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.     

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.     

静压-剪切微粉碎工艺对魔芋粉理化性能的影响

采用静压—剪切微粉碎工艺对魔芋精粉进行处理,结果原椭球形的精粉粒子破碎为形态各异、大多内部有裂纹的微细粒子,魔芋粉有效成分葡甘聚糖平均分子量下降14.70%,但含量增加5.09%。魔芋粉色度有一定改善,溶胀速度与溶胶透明度明显提高,溶胶粘度没有明显变化。分析表明该微粉碎对魔芋粉产生了机械力化学效应,该微粉碎工艺具有较强的实用性     

Milling of Regular and Waxy Starch Hull-less Barleys for the Production of Bran and Flour

Five registered cultivars of hull-less barley (HB) with regular or waxy starch were milled in a Quadrumat Jr. mill to obtain whole grain flour; pearled in a Satake mill (cultivar Condor only), and the pearled fractions examined by microscopy to determine true HB bran. The samples were milled after tempering and drying in a Buhler mill to obtain bran and flour yields. Flour color and composition of HB were unaltered on milling in the Quadrumat Jr. mill. Microscopic evidence showed that a 70% pearl yield was devoid of the grain's outer coverings, including the aleurone and subaleurone layers. Therefore, the balance of 30% constitutes true bran in HB. Dry milling (as-is grain moisture) of regular starch HB in the Buhler mill gave 59% total flour and 41% bran (bran + shorts) yields, the comparative values for the waxy starch HB were 42 and 58%. On tempering HB from 9 to 16% grain moisture, the total flour yield decreased in both types of HB but to a lesser extent in the waxy starch HB due to decreases in reduction flour. On drying HB to 5 or 7% moisture, total flour yields increased due to contamination with bran and shorts. The milling study led to the conclusion that HB, at best, be dry-milled and a bran finisher be used to obtain commercial flour extraction rates. Lower total flour yields in the waxy starch HB than in the regular starch HB milled at the same grain moisture levels seemed due to higher β-glucan rather than grain hardness. Waxy starch HB flour had higher mixograph water absorption and water-holding capacity than regular starch HB or soft white wheat flour milled under identical conditions. Roller-milled HB products offer the best potential for entry into the food market.     

Description of a Micromill with Instrumentation for Measuring Grinding Characteristics of Wheat Grain

A new method for characterizing the grinding characteristics of wheat grain is described. A micromill was designed for this purpose and equipped with on‐line torque transducers to obtain accurate measurements of mechanical energy consumption during milling. This micromill can be used for testing the milling performance of small quantities of grain (100 g). It can distinguish between different types of wheat grain (soft wheat, hard wheat, durum wheat) on the basis of total specific energy during milling. Wheat characterization can be enhanced by taking particle sizes of the milled products into account. A milling index based on energy consumption and particle size reduction was developed to characterize wheat behavior during milling. This index had a high discriminatory potential, ranging from 100 kJ/kg for soft wheat flour to 600 kJ/kg for durum wheat flour. This micromill directly measures the grinding resistance of wheat kernels as a function of both the kernel hardness and vitreousness, contrary to standard kernel hardness measurements obtained by particle size index and near‐infrared reflectance analysis techniques that only reflect the fracture mode (fine particle reduction potential).     

Laboratory Milling Method for Whole Grain Soft Wheat Flour Evaluation

Whole grain wheat products are a growing portion of the foods marketed in North America, yet few standard methods exist to evaluate whole grain wheat flour. This study evaluated two flour milling systems to produce whole grain soft wheat flour for a wire‐cut cookie, a standard soft wheat product. A short‐flow experimental milling system combined with bran grinding in a Quadro Comil produced a whole grain soft wheat flour that made larger diameter wire‐cut cookies than whole grain flour from a long‐flow experimental milling system. Average cookie diameter of samples milled on the short‐flow mill was greater than samples milled on the long‐flow system by 1 cm/two cookies (standard error 0.09 cm). The long‐flow milling system resulted in more starch damage in the flour milling than did the short‐flow system. The short‐flow milling system produced flours that were useful for discriminating among wheat cultivars and is an accessible tool for evaluating whole grain soft wheat quality.     

Retention of provitamin A carotenoids in high beta-carotene maize (Zea mays) during traditional African household processing

High beta-carotene maize, biofortified with beta-carotene through plant breeding, is being developed as a cost-effective, sustainable agronomic approach to alleviating the problem of vitamin A deficiency in Africa. We used high beta-carotene maize (10.49+/-0.16 microg beta-carotene/g) to prepare traditional maize porridges and compared the carotenoid contents in the following: (1) whole kernels; (2) wet milled flour; (3) wet milled flour, fermented; (4) wet milled flour, cooked; (5) wet milled flour, fermented and cooked. The cumulative losses of beta-carotene in the final, cooked products were 24.5% (95% CI 22.8-26.2%) and 24.8% (95% CI 23.1-26.5%), for the fermented and unfermented porridges, respectively. Thus, fermentation, a traditional technology with documented nutritional and other health benefits, does not adversely affect the retention of beta-carotene in porridges prepared with high beta-carotene maize. The relatively good retention of beta-carotene during traditional maize processing provides additional experimental support for the feasibility of maize biofortification as a means to alleviate vitamin A deficiency.     

Environmental Influences on Flour Quality for Sheeted Noodles in Idaho 377s Hard White Wheat

Production of common wheat (Triticum aestivum L.) in the Pacific Northwest of the United States specifically for Asian noodle products is a relatively new goal for grain producers. We surveyed commercial fields of the hard white spring wheat cultivar Idaho 377s in two years to determine the variables contributing to Asian noodle quality and to validate previous observations made with small‐plot research. Fields were surveyed in 1998 and 1999 in two areas of the Snake River Plain of southeastern Idaho separated by ≈100 km, with both irrigated fields and rain‐fed fields sampled in both zones. Samples were evaluated for grain characteristics then milled and evaluated for flour quality, alkaline noodle color, and color and texture of nonalkaline Chinese (salted, neutral pH) noodles. Grain from rain‐fed fields produced brighter and more yellow alkaline noodles than grain from irrigated fields. Grain produced in rain‐fed fields also had lower peak flour pasting viscosity than grain produced in irrigated fields. Flour ash was lowest in grain from rain‐fed fields located in a higher elevation district (Upper Valley) and greatest in grain from irrigated fields located in a lower elevation district (Lower Valley). Noodle hardness and chewiness were greater in Chinese noodles made from grain produced in the Upper Valley than grain from the Lower Valley. Chinese noodle color had significant interaction with the location and irrigation management used for producing the grain. However, Chinese noodle brightness was consistently negatively correlated with flour protein concentration. The color and texture of noodles produced from flours milled from on‐farm commercial production was consistent with previous experiment station small‐plot research.     

Tocopherol and Tocotrienol Content in Commercial Wheat Mill Streams

The content of tocopherols and tocotrienols, collectively known as vitamin E (tocols), was determined in fractions of roller‐milled wheat grains. The results showed that vitamin E components are present in all major flour fractions of wheat, but that the vitamin E content and composition differed significantly between fractions. The total content of vitamin E, calculated as alpha‐tocopherol equivalents, changed from 16.1 mg α‐TE/g in wheat grain to 12.2 mg α‐TE/g in roller‐milled wheat flour. The germ fraction had the highest content of tocopherols, and the content of α‐tocopherol (195.2 μg/g) was 16 times higher (on average) than in any other fraction. The content of tocotrienols was distributed more uniform in the wheat grain with the highest content in the bran fractions, and the content of β‐tocotrienol was higher than the content of α‐tocopherol in all milling fractions except the wheat germ. The content of β‐tocotrienol was 24.1 μg/g in wheat grain, 25.3–31.0 μg/g in the bran fractions, and 14.3–21.9 μg/g in the fractions of endosperm. Overall, germ and fine bran fractions represent good sources of vitamin E and might be used in breadmaking.     

Pearling of hull-less barley: product composition and gel color of pearled barley flours as affected by the degree of pearling

Barley grains from two hull-less varieties, Phoenix and Candle, were pearled to various degrees (10-80%). The composition (starch, protein, beta-glucan, lipid, and ash) of pearled grain (PG) and pearling flour (PF) was determined. Effect of pearling on Hunter L, a, and b color parameters of uncooked and cooked (gel) barley flour (milled from PG) was investigated over a 3 day storage at 4 degrees C.     

一株产常温葡甘聚糖酶的芽孢杆菌的分离、鉴定及产酶发酵条件的研究

以魔芋生粉为唯一碳源的筛选培养基,从魔芋废渣中分离筛选出一株可以降解魔芋生粉的细菌菌株,编号为LS-6。根据16SrDNA序列和生理生化特性,将该菌株鉴定为枯草芽孢杆菌Bacillus subtilis。胞内外葡甘露聚糖酶酶活分析结果表明,LS-6产生的葡甘聚糖酶为胞外酶。LS-6产生葡甘聚糖酶的最佳培养基组分和条件是：1%魔芋生粉,0.5%酵母粉,0.5%NaCl,培养基初始pH为6.0,最佳发酵条件是25℃,摇床转速200r/min,培养48h。酶解产物的高效液相色谱分析结果表明,LS-6粗酶液的酶解产物主要为葡萄糖和甘露糖。LS-6的分离为进一步克隆常温葡甘聚糖酶基因和产酶工程菌的构建奠定了基础。     

Nutritional Composition of Iron,Zinc, Calcium,and Phosphorus in Wheat Grain Milling Fractions as Affected by Fertilizer Nitrogen Supply

Fe and Zn deficiencies are global nutritional problems. N supply could increase Fe and Zn concentrations in wheat grain. This study was conducted to determine the impacts of different N rates (0, 122, 174, and 300 kg/ha) on the distribution and speciation of Fe and Zn in wheat grain milling fractions under field conditions. Zn and protein concentrations were increased, whereas Fe was less affected in the flour fractions with increasing N rates. Further analysis with size‐exclusion chromatography coupled with inductively coupled plasma mass spectrometry revealed that Fe and Zn bound to low‐molecular‐weight (LMW) compounds in the flour fractions (probably Fe‐nicotianamine [NA], Fe‐deoxymugineic acid, or Zn‐NA) were less affected by increasing N supply, representing 3.5–10.9% of total Fe and 2.5–56.6% of total Zn. In the shorts fraction, LMW‐Fe was absent, and LMW‐Zn with higher N supply was over twice as high as that in control and 3–27 times as high as that in the other milling fractions. In the flour fractions, the molar ratios of phytic acid (PA)/Fe and PA/Zn (both less than 30.5) decreased, whereas soluble LMW‐Fe/Zn was not affected with increasing N rates.     

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.     

Corn Dry‐Milled Grit and Flour Fractions Exhibit Differences in Amylopectin Fine Structure and Gel Texture

Corn starch amylopectin (AP) fine structure and gel textural properties of dry‐milled grit and flour fractions were investigated in 10 corn cultivars. Amylopectin was isolated by fractionating the starch derived from these two milled fractions using size‐exclusion chromatography (SEC). Fine structure was characterized by SEC after thorough debranching with pullulanase. SEC revealed three major fractions of debranched AP from the grit and flour portion. Amylopectin in the grit portion had a significantly higher proportion of long chains (DP_n 70–75) and a postulated lower extent of chain branching than its flour counterpart. Texture profile analysis showed that flour gels from the grit fraction had significantly higher values for hardness, gumminess, and springiness compared with gels from the floury fraction. Trends were similar for starch gels of the two dry‐milled fractions, though only springiness was significantly different. The finding that differences in AP fine structure in dry‐milled fractions relate to gel textural differences suggests that dry millers may be able to produce flours of different functionalities that would be suited for different end uses. Additionally, mixing the dry‐milled flour fraction with a grit‐derived flour would result in different product properties.     

Quality of Flours from Waxy and Nonwaxy Barley for Production of Baked Products

One nonwaxy (covered) and two waxy (hull-less) barleys, whole grain and commercially abraded, were milled to break flour, reduction flour, and the bran fraction with a roller mill under optimized conditions. The flour yield range was 55.3–61.8% in whole grain and increased by 9–11% by abrasion before milling. Break flours contained the highest starch content (≤85.8%) independent of type of barley and abrasion level. Reduction flours contained less starch, but more protein, ash, free lipids, and total β-glucans than break flours. The bran fraction contained the highest content of ash, free lipids, protein, and total β-glucans but the lowest content of starch. Break flours milled from whole grain contained 82–91% particles <106 μm, and reduction flours contained ≈80% particles <106 μm. Abrasion significantly increased the amount of particles <38 μm in break and reduction flours in both types of barley. Viscosity of hot paste prepared with barley flour or bran at 8% concentration was strongly affected by barley type and abrasion level. In cv. Waxbar, the viscosity in bran fractions increased from 428 to 1,770 BU, and in break flours viscosity increased from 408 to 725 BU due to abrasion. Sugar snap cookies made from nonwaxy barley had larger diameter than cookies prepared from waxy barley. Cookies made from break flours were larger than those made from reduction flours, independent of type of barley. Quick bread baked from nonwaxy barley had a loaf volume similar to that of wheat bread, whereas waxy barley bread had a smaller loaf volume. Replacement of 20% of wheat flour by both waxy and nonwaxy barley flour or bran did not significantly affect the loaf volume but did decrease the hardness of quick bread crumb.     

细粒魔芋精粉及其复合胶的特性与应用研究

采用胶体磨湿法粉碎工艺制备得到细粒魔芋精粉,在该细粒魔芋精粉中添加10%(w/w)黄原胶制备得到复合胶。对该复合胶及细粒魔芋精粉水溶胶的流变特性以及两者在冰淇淋中的应用进行了比较研究。结果表明,与正常粒度魔芋精粉比较,细粒魔芋精粉的溶胀速度快,溶胶粘度低;相同浓度与测定条件下,复合溶胶的粘度数倍高于细粒魔芋精粉溶胶的粘度,切稀现象也比同粘度魔芋溶胶更为明显;以参考用量为0.25%的复合胶作为稳定剂应用于冰淇淋中时,也同样使冰淇淋浆料粘度显著提高,并导致其产生明显的切稀现象,相应冰淇淋制品的粘稠感明显低于以     

Starch–Hydrocolloid Interaction in Chemically Leavened Gluten‐Free Sorghum Bread

A satisfactory chemically leavened gluten‐free sorghum bread method was developed by using a blend of 90% commercially milled sorghum flour and 10% rice, tapioca, or potato starch as the “flour.” The most effective starch/hydrocolloid combinations in the formula were potato starch with 4% xanthan, tapioca starch with 3% hydroxypropyl methylcellulose, and rice starch with 3% xanthan. Overall, there was not a significant difference in the quality of loaves made with each starch/hydrocolloid combination. Rapid visco analysis showed that batter viscosity did not have a significant impact on loaf volume index but did affect crumb grain properties. Batters with lower viscosity produced loaves with better crumb grain.     

Impact of Chickpea‐ and Raw Plantain‐Based Gluten‐Free Snacks on Weight Gain,Serum Lipid Profile,and Insulin Resistance of Rats Fed with a High‐Fructose Diet

Two gluten‐free snacks containing chickpea, plantain, and maize flours at different concentrations were prepared. The impact of chickpea or plantain flour level on weight gain, insulin resistance, and serum lipid profile of rats fed a high‐fructose diet was evaluated. A dose of 0.93 g/kg was used in the experiments to simulate the snack consumption level by humans (average content of a small package, which is twice the portion recommended by the U.S. Department of Agriculture). Compared with a high‐fructose reference diet, consumption of both snacks decreased weight gain, fasting serum glucose, and triglycerides. The effect was more pronounced for snack B, with higher chickpea content. Consumption of these snacks may also have beneficial effects against obesity and cardiometabolic complications. Chickpea flour is a promising functional ingredient for the development of antiobesity foods.     

Particle Distribution and Composition of Retail Whole Wheat Flours Separated by Sieving

The purpose of this study was to evaluate the differences among four retail whole wheat flours with respect to particle size distribution and composition of fractions separated by sieving. Interestingly, not only were significant differences discovered among the brands for particle size distribution, but lots within two of the brands were significantly different (P < 0.05), suggesting that flour particle size produced by the same company is not always consistent. Starch damage ranged from 4.67 to 7.69%. As expected, darker colors were associated with the larger particle size fractions, and the colors lightened as particle size decreased. This observation suggested that the differences in particle size resulted from differences in the degree to which the bran fraction of the kernel was milled, an observation substantiated by the distribution of ash in each fraction, which ranged from 0.37 to 38.0% of total ash. Distribution of protein ranged from 0.19 to 61.8% of total protein. These data are relevant because differences in particle size distribution and composition affect functionality, sensory acceptability, nutritional properties, and shelf life of whole wheat flour.     

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%.