Whole Grain Wheat Flour Production Using an Ultracentrifugal Mill

Interest has been growing in whole grain products. However, information regarding the influence of the ultracentrifugal mill on whole grain flour quality has been limited. An experiment was conducted to produce whole wheat flour with hard red spring (HRS) wheat using an ultracentrifugal mill. This study determined the effect of centrifugal mill parameters as well as grain moisture (10–16%) on producing whole wheat flour and its final products. Mill parameters studied were rotor speed (6,000–15,000 rpm) and feed rate (12.5–44.5 g/min). Results showed that fine particle size (<150 µm) was favored by low seed moisture content (10–12%) and high rotor speed (12,000–15,000 rpm). Flour moisture content was positively related to seed moisture content. Wheat grain with low seed moisture content (10–12%) milled with high rotor speeds (12,000–15,000 rpm) produced desirable whole grain wheat flour quality, with 70–90% of fine particle size portion and low damaged starch (less than 11%). This whole wheat flour produced uniform and machinable dough that had low stickiness and formed bread with high loaf volume.     

Nutritional Profile of Whole‐Grain Soft Wheat Flour

Whole‐grain wheat flour is used in baking to increase fiber content and to provide vitamins from the bran layers of the kernel. We surveyed whole‐grain soft flour samples from North America to determine the nutritional profile using recently revised fiber quantification protocols, Codex 2009.1. Standard compositional and vitamin analyses were also included in the survey. Three separate studies were included in the survey: sampling of commercial whole‐grain soft wheat flour, a controlled study of two cultivars across three years and two locations, and a regional study of soft white and soft red grain from commercial grain production. The Codex method for fiber measurement estimated total fiber concentration in the commercial sampling at 15.1 g/100 g, dry weight basis (dwb). In the controlled research trial, the largest source of variation in total fiber concentration was attributed to year effects, followed by genotype effects. For the two locations used in this study, location effects on fiber concentration were significant but an order of magnitude less important than the year and genotype effects. The third study of regional variation within North America found limited variation for total fiber, with the resistant oligosaccharide fraction having the greatest variation in concentration. When all three studies were combined into a meta‐analysis, the average total fiber concentration was 14.8 g/100 g dwb. In the meta‐analysis, concentrations of folate, thiamin, riboflavin, niacin, and pyridoxine were lower than in previous summary reports. Vitamin E and pantothenic acid were the exceptions, with concentrations that were nearly identical to previous standard reports. Several other recent studies also point to current cultivars and production systems as producing lower concentrations of the essential vitamins than previously reported. The results suggest that vitamin concentrations in diets of populations using grain‐based diets from modern cereal‐production systems may require review to determine if previous assumptions of vitamin consumption are accurate.     

Effect of Wheat Grain Steaming and Washing on Lipase Activity in Whole Grain Flour

During whole grain flour (WGF) storage, lipase activity causes partial loss of its functionality and the sensory acceptability of products produced from it. The objective of this research was to evaluate the effect of steaming and washing on lipase activity in (fractions of) wheat. Steam treatment conditions were optimized for wheat grains and their bran, shorts, and flour fractions. Lipase activities were determined colorimetrically, as were peroxidase, endoxylanase, and α‐amylase activities. Steaming grains for 180 s effectively inactivated lipase, peroxidase, endoxylanase, and part of the α‐amylase without gelatinizing starch. The work further demonstrated that lipase is mainly, if not only, located in the bran fraction. Separate bran treatment holds promise for obtaining WGF with reduced lipase activity but without altered functional properties. Washing grains did not reduce WGF lipase activity.     

Effect of Single‐Pass and Multipass Milling Systems on Whole Wheat Durum Flour and Whole Wheat Pasta Quality

Single‐pass and multipass milling systems were evaluated for the quality of whole wheat durum flour (WWF) and the subsequent whole wheat (WW) spaghetti they produced. The multipass system used a roller mill with two purifiers to produce semolina and bran/germ and shorts (bran fraction). The single‐pass system used an ultracentrifugal mill with two configurations (fine grind, 15,000 rpm with 250 μm mill screen aperture; and coarse grind, 12,000 rpm with 1,000 μm mill screen aperture) to direct grind durum wheat grain into WWF or to regrind the bran fraction, which was blended with semolina to produce a reconstituted WWF. Particle size, starch damage, and pasting properties were similar for direct finely ground WWF and multipass reconstituted durum flour/fine bran blend and for direct coarsely ground WWF and multipass reconstituted semolina/coarse bran blend. The semolina/fine bran blend had low starch damage and had desirable pasting properties for pasta cooking. WW spaghetti was better when made with WWF produced using the multipass than single‐pass milling system. Mechanical strength was greatest with spaghetti made from the semolina/fine bran or durum flour/fine bran blends. The semolina/fine bran and semolina/coarse bran blends made spaghetti with high cooked firmness and low cooking loss.     

Bran Characteristics and Bread‐Baking Quality of Whole Grain Wheat Flour

Variations in physical and compositional bran characteristics among different sources and classes of wheat and their association with bread‐baking quality of whole grain wheat flour (WWF) were investigated with bran obtained from Quadrumat milling of 12 U.S. wheat varieties and Bühler milling of six Korean wheat varieties. Bran was characterized for composition including protein, fat, ash, dietary fiber, phenolics, and phytate. U.S. soft and club wheat brans were lower in insoluble dietary fiber (IDF) and phytate content (40.7–44.7% and 10.3–17.1 mg of phytate/g of bran, respectively) compared with U.S. hard wheat bran (46.0–51.3% and 16.5–22.2 mg of phytate/g of bran, respectively). Bran of various wheat varieties was blended with a hard red spring wheat flour at a ratio of 1:4 to prepare WWFs for determination of dough properties and bread‐baking quality. WWFs with U.S. hard wheat bran generally exhibited higher dough water absorption and longer dough mixing time, and they produced smaller loaf volume of bread than WWFs of U.S. soft and club wheat bran. WWFs of two U.S. hard wheat varieties (ID3735 and Scarlet) produced much smaller loaves of bread (<573 mL) than those of other U.S. hard wheat varieties (>625 mL). IDF content, phytate content, and water retention capacity of bran exhibited significant relationships with loaf volume of WWF bread, whereas no relationship was observed between protein content of bran and loaf volume of bread. It appears that U.S. soft and club wheat bran, probably owing to relatively low IDF and phytate contents, has smaller negative effects on mixing properties of WWF dough and loaf volume of bread than U.S. hard wheat bran.     

Relationship Between Grain,Semolina, and Whole Wheat Flour Properties and the Physical and Cooking Qualities of Whole Wheat Spaghetti

Durum breeding programs need to identify raw material traits capable of predicting whole wheat spaghetti quality. Nineteen durum wheat (Triticum turgidum L. var. durum ) cultivars and 17 breeding lines were collected from 19 different environments in North Dakota and were evaluated for physical and cooking qualities of whole wheat spaghetti. Raw material traits evaluated included grain, semolina, and whole wheat flour characteristics. Similar to traditional spaghetti, grain protein content had a significant positive correlation with cooking quality of whole wheat spaghetti. Stepwise multiple regressions showed grain protein content, mixogram break time, and wet gluten were the predominant characteristics in predicting cooked firmness of whole wheat spaghetti.     

Stability of Vitamin E in Wheat Flour and Whole Wheat Flour During Storage

The stability of vitamin E during 297 days of storage of wheat flour and whole wheat flour ground on a stone mill or a roller mill, respectively, were studied. One day after milling, the total content of vitamin E, expressed in vitamin E equivalents (α‐TE), was 18.7 α‐TE and 10.8 α‐TE for stone‐milled and roller‐milled wheat flour, respectively. The difference in total vitamin E content was primarily due to the absence of the germ and bran fractions in the roller‐milled flour. The total loss of vitamin E during storage was 24% for stone‐milled wheat flour but 50% for roller‐milled wheat flour. These results indicate that vitamin E, which is present in high amounts in wheat germ, functions as an antioxidant in the stone‐milled wheat flour. Hexanal formation showed that lipid oxidation in roller‐milled flour occurred just after milling, whereas the formation of hexanal in the germ fraction displayed a lack period of 22 days, confirming that vitamin E functions as an effective antioxidant in the wheat germ. Results showed no significant difference in total loss of vitamin E for stone‐milled and roller‐milled whole wheat flour. Total loss after 297 days of storage for both milling methods was ≈32%.     

小麦籽粒均匀度评价方法研究

为了筛选小麦的均匀度鉴定指标,建立可靠的均匀度评价模型,本研究以150份小麦为试验材料,测定其在两个环境下的籽粒形态指标：粒长(X₁)、粒宽(X₂)、直径(X₃)、圆度(X₄)、长宽比(X₅)、周长(X₆)、表面积(X₇)及千粒重(X₈),采用多样性统计、相关性分析、聚类分析、主成分分析和隶属函数法对小麦籽粒均匀度进行综合评价。结果表明,两种环境下籽粒各指标变异幅度为3.56%～9.88%;可将150份小麦材料聚类为4个类群。主成分分析可将8个指标转化为两个相互独立的综合指标,其贡献率分别为61.330%、36.448%,代表全部数据97.778%的信息量。利用隶属函数法计算籽粒均匀度综合评价值(D值),将150份材料分为超高均匀度材料(12份)、高均匀度材料(80份)、中均匀度材料(56份)和低均匀度材料(2份)。通过逐步回归方程建立了小麦籽粒均匀度的数学评价模型：VP=-2.787+0.294 X_2...     

Evaluation of a New Viscometer Performance in Predicting the Technological Quality of Soft Wheat Flour

Gluten aggregation properties were investigated by means of the GlutoPeak device, a viscometer recently proposed as a rapid and sensitive test for measurement of wheat flour technological performance. In this study, 62 soft wheat flour samples of different quality and end use were utilized to evaluate if the GlutoPeak parameters could adequately predict chemical and rheological characteristics of soft wheat flour dough, that is, protein content measured by the Kjeldahl method, dough strength measured by a Chopin alveograph, and dough stability and water absorption measured by a Brabender farinograph. Linear correlation analysis showed that most GlutoPeak curve parameters were strongly correlated with protein content, dough strength, and water absorption. The statistical models, obtained by a stepwise multiple regression method, showed the GlutoPeak device to be a promising tool to characterize wheat flour (R_adj² = 0.84 for protein content, R_adj² = 0.71 for dough strength, and R_adj² = 0.67 for water absorption). The rather high accuracy of the prediction models for the three mentioned parameters confirmed that GlutoPeak parameters are well correlated with other frequently used flour quality parameters and are able to describe flour technological performance.     

Influence of Bran Particle Size on Bread‐Baking Quality of Whole Grain Wheat Flour and Starch Retrogradation

The influence of bran particle size on bread‐baking quality of whole grain wheat flour (WWF) and starch retrogradation was studied. Higher water absorption of dough prepared from WWF with added gluten to attain 18% protein was observed for WWFs of fine bran than those of coarse bran, whereas no significant difference in dough mixing time was detected for WWFs of varying bran particle size. The effects of bran particle size on loaf volume of WWF bread and crumb firmness during storage were more evident in hard white wheat than in hard red wheat. A greater degree of starch retrogradation in bread crumb stored for seven days at 4°C was observed in WWFs of fine bran than those of coarse bran. The gels prepared from starch–fine bran blends were harder than those prepared from starch–unground bran blends when stored for one and seven days at 4°C. Furthermore, a greater degree of starch retrogradation was observed in gelatinized starch containing fine bran than that containing unground bran after storage for seven days at 4°C. It is probable that finely ground bran takes away more water from gelatinized starch than coarsely ground bran, increasing the extent of starch retrogradation in bread and gels during storage.     

Effect of Different Wheat Classes and Their Flour Milling Streams on Textural Properties of Flour Tortillas

Wheat flour tortillas were made from flour streams of three wheat cultivars: Jagger hard red winter wheat, 4AT-9900 hard white winter wheat, and Ernie soft red winter wheat. Wheat samples were milled on a Miag experimental mill. Twelve flour streams and one straight-grade flour were obtained. Tortillas were made from each flour stream and the straightgrade flour by the hot-press method. Tortilla stretchability and foldability were evaluated by a texture analyzer and six panelists, respectively. Flour protein and water absorption affected tortilla texture. The foldability evaluated by panelists was positively correlated with flour protein content, farinograph water absorption, and damaged starch (P < 0.05). The 2BK and 3BK streams of hard wheat produced tortillas with strong stretchability and good foldability. Middling streams of hard wheat yielded tortillas with lighter color and less stretchability. Under the conditions tested in this study, soft wheat flours were not good for producing flour tortillas.     

Effect of Soft Kernel Texture on the Milling Properties of Soft Durum Wheat

Worldwide, nearly 20 times more common wheat (Triticum aestivum) is produced than durum wheat (T. turgidum subsp. durum). Durum wheat is predominately milled into coarse semolina owing to the extreme hardness of the kernels. Semolina, lacking the versatility of traditional flour, is used primarily in the production of pasta. The puroindoline genes, responsible for kernel softness in wheat, have been introduced into durum via homoeologous recombination. The objective of this study was to determine what impact the introgression of the puroindoline genes, and subsequent expression of the soft kernel phenotype, had on the milling properties and flour characteristics of durum wheat. Three grain lots of Soft Svevo and one of Soft Alzada, two soft‐kernel back‐cross derived durum varieties, were milled into flour on the modified Quadrumat Senior laboratory mill at 13, 14, and 16% temper levels. Samples of Svevo (a durum wheat and recurrent parent of Soft Svevo), Xerpha (a soft white winter wheat), and Expresso (a hard red spring wheat) were included as comparisons. Soft Svevo and Soft Alzada exhibited dramatically lower single‐kernel characterization system kernel hardness than the other samples. Soft Svevo and Soft Alzada had high break flour yields, similar to the common wheat samples, especially the soft hexaploid wheat, and markedly greater than the durum samples. Overall, Soft Svevo and Soft Alzada exhibited milling properties and flour quality comparable, if not superior, to those of common wheat.     

Fate of Dwarf Bunt Fungus Teliospores During Milling of Wheat into Flour

Wheat contaminated with teliospores of Tilletia controversa Kühn (TCK) was mixed with uncontaminated wheat and processed through the Kansas State University pilot mill. Two 50-bu lots of the contaminated mixture were cleaned, tempered, and milled. Approximately 500 samples of wheat, cleanings, and mill fractions were collected and examined for the presence of intact and broken TCK teliospores. Whole wheat samples (50 g) were washed, sieved through a 60-μm nylon sieve, and pelleted by centrifugation. Contents of the pellet were examined microscopically for the presence of TCK spores. The procedure was modified as needed to accommodate cleanings and mill fractions. Levels of spore contamination in whole wheat samples decreased at each step during the handling process, and large numbers of spores were found in materials that were sieved or aspirated from the grain. Very few spores were found in bran, germ, and shorts; none were detected in red dog or straight-grade flour. The results showed that a high percentage of spores can be removed from wheat by mechanical cleaning but that it is not feasible to remove all of them.     

Investigation of Wheat Milling Yield Based on Grain Hardness Parameters

The objectives of this study were to investigate the relationship between milling yield and grain hardness. A preliminary study was carried out with 20 samples (both hard and soft wheats) using the Brabender hardness tester (BHT) with two grind settings: one‐step grind (0‐10) and two‐step grind (2‐12: coarse; 0‐8: fine). The two‐step grind was correlated with particle size index, single‐kernel characterization system (SKCS) hardness, break yield, and reduction yield (P < 0.05), whereas there was no correlation with the one‐step grind method. An additional 64 samples were ground with the two‐step grind setting to further validate this method. In terms of the BHT crush profile, no discernible differences were observed between varieties for the coarse grind, whereas for the fine grind, hard wheat gave a higher BHT maximum peak height and shorter grinding time compared with soft wheat. The break and reduction yields were significantly correlated with both BHT and SKCS hardness (P < 0.05). The findings indicated that the BHT method could be used to differentiate for milling yield among the different varieties. Based on the results, two milling yield models were developed, and both gave highly significant correlations between the predicted and Buhler mill break (R² = 0.791, P < 0.05) and reduction yield (R² = 0.896, P < 0.05).     

Exploring Relationships Between Pancake Quality and Grain and Flour Functionality in Soft Wheats

The objective of this study was to observe the influence of differences in genotype (variety) and protein concentration on batter flow and pancake making performance of a collection of soft white winter wheats. Wheats were chosen to express contrasting absorption characteristics and oxidative gelation potentials. Pancakes were processed with two formulations, one (“old”) with egg, soy, and dairy and one (“new”) without. Pancake performance was compared with grain, milling, flour, solvent retention capacity (SRC), pasting, and oxidative gelation characteristics of the flours. Kernel texture, break flour yield, carbonate SRC, and lactic acid SRC were not significantly associated with pancake performance for either formulation. ANOVA showed that flour protein concentration had a dominant effect on pancake batter flow and dimensions. Flour protein concentration affected pancakes more than flour protein quality (lactic acid SRC). Water and sucrose SRCs and Rapid Visco Analyzer pasting temperature were negatively correlated with pancake batter flow and dimensions. Pasting temperature was significantly and positively correlated with flour protein, suggesting that correlations with pancake properties might be simply a cross‐correlation with protein concentration. Notably, and in contrast to our hypothesis, oxidative gelation potential had no relationship with pancake processing or quality.     

Enhanced Lipid Stability in Whole Wheat Flour by Lipase Inactivation and Antioxidant Retention

The purpose of this study was to determine the effectiveness of dry heat, steam, and microwave treatments in decreasing lipase activity, while retaining antioxidant activity, to stabilize whole wheat flour against lipid degradation during storage. Bran was heat‐treated in 230‐g batches using four levels (exposure times) for each of the three treatment methods. Lipase activity and antioxidant activity were quantified for all treatment combinations. None of the treatments significantly decreased antioxidant activity; the levels determined to be optimal, inasmuch as further heating did not significantly decrease lipase activity, were 25 min of dry heat, 60 sec of microwave (1000W), and 60 sec of steam. These treatments effectively decreased lipase activity by 74, 93, and 96%, respectively. Optimum treatments were evaluated for acceptance using a consumer sensory panel during a 12‐month storage period. No significant differences in acceptance were found between the control and any of the samples either at baseline or after storage. This suggests that whole wheat flour can be stabilized against lipolysis by utilizing the treatments described in this study without decreasing antioxidant activity, and that manufacturers may utilize these treatments without risking decreased consumer acceptance.     

Suitability of Ontario‐Grown Hard and Soft Wheat Flour Blends for Noodle Making

This study evaluated the blending of flours made from an Ontario hard red winter wheat (HWF) and an Ontario soft red winter wheat (SWF) and compared it with a commercial standard noodle flour (control) made from Canadian Western Hard Red Spring wheat to assess the impact on white salted noodle‐making performance and texture of cooked noodles. Flour characteristics, gluten aggregation, and starch pasting properties were assessed with a farinograph, GlutoPeak tester, and Rapid Visco Analyzer, respectively. The machinability of dough was evaluated with an SMS/Kieffer rig attached to a TA.XT Plus texture analyzer. Tensile and bite tests of cooked noodles were also conducted. Blending HWF with standard noodle flour decreased gluten strength and dough extensibility linearly proportional to the blend ratio, whereas a curvilinear response from blending SWF with standard noodle flour was observed. HWF demonstrated more favorable pasting properties except for lower peak viscosity for noodle making than standard noodle flour. Below a 20% blend ratio with HWF, no significant changes were seen on dough extensibility, cooking loss, tensile properties, and bite testing parameters of cooked noodles. It can be concluded that blending HWF up to a 20% level caused no significant change in the processing properties of dough and cooked noodle quality. The results also showed that the GlutoPeak tester is a sensitive tool for evaluating gluten strength in wheat flour.     

Effect of Whole Grain Wheat Flour on the Mixing Properties,Oil Uptake,and In Vitro Starch Digestibility of Instant Fried Noodles

The effects of whole grain wheat (WGW) flour on the quality attributes of instant fried noodles were characterized in terms of mixing and oil‐resisting properties as well as in vitro starch digestibility. Higher water absorption and shorter kneading time were required to obtain the optimally mixed dough from WGW flour, and the presence of nonstarch components in the WGW flour lowered the thermal conductivity of the noodles. The use of WGW flour produced instant fried noodles with oil uptake reduced by 30%, which could be correlated with the less porous structure confirmed by the surface and cross‐sectional scanning electron microscope images. When the instant fried noodles were subjected to in vitro starch digestion, the use of WGW flour was effective in suppressing the hydrolysis of starch in the noodles, and the predicted glycemic index of the WGW noodles (80.6) was significantly lower than that of the white wheat noodles (83.3).     

Impact of Wheat Grain Selenium Content Variation on Milling and Bread Baking

Selenium (Se) is an essential micronutrient in animals. High levels of Se can accumulate in wheat grain, but it is not clear how high Se affects milling or baking. Low and high Se grain from the same hard red winter wheat cultivar was milled and used for breadbaking studies and Se analysis. Mill stream yields from the low and high Se wheat were comparable, as were flour yields. The amount of total grain Se retained in the flour mill streams was 71.2 and 66.4% for the low and high Se wheat, respectively. Proportionally, Se content in the bran, shorts, and the first reduction flour stream in high Se wheat was higher by 13–20% compared to the low Se wheat. Flour quality parameters including protein content, ash content, and farinograph traits were similar in low and high Se flours, although high Se flour mill streams exhibited lower farinograph stability. Breadbaking evaluations indicated that high Se had a deleterious effect on loaf volume. There was no evidence of significant Se loss after breadbaking with either low or high Se flour.     

Improved Method for Measuring Wheat Flour Dough Pressure‐Sensitive Adhesiveness

Wheat flour dough adhesiveness was evaluated using a new instrumental method based on the extrusion of a dough strip through a specific Plexiglas cell, and the measurement of adhesiveness to a Plexiglas probe attached to a texturometer (TA.XT2‐250N). Experimental conditions for adherence measurement were based on a central composite experimental design (four parameters, five levels). Effects of both dough water content and dough strip thickness were studied. As dough water content increases, bulk stretching of the dough increases, which gives rise to a shoulder on the recorded force‐displacement curve (in addition to the formation of visible fibrils), more pronounced at higher water contents, and to an increase in the specific energy of separation ω (J/m²). Increasing dough thickness also increases ω, due to additional energy dissipation in a higher volume of dough. The new strip method was then compared with a method using a screen located between dough and probe. The former gave more reproducible and discriminant results.