热塑性微细化淀粉的制备及其结构性能研究

为提高淀粉的热塑性能，优化其加工工艺，以超音速气流粉碎机制备微细化淀粉，确定微细化淀粉的最佳塑化条件，并利用扫描电镜、力学测试和示差扫描量热仪表征热塑性微细化淀粉。结果表明，微细化淀粉的热塑化最佳条件为：丙三醇与聚乙烯醇体积比为5∶1，微细化淀粉含量80%，共混温度160℃，单螺杆转速40 r/min。热塑性微细化淀粉呈现均匀的微观形貌，其拉伸强度为17.36 MPa，断裂伸长率138.29%，于130～155℃温度下熔融，加工性能良好。     

Preparation, isolation, and characterization of cutin monomers and oligomers from tomato peels

Cutin in tomato peels was depolymerized in methanolic base to yield cutin monomers or a mixture of cutin oligomers. These products were isolated by typical solvent extraction methods or by precipitation, and the isolates were characterized by chromatographic and spectroscopic analyses. It was determined that the compositions of the isolates from both isolation procedures were similar, although solvent extraction gave higher yields. However, the precipitation method, which is easy to carry out and avoids the use of undesirable organic solvents, may be preferable in commercial processes for recovering these compounds.     

Isolation and characterization of the lignans, isolariciresinol and pinoresinol, in flaxseed meal.

The isolation and characterization of the lignans, isolariciresinol, pinoresinol, secoisolariciresinol, and matairesinol, potent phytoestrogens, from flaxseed meal are described. This is the first report of isolariciresinol and pinoresinol being detected in a food. The extraction method selected combined the removal of the lignan glycosides from the plant matrix with an alcoholic solvent system, followed by acid hydrolysis to release the aglycons. A reversed-phase high-performance liquid chromatography with diode array detection system was used for initial separation and detection of the lignans at 280 nm in the acid-hydrolyzed methanolic extract. Lignan trimethylsilyl ether derivatives were characterized by gas chromatography/mass spectrometry. Secoisolariciresinol is the major lignan in flaxseed; isolariciresinol, pinoresinol, and matairesinol were identified as minor lignan components.     

Extraction, isolation, and characterization of globulin proteins from Lupinus albus

Lupin has recently been added to the list of allergens requiring mandatory advisory labeling on foodstuffs sold in the European Union, and since December 2008, all products containing even trace amounts of lupin must be labeled correctly. Lupin globulins consist of two major globulins called α-conglutin (11S and "legumin-like") and β-conglutin (7S and "vicilin-like") and another additional two globulins, γ-conglutin and δ-conglutin, which are present in lower amounts. We report on a methodology to facilitate the extraction of each of these proteins using centrifugation and isolation by anion-exchange chromatography followed by size-exclusion chromatography. The isolated subunits were characterized using reducing and non-reducing polyacrylamide gel electrophoresis, western blotting, and peptide mass fingerprinting, all of which revealed that the individual protein subunits are highly pure and can be used as immunogens for the production of antibodies specific for each of the conglutin fractions, as well as standards, and the extraction protocol can be used for the selective extraction of each of the subunits from foodstuffs, thus facilitating a highly accurate determination of the lupin concentration. Furthermore, the subunits can be used to elucidate information regarding the toxicity of each of the subunits, by looking at their interaction with the IgE antibodies found in the serum of individuals allergic to lupin, providing critical information for the definition of the requirements of analytical assays for the detection of lupin in foodstuffs.     

Synthesis and characterization of highly flexible thermoplastic films from cyanoethylated corn distillers dried grains with solubles

Corn distillers dried grains with solubles (DDGS) can be made into highly flexible thermoplastic films without the need for plasticizers. DDGS is an abundantly available coproduct of ethanol production that is inexpensive ($80-130/ton) compared to most of the polymers used for thermoplastic applications. In this research, oil-and-zein-free DDGS was cyanoethylated using acrylonitrile, and cyanoethylation conditions were optimized to obtain high percent weight gain of up to 42%. Cyanoethylated DDGS was characterized using (1)H NMR, FTIR, DSC, and TGA. Cyanoethylated DDGS was compression molded into thermoplastic films, and the tensile properties of the films were studied. It was found that DDGS films with elongation as high as 38% and strength of 14 MPa could be obtained without the use of any plasticizers. Alternatively, films with strength as high as 651 MPa but with relatively low elongation (2.5%) were obtained by varying the extent of cyanoethylation. This research showed that cyanoethylation could be a viable approach to develop biothermoplastics from biopolymers for applications such as packing films, extrudates, and resins for composites.     

菜籽粕植酸提取和分离蛋白的制备

植酸和蛋白是菜籽粕中2种极具经济价值的成份。为提高菜籽粕的综合利用效果,该文以双低冷榨菜籽粕为原料,采用醋酸溶液提取植酸,在膜分离精制植酸粗提液过程中同时回收蛋白;再对植酸提取后的残余物进行蛋白分离,超滤纯化后获得高纯度的蛋白成品。响应面优化的植酸最适提取条件为：醋酸质量分数0.7%,提取温度48℃,液料比10 mL/g,提取时间1.6 h,该条件下植酸得率为1.865%。植酸粗提液中回收出的蛋白和损失植酸分别占菜籽粕的3.63%和0.395%。超滤精制的分离蛋白可达到70%～90%不同纯度的要求,蛋白中多酚含量显著减少,且植酸与硫苷未检出。     

Near-infrared reflectance spectroscopy enables the fast and accurate prediction of the essential amino acid contents in soy, rapeseed meal, sunflower meal, peas, fishmeal, meat meal products, and poultry meal

Near-infrared reflectance spectroscopy (NIRS) calibrations were developed to enable the accurate and fast prediction of the total contents of methionine, cystine, lysine, threonine, tryptophan, and other essential amino acids, protein, and moisture in the most important protein-rich feed ingredients. More than 1000 samples of global origin collected over four years were analyzed on amino acids following the official methods of the United States and the European Union. Detailed data and graphics are given to characterize the obtained calibration equations. NIRS was validated with independent samples for soy and meat meal products and compared to the amino acid predictions using linear crude protein regressions. With a few exceptions, validation showed that 85-98% of the amino acid variance in the samples could be explained using NIRS. NIRS predictions compared to reference results agree excellently, with relative mean deviations below 5%. Especially for meat and poultry meals, NIRS can predict amino acids much better than crude protein regressions. By enabling the amino acid analysis of many samples to be completed in a short time, NIRS can improve the accuracy of feed formulation and thus the quality and production costs of mixed feeds.     

Extraction, characterization, and nematicidal activity of chitin and chitosan derived from shrimp shell wastes

Chitin has been chemically extracted from the Egyptian shrimp shell waste. The obtained chitin was transformed into the more soluble chitosan. Chitin and chitosan were characterized using Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance spectrometry. These products were also characterized by their nematicidal potential against the root-knot nematode, Meloidogyne incognita, infecting tomato in a glasshouse. Chitin or chitosan was incorporated into the soil at the rate of 1, 3, 5, and 10 g/kg, and their nematicidal activity was compared with that of the synthetic nematicide oxamyl at the rate of 0.01 g a.i./kg. The effects of the treatments on the growth of tomato were also examined. The obtained results show that chitin and chitosan reduced tomato root galls and J₂ of M. incognita in the soil in a dose-dependent manner. Chitosan was more effective in the reduction of galls and J₂ in the soil than chitin. However, the efficacy of chitin and chitosan in reducing the number of J₂ in the soil was less than that of oxamyl. As compared to the untreated inoculated plants, the length of shoots and roots was significantly (p ≤ 0.05) increased in soil amended with either chitin or chitosan, whereas both treatments did not significantly (p > 0.05) differ with respect to the inoculated control on the effect on the dry weight of shoot and root systems. Furthermore, neither chitin nor chitosan treatments at the tested rates were phytotoxic to tomato plants.     

Extraction and characterization of soil hydrogenases oxidizing atmospheric hydrogen

Soils are the largest sink of atmospheric hydrogen contributing about 75% to the total budget. Atmospheric H₂ is assumed to be oxidized in soil by abiontic soil hydrogenases. Extraction of a forest soil with a slightly alkaline (pH 8.5) buffer containing polyethylene glycol (PEG), followed by filtration yielded a bacteria-free extract that oxidized H₂ at ambient concentrations (0.2–2.0 ppmv). Hydrogenase activity was assayed by gas chromatographic analysis of H₂ consumption and by conversion of ³H₂ to tritiated water. Only less than 2% of the original activity was recovered in the extract. Kinetic analysis nevertheless resulted in a biphasic kinetics exhibiting two K_m and V_max values that were similar to those detected in the original soil. In addition, activities of both original soil and soil extract showed similar optima at pH 4–6 and at 30 °C, indicating that representative fractions of soil hydrogenases were recovered in the extract. Precipitation with PEG or ultrafiltration allowed further purification of the activity, albeit only about 20% of that in the crude extract could be recovered in the precipitate or the fraction >100 kDa.     

Yield components of soybean plants infected with soybean cyst nematode and sprayed with foliar applications of boron and magnesium 1

Investigations into the effect of soybean cyst nematode (SCN, Heterodera glycines, Ichinoe) on the yield components of soybean [Glycine max (L.) Merr.] have shown that pod numbers are reduced with increasing SCN initial populations (Pi) present in the soil at planting. The main method by which SCN alters pod numbers is through reductions in the number of branches per plant. Foliar applications of boron (B) and B in combination with magnesium (Mg) (B+Mg) increase yield of soybean not infected with SCN by increasing pod number per plant, especially the number of pods on branches. The objective of this research was to determine if foliar applications of B and B+Mg ameliorates the effect of SCN by increasing yield on branches. Field experiments were conducted in 1993 and 1994 in 1 m² microplots to compare foliar applied B and B+Mg to a control treatment. Foliar applications were made at four intervals spaced throughout soybean reproductive development of Pioneer brand 9391, an SCN susceptible cultivar. There were 12 levels of SCN Pi in 1993 and 11 levels in 1994. For each treatment, including control, grain yield was regressed on SCN Pi. Yield was reduced with increasing SCN Pi in both years, but the rate of decrease did not differ among treatments. In addition, ANOVA of yield components revealed no treatment effects on the number of branches per plant, the number of branch pods per plant, or the total number of pods per plant. Thus, foliar applications of B or B+Mg did not ameliorate the effects of SCN on soybean.     

Stable isotope characterization of milk components and whey ethanol.

A multi-isotopic study of several components of milk has been carried out on commercial samples and on milk produced in feeding experiments involving different kinds of diets originating from C(3) or C(4) photosynthetic metabolisms and exhibiting a relatively wide range of isotope ratios. The dispersion of the carbon, hydrogen, and nitrogen isotope parameters of dried matter and of the lactose, protein, and lipid components has been estimated. In addition, the carbohydrates were represented by the site specific isotope ratios (SNIF-NMR) of ethanol resulting from standardized fermentation of lactose. The rates of response of the isotopic parameters to changes in the feeding materials is slower for the minor components, proteins, and lipids than for lactose and ethanol. For similar diets, the nonexchangeable sites of lactose and the methyl site of ethanol, in particular, are relatively enriched in deuterium in the case of polygastric animals, cow, goat, and ewe, as compared to the monogastric species, sow and mare, and woman. From an analytical point of view, the carbon and hydrogen parameters of ethanol provide efficient criteria for identifying a whey origin with respect to other agricultural and fossil sources.     

Biodiversity, current developments and potential biotechnological applications of phosphorus-solubilizing and -mobilizing microbes: A review

As one of the most important and essential macronutrients next to nitrogen,phosphorus(P)is important for plant development,but it is the least mobile nutrient element in plant and soil.Globally,P is mined from geological sediments and added to agricultural soils so as to meet the critical requirements of crop plants for agronomic productivity.Phosphorus exists in soil in both organic and inorganic forms.The various inorganic forms of the element in soil are salts with calcium,iron,and aluminum,whereas the organic forms come from decaying vegetation and microbial residue.There is a huge diversity of plant microbiomes(epiphytic,endophytic,and rhizospheric)and soil microbiomes that have the capability to solubilize the insoluble P and make it available to plant.The main mechanism for the solubilization of inorganic P is by the production of organic acids,which lowers soil pH,or by the production of acid and alkaline phosphatases,which causes the mineralization of organic P.The P-solubilizing and-mobilizing microorganisms belong to all three domains,comprising archaea,bacteria,and eukarya.The strains belonging to the genera Arthrobacter,Bacillus,Burkholderia,Natrinema,Pseudomonas,Rhizobium,and Serratia have been reported as efficient and potential P solubilizers.The use of P solubilizers,alone or in combination with other plant growth-promoting microbes as an eco-friendly microbial consortium,could increase the P uptake of crops,increasing their yields for agricultural and environmental sustainability.     

Extraction and characterization of original lignin and hemicelluloses from wheat straw

Original lignin and hemicelluloses were sequentially extracted with high yield/purity, using acidic dioxane/water solution and dimethyl sulfoxide, from ball-milled wheat straw. The acidic dioxane lignin fraction is distinguished by high beta-O-4' structures and by low amounts of condensed units (beta-5', 5-5', and beta-1'). Hemicelluloses contain arabinoxylans as the major polysaccharides, which are substituted by alpha-l-arabinofuranose, 4-O-methylglucuronic acid, acetyl group (DS = 0.1), and xylose at O-3 and/or O-2 of xylans. It was found that arabinoxylans form cross-links with lignins through ferulates via ether bonds, glucuronic acid via ester bonds, and arbinose/xylose via both ether and glycosidic bonds, respectively, in the cell walls of wheat straw. Diferulates are also incorporated into cross-links between lignin and hemicelluloses as well as lignification of wheat straw cell walls. The guaiacyl unit is considered to be a significant condensed structural constructor in extracted lignin and a connector between lignin and carbohydrates.     

Gas-liquid chromatographic determination of vinyl chloride in vinyl chloride polymers, food-simulating solvents, and other samples.

The determination of vinyl chloride (VC) in polyvinyl chloride (PVC), vegetable oils, food-simulating solvents, mouthwashes, and blood anticoagulant solutions by gas-liquid chromatography is described. PVC polymers are disolved in either tetrahydrofuran or dimethyl acetamide. Vegetable oils are diluted with an equal volume of tetrahydrofuran. The resulting solutions are injected into a gas-liquid chromatograph equipped with a flame ionization detector. Mouthwashes, blood anticoagulant solutions, and 3 food-simulating solvents, 3% acetic acid, 50% ethanol, and heptane, are analyzed by direct injection into a chromatograph. Sensitivities are such that 0.05 ppm VC in solution or 1 ppm VC in PVC can be quantitated.     

The chemical and functional characterization of soil N and its biotic components

The aim of this review is to describe and discuss the concepts that have been employed to interpret N mineralization-immobilization in soil, and how N turnover is related to the characteristics of organic N and the biota conducting the transformations. A brief survey of the period before the arrival of electronic searches became available provides access to the classical literature that can help interpret today's challenges. Classical (acid hydrolysis) and modern spectrometry and spectroscopy techniques indicate that protein N is the prevalent component of organic N in soil. The presence of heterocyclic N can indicate its abiotic, partial synthesis as in fire-affected soils. Clays and pedogenic oxides can protect organic N against microbial degradation. The evidence for such protection is mostly based on in vitro studies involving pure clays, and proteins and their relevance to field conditions requires further work. The proteomic approach, with extraction and characterization of proteins stabilised by soil colloids (structural proteomics) might give further insights into this area. Functional proteomics can improve our understanding of the degradation of organic pollutants and organic debris as well as identifying the molecular colloquia between microorganisms and between soil biota and plant roots. Subdivision of organic N into sub-pools has helped to interpret mechanistic studies and modelling of N dynamics. Uncomplexed organic matter, obtained by physical fractionation procedures, is considered a labile pool. The interpretation of N mineralization measurements is affected by immobilization during microbial attack especially in high-C environments. Transfer of materials among particle size fractions and changes in microbiological properties of aggregates also can occur during fractionation procedures. Classical mineralization-immobilization turnover (MIT) does not always occur since microorganisms (and plants) can take up amino acid N with intracellular deamination. Protozoa, due to their grazing activities, can influence not only N mineralization but also the composition of rhizosphere-plant growth stimulating communities. Differences between N-poor and N-rich microsites, occurring in the same soil, can markedly affect the competition for N between plants and microorganisms especially the nitrifiers. The use of molecular techniques has allowed the identification of unculturable microorganisms and functional genes in the N cycle. Archeae are probably capable of oxidising NH₄⁺ to NO₃⁻ and anerobic ammonia oxidation (Ammonox) bacteria have been identified in biofilms and probably also occur in soils. The use of nitrate as an electron acceptor is encoded by specific gene clusters but nitrate reduction also occurs in dissimilatory nitrate reduction.     

低木质素含量棉秆皮纤维的提取和表征

为了实现棉秆皮纤维在纺纱上的应用,该文在150℃以上的温度下用质量分数为4%的碱从棉秆皮中提取了纤维,测定了温度和时间对棉秆皮纤维细度、木质素质量分数及力学性能的影响。将棉秆皮纤维与棉按质量比30/70的比例进行混纺,研究了木质素的质量分数对混纺纱性能的影响。结果表明:随着温度的升高和时间的延长,棉秆皮纤维的细度和木质素质量分数逐渐下降。但是,当温度升高至170℃后,棉秆皮纤维的断裂强度迅速降低。160℃、60 min提取的纤维性能较理想:纤维细度28.3 dtex、木质素质量分数4.5%、断裂强度1.8 c N/dtex、杨氏模量46 c N/dtex。与闪爆及常压碱处理等方法相比,高温方法提取的纤维木质素质量分数低60%以上。棉秆皮纤维的木质素质量分数从5.5%降至4.5%后,混纺纱的条干变异系数和毛羽指数分别降低了75.1%和29.6%,而断裂强度和伸长率分别提高了11.1%和9.8%。高温提取的棉秆皮纤维可纺出细度为22.4 tex、断裂强度为12.0 c N/tex的纱线。     

Evaluation of the potential of fungal and plant laccases for active-packaging applications

Laccases from Trametes versicolor (TvL), Myceliophthora thermophila (MtL), and Rhus vernicifera (RvL) were investigated with regard to their potential utilization as oxygen scavengers in active packages containing food susceptible to oxidation reactions. The substrate selectivity of the laccases was investigated with a set of 17 reducing substrates, mainly phenolic compounds. The temperature dependence of reactions performed at low temperatures (4-31 °C) was studied. Furthermore, the laccases were subjected to immobilization in a latex/clay matrix and drying procedures performed at temperatures up to 105 °C. The results show that it is possible to immobilize the laccases with retained activity after dispersion coating, drying at 75-105 °C, and subsequent storage of the enzyme-containing films at 4 °C. TvL and, to some extent, MtL were promiscuous with regard to their reducing substrate, in the sense that the difference in activity with the 17 substrates tested was relatively small. RvL, on the other hand, showed high selectivity, primarily toward substrates resembling its natural substrate urushiol. When tested at 7 °C, all three laccases retained >20% of the activity they had at 25 °C, which suggests that it would be possible to utilize the laccases also in refrigerated food packages. Coating and drying resulted in a remaining enzymatic activity ranging from 18 to 53%, depending on the drying conditions used. The results indicate that laccases are useful for active-packaging applications and that the selectivity for reducing substrates is an important characteristic of laccases from different sources.     

Extraction and characterization of water–repellent materials from Australian soils

Organic materials responsible for water–repellency in some Australian soils were extracted with an amphiphilic mixture of iso -propanol/15.7 m ammonia (7:3, v:v) in a Soxhlet apparatus, after which the water–repellent soils were rendered wettable. The successful extraction by an organic solvent system indicates that the bulk of hydrophobicity in these soils is not covalently linked to the surface of the sand. The extracted materials restored hydrophobicity on acid washed sands or ignited sands at levels comparable to the original soils.
Spectroscopic and chromatographic examination of the extracted materials indicated that both free and esterified long–chain, 16–32 carbon atom, fatty acids were present with a bimodal distribution showing maxima at C₁₆ and C₂₂. The ¹³C–NMR and infrared spectra of the most hydrophobic extract suggest that hydrophobicity is caused by molecules with extensive polymethylene chains. Calculations with model compounds indicate that at least a close packed monolayer is required before measurable hydrophobicity can be detected with the molarity of ethanol droplet penetration test.     

Extraction and purification of isoflavones from soybeans and characterization of their estrogenic activities

Soybean isoflavones have multiple beneficial health effects especially on estrogen-deficient diseases such as menopausal symptoms. In this study, isoflavones were produced from soybean flour, and the extraction and purification parameters were optimized to give a high yield of total isoflavones, about 0.62 mg of aglycones/g of soybean flour, which is >2 times the initial yield. HPLC analysis and MTT cell proliferation assay using MCF-7 cells revealed that the product thus obtained not only contained a high content of isoflavone aglycones but also had estrogenic activity. MTT data also revealed that both genistein and daidzein exhibited estrogenic effects at lower concentrations and antiproliferative effects at higher concentrations, and 1 microM genistein and 10 microM daidzein exerted significant estrogenic activities, which were not more than that of the endogenous level of 17beta-estradiol (E2). The production method developed can be used as a guideline for manufacturing soy isoflavones, and the MTT assay was demonstrated to be suitable for quality control on isoflavone products. The results on the estrogenic properties of isoflavones can be used as reference data for their effective and safe usages in estrogenic therapy.