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1.
A small‐scale (100 g of grain) procedure was developed to wet‐mill grain sorghum into six fractions by modifying the procedure of Eckhoff et al (1996). The wet‐milling process was repeated five times on commercial grain sorghum, and the mean yield (69.4%) of starch (≤0.3% protein) varied by 0.3%, whereas the yields of fiber, gluten, and germ plus bran fractions varied by 5–6%. The starch fraction accounted for ≈95% of that in the grain, while the total solids recovered was 99.0%. Four other samples of grain sorghum gave 92–95% recoveries of starches and 98.2–99.8% recoveries of total solids. All grain sorghum starches had lightness (L*) values and pasting curves nearly equal to those of a commercial maize starch. 相似文献
2.
Field pea has ≈23% protein, 48% starch, 8% sugars, 4% lipids, 7% crude fiber, and 3% ash. Pin milling at 1 × 14,000, 3 × 14,000, 9 × 14,000, and 12 × 14,000 rpm followed by air classification according to particle size resulted in fine fractions (<18 μm) with high protein content and coarser fractions (>18 μm) with high starch content. The yield of the high protein fraction increased with the intensity of grinding before air classification. The starch content of the high starch fraction increased with the intensity of grinding and subsequent air classification. Both whole pea and dehulled pea responded well to fine grinding and air classification, and the dehulled pea gave higher protein content and higher starch content than the corresponding fraction from whole pea. The protein fraction had high lysine content and met all the amino acid requirements of the World Health Organization for children older than two years and adults. 相似文献
3.
Effect of corn degermination mill parameters (clearance between mill plates and rpm) were assessed on the broken germ and number of whole kernels in mash so as to optimize the cracking procedure for the intermittent milling and dynamic steeping (IMDS) process. The dynamic steep time and number of intermittent milling stages for the IMDS process were also optimized for maximum starch recovery. A comparison was made between the IMDS and the conventional steeping process for fraction yields. A clearance of 0.45–0.48 cm between the plates gave the most optimum processing conditions (minimum broken germ and least amount of whole kernels in mash after cracking). Effect of rpm on germ damage and kernel cracking was not significant when optimum clearance between the degermination plates was maintained. Two stages of intermittent milling with a dynamic steep time of 30 min or higher was recommended because it produced the highest yield of starch and germ. Comparison of the IMDS process with the conventional wet‐milling process showed that starch and gluten yield increased by 1.6 and 4.26%, respectively, in the IMDS process. Germ recovered from the IMDS process was 0.54% lower than that from the conventional steeping process. 相似文献
4.
《Cereal Chemistry》2017,94(6):963-969
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. 相似文献
5.
R. S. Bhatty 《Cereal Chemistry》1997,74(6):693-699
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. 相似文献
6.
Bruce S. Dien David B. Johnston Kevin B. Hicks Michael A. Cotta Vijay Singh 《Cereal Chemistry》2005,82(5):616-620
A modified dry‐grind corn process has been developed that allows recovery of both pericarp and endosperm fibers as coproducts at the front end of the process before fermentation. The modified process is called enzymatic milling (E‐Mill) dry‐grind process. In a conventional dry‐grind corn process, only the starch component of the corn kernel is converted into ethanol. Additional ethanol can be produced from corn if the fiber component can also be converted into ethanol. In this study, pericarp and endosperm fibers recovered in the E‐Mill dry‐grind process were evaluated as a potential ethanol feedstock. Both fractions were tested for fermentability and potential ethanol yield. Total ethanol yield recovered from corn by fermenting starch, pericarp, and endosperm fibers was also determined. Results show that endosperm fiber produced 20.5% more ethanol than pericarp fiber on a g/100 g of fiber basis. Total ethanol yield obtained by fermenting starch and both fiber fractions was 0.370 L/kg compared with ethanol yield of 0.334 L/kg obtained by fermenting starch alone. 相似文献
7.
Starch was isolated from three different barleys with normal, highamylose, or high‐amylopectin (waxy) starch. The laboratory‐scale starch isolation procedure included crushing of grains, steeping, wet milling, and sequential filtration and washing with water and alkali, respectively. Yield and content of starch, protein, and dietary fiber, including β‐glucan, were analyzed in isolated starch and in the by‐products obtained. Starch yield was 25–34%, and this fraction contained 96% starch, 0.2–0.3% protein, and 0.1% ash. Most of the remaining starch was found in the coarse material removed by filtration after wet milling, especially for the high‐amylose barley, and in the starch tailings. Microscopy studies showed that isolated starch contained mostly A‐granules and the starch tailings contained mostly B‐granules. Protein concentration was highest in the alkali‐soluble fraction (54%), whereas dietary fiber concentration was highest in the material removed by filtration after alkali treatment for the normal and waxy barleys (55%). The β‐glucan content was especially high for the waxy barley in this fraction (26%). The study thus showed that it was possible to enrich chemical constituents in the by‐products but that there were large differences between barleys. This result indicates a need for modifications in the isolation procedures for different barleys to obtain high yields of starch and different by‐products. Valuable by‐products enriched in β‐glucan or protein, for example, may render starch production more profitable. 相似文献
8.
A procedure that reduces diffusional limitations by periodically milling the corn to reduce particle size and stirring the ground mash in the presence of sulfur dioxide (SO2) and lactic acid was developed. The process, called intermittent milling and dynamic steeping (IMDS), includes three main stages: initial soaking (a short-time immersion in water) of whole kernels, initial cracking of the partially hydrated kernels, and dynamic steeping with interspersed milling. This study evaluated the three stages of the process separately, evaluating the effect of variables on each stage of the process. Corn fractions yield (germ, fiber, gluten, starch) were used to decide the best conditions for the soaking and steeping stages, and germ damage was used to determine the best kernel cracking method. Starch, gluten, and germ yields were not affected by soak temperatures (52–68°C) or soak time (1–3 hr). A temperature of 60°C was chosen for soaking because it increased the rate of kernel hydration without gelatinizing starch, which happens at higher temperatures. A 2-hr soak time was preferred because there was less fiber in the germ fraction and less germ damage was observed. Although there were no advantage to using SO2 or lactic acid in the soak water, the presence of these compounds during dynamic steeping enhanced starch yield. The starch yield for 3 hr of dynamic steeping was not statistically different from the starch yield for a 7.5-hr dynamic steep. The Bauer mill was preferred over the use of a roller mill or a commercial grade Waring blender for kernel cracking. The IMDS process produced, on an average, 1 percentage point more starch than the conventional 36-hr steeping process. Total steep or kernel preparation time was reduced from 24–40 hr for conventional wet-milling to 5 hr for the IMDS process. 相似文献
9.
M. S. Izydorczyk J. E. Dexter R. G. Desjardins B. G. Rossnagel S. L. Lagasse D. W. Hatcher 《Cereal Chemistry》2003,80(6):637-644
Roller milling of hull‐less barley generates mill streams with highly variable β‐glucan and arabinoxylan (AX) content. For high β‐glucan cultivars, yields >20% (whole barley basis) of a fiber‐rich fraction (FRF) with β‐glucan contents >15% can be readily obtained with a simple short mill flow. Hull‐less barley cultivars with high β‐glucan content require higher power consumption during roller milling than normal β‐glucan barley. Recovery of flour from high β‐glucan cultivars was greatly expedited by impact passages after grinding, particularly after reduction roll passages. Pearling before roller milling reduces flour yield and FRF yield on a whole unpearled barley basis, but flour brightness is improved and concentration of β‐glucan in fiber‐rich fractions increases. Pearling by‐products are rich in AX. Pearling to 15–20% is the best compromise between flour and FRF yield and flour brightness and pearling by‐products AX content. Increasing conditioning moisture from 12.5 to 14.5% strongly improved flour brightness with only a moderate loss of flour yield on a whole unpearled barley basis. As moisture content was increased to 16.5%, flour yield declined without a compensating improvement in brightness, but the yield of fiber‐rich fraction continued to increase and concentration of β‐glucan in FRF also increased. 相似文献
10.
Oswaldo Taboada‐Gaytan Linda M. Pollak Lawrence A. Johnson Steven R. Fox 《Cereal Chemistry》2009,86(2):204-209
The use of corn (Zea mays L.) hybrids with high grain yield and starch extractability has steadily increased in the processing industry. In light of widespread corn seed industry participation in the Germplasm Enhancement of Maize Project (GEM), which seeks to enhance exotic germplasm, future hybrids may contain more exotic sources in genetic backgrounds. It is necessary to establish and monitor physical, compositional, and milling characteristics of the new exotic breeding materials to determine the processing value. The present study was conducted to determine the wet‐milling characteristics of a set of GEM lines compared with typical Corn Belt lines. Ten GEM lines introgressed with exotic materials from Argentina, Chile, Cuba, Florida, and Uruguay and previously identified as having different starch yields, three commercial inbred lines, and two public inbred lines (B73 and Mo17) were analyzed using both near‐infrared transmittance (NIT) and a 100‐g wet‐milling procedure. There were statistical differences (P < 0.05) in the yield of wet‐milled fractions (starch, fiber, gluten, and germ). The GEM lines AR16035:S19‐227‐1‐B and CUBA117:S1520‐562‐1‐B had similar or better starch yield and starch recovery than B73 and the other adapted inbred lines, indicating that they may be useful in improving the proportion of extractable starch present in kernels of hybrids. Residual protein levels in the starch and gluten fractions were 0.26–0.32% and 38–45%, respectively. The starch yield of GEM lines from wet milling correlated positively with starch content from NIT and was negatively correlated with protein content of the corn kernels. Oil content in the germ varied from 50 to 60%. Our results indicate that incorporating GEM lines in a breeding program can maintain or even improve wet‐milling characteristics of Corn Belt materials if lines with appropriate traits are used. 相似文献
11.
P. Yang L. Du D. L. Wang B. H. Li K. D. Rausch P. Buriak S. R. Eckhoff 《Cereal Chemistry》2000,77(2):128-132
Starch yield was significantly affected by all three main unit operations in alkali wet‐milling (debranning, roller milling, and steeping). The conditions for the three unit operations were studied using a single hybrid. Studies on debranning showed that optimal separation between pericarp and corn endosperm was obtained when corn was soaked in a 1.5–2% NaOH solution at 85°C for 5 min. Passing debranned corn through smooth roller mill once or twice did not affect the product yields, but passing the corn through the roller mill three times decreased the germ yield because of a large amount of broken germ. A 62% higher processing rate could be achieved when passing corn through the mill twice than by passing it through the mill once. The gap should be set at 2.0 mm when passing corn through the mill once, and it should be set at 3.5 mm for the first pass and 2.0 mm for the second pass when passing corn through the mill twice. Starch yield was more sensitive to NaOH concentration and steep temperature than to steep time. The highest starch yield was obtained when steeping corn in 0.5% NaOH for 1 hr at 45°C. 相似文献
12.
S. R. Eckhoff L. Du P. Yang K. D. Rausch D. L. Wang B. H. Li M. E. Tumbleson 《Cereal Chemistry》1999,76(1):96-99
A corn wet-milling process in which alkali was used was studied as an alternative to the conventional corn wet-milling procedure. In the alkali wet-milling process, corn was soaked in 2% NaOH at 85°C for 5 min and then debranned mechanically to obtain pericarp as a coproduct. Debranned corn was cracked in a roller mill, and the cracked corn was steeped with agitation for 1 hr in 0.5% NaOH at 45°C. The cracked and steeped corn was then processed to separate germ, fiber, and gluten by steps similar to those in conventional wet-milling. Alkali wet-milling yielded soakwater solids, pericarp, germ, starch, gluten, and fine fiber. The protein content of the starch and the starch content of the fiber from the alkali process were lower than those from the conventional process. 相似文献
13.
Two hull‐less barley cultivars, one with waxy starch and the other with high‐amylose starch, were roller‐milled unpearled and after 15% pearling. Flows of varying length, with diverse roll settings and roll surfaces were used to determine effects on the yield, composition, and properties of milled products. Similar trends were noted for the two cultivars. When using a short flow comprising four break passages and a sizing passage, power consumption during grinding was reduced by 10% when roll flute orientation was changed from dull‐to‐dull (D/D) to sharp‐to‐sharp (S/S). Flute orientation had minimal effects on the yield and brightness of flour, but SS grinding gave a higher yield of a fiber‐rich fraction (FRF). FRF yield and composition are of particular interest because FRF has potential as a functional food ingredient due to elevated levels of β‐glucans (BG) and arabinoxylans (AX). When using smooth frosted rolls (SM) for the sizing passage, power consumption increased by several times over using fluted sizing rolls with little advantage for either yield or BG content of FRF. FRF starch damage increased when smooth sizing rolls were used, and water swelling, a measure of water hydration capacity, also increased. Setting break and sizing rolls sharp‐to‐sharp significantly lowered the mean particle size of the FRF fraction, accompanied by moderate declines in FRF BG and AX contents. FRF yield decreased ≤50% when milling flow was lengthened to three sizing passages with intermediate impact passages, with only a moderate accompanying increase in FRF fiber content, regardless of roll conditions. Pearling 15% before milling reduced the yield of FRF by ≈30% while moderately reducing flour yield. Flour brightness was improved by pearling. When barley was pearled, FRF contained higher amounts of BG, but lower amounts of AX, phenolics, ash, and protein. 相似文献
14.
Jet milling is a fluid energy impact‐milling technique generally used for the ultrafine reduction of higher value materials. The efficiency of jet milling combined with air classification appears very efficient to separate starch from other wheat flour aggregate components and to produce wheat starch with very low residual protein content. Indeed, residual protein content of the starch‐rich fraction can be reduced to <2% db with a series of successive grinding and air classification operations. Lipid and pentosan contents were also reduced in the starch‐rich fraction. Nevertheless, jet milling cannot eliminate grinding differences observed between different types of wheat. Wheat hardness continues to have an effect on milling and classification yields and on the composition of air classification fractions. To obtain starch‐rich fraction with only 2% protein content, hard wheat flour required a series of at least five grinding steps, whereas only three steps are necessary for soft wheat flour. Under these conditions, hard wheat flours give 24% mass yield with 12% starch damage compared with 39% yield and a low starch damage content (6.4%) for soft wheat flour. These results highlight new prospects for the development of cereal flours, especially soft wheat flours. 相似文献
15.
Kent D. Rausch Larry E. Pruiett Ping Wang Li Xu Ronald L. Belyea M. E. Tumbleson 《Cereal Chemistry》2009,86(4):434-438
The objective was to describe a laboratory‐scale dry‐milling procedure that used single‐stage tempering and determine the effect of hybrid on yields and fraction compositions in milled corn. Samples of 11 commercially available hybrids were processed through a laboratory dry‐milling procedure that used 1 kg samples of corn to produce milling fractions of large grits, small grits, fines, germ, and pericarp. Compositions of milling fractions (protein, neutral detergent fiber, ash, and crude fat) were determined. The procedure used a single‐stage tempering step that increased corn moisture from 15 to 23.5% wb during an 18‐min tempering period. Germ were separated from endosperm particles using a roller mill followed by screening over a sieve with 1.68‐mm openings. Coefficients of variability were small, indicating acceptable repeatability. Overall yield means were 39.2, 25.3, 13.8, 78.2, 14.3, and 6.8 g/100 g (db) for large grits, small grits, fines, total endosperm, germ, and pericarp, respectively. There were effects due to hybrid (P < 0.05) on fraction yields and compositions of milling fractions. Correlations (r) among endosperm fractions (large grits, small grits, and fines) ranged from 0.54 to |–0.92|. Correlations among endosperm fractions and germ and pericarp were <0.68. The developed dry‐milling method estimated milling yields among hybrids with low standard deviations relative to the means and should be a useful tool for research and industry in measuring dry‐milling characteristics. 相似文献
16.
The objectives of this research were to study the effects of slurry specific gravity, starch table slope, slurry pumping rate, and their interactions on starch recovery and purity; and to propose a small‐scale laboratory wet‐milling procedure for wheat. First‐order and second‐order response surface regression models were developed to study the effects and interactions of slurry specific gravity, starch table slope, and slurry pumping rate on starch and gluten separation for a 100‐g wheat wet‐milling procedure. The starch and starch protein content data fit the first‐order models (R2 = 0.99 and 0.96) better than the second‐order models (R2 = 0.98 and 0.93). Regression results from the first‐order models indicated that specific gravity, table slope, pumping rate, and their interactions all had a significant effect on starch yield and purity. However, these effects could be simplified as the effect of the resident time of starch and gluten slurry on the starch table and the specific gravity. Starch yield increased as resident time increased and specific gravity decreased. Protein content in starch decreased as the resident time decreased and the specific gravity increased. The separation condition with specific gravity of 3 Bé, table slope of 1.04 cm/m, and pumping rate of 50 mL/min was recommended. Under this condition, starch recovery was 85.6% and protein content of starch was 0.42%, which was similar to the 1.5‐kg laboratory methods in starch recovery. Total solids recovery was 98.1%, which is similar to that from 1.5‐kg laboratory methods. These results indicated that precision of the 100‐g wheat wet‐milling procedure was similar to that of the 1.5‐kg laboratory methods. 相似文献
17.
U.S. No. 2 yellow dent corn was randomly probe‐sampled from rail cars being shipped to a wet‐milling plant from a Corn Belt local elevator. The probe samples were blended together and kernels were sorted into four levels of stress cracks (0, 1, 2, or multiple). Each level of stress cracking was then laboratory wet‐milled in triplicate. The only statistically observed differences were in total fiber and in protein content of the gluten meal fraction. The starch yield difference between zero stress cracked corn and multiple stress cracked corn was smaller (0.8%) than would be expected if stress cracking were an indicator of damage to the wet‐milling characteristics of the corn. 相似文献
18.
Recovering starch from barley is problematic typically due to interference from β‐glucan (the soluble fiber component), which becomes highly viscous in aqueous solution. Dry fractionation techniques tend to be inefficient and often result in low yields. Recently, a protocol was developed in our laboratory for recovering β‐glucan from barley in which sieving whole barley flour in a semiaqueous (50% ethanol) medium allowed separation of the starch and fiber fractions without activating the viscosity of the β‐glucan. In this report, we investigate an aqueous method which further purifies the crude starch component recovered from this process. Six hulless barley (HB) cultivars representing two each of waxy, regular, and high‐amylose cultivars were fractionated into primarily starch, fiber, and protein components. Starch isolates primarily had large granules with high purity (>98%) and yield range was 22–39% (flour dry weight basis). More importantly, the β‐glucan extraction efficiency was 77–90%, meaning that it was well separated from the starch component during processing. Physicochemical evaluation of the starch isolates, which were mainly composed of large granules, showed properties that are typical of the barley genotypes. 相似文献
19.
Andrew C. Hogg John M. Martin Frank A. Manthey Michael J. Giroux 《Cereal Chemistry》2015,92(4):395-400
Food products that are high in fiber and low in glycemic impact are healthier. Amylose is a form of resistant starch that mimics dietary fiber when consumed. A durum wheat (Triticum durum) line was created that lacks starch synthase IIa (SSIIa) activity, a key enzyme in amylopectin biosynthesis, by identifying a null mutation in ssIIa‐B following mutagenesis of a line that has a naturally occurring ssIIa‐A null mutation. Our objective here was to compare seed, milling, pasta, and nutritional characteristics of the SSIIa null line with a wild‐type control line. The SSIIa null line had increased amylose and grain protein with lower individual seed weight and semolina yield. Refined pasta prepared from the SSIIa null semolina absorbed less water, had increased cooking loss, had a shorter cook time, and was considerably firmer even after overcooking compared with the wild‐type line. Color of the SSIIa null cooked and uncooked pasta was diminished in brightness compared with the wild type. Nutritionally, the SSIIa null pasta had increased calories, fiber, fat, resistant starch, ash, and protein compared with the control line, along with reduced total and available carbohydrates. Pasta made from high‐amylose durum wheat provides a significant nutritional benefit along with enhanced end‐product quality via firmer pasta that resists overcooking. 相似文献
20.
Vida Skrabanja Ivan Kreft Terezija Golob Mateja Modic Sayoko Ikeda Kiyokazu Ikeda Samo Kreft Giovanni Bonafaccia Martina Knapp Katarina Kosmelj 《Cereal Chemistry》2004,81(2):172-176
Buckwheat seeds (Fagopyrum esculentum Moench) were milled into 23 fractions: seven fine flours, three coarse flours, four small semolina, two big semolina, six bran, and one husk fraction. A considerable variation in gross chemical composition was found among the milling fractions. The protein content varied from 4.4 to 11.9% (db) in flours and from 19.2 to 31.3% in bran fractions; starch varied from 91.7 to 70.4% in flours and from 42.6 to 20.3 in bran. The percentage of soluble dietary fiber contained in total dietary fiber was higher in flours than in semolina and bran fractions. Ash, Fe, P, tannin, phytate content, and color were also investigated. A unique distribution of phytate was found in starch. Correlation is significantly positive in husk, bran, and semolina fractions, while correlation is significantly negative in flour fractions. Depending on technological or nutritional demands, appropriate fractions may be chosen to achieve the desired end‐use product. 相似文献