regardless of foxtail millet genotype or phenotype. Thus simply knowing N enables one to predict the amino acid composition of any foxtail millet grain sample. Amino acids in crude protein of grain (g 16 g^?1N)changed as quadratic functions of N, which decreased for glycine, cysteine, tysine, histidine and arginine, remained nearly constant for valine, threonine, tyrosine, methionine and aspartate plus asparagine, and increased for other amino acids. Foxtail millet appeared as the only cereal in which lysine is the only limiting essential amino acid. However, the lysine score was low and intermediate between that of maize and sorghum, falling from 48 to 31 % when N increased from 1·82 to 3·65 g per WO g DM. The N-to-protein conversion factor strongly increased with N and was the highest of all cereals within the N range studied. The results also showed that the composition of storage proteins accumulated in grains remained constant, with a prolamin to glutelin ratio close to three and independent of grain protein content.     

Variation in protein and trypsin inhibitor activity with maturity and amino acid composition of winged bean (Psophocarpus tetragonolobus) seeds

The protein and trypsin inhibitor activity in pods and seeds of winged bean (Psophocarpus tetragonolobus (L) DC) increase, and in the pod hull decrease, with the maturity of plant. The seeds of 21 cultivars both exotic and of Indian origin cultivated on marginal alkaline soil (pH 8.7) were analysed for protein (36.4–45.3) and amino acid composition (lysine 4.8 to 6.7).     

Effect of potassium,magnesium and sulphur applied in different forms of fertilisers on free amino acid content in leaves of tea (Camellia sinensisL)

Free amino acids in tea leaves are important chemical constituents that considerably influence the quality of tea, especially that of green tea. The present study was conducted to investigate the effects of the nutrients potassium, magnesium and sulphur on biomass production and amino acid accumulation in tea leaves in pot and field experiments. The results show that biomass production and the free amino acid contents in tea leaves increased considerably following the application of potassium and magnesium. Combined application of both nutrients produced the highest increment in free amino acids. The increased free amino acid content in tea leaves was accompanied by enhanced nitrate reductase activity. This indicates that potassium and magnesium application improved the nitrogen metabolism, leading to an increased synthesis of amino acids. A comparison between K₂CO₃ vs K₂SO₄ and MgO vs MgSO₄ revealed significantly higher amino acid contents in tea leaves when both potassium and magnesium were applied in the sulphate form, indicating that not only potassium and magnesium but also sulphur plays an important role in the accumulation of amino acids in tea leaves. A pot experiment using KCl and K₂SO₄ was carried out in order to compare the two commercially available potassium fertiliser forms in their effect on biomass production and the content of free amino acids in tea leaves. The results showed no difference on biomass production between the two fertiliser forms. However, whereas KCl tentatively depressed nitrate reductase activity and hence the accumulation of free amino acids, K₂SO₄ significantly increased the contents of these quality promoting constituents of tea leaves. The role of fertiliser composition, detrimental effects of accompanying anions, eg Cl⁻ and differences in nutrient availability (eg oxide≪sulphate form) and possible impact on soil chemistry as main reasons for the observations, being crucial aspects with regard to fertilisation of tea for good quality are discussed. © 1998 SCI.     

Kinetics of free protein amino acids, free non-protein amino acids and trigonelline in soybean (Glycine max L.) and lupin (Lupinus angustifolius L.) sprouts

A contribution for a better nutritional knowledge of lupin (Lupinus angustifolius L. var. zapaton) and soybean (Glycine max L. var. merit and var. jutro) sprouts about free protein amino acids (FPAA), free non-protein amino acids (FNPAA such as β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP), α-aminoadipic acid, γ-aminobutyric acid (GABA) and β-alanine) and trigonelline content has been carried out. Seeds were germinated at 20 °C and darkness during several days in order to obtain good appearance sprouts. The content of FPAA and FNPAA varied among species and varieties. FPAA increased dramatically during germination and the lowest concentrations were found for G. max L. var. jutro. Cys was not detected as FPAA in seeds and seedlings of both legumes. Asn was present in the highest amounts in soybean and lupin seedlings. The α-aminoadipic acid gliotoxin, which was not present in raw soybean seeds, appeared in low amounts during germination. Later stages of germination caused significant increases of β-alanine and GABA, amino acids with beneficial properties. Germination also affected the content of the multifunctional plant hormone trigonelline and slight changes were observed. Highest levels of FPAA, beneficial FNPAA and trigonelline were found at 4, 6 and 9 days of germination for G. max L. var. jutro, G. max L. var. merit and L. angustifolius L. var. zapaton, respectively. Furthermore, these selected germination conditions showed low levels of the gliotoxic α-aminoadipic acid ensuring nutritional safety of the studied seedlings.     

Amino acid composition of storage proteins of a promising chickpea (Cicer arietinum L) cultivar

The amino acid compositions of flours made from the cotyledons and from the whole seeds of a disease-resistant, stable and high-yielding cultivar of chickpea (Cicer arietinum L) cv H75–35, known locally as Gaurav, have been analysed. These, together with similar analyses of the albumin, globulin, legumin and vicilin protein fractions, have been compared with those of other legumes. Seed protein content was 19·8 % with globulin constituting 62·4 % of the total seed protein. The ratios of albumin to globulin and legumin to vicilin were 1:4 and 6:1, respectively. The proportion of basic amino acids in the albumin was low whereas the reverse was true in the globulin. The legumin fraction seems to be superior in terms of total essential amino acids to those from other sources. Sulphur amino acids were the most limiting, followed by tryptophan or threonine depending on the fraction. However, the ratio of methionine to cystine was high (2·76:1). The extent of the sulphur amino acid deficiency was assessed, and possible approaches for its improvement are outlined.     

一种蛋白质游离氨基含量测定方法—三硝基苯磺酸法的探究

三硝基苯磺酸(trinitrobrnzen sulfonic acid,TNBS)法是测定蛋白质中游离氨基含量的方法。该文比较了该方法的2种终止反应条件及分析方法,探究了该方法对不同蛋白质(牛血清蛋白、胰蛋白酶、溶菌酶)的适用性。结果表明,碱性条件下的响应值显著高于酸性(P<0.01);紫外可见分光光度计和酶标仪2种测定方法对蛋白质游离氨基含量的测定结果在一定范围内没有显著差异(P>0.05),紫外可见分光光度计测定结果精确度较高,对浓度变化的响应更灵敏。蛋白质种类不仅影响到该方法的取样浓度,而且蛋白质中的巯基含量会干扰该方法的准确性。     

The nitrogen content of potato (Solanum tuberosum L.) tubers in relation to nitrogen application—the effect on amino acid composition and yields

The effect of nitrogen application on the nitrogen content and yield of amino acids from potato tubers was studied in one experiment in 1983 and two in 1984. Increasing fertiliser N over the range 0–250 kg ha^?1 raised tuber nitrogen concentrations from 0.68–0.81 to 1.27–1.49% DM. Applying half the fertiliser on the seedbed and half at tuber initiation did not increase tuber nitrogen concentrations compared with a single broadcast application at planting. Increasing tuber nitrogen concentrations had little effect upon the proportion recovered in amides or the different amino acids. Yields of some nutritionally essential amino acids were, therefore, substantially increased up to a maximum of 256 kg ha^?1 in 1982 and 308 and 384 kg ha^?1 in 1984 at the highest fertiliser level. These yields were significantly higher (P<0.01) than those found with the nitrogen application rate optimal for tuber dry matter production (213, 195 and 331 kg N ha^?1, respectively) in the same experiments. Methionine and cystine were the limiting essential amino acids. As the amount of each amino acid contained in a unit weight of fresh tuber increased with nitrogen supply, application of more nitrogen than is needed for maximal tuber dry matter production increased protein yields without decreasing the nutritional quality.     

Reaction of winter wheat (Triticum aestivum L.) cultivars to infection with Fusarium spp.: mycotoxin contamination in grain and chaff

This study compares the susceptibility of winter wheat (Triticum aestivum L.) cultivars to Fusarium head blight (FHB) and accumulation of mycotoxins in kernels and chaff under different climatic conditions in two locations–Cerekwica near Poznan (Central West Poland) and Sitaniec, near Zamosc, Lublin region (South East Poland). Very high variations were found in the concentrations of mycotoxins (zearalenone, ZEA; nivalenol, NIV; deoxynivalenol, DON; moniliformin, MON) in examined fractions: Fusarium-damaged kernels (FDK) and healthy looking kernels (HLK) and in chaff for individual cultivars in both locations. In most cases, significantly higher concentrations of investigated toxins were recorded in wheat from the area of Lublin than from Poznan (p < 0.05). The highest Fusarium infection rates and mycotoxin biosynthesis levels were observed in the Lublin location, with the percentage of the FDK fraction ranging 8.1–81.6. In this region, ZEA concentration (µg g^?1) after inoculation with F. culmorum and F. graminearum ranged from 0.02–0.48 and 0.32–1.04, respectively. In the Poznan area, the toxin concentrations were considerably lower, ranging 0.01–0.10 and 0.03–0.13 µg g^?1 for both isolates, respectively. The concentration of DON was significantly higher than ZEA or NIV levels. The levels of MON accumulation (µg g^?1) in the FDK fraction were between 0.14 and 1.73 (Poznan area) and ND (not detected) to 2.51 (Lublin area). F. avenaceum infection rate ranged 7–35% in samples where the toxin was detected.     

Walnuts (Juglans regia L): proximate composition,protein solubility,protein amino acid composition and protein in vitro digestibility

Walnuts contained 16.66% protein and 66.90% lipids on a dry weight basis. Non‐protein nitrogen values ranged from 6.24 to 8.45% of the total nitrogen when the trichloroacetic acid concentration was varied within the range 0.25–1.0 M . Albumin, globulin, prolamin and glutelin respectively accounted for 6.81, 17.57, 5.33 and 70.11% of the total walnut proteins. Walnut proteins were minimally soluble at pH 4.0. The majority of total walnut protein polypeptides had estimated molecular weights in the range 12 000–67 000. The Stokes radius of the major protein in walnuts (glutelin fraction) was 66.44 ± 1.39 Å. Lysine was the first limiting essential amino acid in total walnut proteins as well as in the globulin and glutelin fractions. Leucine and methionine plus cysteine were the second limiting essential amino acids respectively for the prolamin and albumin fractions. Hydrophobic and acidic amino acids dominated the amino acid composition in all protein fractions. Native and heat‐denatured walnut glutelins were easily hydrolysed by trypsin, chymotrypsin and pepsin in vitro. © 2000 Society of Chemical Industry     

Meat fatty acid composition of llama (Lama glama) reared in the Andean highlands

This study reports the results of the chemical analysis of the Longissimus thoracis and lumborum taken from 20 llama males, reared in the Andean highlands. The animals were slaughtered at 25 months and had a mean final body weight of 63kg. Llama meat shows a low fat (3.51%) and cholesterol content (56.29mg/100g). The fatty acid composition in llama meat contains 50.34% saturated fatty acids, 42.48% monounsaturated fatty acids and 7.18% polyunsaturated fatty acids. Llama meat appears to be a healthy alternative red meat choice.     

Chemical composition,protein fractionation,essential amino acid potential and antimetabolic constituents of an unconventional legume,Gila bean (Entada phaseoloides Merrill) seed kernel

Physical characteristics of pods and seeds, proximate composition, different protein fractionation, SDS‐PAGE analysis of proteins, amino acid composition, starch content, fatty acid profiles and various antimetabolic substances of Gila bean (Entada phaseoloides Merrill) were studied. The pod length and the number of seeds per pod ranged from 55 to 90 cm and from 5 to 11 respectively. The kernel comprised 66.1% of the seed weight (18.41 ± 1.14 g). The seed kernels contained 256.7 g kg^?1 crude protein, 108.1 g kg^?1 lipid, 27.3 g kg^?1 ash and a high content of carbohydrate (585.7 g kg^?1). The levels of potassium, phosphorus, zinc and iron were similar to those in conventional pulses. Among the different protein fractions of seed kernels, albumins constituted the major storage proteins (69.7%). The kernel proteins were rich in essential amino acids, particularly sulphur‐containing amino acids, and their values appeared to be higher than the FAO/WHO (1990) reference protein for a 2–5‐year‐old growing child and soybean, and comparable to hen egg. Seed kernel lipids contained high levels of unsaturated fatty acids, oleic and linoleic acids, which accounted for 83% of the total fatty acid recovered. The kernel exhibited high trypsin and chymotrypsin inhibitor activities (96.65 mg TI g^?1 and 30.02 CIU mg^?1 sample respectively) in addition to containing phenolics, phytic acid, lectins and oligosaccharides. Another major toxic constituent was identified as a group of triterpenoid saponins (3.21%), which had high haemolytic activity (HeU) against cattle erythrocytes and caused high mortality in fish. The in vitro digestibility of the kernel protein was low (67%). © 2001 Society of Chemical Industry     

Genetic and environmental variability in protein,oil and fatty acid composition in high-alkaloid hite lupin (Lupinus albus)

Protein, oil and fatty acid composition ere determined on seed samples of Lupinus albus L cultivars gron in to different locations, Villafranca and Córdoba. Seeds planted in the latter location ere inoculated ith Rhizobium leguminosarum f lupini as soil pH as 7·5-7·9. Locations clearly caused differences in both protein and oil contents. Interactions beteen localities and genotypes ere not significant. Environmental effects ere much greater than the genotypic factors except for oleic and linoleic acids. Both locality and genotype effects ere clearly significant for all fatty acids studied except for palmitic acid. A negative correlation as found beteen protein and oil content. Oil and oleic acid contents ere positively correlated to each other. Linoleic acid content seemed not to be correlated ith any other fatty acid except oleic. Linolenic acid content as also negatively correlated ith that of oleic acid. Covariance analysis shoed a strong positive genetic correlation beteen oil and oleic acid contents; the genetic correlation as higher than the environmental one. Oil content is strongly negatively correlated ith both linoleic and linolenic acid contents at the genotypic level.     

Fermentation and cooking of sicklepod (Cassia obtusifolia) leaves: changes in chemical and amino acid composition, antinutrients and protein fractions and digestibility

Sicklepod leaves after fermentation and drying are commonly known as Kawal in Sudan. Investigation of the samples showed that the dry matter, oil, fibre and carbohydrates fluctuated during processing. The protein content of Algenina increased to 30.01% while that of Zalngy decreased to 24.32%. Cooking increased the ash content to 19.55% and 20.04% for Algenina and Zalngy samples respectively. For both samples the total energy was decreased to 221.59 and 227.39 kcal per 100 g for the samples respectively. The first limiting amino acid is lysine with a score of 73.9. Although cooking of the sample increased lysine score to 76.00 but still is a limiting amino acid. Sulphur amino acids are the second limiting of Zalngy. The protein fractions fluctuated during processing. Cooking of the samples decreased polyphenols to 890.01 and 620.58 mg per 100 g and phytate to 77.90 and 146.28 mg per 100 g for the samples respectively. However, tannin content increased to 1183.65 and 977.65 mg per 100 g for the samples respectively. For Algenina sample the protein digestibility increased to 50% after cooking but for Zalngy it decreased to 30%.