不同种荞麦发芽前后蛋白质及氨基酸变化主成分分析与综合评价

为评价不同品种荞麦发芽前后蛋白质及氨基酸的综合质量,探讨发芽对荞麦蛋白质和氨基酸的影响,利用凯氏定氮法和氨基酸自动分析仪分析测定了10个品种荞麦(5种甜荞,5种苦荞)发芽前后蛋白质、氨基酸的含量,对其进行了相关性分析、主成分分析和系统聚类分析。结果表明,荞麦种子及其芽中均富含谷氨酸、精氨酸、赖氨酸、丙氨酸、天冬氨酸等氨基酸。发芽处理可显著提高荞麦蛋白质含量(平均增幅50.0%)、总氨基酸含量(平均增幅37.0%)、总必需氨基酸含量(平均增幅43.7%)及大部分氨基酸的含量。荞麦氨基酸主成分分析提取3个主成分,建立了氨基酸综合评价模型:F=F1×0.766 1+F2×0.103 4+F3×0.066 6,用该模型计算的荞麦氨基酸综合得分可有效评价荞麦氨基酸的综合质量,其与荞麦总氨基酸、总必需氨基酸含量的相关系数分别为0.974 1和0.990 9。结合聚类分析,综合评价结果表明赤峰2号甜荞芽、海子鸽苦荞芽和湖南7-2甜荞芽氨基酸综合质量较好。     

酶法水解荞麦蛋白的研究

采用枯草杆菌蛋白酶水解荞麦蛋白，对酶解过程的主要影响因素进行了研究。正交法试验结果表明：枯苹杆菌蛋白酶在底物浓度为3%、温度35℃、pH7.5、加酶量为500u/g 的条件下，酶解反应4h，其水解度可达36.09%。     

Proximate composition,mineral and amino acid content of mature Canavalia gladiata seeds

The chemical composition and the nutritional quality of protein and carbohydrates of mature seeds of Canavalia gladiata (L.) were investigated. The whole and cotyledon flour of mature seeds contained; crude protein 26.8 and 29.2%; fat 2.8 and 3.1%; fibre 33.2 and 10.2%; ash 3.9 and 4.3%; carbohydrate 33.3 and 53.2% on dry matter basis respectively. The carbohydrate fractions have starch contents of 30.7 and 39.6% and 27.7 and 34.6 mg g⁻¹ low molecular weight carbohydrates on dry matter basis. The energy content of whole seed and cotyledon flour was 11,082 and 14,923 kJ kg⁻¹. Sucrose represents the highest fraction of low molecular weight carbohydrates with fructose being the lowest. The mineral analysis showed K, Mg, Ca, P and S to be present in high quantities. The essential amino acid profile compared well with FAO/WHO recommended pattern except for sulphur containing amino acids, cysteine and methionine. Therefore the chemical composition of the raw mature seeds of Canavalia gladiata (kernel) indicates the bean to be a good supplement to cereal-based diets.     

Studies on the essential amino acid composition, protein fractions and biological value (BV) of some new varieties of rice

The protein quality of newly evolved high-yielding Indian varieties of rice, namely, Improved Sabarmati, Pusa 2-21, Jaya and Padma has been evaluated and compared with an old existing popular variety i.e. Basmati-370. All the new varieties were found superior in their limiting amino acid content (lysine, tryptophan and methionine) and the ratio of various fractions of proteins. The animal feeding tests for biological value (BV), true digestibility (TD), net protein utilisation (NPU) and utilisable nitrogen (UN) also showed their superiority over Basmati-370.     

Comparative studies on protein fractions and amino acid composition from sorghum and pearl millet

A defatted flour sample of sorghum and pearl millet were separated into three fractions. These procedures involve extracting the defatted flour with aqueous sodium hydroxide (pH 11.9) followed by precipitation with diluted HCl acid (pH 4.8). The two protein fractions I (soluble at pH 4.8) and II (insoluble at pH 4.8) along with the remaining residues (fraction III) were lyophilized separately. The amino acid composition of the original flour and the three fractions were determined. Lysine seems to be the most deficient amino acid in the original flour and the remaining residues. Fraction I and II, in which the lysine accumulated, have essentially better amino acid profile and consequently nutritionally better quality than the protein of the original defatted flour. The recovered protein-rich fractions I and II should be useful as a protein ingredient in foods. The remaining residues can be extruded into convenience foods.     

Fractionation and amino acid analysis of the salt-soluble protein fractions of normal and high-lysine barleys

High-lysine barleys derive their high lysine content, in part, from an increase in the salt-soluble proteins. These proteins were extracted in 0.5m sodium chloride from milled grain of the genotypes Hiproly, Risø 1508, Risø 7, Bomi, Vada and Ark Royal. The extracts were subsequently separated into albumins and globulins by dialysis against distilled water, and were examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and amino acid analysis. SDS-PAGE revealed that the polypeptides of both fractions were highly heterogeneous with respect to molecular weight. There were marked differences in the polypeptide composition of the albumin fraction of the high-lysine genotypes compared to the normals, but relatively smaller differences in the globulins which were generally higher in lysine and lower in glutamic acid than the albumins. The albumin fraction of Hiproly had a very high level of lysine compared to the other genotypes and surprisingly the globulin fraction of Risø 1508 had a low lysine content. The consequences of these findings are discussed in relation to strategies for breeding high-lysine barleys.     

小麦蛋白酶解物分子量及氨基酸组成的研究

利用凝胶层析法对小麦蛋白酶解物分子量分布和氨基酸组成进行研究。结果表明:胃蛋白酶酶解物中多肽分子量在300～1 500Da的占52.4%,大于1 500Da的占18%,小于300Da的占29.5%;碱性蛋白酶酶解物中多肽分子量在300～1 500Da的占47.1%,大于1 500Da的占21.9%,小于300Da的占31.0%;必需氨基酸纯化后增加了6.7%,具有更好的营养价值。     

Effect of supplementation with fish protein concentrate on protein and amino acid content of salt biscuit

Fish protein concentrate (FPC) from river Nile bolti fish (Tilapia nilotica) was prepared by two extractions with isopropyl alcohol. This FPC was used as a supplement to manufacture salt biscuit (mixed with cumin) for raising its nutritional quality. The supplementation at level of 4, 5, and 6% increased the protein content by about 2. 6, 3. 5, and 4.5% respectively. Increase was high in some amino acids such as glycine, serine, and threonine while cysteine, lysine, alanine, glutamic acid, arginine, isoleucine, and phenylalanine increased in a low rate. Consumer acceptability was the best at 6% level. The increasing of the supplementation to more than 6%, e. g. 7, and 8% levels caused a drop in the overall quality. There were significant differences in colour and highly significant ones in taste, flavour and texture due to differences in the supplementation level. The presence of all essential amino acids in significant quantities suggests an importance of supplementation of salt biscuit in human nutrition.     

红松仁蛋白氨基酸组成分析及营养评价

以红松仁为原料,利用氨基酸自动分析仪检测红松仁可溶性蛋白中的氨基酸组成,以氨基酸比值系数分和WHO/FAO氨基酸评分为评价标准,对红松仁蛋白质营养价值进行全面的评价。结果表明:红松仁蛋白中氨基酸种类齐全,谷氨酸含量最高,必需氨基酸的含量占氨基酸的总量为25%,属于优质植物蛋白。红松仁中水溶和盐溶蛋白占红松仁蛋白的67.7019%,水溶蛋白和醇溶蛋白的氨基酸组成及评分最为合理,是红松仁组成蛋白中较优的蛋白组分;按照氨基酸比值系数,红松仁组成蛋白中,水溶蛋白(82.9256)>碱溶蛋白(81.453)>醇溶蛋白(79.0838)>总蛋白(77.1625)>盐溶蛋白(46.3652)。总蛋白、水溶蛋白、盐溶蛋白的第一限制氨基酸为缬氨酸,碱溶蛋白和醇溶蛋白的第一限制性氨基酸为蛋氨酸和胱氨酸。     

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。     

新疆驼乳中所含蛋白质和氨基酸的质量分数测定

通过用凯氏定氮法和高效液相色谱法测定了新疆驼乳中蛋白质和氨基酸含量。结果表明,新疆驼乳中蛋白质质量分数为4．45％,其中乳清蛋白占1．25％,大约是牛乳乳清蛋白质量分数的两倍;并含有18种氨基酸,其中8种必需氨基酸质量分数占总氨基酸质量分数的40．70％,药效氨基酸占总氨基酸质量分数的63．95％。     

氨基酸的有效性对于蛋白消化率校正氨基酸评分的影响

蛋白质的传统化学评分是基于相关的氨基酸组成,蛋白消化率校正氨基酸评分综合了蛋白质的传统化学评分和氨基酸有效性的生物学评价。随着蛋白消化率校正氨基酸评分的产生,对于膳食蛋白品质的评价有了一个飞跃。本文重点研究测定蛋白中氨基酸有效性的问题,并讨了采用回肠消化率,粪便消化率,真消化率,实际消化率对于评价蛋白品质的不同影响。     

若羌红枣中蛋白质和氨基酸含量的测定

通过用凯氏定氮仪和高效液相仪测定了若羌红枣中蛋白质及氨基酸含量,结果表明若羌红枣中蛋白质含量为2.67%且含有18种氨基酸。     

Effects of various phytase sources on phytic acid content,mineral extractability and protein digestibility of tarhana

Changes in phytic acid (PA), HCl-extractability (HCl-E) of some minerals and in vitro protein digestibility (IVPD) during the production of tarhana prepared with the addition of different phytase sources (bakers’ yeast, barley malt flour and microbial phytase) were investigated. PA content of tarhana decreased significantly (p < 0.01) after addition of the yeast, malt and phytase. With respect to wheat flour used as raw material, PA content of tarhana decreased by 95.3%. After tarhana production, average values of HCl-E of Ca, Mg, Zn and K, and also IVPD of tarhana increased up to 80.2%, 86.4%, 73.9% and 92.6%, and 91.9%, respectively. Significant negative correlation coefficients were found between the PA and HCl-E of the minerals, and also IVPD. Tarhana production processes, including fermentation, drying and grinding, were able to remove the antinutritional effects of PA. Each one of the phytase sources used alone decreased the PA content to a limited extend. The results show that tarhana has good potential in the total amounts and bioavailability of the minerals and proteins.     

外加蛋白酶对提高酵母水解物氨基酸含量的影响

考察几种蛋白酶对提高酵母水解物中氨基酸含量的影响，确定复合风味蛋白酶作为外加蛋白酶，通过优化实验，确定该酶最适加量为5LAPU／g干酵母，最终氨基氨和总氮收率分别提高151％和40．18％，其量分别为23．1mg/g干酵母，60.85mg/g干酵母。     

Chemical composition,amino acid content and protein quality of Canavalia spp. seeds

Canavalia ensiformis is a grain legume that offers good possibilities for its use, but reports on its chemical composition and nutritive quality are not readily available. This study presents chemical and nutritional data on C. ensiformis, C. gladiata and C. maritima grains. The three species varied in protein content mainly because of differences in crude fibre content. Protein varied from 26.9 to 22.4%, and crude fibre varied from 8.5 to 17.3%. This was due to differences in seed-coat percentage. The amino acid content in C. ensiformis and C. gladiata was essentially the same, and both were deficient in sulphur-containing amino acids but rich in lysine. Pressure cooking and roasting reduced lysine levels. Mineral content in the three species was essentially the same, with high potassium levels as is the case with most food legumes. Feeding trials indicated low nutritional quality for the raw grain, which was significantly improved by pressure cooking and roasting. Protein digestibility was 47.9%, and cooked and roasted samples had 76.4 and 78.7%, respectively. Both C. ensiformis and C. gladiata had the same protein quality (PER = 1.24), and it was significantly improved with methionine supplementation.     

Fatty acid and free amino acid content of some mushrooms

Free amino acids and fatty acids of seven Basidiomycetes belonging to the families Hygrophoraceae and Russulaceae were determined. Pro, Glu, Ser and Val are the main free amino acids. Linoleic, oleic and palmitic acids are essentially the only fatty acids.     

Effect of preliminary and culinary processing on amino acid content and protein quality in frozen French beans

The aim of the study was to evaluate the content of amino acids and protein quality of French bean pods. The investigated material consisted of the raw vegetable, fresh pods cooked to consumption consistency, and two kinds of frozen products stored for 12 months at ?20 °C and then prepared for consumption: frozen beans obtained using the traditional method (blanching before freezing) and frozen products of the ready‐to‐eat type (cooking before freezing). A comparison of the amino acid content in the product prepared for consumption showed that the lowest quantities were found in French beans obtained using the traditional method; products obtained using the modified technology and beans cooked directly after harvest had similar levels of most amino acids. The content of amino acids in 16 g N was less varied than in 100 g of the product. The protein in all the three products prepared for consumption as well as that in fresh bean pods hardly differs, as confirmed by the values in the essential amino acid index (EAA). The first limiting amino acid was methionine with cystine and the second was lysine.     

Phytate and mineral content in different milling fractions of some Pakistani spring wheats

Six Pakistani wheat cultivars, namely C-273, Inqulab-91, Pasban-90, Parwaz-94, Shahkar-95 and Rohtas-90, were included in the present study. The kernel weight of the wheat cultivars varied from 31.43 to 36.76 g (per thousand kernels), Parwaz-94 having the highest and Rohtas-90 having the lowest. The test weight of cultivars ranged from 70.23 (Shakar-95) to 76.13 kg hL^–1 (Pasban-90). The bran contained the highest amount of phytic acid (6.12%) in C-273 followed by whole-wheat flour (2.23%) in Inqulab-91, and straight-grade flour (0.24%) in Parwaz-94. The phytate content was reduced during the baking of bread and chapati. The bread scores and other quality characteristics varied significantly among cultivars. The total bread scores ranged from 35.20 to 42.00, out of a possible fifty, with Parwaz-94 being the highest. The concentration of minerals varied widely in different milling fractions of various wheat cultivars. The concentration of Cu, Fe, Mn and Zn ranged from 5.00 to 52.50, 26 to 147.50, 0.00 to 97.00, 9.0 to 80.80 ppm, respectively, in different milling fractions of the wheat cultivars. The total chapati scores ranged from 22.40 to 24.20 of a possible score of 30. The minimum chapati scores were found in Rohtas-90 and Parwaz-94, while Inqulab-91 produced the maximum score.     

Effect of amino acid,pH and mineral salts on glass transition and flow behaviour of soy protein concentrate

The objective of this study was to assess the effect of proline, mineral salts (NaCl and Na₂SO₄) and pH combined with moisture content on the glass transition temperature (T_g) and flow‐starting temperature (T_f) of soy protein concentrate (SPC). Initial screening of the variables based on fractional factorial design showed insignificant effect of NaCl on T_g and T_f. The design was extended to a face‐centred central composite design (CCD) excluding NaCl and data evaluated by use of response surface methodology. The established model for T_g (R² = 0.824) shows significant negative first‐order effects of moisture, proline and Na₂SO₄, and a positive interaction effect of moisture and Na₂SO₄. The T_f model (R² = 0.937) shows significant negative first‐order effects of moisture and proline, a positive first‐order and negative square effect of pH, and a negative interaction effect of moisture and proline. The main effect on T_g and T_f was 2.2 and 1.3 times higher, respectively, for moisture compared to proline. The study confirms that proline (or other free amino acids) can replace moisture as protein plasticiser in the extrusion process. Minor effects can also be obtained by reduction in pH.