Break Flour Research Articles

Quality characteristics of wheat flour milled streams

In order to develop specific quality flour for use in different bakery products, quality characteristics such as sedimentation value, flour color and oil and its fatty acid composition of flour mill streams obtained from three different commercial roller flour mills were determined. The studies showed there was an increase in the sedimentation value, protein, falling number and oil and a decrease in flour color with increasing number of break flour streams, and the trend was similar for the streams obtained from the three different mills. However, no appreciable difference with regard to the above parameters was observed in reduction flour streams. Palmitic and linoleic acid contents were the predominant saturated and unsaturated fatty acids respectively present in oil of the milled streams. The levels of these fatty acids were high in V break, 1st, 2nd, 3rd and 6th reduction streams in all three mills. The flours from the reduction passages in general had more saturated fatty acid compared to break flour streams.

Protein Functionality Differences in Eastern U.S. Soft Wheat Cultivars and Interrelation with End–Use Quality Tests

Fifty-nine samples of eastern U.S. soft winter wheat consisting of eight cultivars, with six to eight replications, were investigated for milling, cookie baking, and physical and chemical tests of quality and interrelations for predicting end-use quality. Three of the cultivars with 5+10 Glu-D1 high molecular weight subunit composition yielded significantly higher (P=0.01) break flour and gave lower damaged starch, lower gluten hydration, longer dough mixing times and larger diameter cookies with superior top grain compared to those of five cultivars with 2+12 Glu-D1 high molecular weight subunit composition. Dough development time and gluten hydration tests showed significant positive correlations with the milling parameters and a negative correlation with damaged starch contents of the flours. Due to the highly significant correlation coefficient (r=0.94, n=59) of Zeleny- and sodium dodecyl sulfate-sedimentation values, either can be used to test the strength of protein in the soft wheat flours. For better prediction of end-use quality, the results suggest integration of protein/gluten functionality testing with existing tests as an important facet of quality testing in soft wheats.

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

ABSTRACTOne 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.

Wheat Grain Hardness Among Chromosome 5D Homozygous Recombinant Substitution Lines Using Different Methods of Measurement

ABSTRACTThe level of grain hardness of wheat (Triticum aestivum) cultivars profoundly affects milling properties and end‐use. We examined grain hardness among a genetically defined set of 83 chromosome 5D homozygous recombinant substitution lines derived from soft wheat cv. Chinese Spring and hard wheat cv. Cheyenne and compared four common methods of measuring wheat grain hardness. Measures of grain hardness included a modified particle size index, Brabender Quadrumat flour milling, near‐infrared reflectance (NIR) spectroscopy, and the single‐kernel characterization system (SKCS). Duncan's multiple range test was used to group recombinant lines according to parental classes. Quadrumat milling fractions, percent bran and middlings, were well correlated to NIR and SKCS grain hardness, whereas break flour, a traditional measure of grain hardness, was poorly correlated to other hardness measures. NIR and SKCS grain hardness measures provided the greatest and similar mean separations. Both methods identified recombinant lines as being significantly outside either parental class and significantly different from and in between the two parental classes. Between two divergent environments, correlations (r) for Quadrumat bran and middlings percents and NIR and SKCS hardness ranged from 0.83 to 0.94. Analysis of variance indicated that lines differed substantially for hardness, and hardness was highly influenced by environment, albeit consistently, as indicated by low line‐location model interaction terms. The results confirmed the presence of major allelic differences assignable to chromosome 5D and suggested the action of minor gene(s). Break flour, in particular, showed strong indications of transgressive segregation independent of the Hardness (Ha) locus. The Perten 4100 SKCS provided the best (most discriminating) measure of the material properties of the wheat endosperm manifested by the action of the Ha locus.

Comparison of Gas Chromatography–Electron Capture and Enzyme-Linked Immunosorbent Assay for Deoxynivalenol in Milled Fractions of Naturally Contaminated Wheat

An enzyme-linked immunosorbent assay (ELISA) for deoxynivalenol was compared with a gas chromatography–electron capture assay to determine deoxynivalenol levels in milled fractions of wheat. The milling provided eight fractions: first, second, and third break flours; first, second, and third reduction flours; brans; and shorts. The difference between levels of deoxynivalenol quantitated by ELISA or gas chromatography did not depend significantly on the wheat samples or milled wheat fractions. For none of the fractions or samples did the differences differ significantly (P = 0.05) from zero. Based on these comparative tests, EUSAs for deoxynivalenol in milled wheat fractions should provide reliable results rapidly and economically in a commercial setting.

A comparison of equilibrated lipid water systems and the effect of added lecithin on dough rheology of flour milling-streams

The lipid part of four wheat flour milling streams was extracted by ethanol. The flours were two spring wheats and two winter wheats, where one of each spring and winter wheats were obtained from the reduction-roll system and the other one from the break-roll system. Equilibrated lipid water mixtures were prepared and centrifuged to distinguish between non-polar and polar lipids. The lipids interacting with water were investigated in the microscope under polarised light to establish the presence of the lamellar liquid-crystalline phase. The stress relaxation behaviour of flour water doughs and doughs made with lamellar lecithin added were also studied. The largest amount of lipids able to form the lamellar liquid-crystalline phase was recovered for the winter wheat from the reduction milling-stream. The corresponding spring wheat also formed the lamellar phase, while the break flours did not. A large amount of oil phase was obtained from the two break flours. The rheological parameters increased to the same value for the two break flours and the two reduction flours when lecithin was added. This suggests that a flour containing protein and lipids of approximately the same quality will be improved to the same extent when lamellar lecithin is added. © SCI 1998.

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

ABSTRACTSmall 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.

Aleurone and Pericarp Fluorescence as Estimators of Mill Stream Refinement for Various Canadian Wheat Classes

Mill streams from laboratory-scale and pilot-scale millings of seven Canadian wheat classes were used to extend previous evaluations of fluorescence imaging as a flour refinement estimator. Flour streams and diverse mill streams derived from throughout the Grain Research Laboratory (GRL) Pilot Mill during the milling of Canada Western Red Spring (CWRS) wheat were subjected to fluorescence measurement of pericarp and aleurone tissue. Both techniques showed clear differentiation among the mill streams. Strong linear relationships of pericarp fluorescence to ash content, grade colour and L* (brightness) were found. Relationships of aleurone fluorescence to the same refinement indices, although still statistically significant (P<0·05), were weaker because of the previously established tendency for break flours to exhibit lower aleurone fluorescence than reduction flours of comparable refinement. Extending the GRL Pilot Mill break system to broaden the refinement range within CWRS break flours confirmed a strong linear relationship between break flour refinement and aleurone fluorescence. The robustness of fluorescence as a flour refinement indicator under different milling conditions was examined for commercially grown wheats from seven Canadian wheat classes using three different mills. For every wheat class and every milling process both fluorescence techniques showed clear differentiation among flour streams. Pericarp fluorescence was strongly related to flour refinement for all wheat classes, aleurone fluorescence was less strongly related because of anomalous low fluorescence of break flours. The relationships of pericarp fluorescence to the flour refinement indices were heterogeneous among wheat classes. It is well established that flour ash content and flour colour have limitations for estimating the refinement of flours from wheats of diverse origin. Therefore, the heterogeneity of pericarp flourescence relations among wheats provides evidence that pericarp fluorescence is a more objective flour refinement estimator. The regression equations of pericarp fluorescence to flour refinement indices when a single wheat was milled by different mills were clustered closely, although heterogeneity was evident for several wheats.

Carbohydrate Digestibility and Resistant Starch of Steamed Bread

AbstractSixteen Australian hard and soft wheats and two U.S. hard wheats were milled into flours (break and reduction) for preparation of steamed breads. Chemical composition and rheological properties of the flour were determined. Steamed breads were analyzed for carbohydrate digestibility and resistant starch. There was no relationship between flour type, protein content and specific volume of steamed breads. Carbohydrate digestibility of steamed breads from soft wheat flour was higher than that of breads from hard wheat flour. Reduction flours produced steamed breads with higher carbohydrate digestibility than break flours. Resistant starch was higher in steamed breads from soft wheat flours than in those from hard wheat flours. Reduction flour produced higher resistant starch levels than break flours. Commercial white bread had resistant starch levels similar to those of steamed breads from soft wheat flour and hard wheat reduction flour.

Canadian short process bread: Potassium bromate response of flour streams and divide flours milled from Canadian red spring wheat

Mill streams and divide flours from a pilot-scale milling of commercially grown No. 1 Canada Western Red Spring wheat were baked by a short (no bulk fermentation) baking procedure at various levels of potassium bromate. The quality of bread produced, measured in terms of loaf volume, loaf volume per unit protein and overall bread score showed a wide range of response to potassium bromate level. Household patent flour and the highly refined reduction flours exhibited relatively little baking response to increasing bromate levels, achieving optimum baking performance between 0 and 50 ppm. The least refined reduction flours required higher bromate levels (80–120 ppm) to achieve maximum response, and also demonstrated a greater relative response than the more refined reduction flours. Baker's patent flour and the most refined break flours responded very strongly to bromate, and required higher levels (100–150 ppm) to attain full response. Poorly refined break flours exhibited the highest bromate requirement (225 ppm). Straight-grade flours of 62, 75 and 79% extraction exhibited very little difference in bromate requirements. It appears that stream selection has limited potential as a means of reducing the bromate requirement of bakery flour prepared from Canada Western Red Spring wheat. Key words: Red spring wheat, milling, baking quality, bread, mill streams, bromate response

Smooth and wrinkled peas. 2. Distribution of protein, lipid, and fatty acids in seed and milling fractions

The yield, protein and lipid distribution, and fatty acid composition of fractions from roller-milling of smooth and wrinkled pea seeds were compared with the composition of hand-dissected germ, whole cotyledon, and hull and pea cotyledon layers removed by abrasion. When peas were abraded to remove up to 65% of the kernel, there was a gradual decrease in protein and lipid; the protein and lipid concentrations in the residual 35% were only about 75% and 50%, respectively, of that in the original seed. Both protein and lipid concentrations decreased from shorts, to reduction flour, to break flour, and to bran. Linoleic acid was the main fatty acid. In smooth peas, oleic acid was higher in germ lipid than in the cotyledon lipid

Surface properties of wheat flour-milling streams and rheological and thermal properties after hydration

Five different flour streams together with the main white flour from a winter-wheat mixture and a spring-wheat mixture, respectively, were obtained from a commercial mill. Physical properties of these flour streams were investigated and related to a model of the dough describing it as a foam. Interfacial behaviour of spread material, rheological properties of doughs and gelatinization of starch were investigated. The flours from the reduction system were all very similar in their interfacial behaviour, and decreased the surface tension of water to about the same extent. An early break flour stream was found to be more surface-active, i.e. a smaller amount of flour was required to get the same decrease in surface tension of water. The relaxation modulus (G) was higher for doughs made from reduction flour streams than for doughs made from break flour streams. The gelatinization behaviour could be related to starch damage and protein content of flour. There were also differences in physical properties of flours from the two wheat mixtures. If complete spreading of protein was assumed, the results indicated the formation of thicker proteins films in case of the spring wheat. The lower protein winter-wheat doughs were weaker (i.e, lower G values) than the spring-wheat doughs. The gelatinization temperature was higher for the spring-wheat flours.

Black point in bread wheat: effects on quality and germination, and fungal associations

Quality measurements were made on subsamples of wheat grain with high, medium and low levels of black point prepared from 12 grain samples. Test weight, falling number, total flour yield, break flour yield and dough stability were slightly lower in subsamples with high levels of black point. In contrast, grain weight, pollard yield, flour colour grade and water absorption were slightly higher in subsamples with high black point. Baking quality was unaffected. As the changes in quality detected were very slight, the condition had little effect on the value of the grain for bread making. Alternaria alternata was the predominant fungal species isolated from surface sterilized grains, being present in 72% of grains with black point and in 39% of symptomless grains. Seed germination was not affected by black point but seedling emergence was reduced by 3.2% from black-pointed seed.

SEVERITY OF SPROUTING AS A FACTOR INFLUENCING THE DISTRIBUTION OF AMYLASE LEVELS IN PILOT MILL STREAMS OF CANADIAN WHEATS

Wheats from a wet harvest year, 1978, and a dry harvest year, 1979, were examined for levels of α-amylase in Grain Research Laboratory pilot mill streams. Specific α-amylase determinations were more discriminating than use of the amylograph in discerning differences in levels of enzyme. Wheats grown in 1978 had more enzyme present in the break flours and less in the middlings than wheats grown in 1979. On a per gram basis, a 1 CWRS wheat from 1978 and a 2 CWRS wheat from 1978 with comparable α-amylase activities had different distributions of enzyme in the mill streams. Thus the 1 CWRS 1978 contained a higher activity per gram in the 1st break, 6th middlings and bran flour but contained equal or less activity per gram in the other fractions. Model wheat systems containing 1.8% of 44-h germinated wheat and 0.3% of 96-h germinated wheat were examined for α-amylase levels per gram in pilot mill streams. It was found that the less severely sprouted system had less activity in the sizings and early middlings relative to the later middlings. These findings suggest that the observed differences in distribution of α-amylase in mill streams of wheats harvested in 1978 and 1979 can be explained by a greater severity of sprout damage in the 1978 crop year. The α-amylase versus mobility relationships for the different flour streams varied widely and was influenced by starch damage as well as other factors, β-amylase levels in the 1978 and 1979 pilot mill streams were found to have a different distribution than α-amylase.

Actinomycetales from Corn

Mesophilic Actinomycetales were isolated from whole corn, brewer's grits, and break flour received from three different mills. In addition, strains were isolated from high-moisture (27%) field corn; high-moisture, silo-stored corn (untreated); and high-moisture corn treated with ammonia, ammonium isobutyrate, or propionic-acetic acid. According to standard techniques, 139 strains were extensively characterized and 207 additional strains were partially characterized. On the basis of these characterizations, the streptomycete strains were identified by both the systems of Pridham et al. and Hütter because these systems are rapid and accurate. In general, only Streptomyces griseus (Krainsky) Waksman and Henrici was isolated from high-moisture whole corn (treated or untreated) except from grain exposed to ammonium isobutyrate. Strains isolated from high-moisture corn subjected to that treatment represented both S. griseus and S. albus (Rossi Doria) Waksman and Henrici. The strains isolated from corn and corn products from the three mills were identified with a number of streptomycete species. Of all Actinomycetales isolated, only three were not streptomycetes—two from brewer's grits and one from break flour.

Actinomycetales from Corn

Mesophilic Actinomycetales were isolated from whole corn, brewers grits, and break flour received from three different mills. In addition, strains were isolated from high-moisture (27 per cent) field corn; high-moisture, silo-stored corn (untreated); and high-moisture corn treated with ammonia, ammonium isobutyrate, or propionic-acetic acid. According to standard techniques, 139 strains were extensively characterized and 207 additional strains were partially characterized. On the basis of these characterizations, the streptomycete strains were identified by both the systems of Pridham et al. and Hütter because these systems are rapid and accurate. In general, only Streptomyces griseus (Krainsky) Waksman and Henrici was isolated from high-moisture whole corn (treated or untreated) except from grain exposed to ammonium isobutyrate. Strains isolated from high-moisture corn subjected to that treatment represented both S. griseus and S. albus (Rossi Doria) Waksman and Henrici. The strains isolated from corn and corn products from the three mills were identified with a number of streptomycete species. Of all Actinomycetales isolated, only three were not streptomycetes--two from brewer's grits and one from break flour.

Evaluating Soft Wheat Quality of Early Generation Progenies1,3

A procedure is proposed for evaluating the milling and baking qualities of early generation soft wheat (Triticum aestivum L.) progenies. Twenty grams of wheat are ground for flour granularity and protein content determinations.A portion is reground and sifted, and tested for alkaline water retention capacity (AWRC). lqour granularity is associated with break flour yield during milling and with cake quality potential, while AWRC is correlated with cookie quality. A test line is considered to have suitable soft wheat quality potential if it is at least as low in protein and AWRC and at least as high in particle‐size index as a standard (commercial) cultivar.

Correlation of Uric Acid Content with Fragment Counts in Insect-Infested Flours and Wheat Grains

Abstract Seven samples of naturally insect-infested wheat were examined for (a) uric acid content, (b) per cent agricultural damage, (c) whole or equivalent insects, and (d) insect damage as determined by X-ray technique. Thirteen different forms of flours obtained by milling these wheat grains in a Buhler pilot mill were analyzed for uric acid and insect fragment counts. For wheat grains, the correlation between uric acid contents and X-ray data was found to be the best among the six possible intercomparisons. The results for the first break flour samples also indicated good correlation between the uric acid levels and insect fragment counts.