Structural comparison of arabinoxylans from two barley side-stream fractions

The structures of barley ( Hordeum vulgare) arabinoxylans isolated from two industrial side fractions, barley husks (BH) and barley fiber (BF), were characterized. Arabinoxylans were extracted with saturated barium hydroxide after enzymatic pretreatment. Barium hydroxide was selective toward arabinoxylans, and only a minor amount of glucose-containing material was coextracted. Acid methanolysis followed by gas chromatography, 1H NMR spectroscopy, and specific enzymatic treatments followed by anion exchange chromatography with pulse amperometric detection (HPAEC-PAD) revealed that the chemical structure of barley husk arabinoxylan (BHAX) clearly differed from that of barley fiber arabinoxylan (BFAX). BFAX was more branched, containing more beta-D-xylopyranosyl (beta-D-Xylp) residues carrying alpha-L-arabinofuranosyl (alpha-L-Araf) units at both O-2 and O-3 positions. BHAX, on the other hand, contained more 2-O-beta-D-Xyl p-alpha-L-Ara f substituents than BFAX. BHAX and BFAX also differed with respect to the hydrodynamic properties investigated with multidetector size exclusion chromatography. BFAX had a higher weight-average molar mass and larger hydrodynamic volume, the latter indicating less dense conformation than BHAX. Mn, Mw /Mn, Rh, and the Mark-Houwink a value were also determined for both arabinoxylans.     

Influence of cross-linked arabinoxylans on the postprandial blood glucose response in rats

Viscous dietary fibers are well established to reduce the blood glucose response to a meal. In this study, arabinoxylans, the most abundant dietary fiber in most cereals, were extracted under alkaline conditions and cross-linked by using laccase. Cross-linking of the arabinoxylans led to gel formation and increased in vitro viscosity almost 100-fold after drying and rehydration. To determine the ability of these cross-linked arabinoxylans to blunt the postprandial blood glucose curve of a meal, arabinoxylans, either native or cross-linked, and either prehydrated or not, were fed to rats as part of a meal, and blood glucose was monitored at intervals after the meal. Cellulose, a nonviscous fiber, served as a control. Cross-linked, but not native, arabinoxylans significantly reduced the area under the blood glucose time curve 5-9% relative to cellulose, indicating that they remained viscous within the gastrointestinal tract, and thus likely provide the health benefits found with other viscous fibers.     

Oxidative Cross-Linking of Pentosans by a Fungal Laccase and Horseradish Peroxidase: Mechanism of Linkage Between Feruloylated Arabinoxylans

The potential of a laccase from the fungus Pycnoporus cinnabarinus to cross-link feruloylated soluble wheat arabinoxylans was investigated using capillary viscometry, size-exclusion HPLC, and reverse-phase HPLC of phenolic compounds. The laccase results were compared with those for a hydrogen peroxide/horseradish peroxidase system. The oxidants provoked an increase in viscosity of a 0.2% (w/v) arabinoxylan solution. A gel was formed after 30 min with laccase. Hydrogen peroxide was consumed rapidly before a gel could be formed. Free ferulic acid, methyl ferulate, and vanillic acid inhibited the gelation, whereas fumaric acid had no effect. This suggests that the aromatic ring, and not the propenoic chain of ferulic acid, was the initiating site for arabinoxylan cross-linking. Ferulic acid and its 8-O-4′, 8-5′, and 5-5′ dehydrodimers were present in nonoxidized arabinoxylans. Upon oxidation, the 8-8′ and 8-5′ benzofuran dehydrodimers appeared and the 8-O-4′ and 8-5′ dimers increased. The production of dimers was proportional to the consumption of ester-bound ferulic acid. In cross-linked arabinoxylans, the major dimers were 8-5′ benzofuran, 8-8′, and 8-O-4′, whereas the 5-5′ dehydrodimer remained at the same level as in the nonoxidized solution.     

Distribution of Total,Water‐Unextractable,and Water‐Extractable Arabinoxylans in Wheat Flour Mill Streams

Arabinoxylans are a minor but important constituent in wheat that affects bread quality, foam stability, batter viscosity, and sugar snap cookie diameter. Therefore, it is important to determine the distribution of arabinoxylans in flour mill streams to better formulate flour blends. Thirty‐one genetically pure grain lots representing six wheat classifications common to the western U.S. were milled on a Miag Multomat pilot mill, and 10 flour mill streams were collected from each. A two‐way ANOVA indicated that mill streams were a greater source of variation compared to grain lots for total arabinoxylans (TAX), water‐unextractable arabinoxylans (WUAX), and water‐extractable arabinoxylans (WEAX). TAX and WUAX were highly correlated with ash at r = 0.94 and r = 0.94, respectively; while the correlation for WEAX and ash decreased in magnitude at r = 0.60. However, the 5th middlings mill streams exhibited disparity between TAX and ash content as well as between WUAX and ash content. This may indicate that TAX and WUAX in mill streams are not always the result of bran contamination. Cumulative extraction curves for TAX, WUAX and WEAX revealed increasing gradients of arabinoxylans parallel to extraction rate. Therefore, arabinoxylans may be an indicator of flour refinement.     

Antioxidant constituents of almond [Prunus dulcis (Mill.) D.A. Webb] hulls

Almond hulls (Nonpareil variety) were extracted with methanol and analyzed by reversed phase HPLC with diode array detection. The extract contained 5-O-caffeoylquinic acid (chlorogenic acid), 4-O-caffeoylquinic acid (cryptochlorogenic acid), and 3-O-caffeoylquinic acid (neochlorogenic acid) in the ratio 79.5:14.8:5.7. The chlorogenic acid concentration of almond hulls was 42.52 +/- 4.50 mg/100 g of fresh weight (n = 4; moisture content = 11.39%). Extracts were tested for their ability to inhibit the oxidation of methyl linoleate at 40 degrees C. At an equivalent concentration (10 microg/1 g of methyl linoleate) almond hull extracts had higher antioxidant activity than alpha-tocopherol. At higher concentrations (50 microg/1 g of methyl linoleate) almond hull extracts showed increased antioxidant activity that was similar to chlorogenic acid and morin [2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one] standards (at the same concentrations). These data indicate that almond hulls are a potential source of these dietary antioxidants. The sterols (3beta,22E)-stigmasta-5,22-dien-3-ol (stigmasterol) and (3beta)-stigmast-5-en-3-ol (beta-sitosterol) (18.9 mg and 16.0 mg/100 g of almond hull, respectively) were identified by GC-MS of the silylated almond hull extract.     

Variations in Content and Molecular Structure of Barley Nonstarch Polysaccharides Associated with Genotypic and Cellular Origin

Barley cell walls are an excellent source of soluble and insoluble dietary fiber. Despite variations due to genetic and environmental factors within cereal grains, generally the content of total dietary fiber in whole barley grain (17.3%) is higher than in other cereal grains. Arabinoxylans and mixed linkage (1→3)(1→4)‐β‐d ‐glucans are the major nonstarch polysaccharides present in various tissues of barley, but other polysaccharides such as cellulose, glucomannans, and arabinogalactans also occur, although in much smaller amounts. Depending on the genotypic or cellular origin, both polymers exhibit variations in molecular features. The molecular structures of β‐glucans and arabinoxylans are important determinants of physicochemical properties and may affect physiological functionality in the gastrointestinal tract. Barley β‐glucans have been associated with lowering plasma cholesterol, reducing glycemic index, and reducing the risk of colon cancer. Furthermore, arabinoxylans offer nutritional benefits of soluble and insoluble fiber and, because of phenolic moieties bound to arabinoxylans, they may also have some antioxidant properties.     

Solubilization of Arabinoxylans from Isolated Water-Unextractable Pentosans and Wheat Flour Doughs by Cell-Wall-Degrading Enzymes

Water-unextractable pentosans (WUP) isolated from the flours of three wheat cultivars (Apollo, Soissons, Thésée) were treated with enzymes to solubilize the arabinoxylans. The water-unextractable arabinoxylans from the three cultivars had similar susceptibility to solubilization by enzymes: Grindamyl S 100 (GS100), a commercial preparation for baking, rich in pentosanase activities that originated from an Aspergillus niger culture; and three endoxylanases (E1, E2, E3), an arabinofuranosidase (Af), a β- glucanase (βG), and a ferulate esterase (FAE) purified from GS100. A cellulase (C) and a pure endoglucanase (eG) from Trichoderma reesei were also used. GS100 was able to solubilize high molecular weight arabinoxylans (HMWAX) from WUP that markedly enhance the viscosity of the reaction mixture supernatants. The endoxylanase E1 was responsible for this solubilizing activity of GS100, whereas E2 and E3 made only a very low contribution. Combining E1 with FAE led to a limited increase in the arabinoxylan-solubilizing effect. Also, enzymes hydrolyzing cellulose and β-glucans slightly improved the arabinoxylan solubilization from WUP when combined with GS100 or E1, but produced arabinoxylans of lower intrinsic viscosity. Similar effects of the enzymes were observed on arabinoxylan solubilization when applied to dough instead of isolated WUP.     

Genotype and Environment Variation for Arabinoxylans in Hard Winter and Spring Wheats of the U.S. Pacific Northwest

The development of high‐quality wheat (Triticum aestivum L.) cultivars depends on a thorough understanding of the constituents of grain and their variation due to genetics and environment. Arabinoxylans (pentosans) are key constituents of wheat grain and have broad and far‐reaching influences on milling and baking quality. However, variation in arabinoxylans due to genotype and environment are not fully understood. In this study, 25 hard winter and 25 hard spring wheat commercial cultivars and advanced breeding lines developed from eight public and private breeding programs in the U.S. Pacific Northwest were analyzed for water‐extractable and total arabinoxylan contents (WE‐AX and total AX), and the proportion of total AX that was water‐extractable. Winter and spring genotypes were grown in three environments each. The results indicated that there were significant differences among both sets of hard wheat genotypes for WE‐AX, total AX, and proportion of total AX that was WE‐AX. The WE‐AX and total AX mean content ranges for the winter cultivars were 0.390–0.808 and 3.09–4.04%, respectively; and for the spring cultivars 0.476–0.919 and 3.94–4.70%, respectively. WE‐AX as a percentage of total AX was similar between the two genotype sets, 11.7–23.0%. Arabinoxylan fractions were generally not correlated with grain protein, test weight, and kernel hardness. The two highest correlations for winter wheats were between protein and total AX (r = –0.40) and test weight and percentage of total AX that were water‐extractable (r = 0.37) for winter wheats. Among spring wheats, single‐kernel characterization system hardness was negatively correlated with WE‐AX and proportion of total AX that was WE‐AX (r = –0.46 and –0.51, respectively). Although often significant, arabinoxylan fractions were usually not highly intercorrelated, indicating some independence of traits. Notable genotypes, being especially high or low for one or more arabinoxylan fraction and, thus, candidates for further genetic study and cross‐breeding, included Juniper, Eddy, and ORN980995 winter wheats, and Hollis, Alta Blanca, and WQL9HDALP spring wheats. Although the results indicate that arabinoxylan fractions of wheat grain can be highly influenced by environment, there is clear support for the existence of genetic differences, especially for WE‐AX and the proportion of total AX that is water‐extractable. As such, the manipulation of arabinoxylan content of wheat grain seems to be a reasonable breeding objective.     

Characterization of Indigestible Carbohydrates in Various Fractions from Wheat Processing

Fractions rich in indigestible carbohydrates, such as fructan and arabinoxylan, are obtained as by‐products when ethanol, starch, and gluten are produced from wheat flour. Today, these fractions are used as animal feed. However, these components may have positive physiological effects in humans. In this study, the content of indigestible carbohydrates in distillers' grains and process streams from the wet fractionation of wheat flour was determined. The fractions were further characterized by ethanol extractability analysis, anion‐exchange chromatography, NMR, and size‐exclusion chromatography. One fraction from wet fractionation contained (g/100 g, db) 6.0 ± 1.0 fructan and 10.3 ± 1.1 dietary fiber (66 ± 4% arabinoxylan), while distillers' grains contained 20.7 g/100 g (db) dietary fiber (30% arabinoxylan). In addition to indigestible carbohydrates from wheat, distillers' grains contained β‐(1→3) and β‐(1→6) glucans and mannoproteins from the yeast and low molecular weight carbohydrates mainly composed of arabinose. The use of endoxylanase in wet fractionation decreased the molecular weight of the arabinoxylans and increased the arabinose to xylose ratio but had no effect on the fructans. In conclusion, waste streams from industrial wheat processing were enriched in fructan, arabinoxylan, and other indigestible carbohydrates. However, the physiological effects of these fractions require further investigation.     

Effects of molecular weight and concentration of arabinoxylans on the membrane plugging

In this paper, arabinoxylans from wheat were isolated, purified, and degraded into four fractions with different molecular weight. The distribution of particle size was employed to evaluate the membrane plugging by beer. These arabinoxylans fractions were added into arabinoxylan-free beer to investigate the effects of molecular weight and concentration on the distribution of particle size in beer. Results showed that the fraction of arabinoxylans retained by a 0.22-mum pore size membrane was more easily affected by shearing and arabinoxylan concentration than the fraction of arabinoxylans retained by a 0.45-mum membrane. The effects of shearing, pH, and ethanol concentration of beer on the particle size distribution of the highest molecular weight arabinoxylan fraction in beer were also examined. General linear models (GLM) equations indicated that there was a positive correlation between the particle size distributions of arabinoxylans and shearing and ethanol content, while high molecular weight arabinoxylans particle size retained by the 0.45-mum membrane was not significantly (p > 0.05) influenced by pH value. Scanning electron microscope (SEM) photos showed that membrane plugging was significantly affected by the molecular weight of the arabinoxylans.     

Poultry litter and tillage influences on corn production and soil nutrients in a Kentucky silt loam soil

Broiler chicken (Gallus gallus) manure, a rich source of plant nutrients, is generated in large quantities in southeastern USA where many row crops, such as corn (Zea mays L.), are also extensively grown. However, the use of broiler manure as an economical alternative source of nutrients for corn production has not been extensively explored in this region. This study was conducted to examine the use of broiler litter as a source of nutrients for corn production, as influenced by tillage and litter rate, and any residual effects following application. In addition, the consequence of litter application to soil test nutrient levels, particularly P, Zn and Cu, was explored. The treatments consisted of two rates of broiler litter application, 11 and 22 Mg ha⁻¹ on a wet weight basis, and one rate of chemical fertilizer applied under no-till and conventional tillage systems. Treatments were replicated three times in a randomized complete block design. Corn was grown with broiler litter and inorganic fertilizer applied to the same plots each year from 1998 to 2001. In 2002 and 2003, corn was planted no-till, but only N fertilizer was applied in order to make use of other residual litter nutrients. Soil samples were taken yearly in the spring prior to litter application and 4 years after the cessation of litter application to evaluate the status of the residual nutrients in soil. Two years out of the 4-year experiment, broiler litter application produced significantly greater corn grain yield than equivalent chemical fertilizer application and produced similar grain yield in the other 2 years. Corn grain yield was significantly greater under no-till in 1999, but significantly greater under conventional-till in 2000, and no difference between the two tillage systems were observed in 1998 and 2001. With 4 years of litter application, Mehlich-3 P increased from an initial 18 mg kg⁻¹ to 156 mg kg⁻¹ with 11 Mg ha⁻¹ litter and to 257 mg kg⁻¹ with 22 Mg ha⁻¹ litter. For every 6 kg ha⁻¹ of P applied in poultry litter Mehlich-3 P was increased by 1 mg kg⁻¹. Modest increases in Mehlich-3 Cu and Zn did not result in phytotoxic levels. This study indicated that an optimum rate of broiler litter as a primary fertilizer at 11 Mg ha⁻¹ applied in 4 consecutive years on a silt loam soil produced corn grain yields similar to chemical fertilizer under both no-till and conventional tillage systems and kept soil test P, Cu and Zn levels below values considered to be harmful to surface water quality or the crop.     

Temperature and Chemical Changes During Composting of Broiler Litter

Composting broiler litter (a mixture of manure, bedding material, and wasted feed) with commonly available high-C substrates may be a viable alternative to reduce current land disposal practices for litter. Broiler litter with wood shavings as a bedding material and broiler litter with peanut hulls as a bedding material were composted with wheat straw, peanut hulls, pine bark and paper mill sludge in 0.33 m³ batch reactors. Litters and C substrates were mixed to achieve C:N ratios of approximately 30:1. Dry weight, total N, total C, temperature, electrical conductivity and pH were determined at regular intervals. Maximum temperatures peaked near 70°C within 2.25 d after mixing peanut hulls with litter and within 2.58 d for pine bark and litter. Composts made from paper mill sludge approached 50°C within 3.71 d. Wheat straw composts never exceeded 40°C which could present potential health problems associated with pathogenic microorganisms. Mass loss and C:N ratio gradually declined and stabilized approximately 84 d after mixing. Mass loss averaged 73 percent for wheat straw compost, 33 percent for peanut hull composts, and 16 percent for the other mixes. Wheat straw compost C:N ratios stabilized near 14:1 and other mixes remained above 20:1, indicating N limited conditions for complete composting. Compost pH was 5.8 after 84 d from pine bark composted with wood shaving litter and was significantly lower than pH from paper mill sludge compost with an average pH of 6.9 but similar to all other compost mixes (pH 6.7). Electrical conductivity ranged from 0.35 S m^?1 for paper mill sludge composted with wood shaving litter to 0.91 S m^?1 from wheat straw composted with peanut hull litter. Composting temperature varied considerably among C sources and all required at least 72 d of curing to stabilize the C:N ratio. Composts made from wheat straw were most effective for waste reduction but temperatures were below the 50°C level generally considered necessary to kill pathogens.     

Enzymatic solubilization of arabinoxylans from native, extruded, and high-shear-treated rye bran by different endo-xylanases and other hydrolyzing enzymes

The overall objective of this research was to find a new way to valorize rye bran, by producing a gellifier from the enzymatic solubilization of arabinoxylans (AX). The effects of three pure endo-xylanases from Aspergillus niger (Xyl-1), Talaromyces emersonii (Xyl-2), and Bacillus subtilis (Xyl-3) and of Grindamyl S100 (GS100), a commercial enzyme preparation containing a Xyl-1 type endo-xylanase, were tested on rye bran to study the solubilization of water-unextractable arabinoxylans (WUAX). Eight different extrusion-treated rye brans were also used as substrates to find the best physical treatment to facilitate enzymatic arabinoxylan (AX) solubilization. Arabinoxylans were better solubilized from the bran extruded at high temperature using Xyl-3. This enzyme was then tested in combination with pure (1,4)-beta-d-arabinoxylan arabinofuranohydrolase (AXH) and endo-beta-d-glucanase or ferulic acid esterase (FAE), from A. niger. Only beta-glucanase in combination with Xyl-3 improved the AX extraction, but it did not have a marked effect on the viscosity of the extracts. Xyl-3 was then tested on a high-shear-treated rye bran, and results were compared to those obtained with the high-temperature-extruded rye bran. The high-shear treatment did not improve the bran AX enzymatic solubilization. The combination of FAE with Xyl-1 or Xyl-3 did not improve the AX extraction from untreated and high-shear-treated rye bran. Finally, to study the gelation capacity of the enzymatically solubilized AX, the effect of the hydrogen peroxide/horseradish peroxidase (H(2)O(2)/POD) was tested on the Xyl-3 high-temperature-extruded bran extracts. Solubilized AX did not gel in the presence of the oxidizing system.     

Combined Effects of Endoxylanases and Reduced Water Levels in Pasta Production

The combined effects on pasta properties of 1) varying dosages of endoxylanases (EC 3.2.1.8) from Aspergillus aculeatus and Bacillus subtilis and 2) lower levels of water during pasta dough processing were studied. The A. aculeatus endoxylanase has high selectivity toward water‐extractable arabinoxylan (WE‐AX), whereas B. subtilis endoxylanase preferentially hydrolyzes water‐unextractable arabinoxylan (WU‐AX). Pasta was produced on a microscale (50.0 g) from the semolinas of both a strong (AC Navigator) and a moderately strong (AC Avonlea) durum wheat cultivar. The levels of added water in endoxylanase‐treated pastas were adjusted to obtain the same maximal farinograph consistencies as for the control pastas. The extruded pastas were dried with drying cycles at 40, 70, or 90°C. Apart from increasing levels of solubilized arabinoxylans, these treatments had little effect on the color, optimal cooking time, and firmness of the resulting pasta. High enzyme concentrations and low (40°C) drying temperature resulted in clearly or much less checked final products for the B. subtilis and A. aculeatus enzyme, respectively. Upon cooking, the enzymically formed low molecular weight arabinoxylans were retained better in the pasta strands than their equally low molecular weight arabinogalactan counterparts.     

Influence of Cultivar and Environment on Water‐Soluble and Water‐Insoluble Arabinoxylans in Soft Wheat

Arabinoxylans are hydrophilic nonstarch polysaccharides found in wheat grain as minor constituents. Arabinoxylans can associate with large amounts of water through hydrogen bonding and can form oxidative gels. These properties are important factors in end‐use quality of wheat. The objective of this study was to delineate the influence of wheat cultivar and growing environment on variation in water‐soluble (WS‐AX), waterinsoluble (WI‐AX), and total (TO‐AX) arabinoxylan contents of flour and whole grain meal. This study included seven spring and 20 winter soft white wheat cultivars grown in 10 and 12 environments, respectively (each evenly split over two crop years). Univariate analysis of variance (ANOVA) and multivariate analysis of variance with canonical analysis (MANOVA) was used to evaluate sources of variation. Variation in arabinoxylan contents and absolute amounts (xylose equivalents) among the two cultivar sample sets (spring and winter) was similar, and both cultivar and environment were significant sources of variation. The cultivar‐by‐environment interaction was relatively unimportant. Results indicate that the variation in arabinoxylan content is primarily influenced by cultivar and secondarily influenced by environment. Within arabinoxylan fractions, WS‐AX content is primarily influenced by genotype, while WI‐AX content is more greatly influenced by the environment.     

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.     

食用菌栽培对棉籽壳营养价值及山羊瘤胃动态降解率的影响

为了研究4种食用菌栽培后对栽培基质棉籽壳的营养价值和山羊瘤胃动态降解率的影响,选用6只年龄(10月龄)、体重[(35.42±3.96)kg]接近并装有永久瘤胃瘘管的槐山羊羯羊,通过化学分析法测定了棉籽壳和4种菌糠的化学成分,并采用尼龙袋技术,分5批次测定了棉籽壳、平菇菌糠、木耳菌糠、金针菇菌糠和白灵菇菌糠瘤胃动态降解率。结果表明:(1)4种菌糠干物质(DM)和有机物(OM)含量分别比其栽培原料棉籽壳的含量降低13.09%~19.67%(P<0.01)和14.13%~39.52%(P<0.01),粗蛋白(CP)含量分别比棉籽壳提高40.20%~34.29%(P<0.01),中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量分别比棉籽壳降低3.07%~39.72%和17.80%~45.91%(P<0.01);(2)木耳菌糠、金针菇菌糠、白灵菇菌糠的DM和OM在瘤胃内的有效降解率和a+b值(快速降解部分和慢速降解部分之和)均极显著高于棉籽壳(P<0.01),平菇菌糠的DM和OM在瘤胃内的有效降解率显著高于棉籽壳(P<0.05);平菇菌糠、金针菇菌糠、白灵菇菌糠的CP在瘤胃内的有效降解率和a+b值均极显著高于棉籽壳(P<0.01);4种菌糠的NDF和ADF在瘤胃内的有效降解率分别比棉籽壳提高76.72%~702.63%(P<0.01)和137.41%~575.31%(P<0.01)。因此,在棉籽壳上栽培4种食用菌均能改善棉籽壳的营养价值和提高山羊瘤胃消化率,栽培食用菌后的菌糠更有利于作为反刍动物饲料进行利用。     

Chemical and physicochemical characterization of agrowaste fibrous materials and residues

The objective of this study was to evaluate the chemical, physicochemical, and functional properties of agrowastes derived from okara ( Glycine max), corn cob ( Zea mays sp.), wheat straw ( Triticum sp.), and rice husk ( Oryza sativa) for potential applications in foods. The fibrous materials (FM) were treated with alkali to yield fibrous residues (FR). Rice husk contained the highest ash content (FM, 8.56%; FR, 9.04%) and lowest lightness in color (FM, 67.63; FR, 63.46), possibly due to the abundance of mineral constituents. Corn cob contained the highest amount of soluble dietary fiber (SDF), whereas okara had the highest total dietary fiber (TDF). The high dietary fiber fractions of corn cob and okara also contributed to the highest water- and oil-holding capacities, emulsifying activities, and emulsion stabilities for both FM and FR samples. These results indicate that these agrowastes could be utilized as functional ingredients in foods.     

l‐Arabinose Release from Arabinoxylan and Arabinogalactan Under Potential Gastric Acidities

Arabinofuranosyl groups are present in many hemicelluloses as single or multiple units attached to the main xylan or galactan chain where they are sensitive to acid hydrolysis. Under acidic conditions of the human stomach, up to 10% of the L‐arabinose is released from the hemicellulose of corn hull, larch wood, and banana peel hemicellulose.     

Comparison of broiler litter and inorganic nitrogen,phosphorus, and potassium for double‐cropped sweet corn and broccoli

Two rates of broiler litter (20 and 40 mt/ha) were compared to recommended rates of inorganic nitrogen (N), phosphorus (P), and potassium (K) in a double cropping system of spring sweet corn (Zea mays L. ‘Silverqueen') and fall broccoli (Brassica oleracea L, ‘Southern Comet')‐ Sweet corn matured one week earlier both years when fertilized with 40 mt/ha of broiler litter compared to commercial fertilizer. The early maturity may be due to improved P nutrition. Similar or higher yields of fall broccoli were produced with broiler litter following sweet corn than with commercial fertilizer.