A survey of β-glucan and arabinoxylan content in wheat

BACKGROUND: Dietary fibre lowers the risk of coronary heart disease and colorectal cancer. This survey quantifies mixed link β‐glucan (MBG) and arabinoxylan (AX) in wheat and investigates relationships between the grain carbohydrates. MBG and AX contents were measured in 500 and 200 wheat accessions respectively, including diploid, tetraploid and hexaploid genotypes comprising primitive, synthetic and elite lines. RESULTS: Overall, MBG contents ranged between 1.8 and 18.0 g kg^?1 grain dry weight. In wheat–barley addition lines and triticale hexaploids the levels were 9.0–11.3 and 3.5–9.6 g kg^?1 respectively. The amounts in synthetic wheats were nearer their tetraploid parents than their diploid parents. AX and total non‐starch polysaccharide (NSP) contents ranged from 23.7 to 107.5 g kg^?1 and from 31.7 to 136.7 g kg^?1 respectively. Linear regressions showed that the relationships of starch and grain weight with NSP glucose were stronger than those with AX. CONCLUSION: The results indicated insufficient genetic diversity in the germplasm surveyed to initiate a breeding programme to increase the amount of MBG in wheat grain to 20 g kg^?1, a level considered high enough to confer a 10–15% reduction in blood cholesterol. Copyright © 2011 Society of Chemical Industry     

Water mobility within arabinoxylan and β-glucan films studied by NMR and dynamic vapour sorption

BACKGROUND: The main purpose of this research was to determine the impact of the structure and organisation of polysaccharides on the hydration properties of the cell walls of cereal grains. In order to remodel the lamellar assembly of arabinoxylan (AX) and (1 → 3)(1 → 4)‐β‐D ‐glucan (BG) within the endosperm cell walls, films were prepared and analysed using dynamic vapour sorption and time domain nuclear magnetic resonance spectroscopy. RESULTS: The water diffusivities within the AX and BG films were measured at 20 °C by observing the water sorption kinetics within a mathematical model based on Fick's second law. The evolution of spin–spin relaxation times of water protons measured by increasing the temperature is explained by the additional contributions of motion of the protons of polysaccharides and/or rapid chemical exchanges of protons between water and hydroxyl groups of polysaccharides. CONCLUSION: The difference between patterns of water behaviour within the AX and BG films can be related to the difference in their nanostructures. The smaller nanopores of the BG films cause their nanostructure to be more compact. Copyright © 2011 Society of Chemical Industry     

Production of L-arabinose from corn hull arabinoxylan by Arthrobacter aurescens MK5 α-L-arabinofuranosidase

Arabinoxylans, which are comprised of a xylan backbone to which are attached glycosyl units that are primarily L-arabinofuranosyl units, are ubiquitous among plant species where it is a constituent of the cell wall. Arabinoxylan has attracted much attention as a potential biomass resource and L-arabinose has recently been reported to possess functional properties that are effective in the treatment of diabetes. Here, we report an α-L-arabinofuranohydrolase, isolated from the soil microbe Arthrobacter aurescens strain MK5, effective in releasing L-arabinose from corn hull arabinoxylan. When A. aurescens strain MK5 was grown in a liquid medium, corn hull arabinoxylan, which has a higher arabinose content (Ara/Xyl = 0.6) than oat spelts xylan (Ara/Xyl = 0.12), induced more efficient arabinoxylan hydrolase production. Analysis of enzyme activity in the culture broth revealed that arabinoxylan hydrolase activity was high, and α-L-arabinofuranosidase and β-xylosidase activities were low. The optimum pH of the MK5 arabinoxylan hydrolase at 40 °C was around 7 and enzyme activity was relatively stable at an alkaline pH up to 9.5. The optimum temperature at pH 7 was around 50 °C and enzyme activity was stable under 50 °C. During the hydrolysis of corn hull arabinoxylan, only L-arabinose was released and 45.1% maximum sugar recovery was achieved. The A. aurescens MK5 enzyme was a typical arabinoxylan α-L-arabinofuranohydrolase and was most effective at releasing L-arabinose from corn hull arabinoxylan, which has a high arabinose content. This enzyme may have important industrial applications.     

Preparation of and studies on the functional properties and bactericidal activity of the lysozyme–xanthan gum conjugate

The purpose of this research was to produce a xanthan gum–lysozyme conjugate (Lyz–XM) and to investigate the effect of conjugation on functional properties and antimicrobial properties of the conjugated products. The antimicrobial activity of Lyz is limited to Gram positive bacteria, but its antibacterial spectrum can be extended towards Gram negative bacteria by conjugation with carbohydrate through the Maillard reaction. Lyz was allowed to react with XG under mild Maillard reaction condition (pH 8.5 and 60 °C for 10 days) and conjugation was confirmed by SDS-PAGE, enzyme activity and determination of sugar content of the product. Results showed that under optimal conditions approximately 1.9 mmol XG was attached to one mol Lyz. The Lyz–XG conjugate showed higher solubility at acidic pHs and at different temperatures, increased heat stability with improved emulsion and foaming properties. Additionally, Lyz–XG conjugate showed antioxidant properties and significantly inhibited the growth of Staphylococcus aureus and Escherichia coli in a dose dependent manner. These findings may broaden food applications of Lyz as a functional ingredient with high quality emulsifier, foam producer or natural antibacterial agent in food or pharmaceutical industries.     

Elucidating the relative roles of ammonia oxidizing and heterotrophic bacteria during the biotransformation of 17α-Ethinylestradiol and Trimethoprim

The biological fate of 17α-ethinylestradiol (EE2; 500 ng/L to 1 mg/L) and trimethoprim (TMP; 1 μg/L to 1 mg/L) was evaluated with flow through reactors containing an ammonia oxidizing bacterial (AOB) culture, two enriched heterotrophic cultures devoid of nitrifier activity, and nitrifying activated sludge (NAS) cultures. AOBs biotransformed EE2 but not TMP, whereas heterotrophs mineralized EE2, biotransformed TMP, and mineralized EE2-derived metabolites generated by AOBs. Kinetic bioassays showed that AOBs biotransformed EE2 five times faster than heterotrophs. The basal expression of heterotrophic dioxygenase enzymes was sufficient to achieve the high degree of transformation observed at EE2 and TMP concentrations ≤ 1 mg/L, and enhanced enzyme expression was not necessary. The importance of AOBs in removing EE2 and TMP was evaluated further by performing NAS experiments at lower feed concentrations (500-1000 ng/L). EE2 removal slowed markedly after AOBs were inhibited, while TMP removal was not affected by AOB inhibition. Two key EE2 metabolites formed by AOB and heterotrophic laboratory-scale chemostats were also found in independent laboratory-scale mixed culture bioreactors; one of these, sulfo-EE2, was largely resistant to further biodegradation. AOBs and heterotrophs may cooperatively enhance the reliability of treatment systems where efficient removal of EE2 is desired.     

Enzymatic scouring and bleaching of cotton terry fabrics – opportunity of the improvement on some physicochemical and mechanical properties of the fabrics

In the present study, an attempt was made to treat cotton terry fabrics with alkaline pectinase enzyme and observe the effects on the properties including the degree of whiteness, water absorbency, pill formation, weight loss after abrasion, tenacity at maximum load, degree of polymerization (DP), and hand feeling of the fabric. The enzymatic treatment of cotton terry fabrics had a positive influence on some of their properties. The degree of damage of cotton terry fabrics after 20 washings in a domestic washing machine was determined by analyzing the tenacity at maximum load, weight loss after abrasion, fabric hand feeling, and the DP. Enzymatic-scoured fabrics had a higher resistance to abrasion, a lower decrease in the DP, and a higher rating of the fabric hand feeling compared with alkaline-scoured fabrics. Enzymatic processing was accompanied by a significant lower demand of energy and water. Consequently, at these processes arises the lowest amount of effluents and the produced wastewater is biodegradable. This study attempted to introduce enzymatic scouring (ES) and bleaching with peracetic acid (PAA) of the cotton terry fabrics.     

Interaction of phosphatidylcholine and α-tocopherol on the oxidation of sunflower oil and content changes of phosphatidylcholine and tocopherol in the emulsion under singlet oxygen

Abstract: Interaction of phosphatidylcholine (PC) and α‐tocopherol (α‐Toc) on the oxidation of oil in the emulsion consisting of sunflower oil and water under singlet oxygen at 25 °C was studied by determining peroxide value (PV) and conjugated dienoic acid (CDA) contents. Singlet oxygen was produced by chlorophyll b under 1700 lux. Single addition of PC or α‐Toc decreased the values of peroxides and CDAs of oil in the emulsion via singlet oxygen quenching. PC and α‐Toc showed simply additive interaction in decreasing the singlet oxygen oxidation of oil in the emulsion. α‐Toc was a physical quencher of singlet oxygen in the emulsion, but PC involved chemical quenching in the antioxidant action. Chlorophyll and PC contents were decreased in the emulsion under singlet oxygen, while α‐Toc was not. α‐Toc protected chlorophyll and PC from degradation, and was a more important component than PC in the oil oxidation under singlet oxygen in the emulsion.     

Investigation into the Maillard reaction between ɛ-polylysine and dextran in subcritical water and evaluation of the functional properties of the conjugates

The effects of temperature and pressure on the Maillard reaction between ?-polylysine and dextran in subcritical water were investigated. Browning index was determined at 420 nm, and degree of graft was estimated by O-phthaldialdehyde (OPA) method. The formation of conjugates by Maillard reaction was testified by UV–vis spectrum and SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The emulsifying activity of the conjugates was greatly improved with the rise of temperature. The antimicrobial activity of the conjugates formed below 110 °C remained the same as ?-polylysine, and then decreased obviously when the reaction temperature was above 120 °C. The reaction pressure (0–10 MPa) had no effect on the emulsifying and antimicrobial activities, but higher pressure could effectively inhibit the formation of browning compounds.     

Influence of the overall charge and local charge density of pectin on the complex formation between pectin and β-lactoglobulin

The complex formation between β-lactoglobulin (β-lg) and pectin is studied using pectins with different physicochemical characteristics. Pectin allows for the control of both the overall charge by degree of methyl-esterification as well as local charge density by the degree of blockiness. Varying local charge density, at equal overall charge is a parameter that is not available for synthetic polymers and is of key importance in the complex formation between oppositely charged (bio)polymers. LMP is a pectin with a high overall charge and high local charge density; HMP_B and HMP_R are pectins with a low overall charge, but a high and low local charge density, respectively. Dynamic light scattering (DLS) titrations identified pH_c, the pH where soluble complexes of β-lg and pectin are formed and pH_?, the pH of phase separation, both as a function of ionic strength. pH_c decreased with increasing ionic strength for all pectins and was used in a theoretical model that showed local charge density of the pectin to control the onset of complex formation. pH_? passed through a maximum with increasing ionic strength for LMP because of shielding of repulsive interactions between β-lg molecules bound to LMP, while attractive interactions were repressed at higher ionic strength. Potentiometric titrations of homo-molecular solutions and mixtures of β-lg and pectin showed charge regulation in β-lg–pectin complexes. Around pH 5.5–5.0 the pK_as of β-lg ionic groups are increased to induce positive charge on the β-lg molecule; around pH 4.5–3.5 the pK_a values of the pectin ionic groups are lowered to retain negative charge on the pectin. Since pectins with high local charge density form complexes with β-lg at higher ionic strength than pectins with low local charge density, pectin with a high local charge density is preferred in food systems where complex formation between protein and pectin is desired.     

The Ministry of Environmental Protection Issued the Technical Guide for Pollution Prevention and Control of the Pulp and Paper Industry

正In order to implement the Environmental Protection Law of the People’s Republic of China and improve the quality of the environment,to implement the Notice of the General Office of the State Council on Issuing the Implementation Plan for the Control     

The effect of dietary supplementation of vitamins C and E on the α-tocopherol content of muscles, liver and kidney, on the stability of lipids, and on certain meat quality parameters of the longissimus dorsi of rabbits

The trial was carried out to investigate the effects of adding to the diet of rabbits vitamin E (40; 300; 500 ppm) and C (0; 500 ppm), on vitamin E deposition in the muscles and organs, on the oxidative stability of muscular lipids, and on various meat quality characteristics. The α-tocopherol content in muscles and organs was roughly doubled by feeding the highest levels of vitamin E; it was also increased by giving 500 ppm of vitamin C, but only in those muscles of rabbits receiving 40 ppm of vitamin E. The α-tocopherol content in tissues was negatively correlated with TBARS values of the longissimus dorsi (LD) at days 6 and 8 post mortem (p.m.). Five hundred parts per million (ppm) of vitamin C increased lipid stability of the LD at both 6 and 8 days p.m., though its effect was significant only with 40 ppm of vitamin E. Moreover, 500 ppm of vitamin C resulted in the lowest L(*) and highest pH values at all p.m. times, when the dietary vitamin E was equal to 40 ppm, and in the highest L(*) and lowest pH values when the vitamin E was equal to 300 ppm. Conversely, weight losses of the LD were the lowest, at days 6 and 8 p.m., in the group fed the highest levels of both vitamins.     

Comparison of the gel-forming ability and gel properties of α-lactalbumin,lysozyme and myoglobin in the presence of β-lactoglobulin under high pressure

α-Lactalbumin (α-La) and lysozyme (LZM) each contain four disulfide bonds but no free SH group, whereas myoglobin (Mb) possesses no disulfide bond or free SH group. In this work, the pressure-induced gelation of α-La, LZM and Mb in the absence and in the presence of β-lactoglobulin (β-Lg) was studied. Solutions of α-La, LZM and Mb (1–24%, w/v) did not form a gel when subjected to a pressure of 800 MPa and circular dichroism analysis revealed that both α-La and LZM are pressure-resistant proteins. In the presence of β-Lg (5%, w/v), however, a pressure-induced gel formed for α-La and LZM (each 15%, w/v) but not for Mb (15%, w/v). One- and two-dimensional SDS-PAGE demonstrated the disulfide cross-linking of proteins was responsible for the gelation. Although α-La and LZM are homologous and have the same disulfide bond arrangement, the texture and appearance of the gels formed from α-La/β-Lg and LZM/β-Lg were markedly different even when induced under the same experimental conditions. Microscopic analysis indicated that phase separation occurs during the gelation of LZM/β-Lg but not during the gelation of α-La/β-Lg. NMR relaxation measurement revealed that the association of water molecules with the protein matrix in the α-La/β-Lg gel is tighter compared to that in the LZM/β-Lg gel. These results indicate that the gel-forming ability of a globular protein under high pressure is related to the primary structure of the protein, and that the gel properties depend on the cross-linking reaction and on the phase behavior of protein dispersion under high pressure.     

How the surface wettability and modulus of elasticity of the Amazonian paricá nanofibrils films are affected by the chemical changes of the natural fibers

The use of natural resources for the production of nanostructured cellulosic films of high quality could reduce pollution and raw material costs for cellulose industry. This work provides innovative information about the use of Amazonian species not explored in studies involving the production of nanostructured films, as well as the evaluation of important characteristics that may be decisive for the destination of the product. The aim of this study was to modify Schizolobium parahyba var. amazonicum (paricá) waste fibers through alkaline (NaOH) and bleaching (NaClO₂) treatments for cellulose nanofibrils (CNFs) production and evaluate the characteristics of the nanofibrils and the surface as well as the mechanical resistance of the films obtained. The alkaline treatment was carried out with sodium hydroxide (5% NaOH solution (w/v); 2 h), while the bleaching was performed using sodium chlorite and glacial acetic acid (1.5 g NaClO₂; 10 drops of glacial acetic acid; 1 h). The treatments were performed in sequence, producing nanofibrils after alkaline treatment and after bleaching. Lignin content did not change with the alkaline treatment, but it significantly decreased with bleaching (from 26.1 to 6.8%). Hemicelluloses content decreased with the sequence of treatments. FTIR results showed that the mechanical defibrillation caused disruption of the fiber bonds. The temperature of thermal degradation observed in DTG analysis increased from the natural fibers (243 °C) to alkaline?+?bleached fibers (255 °C). The defibrillation process led to higher thermal stability of the alkaline?+?bleached nanofibrils in comparison to fibers. Moreover, films were prepared from the obtained CNFs and evaluated by the mechanical properties and surface contact angle. The mechanical properties showed values of 6.93?±?0.18 GPa for modulus of elasticity (MOE) for the films produced from material which was submitted to the bleaching treatment. The results highlighted a more hydrophobic surface of the film produced with the CNFs generated from the bleached fibers. The results of mechanical properties showed the superiority of the films produced from the alkaline?+?bleached fibers.     

Antigenic response of whey proteins and genetic variants of β-lactoglobulin — the effect of proteolysis and processing

Limited enzymatic hydrolysis trials of WPC-80 and β-lactoglobulin AA, AB and BB were performed using specific enzymes (trypsin, Neutrase, Corolase PP, Corolase PS) in a pH-stat under controlled conditions. The hydrolysates of WPC-80 and β-lactoglobulin were fractionated into high and low molecular fractions. Residual antibody binding activity of the peptides was dependent on the degree of hydrolysis (DH 2-20), but also on the enzyme used. Heat treatment affected the solubility and thereby the antigenic response. Dialysis influenced the antibody binding activity of the peptides. Tryptic hydrolysis of β-lactoglobulin AA was slower than for β-lactoglobulin BB and AB. Antigenic responses of the hydrolysates and fractions were measured by SLOT-BLOT and ELISA. SLOT-BLOT, a rapid screening method, was not able to differentiate the hydrolysates. The ELISA, being a more sensitive method, differentiated between the genetic variants, but was more time consuming. The lowest antigenicity was observed in the 1000–5000 Da fraction and β-lactoglobulin AA showed the lowest response.     

Comparative assessment of the global fate of α- and β-hexachlorocyclohexane before and after phase-out

Technical hexachlorocyclohexane (HCH) was one of the most widely used pesticides during the 20th century. Although production and use were phased-out during the 1990s, two of its major components, α- and β-HCH, are still ubiquitous in the environment. Here, we have collected and analyzed data on concentrations of α- and β-HCH in the atmosphere and oceans, including spatial and temporal trends and seasonalities. We apply a global fate and transport model to both isomers over the period 1950 to 2050 to rationalize current levels and trends at remote locations with estimated emissions and to forecast into the near future. Our model results indicate that secondary emissions from soils and oceans are currently controlling the observed rates of decline in the atmosphere. β-HCH is declining more slowly than α-HCH due to its higher persistence, and we hypothesize that it will eventually become the predominant isomer of HCH in the environment. The model reproduces over 70% of measured concentrations of α-HCH in air and ocean water within factors of 3 and 5, respectively, and over 70% of measured concentrations of β-HCH within factors of 8 and 20, respectively. The model results are only weakly sensitive to climate change-induced trends in Arctic sea-ice cover and temperature.     

Hygienic evaluation of the state of nutrition and noninfectious sickness rate of digestive organs of the Primorskiĭ Kraĭ population

The research of nutrition status of Primorsky Krai population in 1996-1999 showed positive tendency to quantitative improvement of structure of nutrition set. At the same time in connection a nutrition of Primorsky Krai population doesn't correspond to the standard of balanced nutrition. Some decrease of deficiency of basic food products in nutrition and an increase of energy value of food ration are observed. Children group of population is the most susceptible to unbalanced and defective nutrition that is why a pathology of digestive system of noninfectious nature develops intensively among children.     

Effect of γ-polyglutamate on the rheological properties and microstructure of tofu

The effects of γ-polyglutamates with different concentrations (0.1%, 0.15%, 0.2%) and molecular weights (high, medium, low) addition on the rheological properties, microstructure, and syneresis of tofu were studied. The addition of γ-polyglutamate increased the gelation time, and decreased the storage modulus (G′) and the loss modulus (G″) of tofu. The molecular weight and concentration of γ-polyglutamate effectively changed the rheological properties of tofu. The network of tofu without γ-polyglutamate addition was constructed by fine strands in a dense arrangement as seen by using scanning electron microscope. However, the addition of γ-polyglutamate reduced the thickness of the strands in tofu network. Tofu syneresis was also reduced by the addition of γ-polyglutamate. Increase the concentration of γ-polyglutamate significantly decreased the syneresis of tofu. This trend was more evident on the tofu with high molecular weight γ-polyglutamate.     

Effect of temperature and pH on the solubility of caseins: environmental influences on the dissociation of α(S)- and β-casein

Selective precipitation is a common method for the isolation of β-casein, using the different calcium sensitivities of the individual caseins and the selective solubility of β-casein at a low temperature. In previous studies, it has been indicated that the β-casein yield depends on the physicochemical characteristics of the casein raw material used for fractionation. The objective of this study was to evaluate and compare the solubility of α(S)- and β-casein in solutions of micellar casein, sodium caseinate, and calcium caseinate as a function of pH and temperature. Additionally, the solubility of isolated α(S)- and β-casein fractions in demineralized water, ultrafiltration permeate, and a calcium-depleted milk salt solution was investigated depending on the pH and temperature. Furthermore, micellar casein, sodium caseinate, and calcium caseinate were subjected to a calcium chloride-precipitation process to determine the solubility of α(S)- and β-casein in calcium chloride precipitate, which is produced during selective precipitation, as a function of temperature and pH. Generally, the temperature had only a marginal influence on the α(S)-casein solubility compared with the β-casein solubility, whereas the solubility was shown to be strongly influenced by the pH. Our results suggest that the yield of β-casein obtained during isolation by means of selective precipitation may be a result of the solubility characteristics of α(S)- and β-casein in calcium chloride precipitate. Manufacturers may consider a simple solubility experiment before the β-casein isolation process by means of selective precipitation to predict β-casein yield.     

Advantages of BFRI Sifter and the Prototype Experiment Report

~~Advantages of BFRI Sifter and the Prototype Experiment Report