Single-Kernel Characteristics of Hard Winter Wheats in Relation to Milling and Baking Quality

To investigate relationships of wheat single kernel (SK) characteristics with end-use properties, we used 12 hard winter wheat cultivars harvested at six regions in Kansas in 1993. Significant positive correlations occurred among wheat hardness parameters including near-infrared reflectance hardness score, SK hardness index (SK-HI), and SK peak force (SK-PF) obtained by the Single Kernel Characterization System (SKCS). The SKCS characteristics also were significantly correlated to conventional wheat quality parameters such as test weight, kernel density, and kernel sizing. Flour yields were significantly correlated with SK-PF, SK-HI, and SK weight (SK-WT), suggesting the usefulness of SKCS in evaluating milling quality. The negative correlation of milling score with the standard deviation of SK-HI and SK-PF indicated that uniformity of SK hardness is desirable for good milling performance. However, bread loaf volumes had significant negative correlations with SK diameter and SK-WT, mainly due to the inverse relationship between wheat protein contents and kernel weights or sizes. Loaf volume regression values, the changes in loaf volumes per one percentage point of flour protein, also had significant negative correlations with SK-HI, SK-PF, and SK-WT.     

Influence of Kernel Size and Shriveling on Soft Wheat Milling and Baking Quality

Small kernels of soft wheat are sometimes considered to be harder than larger kernels and to have inferior milling and baking characteristics. This study distinguished between kernel size and kernel shriveling. Nine cultivars were separated into large, medium, and small kernels that had no shriveling. Eleven cultivars were separated into sound, moderate, and severely shriveled kernels. Shriveling greatly decreased the amount of flour produced during milling. It adversely affected all other milling quality characteristics (ash content, endosperm separation index, and friability). Shriveled kernels produced flour that had inferior soft wheat baking qualities (smaller cookie diameter and higher alkaline water retention capacity). In contrast, test weight and milling qualities were independent of kernel size. Small, nonshriveled kernels had slightly better baking quality (larger cookie diameter) than larger nonshriveled kernels. Small kernels were softer than large kernels (measured by break flour yield, particle size index, and flour particle size). Small nonshriveled kernels did not have diminished total flour yield potential or other reduced flour milling characteristics. Those observations suggest a possibility of separating small sound kernels from small shriveled kernels to improve flour yield and the need to improve dockage testing estimation techniques to distinguish between small shriveled and small nonshriveled kernels.     

Apparent Dough Stickiness of Selected 1BL/1RS Translocated Soft Wheat Flours

A new method, called the Schwarzlaff‐Shephard Dough Stripping Method, was used to determine apparent dough stickiness in seven 1BL/1RS translocated soft, red, winter wheat (SRWW) lines and five SRWW lines without the translocation. Pairwise comparisons of all 1BL/1RS versus all non‐1BL/1RS lines indicated that doughs made from the 1BL/1RS lines were significantly stickier, on average, than doughs made from the non‐1BL/1RS lines. However, there was no significant difference in the apparent dough stickiness of one set of sister lines that shared a similar pedigree, 1BL/1RS line VA 93‐54‐18 versus its non‐1BL/1RS sister line VA 94‐54‐21. Another 1BL/1RS line, VA 92‐52‐22, ranked last in apparent dough stickiness and was significantly less sticky than two non‐1BL/1RS lines. VA 92‐52‐22 has a distinctly different pedigree from the other 1BL/1RS lines that we evaluated. These findings suggest that there are strong genotypic effects on dough stickiness, making it possible to develop non‐sticky cultivars of 1BL/1RS SRWW.     

Effect of Kernel Size and Mill Type on Protein,Milling Yield,and Baking Quality of Hard Red Spring Wheat

Optimization of flour yield and quality is important in the milling industry. The objective of this study was to determine the effect of kernel size and mill type on flour yield and end‐use quality. A hard red spring wheat composite sample was segregated, based on kernel size, into large, medium, and small kernels, as well as unsorted kernels. The four fractions were milled in three roller mills: Brabender Quadrumat Jr., Quadrumat Sr., and Bühler MLU‐202 laboratory mills. Large kernels had consistently higher flour yield than small kernels across mills, with the Quadrumat Jr. mill showing the lowest flour yield. Mill type and kernel size significantly affected variation in flour protein molecular weight distribution. When compared with larger kernels, flour milled from the small‐kernel fraction contained a higher gliadin fraction and SDS‐unextractable high‐molecular‐weight polymeric proteins, which had positive correlations with bread loaf volume (r = 0.61, P < 0.05) and mixograph peak time (r = 0.84, P < 0.001). Overall, small kernels could contribute to enhancing flour breadmaking quality while having a detrimental effect on milling yield.     

Identification of Wheat Lines Possessing the 1AL.1RS or 1BL.1RS Wheat-Rye Translocation by Near-Infrared Reflectance Spectroscopy

Wheat-rye chromosomal translocations, particularly those involving the short arm of rye chromosome 1R, have been used during the past 25 years to instill resistance to plant pathogens and insects and improve the hardiness, adaptation, and yield of wheat. Unfortunately, the presence of the 1AL.1RS or 1BL.1RS rye translocations in wheat has been shown to impart inferior dough handling and baking characteristics. Although numerous analytical techniques (e.g., HPLC, monoclonal antibody tests, high-performance capillary electrophoresis) have been developed for detecting these translocations, the complexity of the analytical procedures restricts their use to research and analytical laboratories. The purpose of this study was to examine the potential of diffuse reflectance near-infrared spectroscopy, a well-accepted technique in the grain industry, for detecting 1RS-containing genotypes. This research used three independent groups of wheat samples, ranging in genetic diversity from sister lines derived from 1RS breeding populations to commercial cultivars. Based on the diffuse reflectance spectra (1,100–2,500 nm) of flour, partial least squares (PLS) models, through cross-validation, exhibited misclassification rates as low as 0%, particularly for commercial cultivars. Misclassification rates for corresponding, but separate, test sets were as low as 1%. When the same modeling procedure was applied to samples of more closely related genetic backgrounds, cross-validation misclassification rates rose to 15–20%. Most problematic were samples that were heterogeneous for 1RS such as the cultivar Rawhide. Incorporating heterogeneous samples into a calibration equation improved the classification accuracy of these samples but diminished the prediction accuracy of nonheterogeneous samples.     

Effects of Kernel Vitreousness and Protein Level on Protein Molecular Weight Distribution,Milling Quality,and Breadmaking Quality in Hard Red Spring Wheat

Dark, hard, and vitreous kernel content is an important grading characteristic for hard red spring (HRS) wheat in the United States. This research investigated the associations of kernel vitreousness (KV) and protein content (PC) levels with protein molecular weight distribution (MWD), milling quality, and breadmaking quality characteristics of HRS wheat. The U.S. regional crop quality survey samples from three consecutive growing years were combined into three composite samples with different levels of wheat PC and then further segregated into separate samples with three different levels of KV. Analysis of variance showed that KV level had significant (P < 0.001) effect on variation in test weight, break flour yield, and damaged starch content. Among protein MWD parameters analyzed by size‐exclusion HPLC, the high‐molecular‐weight polymeric proteins in the SDS‐unextractable fraction had significant (P < 0.01) association with KV. Regression analysis indicated that addition of KV to the PC level improved the model for both farinograph and baking water absorption values in all three growing years. This information could help the flour milling and baking industries to further segregate HRS wheat based on KV levels in addition to PC levels for their intended end‐use applications.     

Rheological Properties of Full-Formula Doughs Derived from Near-Isogenic 1BL/1RS Translocation Lines

Four pairs of near-isogenic wheat lines, with and without the 1BL/1RS translocation, and differing at the Glu-1 loci (coding for high molecular weight [HMW] glutenin subunits) were evaluated for their dough mixing properties, dough stickiness, and baking performance. In all 1BL/1RS translocation lines, weakening of the dough consistency occurred within 2 min past peak time. The full-formula dough from every 1BL/1RS translocation line exhibited poor dough mixing characteristics and increased stickiness compared to the corresponding wheat control. The HMW glutenin subunits coded by the Glu-A1 locus had no apparent effect on mixing properties, but did have a slight effect on the dough stickiness at two of the four stages of dough mixing. Glu-B1 and Glu-D1 loci encoded glutenin subunits produced significant changes in dough mixing properties and dough stickiness, respectively. With respect to baking performance, there was no significant difference between loaf volumes of 1BL/1RS versus control wheats for three of four near-isogenic pairs. Within the 1RS-group, the translocation lines containing HMW glutenin subunits 5+10 produced bread with greater loaf volumes than the pairs containing its allelic counterpart 2+12. Loaf volume was not influenced by the subunits associated with the Glu-B1 loci. In general, the breads baked from 1BL/1RS translocation lines had a relatively poor crumb and crust quality and contained larger gas cells than the wheat controls. In comparing isogenic pairs, the magnitude of the difference in loaf volume between the control wheat and the corresponding 1BL/1RS translocation line was greater in the pair unique for HMW subunits 5+10; the difference was primarily due to the stronger mixing properties of the wheat control.     

Protein Structural Features in Winter Wheat: Benchmarking Diversity in Ontario Hard and Soft Winter Wheat

A set of 32 winter wheat lines and varieties was selected to benchmark Ontario winter wheat as a first step toward improving quality. Protein secondary structure, total and accessible thiols, rheological properties, gluten aggregation kinetics, and network forming capabilities of different polymers were determined for each wheat line. Results revealed that there were statistically significant differences among the lines selected (P < 0.05). The differences between hard and soft wheat classes were not as large as would be expected, however, despite the range of quality parameters measured. Benchmarks revealed that several soft wheat lines outperformed hard wheat lines in standard breadmaking quality measures. Protein conformation changed significantly as the moisture content of the samples increased to mimic different model product systems: flour, dough, and batter. The conformation of the flour samples exhibited different patterns between hard and soft wheat classes, although these differences became narrower in the dough and batter states. Principal component analysis (PCA) factors included most quality parameters measured, with the notable exceptions of solvent retention capacity tests and total thiols. Protein conformation and accessible thiols were significant PCA factors that tended to override the rheological measures of quality they represented, suggesting that protein secondary structure and disulfide bonding patterns are fundamental aspects of rheological quality measures.     

Levels of Protein and Protein Composition in Hard Winter Wheat Flours and the Relationship to Breadmaking

Protein and protein fractions were measured in 49 hard winter wheat flours to investigate their relationship to breadmaking properties, particularly loaf volume, which varied from 760 to 1,055 cm³ and crumb grain score of 1.0–5.0 from 100 g of flour straight‐dough bread. Protein composition varied with flour protein content because total soluble protein (SP) and gliadin levels increased proportionally to increased protein content, but albumins and globulins (AG), soluble polymeric proteins (SPP), and insoluble polymeric protein (IPP) levels did not. Flour protein content was positively correlated with loaf volume and bake water absorption (r = 0.80, P < 0.0001 and r = 0.45, P < 0.01, respectively). The percent SP based on flour showed the highest correlation with loaf volume (r = 0.85) and low but significant correlation with crumb grain score (r = 0.35, P < 0.05). Percent gliadins based on flour and on protein content were positively correlated to loaf volume (r = 0.73, P < 0.0001 and r = 0.46, P < 0.001, respectively). The percent IPP based on flour was the only protein fraction that was highly correlated (r = 0.62, P < 0.0001) with bake water absorption followed by AG in flour (r = 0.30, P < 0.05). Bake mix time was correlated positively with percent IPP based on protein (r = 0.86) but negatively with percent SPP based on protein (r = ‐0.56, P < 0.0001).     

Protein Profile and Molecular Markers Related to the Baking Quality of Brazilian Wheat Cultivars

To carry out wheat breeding programs, proteins were identified and quantified (through sodium dodecyl sulfate polyacrylamide gel electrophoresis [SDS‐PAGE] and size‐exclusion high‐performance liquid chromatography [SE‐HPLC]) and six allele‐specific markers were tested on 45 Brazilian cultivars. A microscale baking test was applied to associate analytical and genetic responses with baking quality. The results suggested a prevalence of the subunits 2* and 1 in chromosome 1A; 7+8, 7+9, and 17+18 in 1B; and 5+10 in 1D; absence of 1BL/1RS translocation in 62.2% of the genotypes; and presence of Pinb‐D1b and Glu‐A3d in 8.9% of the genotypes. The average SE‐HPLC values were 37.50 and 45.42% for polymeric protein in total protein (PPP) and unextractable polymeric protein (UPP), respectively, and 1.29 for the gliadin‐to‐glutenin (GLI/GLU) ratio, with significant variation among the genotypes (P ≤ 0.05). The baking test also showed a significant difference (P ≤ 0.05) between the cultivars under the same conditions. The cultivars without the 1BL/1RS translocation with rye also showed better results for UPP, PPP, and GLI/GLU in relation to those possessing translocation. These results corroborate for selection of HMW subunits 5+10, cultivars without translocation with rye, with high UPP values and a balanced GLI/GLU ratio (around 1.0) with the objective of obtaining greater wheat baking quality.     

Quality Requirements of Soft Red Winter Wheat for Making Northern‐Style Chinese Steamed Bread

Flours of 19 soft red winter (SRW) wheat varieties having protein contents of 6.6–9.9% were used to determine the suitability of SRW wheat for making northern‐style Chinese steamed bread (CSB) and the influences of flour characteristics on the quality attributes of CSB. Fourteen varieties produced CSB of acceptable to good quality with a total score greater than 70. Both protein content and dough strength‐related parameters, including sodium dodecyl sulfate sedimentation (SDSS) volume, wet and dry gluten contents, and midline peak time (MPT), were significantly associated with the quality attributes of CSB. The rapid viscosity analyzer setback value exhibited significant negative correlations with specific volume, smoothness, crumb structure, and total score of CSB. Stepwise multiple regression analysis indicated that 89% of variability in total scores of CSB could be predicted from SDSS volume, wet gluten content, and MPT. Contributions of high‐molecular‐weight glutenin subunits 7*+8 and 5+10 to flour characteristics, specific volume, stress relaxation score, and total score of CSB were greater than those of their counterpart allelic variations. Absence of the 1B/1R translocation in SRW wheat varieties was desirable for the production of CSB.     

硅肥对冬小麦磷素吸收转运的影响

研究了大田条件下硅对小麦(Triticum aestivum L.济麦22)干物质积累与分配比例,磷吸收转运的影响。结果表明:施用硅酸钾肥料促进作物对P的吸收与利用,从而促进小麦生长和提高生物量;在适宜的硅酸钾肥料施用量90 kg hm^-2下,小麦地上部干物质积累及分配表现出最优,不适宜的硅酸钾肥料施用量将不利于穗形成期干物质在穗部的优先分配;小麦总硅吸收量与总磷吸收量呈显著线性相关;穗中13.8%～28.3%的磷素是靠秸秆转运而来,施硅肥显著促进了磷素在穗的累积,且累积量随着施硅肥增加而降低,各施硅肥处理的磷素转运效率在36.6%～44.3%之间,随着施硅肥量增加而降低。本研究表明,在土壤酸化严重的胶东地区,推荐T2处理(90 kg硅酸钾hm^-2),能取得较好的小麦增产效果。     

Milling Quality and White Salt Noodle Color of Chinese Winter Wheat Cultivars

Improvement of milling quality is an important aspect in wheat breeding programs. However, the milling quality of Chinese wheats remains largely unexplored. Fifty‐seven Chinese winter wheat cultivars from four regions were used to investigate the variation of milling quality parameters and to determine the associations between milling quality traits and color of noodle sheet. Substantial variation was presented for all measured parameters in this germplasm pool. Complete soft, hard, and medium‐hard types were observed. Soft wheat and hard wheat show significant differences in flour ash content, flour bran area, and flour color grade. No simple trait can be used to select for flour milling quality. High flour ash content and bran speck area contributed negatively to brightness of dry flour. Correlation coefficients (r) between L* value of dry flour and flour ash content and bran speck area were ‐0.47 and ‐0.65 for hard cultivars, and ‐0.51 and ‐0.72 for soft cultivars, respectively. Flour color grade (FCG) was significantly and positively associated with bran speck area; r = 0.56 and 0.73 for hard and soft wheats, respectively. There was a high correlation between FCG and L* value of flour water slurry (r = ‐0.95). Strong associations were also established between milling quality index (MQI) and FCG, L* value of dry flour, flour‐water slurry, and white salted noodle sheet for both hard and soft wheats. In conclusion, substantial progress could be achieved in improvement of milling quality in Chinese winter wheats through genetic selection, and FCG and MQI could be two important parameters for evaluation of milling quality in breeding programs.     

Novel Ha Locus,Pina‐D1c/Pinb‐D1h,Affects Soft White Spring Wheat Milling and Baking

Wheat (Triticum aestivum L.) grain hardness is controlled by the Hardness locus on chromosome 5D which consists of the linked genes Puroindoline a and b (Pina and Pinb, respectively). The Ha locus haplotype, Pina‐D1a/Pinb‐D1a, is found in all soft hexaploid wheats. While Pin diversity is low among soft wheats, several novel Ha haplotypes were reported among synthetic hexaploid wheats created using the D genome donor, Aegilops tauschii. One haplotype, Pina‐D1c/Pinb‐D1h, confers a soft phenotype with increased grain hardness over Pina‐D1a/Pinb‐D1a wheats. Here, the Pina‐D1c/Pinb‐D1h haplotype was backcrossed into the soft white spring wheat cultivars ‘Vanna’ and ‘Alpowa’. Then the effect of the two haplotypes on soft wheat milling and baking quality was compared. The effects of the Pina‐D1c/Pinb‐D1h Ha locus haplotype were similar in both the Vanna and Alpowa backgrounds. The Pina‐D1c/Pinb‐D1h lines had significantly more large and fewer small flour particles in both backgrounds and 1.51% higher flour yield in the Alpowa background. The Pina‐D1c/Pinb‐D1h haplotype group was not associated with any consistent differences in solvent retention capacities or sugar snap cookie quality parameters. The results indicate that the Pina‐D1c/Pinb‐D1h haplotype could be used to modify soft wheat milling properties without substantial effects on baking quality.     

Storage Conditions Affecting Increase in Falling Number of Soft Red Winter Wheat Grain

Falling number (FN) of wheat grain, a measure of preharvest sprouting, tends to increase during storage; however, grain and storage conditions that impact FN changes are poorly understood. Wheat grain samples of varying FN from several cultivars were obtained by artificial sprouting, by incubating wheat stalks, or directly from the field and were used to determine the effects of cultivar, storage temperature, grain moisture content, and initial FN on changes in FN and α‐amylase activity. Increases in FN of artificially sprouted grain during storage were affected by temperature but not evidently by grain moisture in the range of 10.0–13.0%. The FN of artificially sprouted grain increased when stored at 5, 23, and 35°C for 20 weeks by averages of 9.4, 24.1, and 34.4, respectively. The influences of storage temperature and initial FN of grain obtained from incubated stalks were different between cultivars when stored for 8 weeks. Wheat grain obtained directly from the field also exhibited significant increases in FN during 8 weeks of storage at 5, 23, and 35°C with average increases of 10.0, 27.1, and 38.5, respectively. The impact of α‐amylase activity on the increase in FN during storage was evident only for field‐harvested grain of varying FN. α‐Amylase activity exhibited a negative logarithmic relationship (R² = 0.87) with FN in field‐harvested grain. The magnitude of the changes in α‐amylase activity varied by cultivar.     

小麦蛋白淀粉品质指标与面包品质关系的研究

选用近年来黄淮麦区大面积推广种植的小麦品种和新育成高代品系为材料,采用近红外(NIR)、面筋仪、粉质仪、快速粘度分析仪(RVA)和凝胶色谱(SE-HPLC)方法等对蛋白品质指标及淀粉糊化参数进行分析,分析各品质参数间的关系及其与面包烘焙品质的关系。结果表明,谷蛋白大聚体(GMP)、SDS(十二烷基硫酸钠)-沉降值、湿面筋指数、弱化度与多数蛋白品质指标间存在正向0.01或0.05水平相关,GMP、SDS-沉降值、湿面筋指数、干面筋含量、面粉蛋白含量、麦谷蛋白含量、形成时间、稳定时间均与面包烘焙品质间达0.01水平正相关,湿面筋含量与面包体积和评分间分别达0.01和0.05水平正相关;醇溶蛋白含量及弱化度与面包体积和评分间分别达0.05和0.01水平负相关。吸水率与糊化温度、最终粘度、回生值间达0.01水平负相关,形成时间与峰值粘度和稀澥值间达0.05水平正相关,GMP与糊化温度间达0.05水平负相关。各品质参数对面包体积的作用大小依次为湿面筋指数>弱化度>形成时间>湿面筋含量>糊化温度等,对面包评分的作用大小依次为麦谷蛋白>稳定时间>醇溶蛋白>面粉蛋白含量>吸水率等。小麦品质测试指标间有着广泛的相关性,湿面筋指数、弱化度和麦谷蛋白、稳定时间是反映面包烘焙品质的重要指标;早代可进行GMP或SDS-沉降值测定,中高代可进行面筋仪、粉质仪测定;在品质测试过程中应重视湿面筋指数、弱化度的重要性,小麦粉淀粉品质对面包品质的影响也应引起关注。     

Effects of Wheat Cultivar and Nitrogen Application on Storage Protein Composition and Breadmaking Quality

Influences of cultivar and nitrogen application on protein concentration and composition, and amount and size‐distribution of different protein components, were investigated in 10 spring wheat cultivars (Triticum aestivum L.) with widely varying gluten strength, grown under four nitrogen fertilizer conditions. The results showed that cultivar differences in gluten strength were determined by storage protein composition, differences in total amount of HMW glutenin subunits, the glutenin‐to‐gliadin ratio, and the relationship between SDS‐soluble and SDS‐insoluble protein polymers. Negative correlations were found between protein parameters related to gluten strength and bread volume. No cultivar stability for gluten strength in relation to differences in nitrogen application was found. Thus, the gluten strength was influenced by the nitrogen application in all the investigated cultivars. Increased nitrogen supply correlated significantly to an increase in all protein components containing gliadins and glutenins, but not to those containing albumins and globulins. The increase in protein components containing gliadins and glutenins correlated significantly with an increase in protein concentration and bread volume.