Composition of Functional Lipids in Hulled and Hulless Barley in Fractions Obtained by Scarification and in Barley Oil

Two cultivars of hulled barley (Thoroughbred and Nomini) and two cultivars of hulless barley (Doyce and Merlin) were scarified to abrade the outer layers of hull and pericarp. The resulting scarification fines fractions were evaluated as potential sources of functional lipids (phyto‐sterols, tocopherols, and tocotrienols). The levels of total phytosterols and total tocotrienols in the barley scarification fine fractions were probably not high enough to justify their use as functional foods. However, the levels of total phytosterols and total tocotrienols in the oils extracted from both whole kernels and scarified fines were both sufficiently high to make it reasonable to consider their potential use as new functional oils. Indeed, the levels of total tocotrienols in barley oils (2,911–6,126 mg/kg of oil) are several‐fold higher than those reported in two other oils that are being marketed as high in tocotrienols: palm oil (530 mg/kg) and rice bran oil (770 mg/kg). The levels of total phytosterols in barley oils range from 1.20 to 9.60 g/100 g of oil.     

Surface Abrasion of Hulled and Hulless Barley: Physical Characterization of the Milled Fractions

Abrasion techniques were used to remove the hull and pericarp layers of barley kernels to obtain a smaller kernel enriched in endosperm. The objective of this study was to evaluate the fractions produced by two alternative abrading systems on four barley cultivars for potential use in fuel ethanol processes that feature an upstream (of the fermentation) dry fractionation system. Four barley cultivars, two hulled (Thoroughbred and Nomini) and two hulless (Doyce and Merlin), were scarified and whitened at 22 scarification times and three milling degrees (settings 2, 4, and 6), respectively. Three different abrasive surfaces (36, 40, and 50 grit) were used in the scarifier to determine the material removal ratio for each barley cultivar. Material balances and color analyses were conducted for all of the fractions produced. Three fractions were produced with the whitener at each milling degree: broken kernels, fine fractions >323 μm, and fine fractions <323 μm. Setting #2 seems to be the milling level that releases most of the hull in the hulled barley with the whitener. After 50 sec of scarification, rougher surfaces produced more fine material (<1,410 μm diameter) and consequently less coarse material (>1,410 μm diameter). A lower grit (36 grit) abrasive surface induced faster hull removal in hulled barley. Color parameters L* and b* were good indicators of the fine and coarse fractions produced by abrasive methods because they indicate the kernel layer removed and were modeled as a function of the fraction of the material produced. The information obtained in this study has application in designing processes capable of removing and recovering hull and pericarp layers of barley kernels and thereby producing smaller kernels or kernel pieces containing mainly endosperm tissue.     

Analysis of Alkylresorcinols in Wheat Germ Oil and Barley Germ Oil via HPLC and Fluorescence Detection: Cochromatography with Tocols

Alkylresorcinols are long‐chain phenolic compounds that have been reported to be localized in the outer layers of the kernels of wheat, rye, barley, and other grains. A sensitive HPLC method with fluorescence detection was recently reported for the quantitative analysis of alkylresorcinols in cereal grains and products. Using this new HPLC method we report for the first time that wheat germ oil contains moderate levels of alkylresorcinols, approximately 800–1,500 µg per gram of oil. We also found that commercial wheat germ oil and some experimental samples of wheat germ oil and barley germ oil also contained three unknown peaks. Upon further evaluation of these peaks it was found that the peaks appeared to be tocopherols (one peak of α‐tocopherol, one peak of δ‐tocopherol, and a peak with the combination of β‐ and γ‐tocopherol), even though the excitation and emission wavelengths for alkylresorcinols (excitation 274 nm and emission 300 nm) are different than those for tocols (excitation 294 nm and emission 326 nm). We also found that with this HPLC system one alkylresorcinol, AR17, had the same retention time (7.6 min) as δ‐tocotrienol and that another alkylresorcinol, AR19, had the same retention time (10.8 min) as α‐tocotrienol.     

Rapid High‐Performance Liquid Chromatography Determination of Tocopherols and Tocotrienols in Cereals

A rapid normal‐phase high‐performance liquid chromatography (NP‐HPLC) method has been developed for rapid determination of the total content of tocopherols (T) and tocotrienols (T3) in cereals. The new method uses a one‐step extraction followed by NP‐HPLC coupled with a fluorescence detector. The new method provides a baseline separation of the critical peaks of beta‐tocotrienol (β‐T3) and gamma‐tocopherol (γ‐T) within a short time of analysis. The extraction step requires no saponification step or addition of antioxidant. Addition of butylated hydroxytoluene (BHT) had no effect on the stability of vitamin E during sampling. The recovery was 96–100%. The method is demonstrated by successful quantification of vitamin E in barley, wheat, and spelt grains, as well as wheat germ and flours from wheat, spelt, and rye.     

青稞胆碱单加氧酶基因cDNA全长开放阅读框克隆及序列分析

甜菜碱是一种存在于多种生物体内的季胺类高效渗透调节剂,是由甜菜碱合成酶系催化的。为了研究甜菜碱合成酶系基因的表达和青稞高抗逆性之间的关系,我们以经200mmol/L NaCl预处理72h的青稞幼苗叶片及根中提取的总RNA为模板,采用RT-PCR技术,扩增得到全长1224bp,推测编码407个氨基酸残基的青稞胆碱单加氧酶(choline monooxygenase,cmo)基因cDNA全长开放阅读框(open reading frame,ORF),将其命名为hvcmo1并在GenBank中注册,获得登录号为GU810840。生物信息学分析表明,推定的氨基酸序列中含有与已报道高等植物胆碱单加氧酶氨基酸序列中的Rieske型铁硫簇结合区和单核铁结合基序等特征性结构域具有高度保守性的特征性结构域。与多种高等植物cmo基因进行序列同源性比对分析结果显示:hvcmo1的核苷酸序列与甜菜、盐角草、菠菜、辽宁碱蓬、拟南芥、玉米、水稻、高粱、羊草和大麦等植物的cmo mRNA编码区相似性分别为55.3%、55.4%、55.6%、5.9%、61.3%、82.6%、83.3%、83.4%、95.5%和99.5%。实验过程中,我们发...     

Aromatic Composition and Physicochemical Characteristics of Crackers Containing Barley Fractions

Currently, the predominant use for barley in Ireland is as animal food and in brewing. The aim of this study was to find an alternative novel food use for the milling fractions of barley. Three barley milling fractions consisting of the 1) bran (B), 2) middlings (M), and 3) endosperm (E) from Mickle barley were studied in a sourdough saltine cracker formulation. The M and E fractions were combined to form the ingredient ME. Crackers containing 35% ME had a reduced specific volume (1.6 cm³/g) and an increased density (0.7 g/cm³) compared with the control cracker (based entirely on wheat flour, volume = 2.1 cm³/g and density = 0.5 g/cm³, P < 0.001). The control cracker was harder in texture compared with the crackers that contained barley. The control cracker was also found to be crunchier compared with the crackers containing barley. Crackers containing 35% ME and 15% B had a higher fiber content (5.3 and 5.8%) compared with the control cracker (3.6%, P < 0.05). The volatile profiles were considerably altered in samples containing 15% B and 35% ME samples compared with the control sample. This study demonstrated that barley fractions can be incorporated into a saltine cracker product, leading to a crispier cracker with an increased total dietary fiber content compared with the control cracker.     

Enzyme-Assisted Wet Separation of Starch from Other Seed Components of Hull-less Barley

A multiple enzyme cocktail containing cellulase, endo-(1→3), (1→4)-β-d -glucanase and xylanase was used in wet separation of starch, protein, β-glucan, bran, and tailings from four hull-less barleys (HB): SB94794 (0% amylose), CDC Candle (5% amylose), CDC Dawn (24% amylose), and SB550831 (40% amylose). Compared to a conventional procedure, the enzyme-assisted wet extraction reduced slurry viscosity by 50–99%, the amount of water and ethanol used in screening and β-glucan precipitation by 30–60%, and screening time by 20–80%. The enzyme-assisted extraction reduced starch contents and yields of tailings and bran fractions, resulting in a 10% increase in average starch extraction efficiency. However, β-glucan yield was reduced in the enzyme-assisted extraction, particularly in high-viscosity HB. The physicochemical properties of isolated starches were not affected by the enzyme-assisted extraction.     

Antioxidant Capacity of Water‐Extractable Arabinoxylan from Commercial Barley,Wheat, and Wheat Fractions

The objective of this research was to analyze the antioxidant capacity directly of water‐extractable nonstarch polysaccharides (NSP) and feruloylated arabinoxylans (WEAX) following their characterization. NSP were isolated from barley, wheat, and wheat fractions (germ, bran, and aleurone). WEAX were extracted only from wheat fractions. Antioxidant capacity of NSP measured with the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS), and oxygen radical absorbance capacity (ORAC) assays was 24.0–99.0, 40.0–122.0, and 140.0–286.0μM Trolox equivalents (TE)/g, respectively. The antioxidant capacity of WEAX was 75.7–84.0, 58.0–105.0, and 110.0–235.0μM TE/g for those three assays. DPPH and ABTS were highly correlated to xylose content (R² = 0.85), degree of substitution (R² = −0.99), total phenolic acids (R² = >0.73), total phenolic content (TPC) (R² = >0.78), and ferulic acid content (R² = >0.86). ORAC was only influenced by TPC (R² = 0.63). By taking yield and antioxidant capacity into account, NSP would provide about 0.4–4.2, 0.6–5.1, and 2.8–12.0μM TE/g of flour of radical scavenging activity as measured by DPPH, ABTS, and ORAC, respectively, compared with WEAX (0.4–1.0, 0.3–1.3, and 0.6–2.8μM TE/g). Our results suggest that NSP or WEAX may play a role in protection against free radicals in a food matrix and likely in the gastrointestinal tract.     

混菌发酵黑青稞甜醅工艺优化及品质特性研究

为改善单一菌株发酵制备青稞甜醅的风味与口感,提高其质量品质,本试验采用米根霉和酵母菌为发酵菌株,以氨基酸态氮含量及感官评分为指标,确定混菌发酵黑青稞甜醅的最佳工艺条件,并比较单一菌株发酵黑青稞制品与混菌发酵黑青稞制品中酚类物质含量、抗氧化活性及风味物质组成的差异。结果表明,混菌发酵黑青稞制品最佳发酵条件为:发酵温度33℃,发酵时间48 h,菌种比例(酵母菌J7∶米根霉)1∶1.20,接种量6.81%,在此条件下混菌发酵黑青稞制品的氨基酸态氮含量为9.32 mg·100 g^-1,感官评分为95.48分。与单一菌株发酵黑青稞制品相比,混菌发酵黑青稞的黄酮含量(32.22 mg·100 g^-1)、 多酚含量(230.68 mg·100 g^-1)及DPPH自由基清除能力(95.03 μmol·L^-1)显著提高。气相色谱-质谱(GC-MS)分析结果表明,酵母菌单独发酵的黑青稞中共检出33种挥发性风味物质,米根霉单独发酵的黑青稞中共检出41种挥发性风味物质,混菌发酵的黑青稞中共检出46种挥发性风味物质,其中酯类和醇类是3种发酵方式黑青稞制品的主要风味组分。混菌发酵黑青稞的醇类、酯类和酸类种类及含量均显著高于其余两种发酵方式,其相对含量分别达到59.09%、29.44%和6.46%,风味更丰富。综上分析,混菌发酵使黑青稞制品在功能及风味方面具有一定的优势。本研究结果为混菌发酵黑青稞制品的开发和应用奠定了基础。     

Isolation and Characterization of High‐Purity Starch Isolates from Regular,Waxy, and High‐Amylose Hulless Barley Grains

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.     

Activity and Inhibition of Polyphenol Oxidase in Extracts of Bran and Other Milling Fractions from a Variety of Wheat Cultivars

Studies were conducted to compare polyphenol oxidase (PPO) specific activities in various milling fractions of a variety of wheat cultivars and determine the levels of activities in a number of cultivars from different localities and harvesting seasons. Substrate specificities were also investigated. Bran was singled out as the richest source of PPO activity, which may also influence the activity in the other milling fractions that are known to have some proportion of bran content. We showed by gel electrophoresis and spectrophotometrically that the protein responsible for PPO activity apparently exists as a single isoform in bran and that the observed enzyme activity is likely to be a tyrosinase type, not a laccase or peroxidase. The specific activity was not significantly different between the reduction shorts and break shorts from the same cultivar, indicating a similar level of bran contamination in these fractions. Very low levels of PPO activity were recorded in the flour of all cultivars studied. Bran was used, therefore, to determine the varietal differences in the PPO activities in a number of cultivars from different localities and seasons of harvest. Results showed that the most significant determinant of PPO activity was the genotype, and this may be influenced by seasonality. We also determined that, apart from substrate preferences by the PPO enzyme, some phenolic acids actually inhibit PPO. Furthermore, we found that bran of some cultivars extracted with acidified methanol inhibited PPO activity substantially, whereas other extracts had less inhibitory properties. Thus, these unknown compounds in wheat may inhibit endogenous PPO activity.     

Tocopherols,Tocotrienols, and γ‐Oryzanol Contents in Japonica and Indica Subspecies of Rice (Oryza sativa L.) Cultivated in Brazil

Whole rice contains several fat‐soluble phytochemicals such as tocopherols, tocotrienols, and γ‐oryzanol which have been reported to possess beneficial health properties. This study was conducted to determine whether brown rice belonging to indica and japonica subspecies were distinguishable from each other regarding the concentration of these compounds by analyzing 32 genotypes. The fat‐soluble compounds were analyzed by normal‐phase HPLC in a single run. The variability of the compounds analyzed was high, but the mean content of γ‐oryzanol across all samples was significantly higher (P < 0.01) in japonica (246.3 mg/kg) than in indica rice (190.1 mg/kg). Similar differences were found for total vitamin E contents which were 24.2 mg/kg in japonica and 17.1 mg/kg in indica rice, respectively. In japonica rice, α‐tocopherol, α‐tocotrienol, and γ‐tocotrienol were the most abundant homologs, while in indica rice the most abundant were γ‐tocotrienol, α‐tocopherol, and α‐tocotrienol. A significant Pearson coefficient (0.80, P < 0.001) between α‐tocopherol and α‐tocotrienol levels was found, independent of the subspecies. Both compounds were positively correlated to total tocols and γ‐oryzanol contents. Although more studies are needed to evaluate the interference of growing rice in different environments and multiple years, the present study provided information on natural variations of the vitamin E isomers and the γ‐oryzanol contents in different rice genotypes.     

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.     

Effect of Cropping on Changes in Phosphorus Fractions of Soils from Arable and Other Forest Land Use: A Greenhouse Bioassay

Abstract

Laboratory and greenhouse studies were conducted on six soils from natural reserves, seven plantation soils, and two arable soils from the Omo biosphere reserves in southwestern Nigeria to assess the phosphorus (P) fractions and the extent to which the soils could support five consecutive cycles of maize (Zea mays L.) harvest. The organic‐P fractions constitutes about 50% of the total P, and the inorganic‐P fractions in the order of abundance was iron (Fe) P>occluded P>aluminum (Al)‐P>calcium (Ca) P. The residual P constituted about 20% of the total P. There were significant reductions in the inorganic‐P fractions after five consecutive maize harvests; this was however, more pronounced in the available P (Bray 1). About 62% reduction in Bray 1 P was recorded after maize harvests. The reductions in the P forms after five cycles of maize harvest was Bray 1 P>Ca P>residual P>Al P>total P>Fe P>organic P>occluded P>reductant P. The capacity of the soils to support maize growth without fertilization varied widely in each of the maize cycle. Soil from natural reserves produced a significantly higher maize yield compared to most plantation soils. The arable soils investigated were depleted of their fertility after the third crop harvest.     

不同施肥水平对青稞豌豆混作根际土壤真菌群落结构及多样性的影响

采用真菌ITS区的Illumina MiSeq高通量测序技术，并结合NMDS、RDA和Mantel test分析，探讨青稞单作(Q)、豌豆单作(W)、青稞豌豆混作(Q×W)3种模式在不施肥(0NP)、低氮磷(LNP)、高氮磷(HNP)3种施肥水平下根际土壤真菌群落结构组成及多样性的差异，同时测定其土壤理化性质，并与根际土壤真菌群落结构进行了相关性分析。结果表明：青稞、豌豆在3种种植模式下土壤均呈碱性，且在不同施肥水平下土壤理化性质差异显著。不同试验处理下共检测到18个真菌类群，子囊菌门(Ascomycota，63.5%~78.5%)、被孢霉门(Mortierellomycota，3.6%~14%)、担子菌门(Basidiomycota，1.1%~6.9%)为共有优势类群，在属水平上，Penicillium、Mortierella在青稞豌豆混作根际土壤中相对丰度最高，可能是驱动土壤有机氮、磷转化为无机氮、磷的主要真菌群落。Bipolaris、Blumeria、Fusarium、Cladosporium为土壤真菌群落丰度最高的4种潜在致病菌属，在青稞豌豆混作根际土壤中的相对丰度低于青稞单作和豌豆单作，混作模式在不同施肥水平下4种具有潜在致病性的真菌间相对丰度存在显著差异；在LNP、HNP水平下混作模式根际土壤中的真菌丰富度(ACE、Chao1)和多样性(Shannon、Simpson)指数均低于青稞单作，混作模式在LNP水平下丰富度(ACE、Chao1)指数显著低于0NP水平，但多样性(Shannon、Simpson)指数高于0NP水平；从不同试验处理属水平下真菌群落相对丰度来看，混作模式可显著增加根际土壤中有益菌群的相对丰度，通过根际土壤微生物优势种群及α多样性分析，青稞豌豆混作模式较青稞单作、豌豆单作可增加根际土壤中属水平下Penicillium、Mortierella等具有溶磷、氨化作用菌群的相对丰度，降低Bipolaris、Blumeria、Fusarium、Cladosporium等潜在致病菌群的相对丰度；相关分析表明，速效氮、速效磷、有机质是影响混作模式根际土壤真菌群落结构差异的主要驱动因子。     

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.     

Effect of Alternative Milling Techniques on the Yield and Composition of Corn Germ Oil and Corn Fiber Oil

The effects of alternative corn wet‐milling (intermittent milling and dynamic steeping (IMDS), gaseous SO₂ and alkali wet‐milling) and dry grind ethanol (quick germ and quick fiber with chemicals) production technologies were evaluated on the yield and phytosterol composition (ferulate phytosterol esters, free phytosterols, and fatty acyl phytosterol esters) of corn germ and fiber oil and compared with the conventional wet‐milling process. Small but statistically significant effects were observed on the yield and composition of corn germ and fiber oil with these alternative milling technologies. The results showed that the germ and fiber fractions from two of the alternative wet‐milling technologies (the gaseous SO₂ and the IMDS) had, for almost all of the individual phytosterol compounds, either comparable or signficantly higher yields compared with the conventional wet‐milling process. Also, both of the modified dry grind ethanol processes (the quick germ and quick fiber) with chemicals (SO₂ and lactic acid) can be used as a new source of corn germ and fiber and can produce oils with high yields of phytosterols. The alkali wet‐milling process showed significantly lower yields of phytosterols compounds in germ but showed significantly higher yield of free phytosterols, fatty acyl phytosterol esters and total phytosterols in the fiber fraction.     

Chemical Composition of Barley Cultivars Fractionated by Weighing,Pneumatic Classification,Sieving, and Sorting on a Specific Gravity Table

Five different barley cultivars, including covered and naked samples containing low, normal, or high-amylose starches were fractionated by weighing, pneumatic classification, sieving, or sorting on a specific gravity table, and analyzed for content of starch, protein, ash, and β-glucan. For ash content, almost no variation could be found between different fractions. Protein content was minimum in the intermediate fractions for all cultivars when sorted by weighing. For the other fractionation methods, the differences in protein content were small. A tendency for decreasing content of starch with increasing grain mass and size could be seen when fractionating grains by weighing and sieving, respectively. The clearest trend was seen in differences in β-glucan content for all cultivars and all methods used. The main interpretation of our results is, however, that the chemical composition within the cultivars studied is very similar for all fractions, and that the differences between the unfractionated barley samples are larger.     

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.     

Some Physicochemical Properties of Small‐, Medium‐, and Large‐Granule Starches in Fractions of Waxy Barley Grain

Barley grain was divided into eight fractions from the surface layer to the center with a machine used to polish brewers' rice. Small‐, medium‐, and large‐granule starches were isolated from classified barley flour, and their physicochemical properties were investigated. The starch granules were oval to round with a median size of 2 μm for small, 10 μm for medium, and 12–19 μm for large granules. From the surface layer to the center, both the median sizes and the ratio of large granules decreased, and the ratio of medium‐ and small‐granules increased. The starches had A‐type X‐ray diffraction patterns typical of cereal starches. The moisture sorption showed a negative correlation to the granule size. The gelatinization temperatures of starch granules in each layer were approximately the same, but the enthalpies decreased in the order of large, medium, and small granules.