Impacts of temperature increase and change in precipitation pattern on crop yield and yield quality of barley

Spring barley was grown in a field experiment under moderately elevated soil temperature and changed summer precipitation (amount and frequency). Elevated temperature affected the performance and grain quality characteristics more significant than changes in rainfall. Except for the decrease in thousand grain weight, warming had no impacts on aboveground biomass and grain yield traits. In grains, several proteinogenic amino acids concentrations were increased, whereas their composition was only slightly altered. Concentration and yield of total protein remained unaffected under warming. The concentrations of total non-structural carbohydrates, starch, fructose and raffinose were lower in plants grown at high temperatures, whereas maltose was higher. Crude fibre remained unaffected by warming, whereas concentrations of lipids and aluminium were reduced. Manipulation of precipitation only marginally affected barley grains: amount reduction increased the concentrations of several minerals (sodium, copper) and amino acids (leucine). The projected climate changes may most likely affect grain quality traits of interest for different markets and utilisation requirements.     

Amaranth Milling Strategies and Fraction Characterization by FT-IR

Amaranth nutritional value has been widely recognized, but the required conditions for its processing cannot be adapted to traditional technologies. For the proposal of alternative strategies, the changes of several components should be understood. Enriched starch and lipid–protein fractions of amaranth flour upon different milling treatments were obtained and characterized by attenuated total reflectance–Fourier transform-infrared spectroscopy. Starch- and lipid–protein-enriched amaranth fractions were obtained by abrasive milling; amaranth starch was isolated by wet-milling procedure, and flour samples were obtained from planetary ball milling. Changes on starch, protein, and lipids relative contents, on starch crystallinity and on lipids and protein stability after milling and 6-month storage, were evaluated. The Fourier transform-infrared (FT-IR) spectroscopy peaks of the main grain components were identified in the middle-infrared range. By calculating the ratios between height intensities of selected specific peaks, several characteristics of the samples could be explained: increased protein content and lipid proportion of the enriched fraction; decrease of the starch crystallinity degree by abrasive milling and especially by ball milling due to starch amorphization during these processes; and lipids modification in milled and in 6-month aged samples. FT-IR analysis can be considered a rapid, nondestructive, solvent-free, sensitive, and useful tool to investigate starch, lipid, and protein modifications provoked by processing and storage as well as to determine, based on intensity ratio, the relative proportion of grain components within amaranth milling fractions. The abrasive milling associated to planetary ball milling to obtain modified different fractions is presented as an interesting strategy for the processing of amaranth grain.     

THE CARBOHYDRATES OF BARLEY GRAINS — A REVIEW

The carbohydrate composition of barley grains and the structure of barley carbohydrates is described and related to their influence on grain quality and utility. The adequacy of methods used for the analysis of barley carbohydrates is also critically evaluated. Low molecular weight carbohydrates, glucose, fructose, sucrose, maltose, fructosylsucrose and raffinose; non-structural polysaccharides, fructans and starch; and cell wall polysaccharides, including beta-glucans and arabinoxylans are included.     

Effects of tannic acid and quebracho tannins on in vitro ruminal fermentation of wheat and corn grain

Current understanding of the effect of moderate amounts of tannins on the utilization of protein contained in forages indicates beneficial effects when fed to ruminants. Nevertheless, there is little knowledge about the effects of tannins on the ruminal hydrolysis of starch‐rich concentrates. Modulation of the hydrolysis of starch may reduce the occurrence of metabolic disorders, such as acidosis, in ruminants consuming high‐grain diets. The effects of commercial tannic acid (hydrolysable tannins) and quebracho tannins (condensed tannins) (50 g kg^?1 DM) on the in vitro fermentation of ground wheat and corn grains by mixed ruminal bacteria was examined. The architecture and chemical composition of wheat and corn endosperms might explain differences in fermentation rates, as well as in response to similar concentrations of tannins. Regardless of the source of tannin, microbial fermentation was inhibited in both grains, as demonstrated by a decline in gas production, DM disappearance, volatile fatty acids and ammonia production. However, these effects were more pronounced for wheat than corn grain, mostly during the initial stages of the incubation. Scanning electron microscopy revealed that both sources of tannins inhibited the microbial hydrolysis of the endosperm protein matrix. Tannins did not prevent bacterial attachment to starch granules, but starch hydrolysis was slowed indirectly as a result of a tannin‐mediated reduction in the degradation of the surrounding protein matrix. Tannins are likely to be more effective at modulating the rate of starch digestion in grains that possess a readily degradable protein matrix. Copyright © 2006 Society of Chemical Industry     

Characterization of marama bean (Tylosema esculentum) by comparative spectroscopy: NMR, FT-Raman, FT-IR and NIR

The marama bean from Southern Africa has proven to be a source for production of various healthy food products. In order to exploit its commercial potential, it is important to know its chemical composition in more detail. In this study, marama beans from different geographical sites and harvest years were analyzed by use of infrared, near infrared, Raman, and ¹H as well as ¹³C nuclear magnetic resonance spectroscopy. These techniques can measure single beans in a rapid and non-destructive manner. By comparative application, the qualitative composition of the marama bean was explored in detail, revealing large amounts of protein, dietary fiber and unsaturated fat. The carbohydrate fraction was largely present as pectins and a minor fraction of smaller water soluble carbohydrates were tentatively assigned to raffinose. It is characteristic that the beans do not contain starch or ??-glucans and that the water soluble part of the proteins/peptides have a high content of the aromatic amino acid tyrosine.     

pH对高效液相色谱法测定保健食品中维生素B12含量结果的影响

摘 要： 目的通过高效液相色谱法研究原料中包含较高含量碳酸钙的复合维生素片且样品溶液pH>7.0不同pH条件下维生素B12 检测结果的差异性并探究其原因。方法 选取原料中添加较高含量碳酸钙且样品溶液pH>7.0的复合维生素片,调节样品溶液pH为4.0~4.5、5.0~5.5、6.0~6.5时测定样品中维生素B12的含量并记录;检测并记录pH分别为4.02、5.01、6.05水稀释得到的标准中间液维生素B12的检测结果. 记录并分析pH为4.0~4.5、5.0~5.5、6.0~6.5的样品和碳酸钙溶液60min内pH的变化。结果不同pH样品溶液维生素B12测得的结果值有显著性差异,调节pH为4.20~4.50时测得的结果值与样品实际结果值相符;维生素B12标准中间液在不同pH下测得的检测结果相同。样品和碳酸钙溶液的pH在60 min内随着时间的变化发生改变,调节溶液pH>5.0时,溶液的酸碱性较不稳定,在10~20 min内溶液会由酸性变为碱性;调节溶液pH<5.0时,溶液在60 min内较稳定始终为酸性,碳酸钙溶液的酸碱性与样品溶液有相同的变化趋势。结论在保健食品维生素B12的检测中需要关注样品中原辅料的种类和配比对样品溶液检测过程中酸碱性的影响,对原料中含较高含量碳酸钙且样品溶液pH>7.0的样品在维生素B12检测中需用柠檬酸调节溶液pH为4.2~5.0之间。     

Characteristics and composition of different seed oils and flours

The nutritional quality and functional properties of paprika seed flour and seed kernel flours of pumpkin and watermelon, and also the characteristics and structure of their seed oils, were studied. Paprika seed and seed kernels of pumpkin and watermelon were rich in oil and protein. All flour samples contained considerable amounts of P, K, Mg, Mn and Ca. Paprika seed flour was superior to watermelon and pumpkin seed kernel flours in contents of lysine and total essential amino acids. Antinutritional compounds, such as stachyose, raffinose, verbascose, trypsin inhibitor, phytic acid and tannins, were detected in all flours. Pumpkin seed kernel flour had higher values of chemical score, essential amino acid index and in-vitro protein digestibility than the other flours examined. The first limiting amino acid was lysine, for both watermelon and pumpkin seed kernel flours, but it was leucine in paprika seed flour. Functional properties were excellent in watermelon and pumpkin seed kernel flours and fairly good in paprika seed flour. Flour samples could be potentially added to food systems such as bakery products and ground meat formulations, not only as a nutrient supplement, but also as a functional agent in these formulations. Oil samples had high amounts of unsaturated fatty acids, with linoleic and oleic acids as the major acids. All oil samples could be fractionated into seven classes including triglycerides as a major lipid class. Data obtained for the oils characteristics compare well with those of other edible oils.     

淡水鱼加工下脚料自溶水解工艺的研究

利用内源性蛋白酶进行淡水鱼加工下脚料自溶水解的工艺进行了研究,以氨基酸态氮的含量作为评价水解程度的指标,探讨时间、加水比、温度和初始pH值对淡水鱼下脚料自溶水解程度的影响。结果表明,响应面优化的自溶水解反应条件为水解温度45℃,水解时间48h,pH5.0。在此条件下,水解液中氨基酸态氮含量达到(1.0463±0.03)g/100mL。     

辅料改善草鱼鱼糜凝胶性能的机理

以草鱼为原料,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、质构分析和化学作用力测定等方法,研究辅料改善草鱼鱼糜凝胶性能的机理。结果表明：草鱼鱼糜蛋白自溶最适温度和pH值分别为65 ℃和6.5;马铃薯淀粉对鱼糜蛋白交联结构的填充能力强于胶原蛋白,而胶原蛋白对鱼糜组织蛋白酶的抑制效果好于马铃薯淀粉;辅料加入后,改变了鱼糜蛋白间的离子键、氢键、疏水性相互作用和二硫键等化学作用力,从而达到改善鱼糜品质的目的。     

Evaluation of Whole Amaranth (Amaranthus cruentus) Flour, Its Air-Classified Fractions, and Blends of These with Wheat and Oats as Possible Components for Infant Formulas

Whole amaranth (Amaranthus cruentus) seed flour, its air-classified fractions and extruded blends of these with wheat and oats were studied with the purpose of evaluating their potential as components in the development in infant formulas. Proximal chemical analyses, mineral content, fatty acid composition of lipid fractions, amino acid analyses and Protein Efficiency Ratio (PER) and Net Protein Retention (NPR) values were obtained for all raw materials, as well as for 50:50 and 60:40 blends of these with oats and wheat. The 50:50 and 60:40 blends of whole amaranth, as well as of the protein-rich air-classified fraction, were found to be highly suitable for utilization in infant formulas.     

Carbohydrate composition of different varieties of cowpea (Vigna unguiculata)

Twenty varieties of cowpea with the following proximate composition: dry matter, 87–94%; crude protein, 24–33% ether extract, 1–2%; crude fibre, 2–5% and ash, 2–5% were analysed for sugar contents, starch, cell wall carbohydrates and lignin. The legume seeds exhibited a total carbohydrate content ranging from 56% to 68%, the major constituent being starch. Starch values as high as 45% to 48% were obtained for some varieties although most values ranged between 37% and 42%. Ethanol-soluble sugars were verbascose, stachyose, sucrose and raffinose in varying amounts but there were only traces of fructose and glucose. Samples had total soluble sugar contents of 6% to 13%. Values for unavailable carbohydrates for most samples were 11% to 13%. Lignin was very low and ranged from 0·6% to 1·8%.     

瑞克纤孔菌发酵条件优化及菌丝化学成分定性分析

研究了瑞克纤孔菌液体发酵适宜的碳源、氮源、温度和pH值,并定性分析了菌丝体的主要化学成分.结果表明,玉米淀粉、甘露醇和葡萄糖为适宜碳源,以玉米淀粉为最适;硝酸钠等无机氮源不适宜该真菌生长,适宜氮源为蛋白胨和酵母粉,以蛋白胨为最适;菌丝生长的适宜pH=6.0～6.5,适宜温度为25～30℃.瑞克纤孔菌菌丝体含有氨基酸、多肽、蛋白质、有机酸、还原糖、多糖和甙、皂甙、甾体和三萜类化合物、内酯、香豆素和挥发油,不含有生物碱、酚类化合物、鞣质、黄酮类化合物、强心甙和蒽醌类物质.     

Suitability of some selected maize hybrids from Serbia for the production of bioethanol and dried distillers' grains with solubles

BACKGROUND: Bioethanol is mostly produced from starchy parts of the corn grain kernel leaving significant amounts of valuable by‐products such as dried distillers' grains with solubles (DDGS) which can be used as a substitute for traditional feedstuff. The suitability of six maize hybrids from Serbia was investigated for bioethanol and DDGS production. The correlation between physical and chemical characteristics of the grain, bioethanol yield and quality of the corresponding DDGS was assessed. RESULTS: All hybrids had very different chemical composition and physical characteristics which could allow various applications. The highest bioethanol yield (94.5% of theoretical) and volumetric productivity (2.01 g l^?1 h^?1) were obtained with hybrid ZP 434 and the lowest with ZP 611k. Regarding chemical composition, all DDGS samples manifested good properties as feed components. Their protein content was higher compared to the kernel. In addition, the samples showed high digestibility and high mineral content, especially of calcium and phosphorus. CONCLUSION: A hybrid ZP 434 was selected as the most promising bioethanol producer. This property is attributed to the highest level of soft endosperm which is more susceptible to starch‐hydrolysing enzymes. A high yield potential per hectare makes it the best candidate for commercial bioethanol production. © 2012 Society of Chemical Industry     

Nutritional evaluation of kidney beans (Phaseolus vulgaris): chemical composition, lectin content and nutritional value of selected cultivars

The chemical composition, lectin content and nutritional value of selected cultivars of kidney beans (Phaseolus vulgaris) were determined. Mainly due to different amounts of reserve globulins deposited, seed N content varied between 3.4 and 5.0%. The amino acid composition and the corresponding chemical score values of 40-60 however, were similar for all the beans, with the sulphur-containing amino acids limiting. Despite similarities in composition, 11 out of the 13 cultivars examined were highly toxic for rats in the raw state. These were all found to contain high concentrations of haemagglutinating lectins (over 10% of the total protein). On the other hand, two low-lectin bean varieties, Pinto III and Great Northern, had no appreciable disruptive effects on the intestines and were essentially non-toxic for rats.     

SOLUBILITY AND EMULSIFYING PROPERTIES OF BETACASEIN MODIFIED ENZYMATICALLY BY TRYPSIN

Beta A1-casein was treated with TPCK-trypsin to give 3.2, 5.0, 5.8 and 7.4% hydrolysis of the peptide bonds. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis the resulting peptides had apparent molecular weights in the range 8,000–4,000. Size-exclusion chromatography of hydrolyzed samples showed four major peaks near 15,000, 5,500, 3,500 and 2,500 molecular weights, representing 17, 15, 7 and 14% of the material, respectively, after 3.2% hydrolysis and 9, 6, 14 and 52% of the material, respectively, after 7.4% hydrolysis. Between the extremes 3.2% and 7.4% hydrolysis, a peak near 8,500 molecular weight was present until 5.8% hydrolysis then disappeared after 7.4% hydrolysis to be replaced by a peak near 12,000 molecular weight. Peptides recovered from reversed-phase high performance liquid chromatography were analyzed by determination of their amino acid composition and identified in the sequence of β-casein. After trypsin treatment, the solubility of β-casein hydrolysates was largely increased at pH 4.0–7.5. The emulsifying activity of the hydrolysates was higher than that of β-casein in the range of pH 1.5–3.5 and 6.5–10.0, but all the emulsions obtained with trypsin-treated β-casein were less stable than those obtained with original β-casein.     

Structures,physicochemical properties,and applications of amaranth starch

Amaranth as a rediscovered “new” crop is becoming a research focus in the recent two decades. The major carbohydrate of some amaranth species is starch, which accounts up to around 60% of the dry grains. This review summarizes the present knowledge of the isolation, composition, structures, physiochemical properties, modifications, and applications of amaranth starches, and provides suggestions for research to further improve the utilization.     

Characterization of various chestnut cultivars by means of chemometrics approach

Chestnuts like other foodstuffs may be characterized by their chemical composition. The chemical composition of ascorbic acid, total acidity, pH, starch, refraction index (°Brix), moisture, ashes, insoluble fibre, soluble fibre, total dietary fibre, total proteins, cations (Na, K, Ca, Fe, Cu, Zn, Mn, Mg) and phosphorous was determined in 19 local chestnut varieties from three areas of production in the island of Tenerife. Significant differences were found between the mean values of moisture, starch, total phenols contents, total soluble and non-soluble fibre, Ca, Cu, K, Mg and Zn, obtained according to the area of production. Distribution patterns of the samples were established for correlating the chemical composition of the chestnuts and varieties, using different chemometrics tools such as cluster analysis, principal component analysis, factor analysis and linear discriminant analysis (LDA). Initially, cluster analysis made it possible to establish a primary relationship between the variables. When applying stepwise LDA the chestnut samples were well classified within their area of production. Also, when the stepwise LDA was used on the chestnut samples from area of production 2, 100% of the chestnut samples were also correctly classified within their variety.     

6种杂粮营养成分分析及评价

目的 对苦荞、白青稞、白藜麦、黄藜麦、红藜麦和黑藜麦等6种杂粮中所含基本营养成分、矿物质元素、氨基酸及脂肪酸的含量进行检测和分析。方法 依据国家标准方法, 采用液相色谱仪、氨基酸自动分析仪、气相色谱仪等进行成分测定并比较分析。结果 6种杂粮在营养成分上存在一定的差异, 其水分含量为8.68~12.22 g/100 g, 蛋白质含量为10.33~15.41 g/100 g, 脂肪含量为1.25~6.31 g/100 g, 粗纤维含量为1.33~6.64 g/100 g, 灰分含量为1.11~2.53 g/100 g, 碳水化合物含量为67.56~75.85 g/100 g。6种杂粮均富含钾、磷和镁, 白藜麦富含铁, 苦荞富含锌。6种杂粮中不饱和脂肪酸占总脂肪酸的含量的75%以上, 除苦荞外, 其他5种杂粮中亚油酸的含量超过了总脂肪酸含量的一半以上。杂粮中氨基酸种类齐全, 尤其是苏氨酸、缬氨酸、亮氨酸及赖氨酸等必需氨基酸含量均较高。氨基酸评分结果表明, 6种杂粮中苏氨酸、缬氨酸、亮氨酸、苯丙氨酸+酪氨酸氨基酸评分均较高, 且含量都高于联合国粮食及农业组织(Food and Agriculture Organization of the United Nations, FAO)的推荐值。结论 苦荞、白青稞、白藜麦、黄藜麦、红藜麦和黑藜麦等6种杂粮营养丰富, 具有较好的开发价值和利用前景。     

虾蛋白自溶与外源酶促水解作用研究

目的:研究虾蛋白的自溶与外源酶促水解作用,为开发新型虾味高档调味品提供实验依据。方法:以基围虾为原料,氨基态氮含量、水解度（DH）为指标,研究pH、温度、时间、料液比对基围虾自溶水解效果的影响,并在最优条件下添加不同外源酶,探讨其对虾蛋白的酶促作用。结果:通过单因素和L₉（3³）正交试验获得基围虾自溶的最佳工艺参数是:料液比1:8（g/mL）,温度60℃,pH6.5,时间8h。结论:在此条件下,氨基态氮含量1.7g/L,水解度45.88%。外源木瓜蛋白酶具有较好的酶促水解作用,菠萝蛋白酶、中性蛋白酶、胰蛋白酶对虾蛋白的酶促水解作用不显著。     

南极磷虾自溶前后氨基酸和胰蛋白酶降解产物的变化

南极磷虾富含内源自溶酶,死后易快速自溶,限制了其加工利用。为研究南极磷虾自溶特性,测定了不同条件下南极磷虾自溶酶的最适温度和pH值,然后在最适自溶条件下研究了南极磷虾自溶3 h前后的氨基酸态氮含量和组成变化,并对南极磷虾自溶前后的胰蛋白酶降解产物进行了分析。结果表明：南极磷虾自溶酶最适温度为55 ℃,最适pH值为7.5,在此条件下南极磷虾自溶后氨基酸态氮质量浓度升高;甘氨酸和脯氨酸为南极磷虾的主要游离氨基酸,其次为谷氨酸和丙氨酸,南极磷虾自溶后鲜味氨基酸如谷氨酸、甘氨酸、丙氨酸质量分数降低,而苦味氨基酸如亮氨酸、异亮氨酸、酪氨酸和苯丙氨酸质量分数升高;南极磷虾自溶后胰蛋白酶降解产物分子质量分布向小分子质量范围偏移。本实验为进一步研究南极磷虾自溶特性提供了理论依据。