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Content and composition of maize endosperm lipids and their partition in the floury and vitreous regions were determined for a set of inbred lines. Neutral lipids, i.e., triglycerides and free fatty acids, accounted for more than 80% of endosperm lipids and are almost 2 times higher in the floury than in the vitreous regions. The composition of endosperm lipids, including their fatty acid unsaturation levels, as well as their distribution may be related to metabolic specificities of the floury and vitreous regions in carbon and nitrogen storage and to the management of stress responses during endosperm cell development. Remarkably, the highest contents of starch lipids were observed systematically within the vitreous endosperm. These high amounts of starch lipids were mainly due to lysophosphatidylcholine and were tightly linked to the highest amylose content. Consequently, the formation of amylose-lysophosphatidylcholine complexes has to be considered as an outstanding mechanism affecting endosperm vitreousness.

The range of methods for assessing the quality of grain and its technological properties in cereal crops, of oat in particular, is extremely limited. The available methods are labor-intensive and not always sufficiently informative. The variety of modern processing methods dictates the necessity in searching for more universal and informative assessment methods. Cereal crop breeding also requires high-speed and low-cost methods for assessing grain quality. The present work is a methodological study that uses a limited set oat accessions from the genetic collection of VIR, differing by geographical origin and contrasting technological properties, with an aim of developing a new grain quality assessment method and testing new methods for analyzing technological properties. The resulting criteria are compared with each other and with more traditional indicators. New systems for assessing the technological properties of grain of naked and covered oat have been proposed. A new method of sedimentation analysis for cereal crops is proposed. The diversity of the oat protein complex is exemplified in the results of sedimentation analysis, and of the carbohydrate complex – in the results of its testing by a micro-visco-amylograph. The variety of interactions between oat grain storage substances and wheat material during joint processing is shown by assessing the rheological properties of the dough mixture using a farinograph. The obtained results can be recommended for the assessment for breeding purposes, as well as for obtaining complete information about the quality of oat grain for the purpose of its further processing.

Relationships between kernel vitreousness and proteins and starch partitioning to the floury and vitreous regions of the endosperm were monitored in a set of 13 maize inbred lines. Decrease of protein contents from the vitreous to the floury endosperms were mainly assigned to α-zeins. Using Raman microspectroscopy, we observed a protein gradient from the periphery to the center of endosperms that well fitted with the inverse relationships between vitreousness and protein content of the vitreous and floury regions. In addition, Raman microspectroscopy highlighted an increase of starch crystallinity from the periphery to the center of the maize endosperms. This agrees with the higher amylose and associated lipid contents within starches of vitreous than in those of floury endosperms. Finally, starch granules from vitreous regions displayed more channels than the floury ones. These channels contain proteins that might favor adhesion of proteins to starch granules or granule–granule contacts to form the close packing of the vitreous endosperm. Therefore transition from vitreous to floury endosperm is at least the result of both protein and starch gradients. These gradients are probably associated with metabolic gradients that have been observed during endosperm development. [ABSTRACT FROM AUTHOR]

Abstract: The interest in the study of the effect of endosperm vitreousness (VT) on the nutritive value of maize is increasing in pig nutrition. Therefore, an experiment was conducted to determine the effect of maize VT on starch digestion, resistant starch (RS) content, dry matter digestibility as well as on large intestine fermentation kinetics and related end products by using several in vitro techniques specifically designed for pigs. A set of 30 maize grains was selected to represent a wide range of VT (as a proportion of vitreous in total endosperm) determined by a manual dissection method. Five distinct VT classes were designed [very low (vlVT), low (lVT), medium (mVT), high (hVT) and very high (vhVT)] and identified by a specific VT value (i.e., 291, 357, 432, 611 and 830g/kg endosperm, respectively), calculated as the mean of VT values of maize samples entering the specific class. Starch digestion (expressed as predicted glycemic index) and the rate of starch digestion decreased linearly (ranging from 42.5 to 14.5 and from 0.018 to 0.006/min respectively, for vlVT and vhVT; P<0.05), whereas RS increased linearly (from 183 to 381g/kg dry matter; P<0.05) with VT classes. The total tract in vitro dry matter digestibility decreased linearly (from 0.96 to 0.75; P<0.05) with VT classes. The in vitro fermentation showed that the rate of fermentation decreased (from 0.060 to 0.044/h; P<0.05), whereas the total short chain fatty acid (SCFA) production increased (ranging from 6.29 to 7.29mmol/g dry matter incubated; P<0.05) linearly with VT classes. The molar ratio of acetate linearly increased, ranging from 0.50 to 0.55 (P<0.05) with VT classes, whereas no differences were observed for other individual SCFA. The loading plot of principal component analysis revealed significant relationships between VT and variables of interest. Results indicated that VT promoted marked effects on in vitro parameters related to starch and dry matter digestibility and fermentable kinetics for pigs. Further in vivo validations are required to validate these findings. [Copyright &y& Elsevier]

The physical and chemical characteristics of five Syrian durum wheat cultivars grown under varying environmental conditions were investigated. Two cultivars were grown under irrigated conditions whilst two were grown under rainfed conditions in five different locations. A known cultivar ( Sham-1) was grown alongside the samples in all locations as a control. Test weight, 1000-kernel weight, the degree of vitreousness, protein content, starch content, amylose content and starch pasting properties were determined for the samples. The effect of the environmental factors and their interaction (site × irrigation) showed that the irrigation factor was more responsible for physical quality variations than the site factor (for instance, site variation of the irrigated conditions was responsible for 61% of the total quality variation and 34% of total quality variations in the rainfed conditions). Starch composition was influenced more by site variations than irrigation, whereas cultivar factor mainly influenced starch quantity, chemical composition and pasting properties (for instance, variations were mostly affected by cultivar (63%) more than site (15%) in the irrigated lands). The interaction of cultivar and site demonstrated significant effects on the degree of vitreousness, amylose content and starch pasting properties. [ABSTRACT FROM AUTHOR]

Abstract: We assessed the effects of vitreousness and particle size of maize grain on ruminal and intestinal in sacco degradation of dry matter, starch and nitrogen. Six maize grain (Zea mays) genotypes characterized by differing vitreousness (proportion of vitreous in total endosperm) were ground (3-mm screen; Gr, ground particles, mean particle size (MPS): 526μm) and cracked with a roller mill using two gap width settings (CS, cracked small particles, MPS: 1360μm; CL, cracked large particles, MPS: 2380μm). The ruminal and intestinal in sacco degradation of dry matter, starch and nitrogen was measured on three dry Holstein cows, fitted with rumen, proximal duodenum and terminal ileum cannulas, fed maize silage ad libitum twice daily. The ruminal starch degradability and intestinal digestibility differed among genotypes (P<0.001) and decreased as particle size increased (P<0.001). For the same particle size, starch ruminal degradability decreased (P<0.05) and intestinal digestibility decreased (P<0.002) with vitreousness. Particle size and vitreousness of maize grain are efficient factors for manipulating the amount of starch escaping rumen degradation, but may be limiting for the amount of starch digested in the small intestine. [Copyright &y& Elsevier]

Abstract: The reduction of coarse farina during milling from five representative hard and soft French bread wheat cultivars was followed step by step. Particle size distribution of the milled products and energy required to dissociate wheat farina revealed large differences between cultivars. A grinding index (required energy to produce 1kg of flour), K′, corresponding to the energy necessary to obtain a given amount of flour, was found to be related with both grain hardness and vitreousness. Analysis of particle size distribution suggested a major influence of hardness in the production of fine particles <50μm during the reduction process. On the other hand, vitreousness appeared to impact on the extent of coarse particle size reduction. Differences in farina reduction behaviour of the wheats analysed were related to their endosperm mechanical properties as determined by compression tests and structural characteristics as measured by Hg intrusion porosity. Vitreousness appeared to affect the endosperm extensibility and degree of porosity. The profile of the different lipid and protein classes in the reduction products of two cultivars showing opposite behaviour as well as different PINA/PINB ratio were determined. The results suggest that the most resistant parts of the grain are enriched in glycolipids, whereas phospholipids appear associated with the most friable parts, at least in the soft wheat grains tested. [Copyright &y& Elsevier]

Some physical and chemical characteristics of nine Syrian durum wheat genotypes were determined in order to investigate the relationships among individual kernel components and kernel quality. All genotypes were grown on fully irrigated plots in Syria. Test weight, 1000-kernel weight, kernel size distribution, hardness and semolina extraction rates were determined along with the chemical characteristics of the kernel (ash, moisture, protein, wet gluten, starch content and falling number). All tested genotypes had high test weight (83.1–85.9 kg hl−1) and 1000-kernel weight (42.5–55.5 g) indicating high milling yield potential. Additionally, all the wheat genotypes demonstrated high falling numbers (433–597 s). Correlation coefficients among the quality properties showed that moisture content did not demonstrate any strong correlations with the studied quality parameters. Protein content exhibited a positive correlation with vitreousness ( r = 0.78), and a negative correlation with ash content ( r = −0.57). Test weight exhibited a negative correlation with 1000-kernel weight ( r = −0.66), and a positive correlation was observed between test weight and starch content of the kernel ( r = 0.78). The results illustrate the commonality between Syrian durum wheat genotypes and US and Canadian durum wheat genotypes reported by researchers previously. [ABSTRACT FROM AUTHOR]

Eight cannulated Holstein steers (average BW: 251 kg) were used in 2 simultaneous 4 × 4 Latin squares in a split-plot arrangement to test the effects of processing method [dry-rolled (DR) vs. steam-flaked (SF); main plot] and vitreousness (V, %; subplot) of yellow dent corn (V55, V61, V63, and V65) on site of digestion of diets containing 73.2% corn grain. No vitreousness × processing method interactions were detected for ruminal digestion, but ruminal starch digestion was 14.4% lower (P < 0.01) for DR than for SF corn. Interactions were detected between vitreousness and processing method for postruminal (P < 0.10) and total tract digestion (P <0.05). With DR, vitreousness tended to decrease (linear effect, P < 0.10) postruminal OM and starch digestion. With SF, vitreousness did not affect (P ≥ 0.15) postruminal digestion of OM and starch. Postruminal N digestion tended to decrease (linear effect, P = 0.12) as vitreousness increased. Postruminal digestion was greater for SF than for DR corn OM (25.7%, P < 0.05), starch (94.3%, P < 0.10), and N (10.7%, P < 0.01). Steam flaking increased total tract digestion of OM (11%, P < 0.05), starch (16%, P < 0.01), and N (8.4%, P < 0.05) but decreased total tract AIJF digestion (26.7%, P < 0.01). With DR, total tract starch digestion was lower for V65 (cubic effect, P < 0.10) than for the other hybrids. With SF, total tract starch digestion was not affected (P ≥ 0.15) by vitreousness. Fecal starch and total tract starch digestion were inversely related (starch digestion, % = 101 - 0.65 × fecal starch, %; r² = 0.94, P < 0.01). Ruminal pH was greater for steers fed DR than for steers fed SF corn (6.03 vs. 5.62, P <0.05). Steam flaking decreased (P < 0.01) the ruminal molar proportion of acetate (24%), acetate:propionate molar ratio (55%), estimated methane production (37.5%), and butyrate (11.3%, P < 0.05). There was a vitreousness × processing interaction (P < 0.01) for acetate:propionate. For DR, acetate:propionate tended to increase (linear effect; P < 0.10) with increasing vitreousness. With SF, acetate:propionate was greater (cubic effect, P < 0.01) for V65. Starch from more vitreous corn grain was less digested when corn grain was DR, but this adverse effect of vitreousness on digestion was negated when the corn grain was SF. Of the 19% advantage in energetic efficiency associated with flaked over rolled corn grain, about ¾ can be attributed to increased OM digestibility, with the remaining ¼ ascribed to reduced methane loss. [ABSTRACT FROM AUTHOR]

Vitreousness and kernel hardness are important properties for maize processing and end-product quality. In order to examine the genetic basis of these traits, a recombinant inbred line population resulting from a cross between a flint line (F-2) and a semident line (Io) was used to search for vitreousness and kernel composition QTLs. Vitreousness was measured by image processing from a kernel section, while NIR spectroscopy was used to estimate starch, protein, cellulose, lipid and semolina yield. In addition, thousand-grain weight and grain weight per ear were measured. The MQTL method was used to map the QTLs for the different traits. An additional program allowed for the detection of interaction QTLs between markers. The total number of main-effect and interaction QTLs was similar. The QTLs were not evenly distributed but tended to cluster. Such clusters, mixing main-effect and interaction QTLs, were observed at six positions : on chromosomes 1, 2, 3, 6, 8 and 9. Two of them, on chromosomes 6 and 9, concerned both QTLs for kernel-weight traits and QTLs for kernel-composition traits (protein and cellulose). Technological-trait QTLs (vitreousness or semolina yield) were located less than 16 cM from a protein-content QTL on chromosome 2, and were co-located with lipid- and starch-content QTLs on chromosome 8. The co-location of a vitreousness and a semolina-yield QTL at the telomeric end of the chromosome 2 (Bin 2.02) is likely to be meaningful since measurement of these related traits, made by completely different methods (NIRS vs image processing), yielded very close QTLs. A similar location was previously reported independently for a kernel-friability QTL. Comparing the map location of the numerous loci for known-function genes it was shown that three zein loci were closely linked to QTLs for vitreousness on chromosome 3, for semolina yield and starch on chromosome 4, and for protein, cellulose and grain weight on chromosome 9. Some other candidate genes linked to starch precursor metabolism were also suggested on chromosomes 6 and 8. [ABSTRACT FROM AUTHOR]