Since the discovery of gluten by Beccari in the 18th century, wheat producers, millers, and bakers have tried to find relatively simple methods of prediction of wheat quality, particularly during the breeding stages. Bearing in mind that endosperm proteins play the governing role in determination of wheat quality, this prediction is generally based on these proteins. Early research concentrated on relations among the macrofractions (i.e., gliadin:glutenin ratio, ratio of acetic acid soluble proteins, etc.). Later, the gliadin polypeptides, the genes coding for these polypeptides, and variety identification became the focus of research. More recent predictions are based on the high-molecular-weight glutenin subunits. Although such predictions are successfully applied in many countries for wheat breeding, the low correlation between predicted and practical quality observed in many cases, and the variability of quality of different wheat varieties, suggests that further studies are needed to improve the reliability of this particular prediction. In the framework of such studies, more attention should be paid to the synthesis and interactions of gluten-forming polypeptides—particularly with respect to the polymerization process of glutenin subunits; the role of redox-system of kernel in the gluten formation; and the formation of gluten complex, including role of nonprotein constituents; consequently, the wheat kernel should be treated as a biological unit. From the methodological point of view, the uses of new techniques such as immunochemistry, nondestructive evaluation methods, etc., hold promise for improved quality prediction. 相似文献
Metabolism of 22 free amino acids (AA) during fermentation(early and later steps) of wheat dough samples started with pure and associated cultures of yeast and lactic acid bacteria, and commercial compressed yeast (CY) were investigated. Unfermented and fermented straight doughs were studied byReversed-Phase HPLC of their dansyl derivatives. Used as starters were strains of Saccharomyces cervisiae, Lactobacillus brevis, Lactobacillus plantarum and Enterococcus faecium. Statistical data analysis indicated clustering of samples with yeast and samples without yeast (including uninoculated doughs) respectively, based on rate of metabolism of acidiC., basiC., aliphatic and aromatic A A. Differences in AA metabolism during the later fermentation step (DF2) categorized bacterial starters into groups according to balance between degree of assimilation(D F2<0) and exoproteolytic release(DF2>0) of amino acids. 相似文献
The cover image is based on the Research Article The Israeli Palestinian wheat landraces collection: restoration and characterization of lost genetic diversity by Sivan Frankin et al., https://doi.org/10.1002/jsfa.9822 .
The sorption of carbon dioxide gas (CO2) by wheat was determined in glass flasks at four temperatures (0, 10, 20 and 30 °C) and four moisture contents (m.c.) (12, 14, 16 and 18% wet basis). The gaseous concentrations were analyzed by gas chromatography and the vacuum developed from the sorption of CO2 by wheat was measured with a mercury manometer. The calculated amount of CO2 sorted at equilibrium was a non-linear function of both temperature and moisture content. Sorption of CO2 by wheat decreased with increasing temperature from 0 to 30 °C at 14% m.c., and the initial rate of sorption increased with increasing m.c. from 12 to 18% at a temperature of 20 °C. Sorption was modelled using non-linear regression at two conditions (0–30 °C at 14% moisture content and 12–18% moisture content at 20 °C). The maximum mass of CO2 sorbed in 60 h was 0.510 g/kg of wheat at 18% m.c. and 0 °C and the lowest was 0.224 g/kg at 18% m.c. and 30 °C. A linear relationship existed between the initial CO2 concentration and the concentration after 60 h when 250 g of wheat of 14% m.c. at 20 °C was exposed in 500 ml flasks. 相似文献
