Comparison of the quality of some Croatian and German wheat varieties according to the German standard protocol

Ten Croatian and five German wheat varieties were tested. They were carried out using the German standard testing protocol. The results demonstrated that the quality of the Croatian wheat varieties could be ranged in A-C quality groups according to the German testing protocol. Croatian wheat varieties were comparable in many parameters (protein content, hardness, water absorption, dough handling properties and volume yield) with chosen German wheat varieties. Some differences were found in falling number, sedimentation value, flour yield, and ash value number.     

Amino acid composition of two Italian durum wheat varieties and their semolina

Two Italian durum wheat varieties and their semolina were analysed for protein content and amino acid composition. There was a difference in protein content between the two varieties. The concentration (in protein) of lysine, methionine and phenyl alanine was equal in both varieties. A large difference was found in glutamic acid and valine. A slight difference was found in other amino acids. There was a difference in the concentration of amino acids between wheat and its semolina. The biological value was equal in both varieties. The difference in results is attributed to the varietal difference.     

Protein characteristics and peroxidase activities of different Indian wheat varieties and their relationship to chapati-making quality

Different wheat varieties grown at a single geographical location were evaluated for protein quantity and quality, rheological properties, and activities of peroxidase as well as polyphenol oxidase. The protein content in these varieties ranged from 11.6 to 14.6%, farinograph water absorption ranged from 70 to 76%, and the damaged starch content varied from 12.3 to 16.3%. The total protein content of whole wheat flours significantly correlated to stiffness (R/E values) of the dough (r=0.73, p<0.05); however, it did not influence any of the quality parameters of chapati. However, the protein quality parameter, Glu-1 score, which reflects the high molecular weight (HMW) glutenin subunit composition, correlated significantly to the cutting force, which indicates the texture of chapati (r=0.78, p<0.05). The quantity of low molecular weight protein fraction having molecular weight of 20 kDa showed significant correlation to over all quality scores of chapati (r=0.78, p<0.05). The color of chapatis was significantly correlated to color of dough (r=0.76, p<0.05), which became darker on resting. Peroxidase activity greatly influenced the color of chapatis (r=0.81, p<0.05).     

Amino acid composition of South African and Australian wheat varieties as a function of their nitrogen content

Samples of six varieties of South African and Australian wheats sown on 4 dates were found to range in total nitrogen content from 2.42 to 3.86%. Analyses of these samples indicated that no major change in the proportions of the amino acids occurred between samples of varying nitrogen content, and an inverse relationship between lysine and nitrogen content (reported in the literature for wheats of low protein content) could not be demonstrated.     

The nutritional quality of some Pakistani wheat varieties.

The nutritional quality of some improved wheat varieties grown in pakistan was measured chemically (including amino acid analyses) and biologically in n-balance experiments with growing rats. the protein content ranged from 12.3 to 16.7%. lysine per 100 g protein varied between 2.46 and 2.90%. the protein of chenab-70, punjab-76 and barani-70 contained 16-18 % more lysine than the sa-75 having highest content of protein. iron content was highest in pari-73. the true protein digestibility (td), biological value (bv), net protein utilisation (npu) and net dietary protein calorie percent (ndp cal %) varied between 91-94 %, 58-69 %, 54-63 % and 7.4-8.8 %, respectively. available carbohydrate, lysine and biological value were lowered in varieties with a higher content of protein.     

Policosanol content and composition of wheat varieties as affected by environment

BACKGROUND: Policosanol (PC) is a mixture of high‐molecular‐weight aliphatic primary saturated alcohols which possesses cholesterol‐lowering properties. Literature on PC contents and compositions of wheat varieties is limited. The main objective of this study was to evaluate the effect of genotype and environment on PC content and composition in wheat grain. RESULTS: Grain samples were collected from three varieties, Jagger, Trego and Intrada, grown at three locations, Alva, Balko and Goodwell, OK, in 2005. Two sets of samples were obtained from Goodwell (irrigated and dryland samples). Total PC content and PC composition in whole wheat grain samples were determined using a gas chromatography system. PC contents of the whole wheat grain samples varied from 15.9 to 28.7 mg kg^?1. Tricosanol, tetracosanol, hexacosanol, octacosanol and triacontanol were the most abundant PC components. Within each location a significant variety effect was observed. There was also a significant location × variety random effect on PC content. CONCLUSION: A fundamental understanding of compositional variation in wheat grain requires multi‐environment testing of genotypes, perhaps over several years. This study is the first step towards achieving this goal by revealing significant genetic differences in a limited set of genotypes. Copyright © 2008 Society of Chemical Industry     

Effect of loaf specific volume on the rate and extent of staling in bread

The quantitative relationships between loaf specific volume and the rate and extent of staling in bread as measured by changes in crumb elastic modulus have been examined. The results show that loaf specific volume is a major factor in determining both the rate and extent of staling, both of which decrease in a linear manner, over the range studied, as loaf volume increases. Only two factors have been found that have a significant influence on these curves, the basic breadmaking process and the storage temperature. The influence of changes in loaf specific volume on staling characteristics is greater in bread prepared by bulk fermentation than in bread prepared by the Chorleywood Bread Process. Bread made by the Chorleywood Bread Process stales less rapidly than bread made by the conventional bulk fermentation process. The effect of loaf specific volume on the rate of staling is more marked as the storage temperature is lowered.     

Identification of some wheat varieties by near infrared reflectance spectroscopy

Variety identification by electrophoresis is not applicable to routine control in industry. In the present work, the feasibility of near infrared reflectance (n.i.r.) analysis was investigated. Two hundred and two wheat samples including 66 samples of six known varieties were collected and their n.i.r. spectra were recorded. Spectral data were mathematically corrected in order to reduce the effect of granularity on n.i.r. spectra, then Principal Component Analysis and Multiple Discriminant Analysis (MDA) were applied to the corrected data. MDA allowed an efficient identification of the genetic origin of unknown samples: on a prediction set, 87% of samples were correctly identified. The computerised identification procedure needed less than 20 records for one sample. Further studies are necessary before recommending n.i.r. as a routine screening method.     

The influence of monoacylglycerol and L‐glutamic acid on the viscoelastic properties of wheat flour dough and sensory characteristics of French loaf product

BACKGROUND: The influence of monoacylglycerol Rimulsoft Super(V) and L ‐glutamic acid added to wheat flour dough was studied. Properties of the doughs were evaluated on the basis of chemical analysis and rheological measurements on a farinograph. Bakery products made from these doughs were subsequently subjected to sensory analyses. RESULTS: It was found that L ‐glutamic acid influenced the water absorption in dough more (50.0 g kg^?1; water absorption 56.6%) than monoacylglycerol Rimulsoft Super(V) (50.0 g kg^?1; water absorption 55.0%). Farinograph measurements showed that doughs with the addition of L ‐glutamic acid resembled flour containing high‐quality gluten, but dough with the addition of monoacylglycerol Rimulsoft Super(V) corresponded to ‘weak’ flour. Sensory analyses revealed that, in comparison with the control sample of French loaf, the saliva‐absorbing capacity increased in the French loaf with the highest addition of L ‐glutamic acid (30.0 g kg^?1). Deterioration in quality and texture in French loaf with addition of L ‐glutamic acid (8.0 g kg^?1, 30.0 g kg^?1) was noted. No other statistically significant differences were found. CONCLUSION: It is acceptable to add both additives to dough in order to modify its rheological properties. Copyright © 2010 Society of Chemical Industry     

小麦微核心种质中育成品种和地方品种的SDS沉降值分析

为加快SDS沉降值在小麦品质改良中的应用,对来自小麦微核心种质中的83份育成品种和146份地方品种的SDS沉降值进行了测定,初步分析了SDS沉降值的遗传多样性及分布规律。结果表明,育成品种和地方品种的SDS沉降值基因型间差异极显著,具有较大的变幅和变异系数;两种类型小麦种质的SDS沉降值均主要分布在25.0～35.0ml,SDS沉降值>45ml和SDS沉降值<15ml的种质所占比例较小;SDS沉降值最高与最低的种质均来自地方品种,分别为白朗灰麦和假红麦,育成品种中SDS沉降值最高与最低的种质分别为东方红3号和农大139。根据SDS沉降值的分布,筛选了7份高SDS沉降值和8份低SDS沉降值的种质,这些种质可作为高、低SDS沉降值小麦品种选育的中间材料加以利用。     

The relationship between HMW glutenin subunit composition and the bread-making quality of British-grown wheat varieties

Based on previous work, which related individual HMW glutenin subunits to bread-making quality by genetical analysis, quality scores were assigned to each of the commonly occurring subunits. The grain proteins of 84 home-grown wheat varieties were fractionated by SDS—PAGE to determine their HMW glutenin subunit composition. The quality scores of each of the subunits were summed to create a Glu-1 quality score for each variety. The results indicated that 47-60% of the variation in the independently established bread-making qualities of this set of varieties could be accounted for by variation in HMW subunits of glutenin. The presence or absence in the varieties of a translocated chromosome, which consisted of the long arm of 1B and the short arm of 1R from rye, was also established because of its known association with poor bread-making quality. A correction factor was applied to the Glu-1 quality score of those varieties that contained the 1 BLURS chromosome. The variations in the rye-adjusted Glu-1 quality scores were compared with those of the bread-making qualities of the varieties, and the proportion of variation in quality accounted for was raised to 55-67%. The Glu-1 quality score and the biscuit-making qualities of the same set of varieties were negatively related. The results are discussed in relation to future strategies recommended to wheat breeders for developing new varieties with improved bread-making quality.     

Comparison of wheat varieties by starch-gel electrophoresis of their grain proteins

Single extraction of wheat flour with water proved to be necessary for obtaining clear electropherograms of the albumin/globulin fraction; triple extraction was required to obtain a clear distinction of the gliadin components. As the ‘electrophoretic mobility’ does not have a constant value, a different characteristic, the R_v value, analogous to the R_t value in chromatography, is suggested as a measure of the relative mobility of the components, a characteristic which is not affected by experimental factors. From densitograms of gliadin fractions, 80 wheat varieties and selected lines from various parts of the world were arranged into five main groups, which formed a morphological series. Each main group comprised of a number of sub-groups which in certain cases were found to be based on genetic relationships. Densitograms of the albumin/globulin fractions could be used in conjunction with those of the gliadins for determination of wheat varieties.     

Dough characteristics of Irish wheat varieties I. Rheological properties and prediction of baking volume

Eight wheat varieties suitable for cultivation in Ireland were examined for the rheological properties and baking quality. Large deformation extensional rheology was used employing the Extensograph, the Kieffer extensibility rig, the Alveograph and biaxial extension by uniaxial compression. Similar discrimination between the wheat samples was achieved with both uniaxial extension methods used. Stress during uniaxial extension was higher at all strains measured than biaxial extension and the difference between uniaxial and biaxial stress increased with increasing strain. Also, differences existed in the strain hardening index between uniaxial and biaxial extension which depended on the sample tested. Significant correlations were established between loaf volume and the rheological properties determined in both uniaxial and biaxial extension. It was found that high loaf volumes can be achieved when biaxial and uniaxial extensibility is high and biaxial extensional viscosity is low. The importance of considering the standard error for validating the value of the correlation for prediction purposes was also demonstrated. When the standard error of the correlation was considered, the value of the correlation for prediction purposes was limited in practice. Nevertheless, the rheological tests provided useful information, and the results were valuable for screening flours for baking quality.     

The influence of irrigation on the composition of soluble amino acids in developing wheat grain

Changes in the composition of soluble amino acids were determined in the endosperm of wheat at different stages of maturation grown under different soil moisture conditions. Significant differences were observed in the composition of soluble amino acids during the course of development. With the irrigated crop, the amount of proline decreased during developmental stages but it rapidly increased with development of grain until little beyond the half maturity stage. It then decreased towards maturity in the case of the unirrigated crop. Many soluble amino acids in the endosperm from the unirrigated crop were at lower levels than that in the endosperm from the irrigated crops during early stages of development, but in the later stages the size of the amino acid pool in the endosperm from the unirrigated field exceeded that from the irrigated field. Protein accumulation in the endosperm was also highly influenced by irrigation.     

Statistical evaluation of different technological and rheological tests of Polish wheat varieties for bread volume prediction

Forty‐two Polish wheat flour were used to establish correlation coefficients between protein content, Zeleny test, falling number value, amylograph viscosity, farinograph water absorption, bread volume and rheological properties of dough, as shown by use of a extrusion chamber and alveograph. The equations expressing the changes of bread volume and flour water absorption as a function of significantly correlated parameters were calculated. The correlations and their significance depended on wheat quality and the alveographic parameters were significantly correlated with the dough extrusion parameters. The dough extrusion parameters were significantly correlated only with the water absorption of soft wheats. The dough rheological tests were correlated to a greater extent with the values of the Zeleny test than to the protein content. The prediction of the bread volume as a function of flour quality parameters and dough rheological properties was best done by grouping wheat varieties into specific qualitative classes.