Roller Milling of Canadian Hull‐less Barley: Optimization of Roller Milling Conditions and Composition of Mill Streams

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.     

Removal and Isolation of Germ‐Rich Fractions from Hull‐less Barley Using a Fitzpatrick Comminuting Mill and Sieves

A process was developed to produce a germ‐enriched fraction from hull‐less barley using a Fitzpatrick comminuting mill (FitzMilling) followed by sieving. Hulled and hull‐less barleys contain 1.5–2.5% oil and, like wheat kernels, which contain wheat germ oil, much of the oil in barley kernels is in the germ fraction. A process that combined FitzMilling and sieving produced a germ‐enriched fraction with an oil content of ≈15% and a yield of ≈1.1%. For comparison, this is higher than the levels of oil in most samples of commercial wheat germ. Experimental conditions were also described to produce a germ‐enriched fraction with a higher yield (2.16%), but it would have lower oil content (10.24%). Germination and compositional analysis studies suggested that FitzMilling hull‐less barley for 2 min or longer reduced germination rates to 1% or less, which was interpreted to mean that almost the entire viable germ was removed. In contrast, FitzMilling conventional hulled barley for 4 min had no effect on germination, and milling for 6 and 8 min resulted in germination rates of 36 and 12%, respectively. The oil extracted from germ‐enriched fractions was rich in free phytosterols (≈1%), phytosterol esters (3–7%), and free fatty acids (2–10%). These germ‐enriched fractions and the extracted oil they contain may have value as nutraceuticals or premium edible oils.     

Isolation and Characterization of Water‐Extractable Arabinoxylan from Hull‐less Barley Flours

A new procedure was developed for the isolation of highly purified water‐extractable arabinoxylan (WE‐AX) from hull‐less barley flour. It included inactivation of endogenous enzymes, removal of proteins with silica gel, and removing β‐glucans, arabinogalactan‐peptides, and starch fragments by enzyme or solvent precipitation steps. WE‐AX recovered by this isolation procedure represented, on average, 47% of all WE‐AX present in hull‐less barley flour. Purified WE‐AX from flour of different hull‐less European barley cultivars contained 84.9–91.8% AX and showed small structural differences. The apparent peak molecular weight of the purified WE‐AX was 730,000–250,000, and the arabinose‐to‐xylose ratio was 0.55–0.63. Proton nuclear magnetic resonance spectroscopy showed that the levels of un‐, O‐2 mono‐, O‐3 mono‐, and O‐2,O‐3 disubstituted xylose residues were 59.1–64.7%, 8.2–10.0%, 5.7–10.6%, and 17.6– 23.1%, respectively, and the ratio of di‐ to monosubstituted xylose was 0.90–1.54. Both O‐3 mono‐ and disubstituted xylose residues occurred isolated or next to disubstituted xylose residues in the WE‐AX chain.     

Starch from Hull‐less Barley: Ultrastructure and Distribution of Granule‐Bound Proteins

Starch granules isolated from waxy, normal, and high‐amylose hullless barley grains were examined by transmission electron microscopy with cytochemical techniques. The micrographs showed two distinct regions of different sizes: 1) densely packed granule growth rings (which varied in size and number depending on the genotype), and 2) a loose filamentous network located in the central region of the granule. The granule ring width decreased with increasing amylose content. In all three genotypes, the growth rings closer to the granule surface were narrower in width than those within the granule interior. The waxy starch had wider intercrystalline amorphous growth rings, semicrystalline growth rings, and more open crystalline lamellae than normal and high‐amylose starches. Granule bound proteins (mainly integral proteins) were located in the central and peripheral (growth ring) regions of the granule.     

Quality Characteristics of Yellow Alkaline Noodles Enriched with Hull‐less Barley Flour

Roller milled flours from eight genotypes of hull‐less barley (HB) with normal, waxy, zero amylose waxy (ZAW), and high amylose (HA) starch were incorporated at 20 and 40% (w/w) with a 60% extraction Canada Prairie Spring White (CPSW, cv. AC Vista) wheat flour to evaluate their suitability as a blend for yellow alkaline noodles (YAN). The barley flour supplemented noodles were prepared using conventional equipment. Noodles containing 40% HB flour required less work input than the corresponding 20% blend noodles due to a higher water absorption at the elevated level of HB flour addition, which probably caused them to soften. The addition of any HB flour at either level to the CPSW flour resulted in significantly decreased brightness (L*) and yellowness (b*), elevated redness (a*), concomitant with a significantly greater number of specks per unit area of noodle sheet compared with the control flour. The addition of 40% HB flour to YAN decreased cook time and cooking losses. Noodle firmness, as determined by maximum cutting stress (MCS), was significantly increased by the addition of 40% HB flour. Noodle chewiness, as determined by the texture profile analysis (TPA), was affected by the type of starch in the barley samples; the addition of waxy and ZAW HB flour decreased chewiness, whereas normal and HA HB flour increased chewiness of composite noodles.     

Distribution of β‐Glucan in the Grain of Hull‐less Barley

Nine hull‐less barley (HB) containing waxy (0–7% amylose), normal (≈25% amylose), or high amylose (≈42% amylose) starch with normal or fractured granule make‐up and 4–9% (1→3)(1→4)‐β‐d ‐glucans (β‐glucan) were pearled to remove 70% of the original grain weight in 10% intervals. The pearled fractions were analyzed for β‐glucan distribution within HB grain. Protein content of the pearled fractions indicated that the three outermost fractions contained pericarp and testa, aleurone, and subaleurone tissues, respectively. For all HB, β‐glucan and acid‐extract viscosity were very low in the outermost 20% of the kernel. For low β‐glucan HB, β‐glucan content was the greatest in the subaleurone region and declined slightly toward inner layers. For high β‐glucan HB, however, more than 80% of grain β‐glucan was distributed more evenly throughout the endosperm. Acid extract viscosity was significantly (P < 0.01) correlated with total (r = 0.75) and soluble (r = 0.87) β‐glucan content throughout the kernel of all HB. Growing conditions, location and year, had significant effects on the concentration of protein, starch and β‐glucan. However, protein, starch, and β‐glucan distribution patterns were not affected by growing conditions. The difference in β‐glucan distribution between low and high β‐glucan HB may explain the difference in milling performance of HB with low or high β‐glucan.     

Tibetan Hull‐less Barley (Hordeum vulgare L.) as a Potential Source of Antioxidants

Tibetan hull‐less barley grows at above 4,000 m altitude. One variety grown in the plain and three varieties grown in Tibet were collected from Tianjin and Lhasa. The barleys were polished into five fractions. Total soluble phenolic content (TSPC), total antioxidant capacity (TAC), and their correlation were investigated. Phenolic compounds were analyzed by HPLC, and TSPC content was evaluated by the Folin–Ciocalteu colorimetric method. TAC was measured using 2,2‐diphenyl‐1‐picrylhydrazyl, 2,2′‐azinobis‐(3‐ethylbenzthiazoline‐6‐sulfonate), and ferric reducing ability of plasma assays. Results showed that TSPC decreased from the outer to the inner fractions, with the outermost layer containing the highest (around 2,803–7,703 μg/g) and inner endosperm the lowest (around 870–1,348 μg/g). TSPC and TAC were highly and positively correlated (r = 0.9583–0.9710). Colored hull‐less barley had higher antioxidant activity than uncolored. TSPC and TAC of Tibetan varieties in the outer layers were more than two‐fold higher than that of Tianjin hull‐less barley. Tibetan hull‐less barley bran extracts are valuable sources of bioactive components with antioxidant activity.     

Composition and Utilization of Barley Pearling By‐Products for Making Functional Pastas Rich in Dietary Fiber and β‐Glucans

Pearling by‐products and the pearled products of two commercial stocks of hulled barley, pearled according to an industrial process consisting of five consecutive pearling steps, were analyzed for β‐glucans, dietary fiber (total, soluble, and insoluble), protein, lipid, ash, and digestible carbohydrate. The data showed that the pearling flour fractions, abraded in the fourth and fifth hullers, contained interesting amounts of β‐glucans (3.9–5.1% db) from a nutritional point of view. These fractions were subsequently enriched in β‐glucans using a milling‐sieving process to double β‐glucan content (9.1–10.5% db). Functional pastas, enriched with β‐glucans and dietary fiber, were produced by substituting 50% of standard durum wheat semolina with β‐glucan‐enriched barley flour fractions. Although darker than durum wheat pasta, these pastas had good cooking qualities with regard to stickiness, bulkiness, firmness, and total organic matter released in rinsing water. The dietary fiber (13.1–16.1% wb) and β‐glucan (4.3–5.0% wb) contents in the barley pastas were much higher than in the control (4.0 and 0.3% wb, respectively). These values amply meet the FDA requirements of 5 g of dietary fiber and 0.75 g of β‐glucans per serving (56 g in the United States and 80 g in Italy). At present, the FDA has authorized the health claim “may reduce the risk of heart disease” for food containing β‐glucans from oat and psyllium only.     

Distribution and Structural Variation of Nonstarch Polysaccharides in Milling Fractions of Hull‐less Barley with Variable Amylose Content

Three hull‐less barley genotypes containing starches with variable amylose content (23.8% normal, 4.3% waxy, 41.8% high‐amylose barley) were pearled to 10% and then roller‐milled to produce pearling by‐products (PBP), flour, and fiber‐rich fractions (FRF). PBP were enriched in arabinoxylans, protein, and ash and contained small amounts of starch and β‐glucans. FRF were considerably enriched in β‐glucans and arabinoxylans. The solubility of β‐glucans was higher in PBP than in FRF. The solubility of arabinoxylans was higher in FRF than in PBP. Small amounts of arabinogalactans detected in barley were concentrated in the outer portion of the barley kernel. The content and solubility of nonstarch polysaccharides (NSP) in various milling fractions was also dependent on the type of barley. To obtain more detailed information about the content and molecular structure of NSP, each milling fraction was sequentially extracted with water, alkaline [Ba(OH)₂], again with water, and finally with NaOH. These extractions resulted in four sub‐fractions: WE, Ba(OH)₂, Ba(OH)₂/H₂O, and NaOH. β‐Glucans and arabinoxylans exhibited structural heterogeneity derived from differences in their location within the kernel as well as from the genetic origin of barley. The WE arabinoxylans from FRF and flour had a substantially lower degree of branching than those from PBP. The WE arabinoxylans from FRF of high‐amylose and normal barley contained more unsubstituted Xylp residues but fewer doubly‐substituted and singly‐substituted Xylp at O‐2 than their counterparts from PBP. The WE arabinoxylans from FRF of waxy barley had a relatively high content of doubly‐substituted, but very few singly‐substituted Xylp residues. In all three barley genotypes, the ratio of tri‐ to tetrasaccharides in β‐glucans from PBP was higher than from flour and FRF. Substantial differences in the molecular weight of NSP in different milling fractions were also observed.     

Yield and Phytosterol Composition of Oil Extracted from Grain Sorghum and Its Wet‐Milled Fractions

Corn fiber contains an oil with high levels of three potential cholesterol‐lowering phytosterol compounds. Little information is available about the levels and types of phytosterols in sorghum. In this study, phytosterols were evaluated in grain sorhgum and its wet‐milled fractions and were compared with the phytosterols in corn. The study showed that sorghum kernels can provide a significant source of two phytosterol classes, free phytosterols (St) and fatty acyl phytosterol esters (St:E). Most of these phytosterols are concentrated in the wet‐milled fiber fraction followed by the germ fraction. In addition to phytosterols, other lipid classes such as wax esters and an aldehyde (50% C28 and 50% C30) are also present in the sorghum oil. Comparison of sorghum and corn kernels show that corn has 72–93% more phytosterols than sorghum.     

Quality Characteristics of Fresh and Dried White Salted Noodles Enriched with Flour from Hull‐less Barley Genotypes of Diverse Amylose Content

Fresh and dried white salted noodles (WSN) were prepared by incorporating up to 40% flour from hull‐less barley (HB) genotypes with normal amylose, waxy, zero amylose waxy (ZAW), and high amylose (HA) starch into a 60% extraction Canada Prairie Spring White (cv. AC Vista) wheat flour. The HB flours, depending on genotype, contained four to six times the concentration of β‐glucan of the wheat flour, offering potential health benefits. The HB‐enriched noodles were made with conventional equipment without difficulty. Noodles containing 40% HB flour required less work input during sheeting, probably due to higher optimum water absorption and weakening of the dough due to dilution of wheat gluten. The addition of HB flour had a negative impact on WSN color and appearance, as evident from decreased brightness, increased redness, and more visible specking. The impact of HB flour on cooked WSN texture varied by starch type. Enrichment with HA or normal starch HB flour produced WSN with bite and chewiness values equivalent to or superior to the wheat flour control. Addition of waxy and ZAW HB flour resulted in WSN with lower values for bite and chewiness. The diversity of HB starch types allows tailoring of WSN texture to satisfy specific markets. HB flour also has potential as an ingredient in novel noodle products targeting health‐conscious consumers who associate darker colored cereal‐based foods with superior nutritional composition.     

Effect of Extraction Conditions on Yield,Composition, and Viscosity Stability of Barley β-Glucan Gum

Cereal β-glucan can function as a thickener, but endogenous β-glucanase enzymes of the grain cleave β-glucan, reducing its viscosity. Although different extraction techniques have been developed, the viscosity stability of β-glucan gum has not been reported. The objective of this study was to investigate the effect of extraction treatments on the yield, purity, and viscosity stability of barley β-glucan (BBG) gum. A regular barley cultivar, Condor, and a waxy cultivar blend were extracted at pH 7–10 and 55°C for 0.5 hr. Four extraction conditions were evaluated: 1) extraction at high pH with no additional heat treatment; 2) boiling of extract; 3) prior refluxing of flour with 70% ethanol; and 4) treatment of extract with thermostable α-amylase for purification. Viscosity of extracts was monitored for ≥24 hr at 25°C. The highest β-glucan purities were achieved with a boiled Condor extract at pH 7 (81.3% db, 4.1% yield) and with refluxed waxy barley extracted at pH 8 and treated with α-amylase and (79.3% db, 5.1% yield). Gums extracted without subsequent heat treatment or prior refluxing of flour had high protein (>17%) and starch (>24%) impurities, respectively. The viscosity of gums obtained without heating was unstable. Prior refluxing treatment was not sufficient to stabilize final extracts. Boiling extracts resulted in stable but low viscosity. Reflux followed by purification treatment produced the highest stable viscosity for 0.5% solutions of both Condor (64 mPa sec^-1, pH 7) and waxy (48.8 mPa sec^-1, pH 8) extracts. Stable BBG gum with high viscosity can be obtained using thermal treatments in combination with high pH. The potential use of such gums as thickeners in food systems needs to be assessed.     

Laboratory Measurement of Yield and Composition of Dry‐Milled Corn Fractions Using a Shortened,Single‐Stage Tempering Procedure

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.     

Effects of β‐Glucan Content and Pearling of Barley in Diet‐Induced Obese Mice

The effects of the β‐glucan content and pearling of barley on abdominal obesity and the proinflammatory state were investigated in diet‐induced obese mice. Male C57BL/6J mice were randomly divided into four groups and fed either a high‐fat diet containing high‐β‐glucan barley (Beau Fiber [BF]) or a high‐fat diet containing β‐glucan‐free barley (Shikoku‐hadaka 84(bgl ) [BGL]) as whole grain flour or 60% pearled flour for 12 weeks. The weights of mesenteric fat, serum total and low density lipoprotein cholesterol levels, serum insulin and fasting glucose levels, oral glucose tolerance test results, and messenger RNA (mRNA) expression of proinflammatory markers in epididymal fat in both BF groups were significantly lower than those of both BGL groups. The abundance of Bacteroides in both BF groups was significantly higher than that in both BGL groups, whereas the abundance of Clostridium clusters in both BF groups was significantly lower than that in both BGL groups. No significant differences between the whole grain and pearled flours were observed. These results suggest that high‐β‐glucan barley attenuates the progression of abdominal obesity and the proinflammatory state in diet‐induced obese mice compared with β‐glucan‐free barley, possibly by modifying insulin secretion and the microbiota.     

Milling Performance of North European Hull‐less Barleys and Characterization of Resultant Millstreams

Four hull‐less barley samples were milled on a Bühler MLU 202 laboratory mill and individual and combined milling fractions were characterized. The best milling performance was obtained when the samples were conditioned to 14.3% moisture. Yields were 37–48% for straight‐run flour, 47–56% for shorts, and 5–8% for bran. The β‐glucan contents of the straight‐run white flours were 1.6–2.1%, of which ≈49% was water‐extractable. The arabinoxylan contents were 1.2–1.5%, of which ≈17% was water‐extractable. Shorts and bran fractions contained more β‐glucan (4.2–5.8% and 3.0–4.7%, respectively) and arabinoxylan (6.1–7.7% and 8.1–11.8%, respectively) than the white flours. For those fractions, β‐glucan extractability was high (58.5 and 52.3%, respectively), whereas arabinoxylan extractability was very low (≈6.5 and 2.0%, respectively). The straight‐run white flours had low α‐amylase, β‐glucanase, and endoxylanase activities. The highest α‐amylase activity was found in the shorts fractions and the highest β‐glucanase and endoxylanase activities were generally found in the bran fractions. Endoxylanase inhibitor activities were low in the white flours and highest in the shorts fractions. High flavanoid, tocopherol, and tocotrienol contents were found in bran and shorts fractions.     

Effects of Alkali Debranning,Roller Mill Cracking and Gap Setting,and Alkali Steeping Conditions on Milling Yields from a Dent Corn Hybrid

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.     

Starch and By‐Products from a Laboratory‐Scale Barley Starch Isolation Procedure

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.     

Pearling Affects the Lipid Content and Composition and Lipase Activity Levels of Wheat (Triticum aestivum L.) Roller Milling Fractions

Wheat bran contains most of the dietary fiber, vitamins, minerals, and antioxidants of the grain. Unfortunately, it readily deteriorates upon storage because it has high lipid contents and lipase activity levels, which can cause rancidity and, hence, when used in food systems, inferior product quality. We here examined the lipid composition and the lipase activities of wheat bran and the impact of pearling prior to milling thereupon. The lipid content of the outer bran layers (2.31% on a dry matter [dm] basis) is lower than that of regular bran (3.81% dm). Nevertheless, these layers have the highest concentration of free fatty acids (FFA, 0.56% dm), which is ascribed to lipid hydrolysis. Indeed, the lipase activity levels in the peripheral layers were three times higher than in the bran itself. Abrading these tissues by pearling prior to milling yielded a bran fraction with about 30% lower FFA content and 30% lower lipase activity level. Pearling offers opportunities to lower the FFA content and lipase activity levels in wheat bran and, hence, to contribute to an improved storage stability of bran.     

Influence of Jet‐Cooking Prowashonupana Barley Flour on Phenolic Composition,Antioxidant Activities,and Viscoelastic Properties

The objective was to study the influence of jet‐cooked Prowashonupana barley flour on total phenolic contents, antioxidant activities, water‐holding capacities, and viscoelastic properties. Barley flour was jet‐cooked without or with pH adjustment at 7, 9, or 11. Generally, the free phenolic content and antioxidant activity decreased after jet‐cooking, while the bound phenolic content and antioxidant significantly increased regardless of pH. Detectable levels of gallic acid, caffeic acid, ferulic acid, and p‐coumaroyl‐pentose in the jet‐cooked barley flour hydrolysates along with vitexin were found among 21 phenolics by LC‐ESI‐Q‐TOF‐MS analysis. Jet‐cooking at an elevated pH resulted in increased pasting viscosities. The oil content was decreased after jet‐cooking and continued to decrease with increased pH values. Jet cooking dramatically increased water holding capacity from 179% for unprocessed flour to 643% for jet‐cooked flour without pH adjustment, and water‐holding capacity was greatly increased to 914% by jet‐cooking at pH 11. The combination of jet‐cooking and pH adjustment had tremendous influence on water‐holding and pasting properties. This increase in functionality should contribute to food applications such as bakery and frozen products because of the release of the bound phenolic content, antioxidant activities, and improved water‐holding and pasting abilities.     

Yield,Protein Content,and Viscosity of Starch from Wet‐Milled Corn Hybrids as Influenced by Environmentally Induced Changes in Test Weight

Forty‐three yellow dent corn samples of five different hybrids varying in test weight and moisture content were obtained from 14 different locations in 1993. The locations for acquired samples were selected randomly to cover a wide range of test weights based on preliminary data from eight states of the corn belt where 94% of the U.S. corn crop was produced in 1993. Samples were wet‐milled using a 100‐g standard laboratory‐scale wet‐milling procedure. Protein content in starch and starch viscosity were determined. Starch yield, protein content in starch, and starch viscosity were not affected significantly by test weight.