Quantitative and qualitative changes in added phosphates in cod (Gadus morhua) during salting,storage and rehydration

Phosphate blend can be used in salted cod processing to improve yields, water holding capacity and appearance of the final product. However, added phosphates are gradually degraded during processing and storage, leading to changes in functional properties of phosphates. The objective of the study was to monitor the quantitative and qualitative changes in added phosphates in cod during salting, storage and rehydration using ion chromatography (IC) and spectrophotometric analysis. The phosphates diffused into the fish muscle during brining but the phosphate content (mg P₂O₅/g sample) decreased again as liquid drained away from the muscle in the following dry salting step. Changes during six months storage of the dry salted products were minor. Further losses were observed during rehydration where the phosphates were washed out to levels lower than in the raw material.The advantage of the IC method was the ability to separate and determine different soluble phosphate species in the fish muscle. The IC results showed that pyrophosphate (P₂O₇) and triphosphate (P₃O₁₀) were partly degraded into orthophosphate (PO₄) during the storage period. Lower values were obtained for the total phosphate content by IC than with the spectrophotometric method, which explained by difference is sample preparation.     

Influence of vitamin (B1, B6, B9, B12, C) and ions (Cu2+, Mn2+, PO4 3−) on kefir grain biomass growth

The aim of the present study was to investigate the effects of additions of various vitamins (B₁, B₆, B₉, B₁₂, and C) and minerals (CuSO₄·H₂O, MnSO₄·H₂O, and Na₃PO₄·12 H₂O) on the propagation of kefir grains. The activated kefir grains were inoculated into very low fat (0.1%) cows’ milk under constant temperature (25°C) and impeller speed (100 rpm) for a propagation time of 24 h. After evaluation of the experimental data, the most influential mineral addition providing 39% increase of kefir grain biomass was found to be Na₃PO₄·12 H₂O with a concentration of 0.30 g phosphate (PO₄ ^3?) ion/L. At this optimal condition, a model was also derived for the kefir grain biomass concentration representing pH dependence. This study demonstrated the basis for further research in the direction of kefir grain biomass growth considering the effect of additions of vitamins and minerals to other researchers working in the same field and to dairy industry as well.     

Combined chemical and enzymic treatments of corn husk lignocellulosics

The potential for using corn (Zea mays L) husk residues (carbohydrates 827 g kg^?1, lignin 66 g kg^?1 DM) as a carbohydrate source for the production of soluble sugars by combined chemical pretreatment and enzymic hydrolysis was assessed. Comparative investigations of acidic and alkaline pretreatments on corn husk have shown that pentose-containing carbohydrates comprised 86–93% of the solubilised fraction. While pretreatments with 1.25 M NaOH at 25.85° C resulted in preferential extraction of hemicellulose having DP; > 12, acid pretreatments 0.51 M H₂SO₄, 0.51 M H₃PO₄ at (85° C) resulted in extensive depolymerisation of this polysaccharide. Xylose and low molecular weight carbohydrates were identified as the major products. Subsequent hydrolysis of the solubilised fraction with crude hemicellulase preparations yielded 40.90% fermentable sugars. When NaOH (0.02–1.25 M), H₂SO₄ and H₃PO₄ (0.02–0.51 M) were used as pretreatment solvents (25–85° C, 2 h), NaOH was the most effective in increasing the susceptibility of the residual husk towards enzymes, yielding 83–96% reducing sugars. This solvent solubilised up to 60.6% of the lignin and appeared to disintegrate the fibrillar structure of husk. The crystallinity of husk residues increased following the chemical pretreatments and was positively correlated with cellulose content. Enzymic hydrolysis with commercial cellulase preparations proceeded in two stages: a rapid breakdown of amorphous cellulose after which the hydrolysis rate levelled off. Similar biphasic patterns were observed for the pyrolysis temperature of cellulose. Under the most optimal conditions for husk saccharification (pretreatment with 1.25 M NaOH, 25° C, 2 h, followed by enzymic hydrolysis using a mixture of cellulase and cellobiase), 96% of the cellulose-enriched residues was hydrolysed to reducing sugars. A cellulase preparation from Trichoderma reesei exhibited substantial hemicellulolytic activity and could, therefore, be used as the sole saccharifying enzyme preparation for husk lignocellulosics.     

Agave sisalana,a biosorbent for the adsorption of Reactive Red 120 from aqueous solution

The textile industry is one of the largest producers of dye effluent. Treatment of these effluents has to be cost effective hence a number of precursors have been studied as a viable alternative adsorbent. Sisal fibre was converted to activated carbon by chemical methods. Sisal fibre was activated with different activating agents such as H₃PO₄, HCl, HNO₃, NaOH and KOH. The adsorption of Reactive Red 120 (RR 120) dye onto sisal fibre activated carbon (SFAC) from aqueous solution was investigated. Adsorption experiments were carried out at different dye concentrations, initial solution pH and carbon dosage. Batch adsorption studies were carried out using activated carbon produced using phosphoric acid yielded better carbon as it good results in terms of Methylene Blue number and Iodine number. These carbons were used to study the batch adsorption studies. Methylene Blue number and Iodine number of SFAC were found to be 240 mg/g and 855 mg/g, respectively. The BET surface area of the carbon was 885 m²/g. The batch experiments adsorption isotherm studies fitted well to Langmuir isotherm and the adsorption capacity was found to be 110 mg/g. Adsorption kinetics data were tested using pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the adsorption data followed a pseudo-second-order reaction.     

Optimization of chemical activation of cotton fabrics for activated carbon fabrics production using response surface methodology

Abstract

The preparation of activated carbon fabric (ACF) from cotton fabric treated with phosphoric acid (H₃PO₄) was optimized using the response surface methodology (RSM). Experimental activation variables including; impregnation ratio, heating rate, activation temperature, and activation time were optimized based on the responses evaluated (adsorption capacity, yield of the produced ACF). The operation conditions for obtaining the ACFs with the highest the adsorption capacity and process yield were proposed. Optimized conditions were: impregnation ratio of 2, heating rate of 7.5 °C min^?1, the activation temperature of 500 °C, and the activation time of 30 min. The ACFs produced under optimized conditions were characterized by scanning electron microscopy (SEM), X-ray energy dispersion spectroscopy (EDX). The surface area and pore volume of carbon nanostructures were characterized by nitrogen adsorption isotherm at 77 °K using BET method. The obtained results showed that the produced ACFs have developed porous structure, fabric shape, BET surface area (690 m²/g) and total pore volume (0.3216 cm³/g), and well-preserved fibers integrity.     

Orientierende Untersuchungen zum Organosolv-Aufschluß von Buchenholz mit einem Propandiol/Wasser-Gemisch

Beech wood (Fagus sylvatica L.) was digested in organosolv processes using ethanol/water (EtOH/H₂O) and propandiol-(1,2)/water (PDO/H₂O). The pulping qualities of both agents were compred. The pulp yield is lower for PDO/H₂O than for EtOH/H₂O. While almost the whole lignin can be recovered in a simple manner from the EtOH spent cooking liquor, the lignin from the PDO-liquors can only be partly isolated. Due to its high boiling point the recovery of PDO from the spent pulping liquors is more difficult than that of EtOH. Schemes of the recovery of pulps and lignins as well as lignin and carbohydrate balances demonstrate the results of the pulping experiments.     

Effects of phosphorus and zinc fertilizer on cadmium uptake and distribution in flax and durum wheat

Cadmium accumulation in crops presents a potential risk to human health. To understand the difference between dicotyledonous and monocotyledonous species in respect of Cd accumulation, and to develop fertilizer management practices to minimise Cd uptake, a growth chamber study was conducted to evaluate the interactive effects of Cd concentration in phosphate and Zn fertilizer on Cd uptake in flax (Linum usitatissimum L) and durum wheat (Triticum turgidum L). Cadmium concentration was higher in flax than durum wheat shoots. Cadmium concentration was lower and Zn concentration higher in the flax seed and durum wheat grain than in the root, shoot or straw of both species. These results suggest that flax has comparatively ineffective barriers discriminating against the transport of Cd from the root to the shoot via the xylem, and that both crops may restrict Cd translocation to the seed/grain via the phloem. Commercial grade monoammonium phosphate (NH₄H₂PO₄) or triple superphosphate (Ca(H₂PO₄)₂) produced higher seed Cd concentrations than did reagent grade P in flax but not in durum wheat. Application of P significantly decreased seed/grain Zn concentration and increased seed/grain Cd concentration. Zinc addition at 20 mg Zn kg^?1 soil with P decreased seed/grain Cd concentration (average 42.2% for flax, 65.4% for durum wheat), Cd accumulation (average 37.2% for flax, 62.4% for durum wheat) and Cd translocation to the seed/grain (average 20.0% for flax, 34.5% for durum wheat) in both crops. These results indicate that there is an antagonistic effect of Zn on Cd for root uptake and distribution within the plant. Copyright © 2004 Society of Chemical Industry     

Characteristics of L-lactic Acid Production byRhizopus oryzae mutant RL6041

A high-yield mutant strain Rhizopus oryzae RL6041 induced by ions implantation was used in the present study. L (+)-lactic acid was generated by RL6041 grown on liquefied corn starch as a substrate. With optimal conditions (Liquefied corn starch 150g/L, (NH₄)₂SO₄ 2.0g/L, MgSO₄·7H₂O 1.0g/L, ZnSO₄·7H₂O 2g/L, KH₂PO₄ 0.2g/L, CaCO₃ 8%, medium size 20/250Ml, seed age 6h, fermentation temperature 38° C), the yield of L (+)-lactic acid in shake-flask reached 133～136g/L after 36h, indicating that the conversion rate was as high as 88%～91%, and the productivity was 3.75g/L·h. There was almost a 70% increase in lactic acid production compared with the original strain RE3303.     

加成法合成氨基硅油

以H₂ PtCl₆ 为催化剂 ,以丙烯胺与含氢硅油加成 ,合成了氨值在 0.8～1.5的侧基型氨基硅油 ,并且在硅油分子中引入了烷氧基。最佳的反应条件是以甲苯为溶剂 ,催化剂用量 0.2mmol g,回流条件下在 2h内滴加丙烯胺 ,继续保温 2～3h ,然后在 30min内加入正丙醇 ,继续反应 90min。     

DETERMINATION OF TRACE AMOUNT FOR GERMANIUM (Ge) BY ATOMIC FLUORESCENCE SPECTROMETRY IN RICE (ORYZA SATIVA L.)

ABSTRACT

The quantification of germanium in rice (Oryza sativa L.) was studied by atomic fluorescence spectrometry (AFS). The optimum experimental conditions or the generation of germanium hydride were 360‐V photomultiplier tube voltage, 80‐mA hollow cathode lamp, 2.5% (w/v) KBH₄ in 0.5% KOH solution and 20% H₃PO₄ mixture with 5% H₂SO₄. With these experimental conditions, the correlation coefficient (R²) of calibration curve was up to 0.9992. As a convenient and sensitive calibration curve, it was proposed for the determination of trace amounts of germanium in brown and milled rice samples. The results showed that the content of germanium in brown rice was higher than that in milled rice. The means of the content of germanium were 4.98 and 18.10 ng/g in milled rice and brown rice, respectively.

PRACTICAL APPLICATIONS

Rice is an important food for human nutrition because it supplies starch, protein and the majority of micronutrients to humans, particularly in Asia. So determination the content of Germanium in rice is important for human health. In this study, we developed the method of AFS which was suitable for determination rice grain. With this method, the content of Ge could be analyzed accurately in rice, so that the good materials would be selected form germplasm resources of rice, which could be used to study physiological and genetic mechanisms and enhance germanium in diets for human.

     

Comparison of the performance of kenaf fiber using different reagents presoak combined with steam explosion treatment

To enhance the degumming effect of steam explosion on kenaf fiber, different chemical reagents including hydrogen peroxide (H₂O₂), sulfuric acid (H₂SO₄), and sodium hydroxide (NaOH) presoak combined with steam explosion were used and compared in this article. Distilled water coupled with steam explosion treatment and kenaf raw samples were used as control. The fiber morphology, chemical composition, crystalline structure, degree of fineness, and breaking tenacity of kenaf fibers after treatment were studied. The results showed that hydrogen peroxide (H₂O₂) performs better on removing lignin. It not only splits fibers, but also keeps the fiber’s tenacity during steam explosion treatment. Dilute sulfuric acid (H₂SO₄) performs better on hemicellulose removal, but it damages the fiber cellulose during steam explosion treatment and cause the fiber strength decrease a lot. Sodium hydroxide (NaOH) performs the best on removing hemicellulose and lignin, and splits fiber well. However, the breaking tenacity of the fiber is lower than the fiber pretreated by H₂O₂. Besides, NaOH is a pollutant to the environment. In conclusion, H₂O₂ could be considered as the most promising reagent to be used in combined presoak-steam explosion system.     

Optimization of medium on exopolysaccharides production in submerged culture of Cordyceps militaris

Statistical experimental design strategy (SES) was applied to optimize the medium for the exopolysaccharides (EPS) production of Cordyceps militaris by submerged culture in shaker flask. A significant influence of the glucose and peptone on the EPS production was first evaluated by using a Plackett-Buman design. Then, steepest ascent method was employed to approach the experimental design space. Last, these factors were further optimized using central composite design (CCD) and response surface methodology (RSM). A quadratic model was found to fit the EPS production. The optimum values of the tested variables for the production of EPS were 48.67 g/L glucose, 12.56 g/L peptone, 1 g/L KH₂PO₄, 10 g/L yeast extract, and 0.5 g/L MgSO₄·7H₂O. Under optimization of culture conditions, the EPS production was enhanced from 0.78 to 1.96 g/L. In comparison with that of original culture conditions, 2.5 fold increase was obtained.     

Comparison of chemical modifiers for direct determination of Cd, Cu and Zn in food stuffs by solid-sampling-ETAAS

In this work, the capability of different chemical modifiers (Pd, Pd/Mg(NO₃)₂, Pd/NH₄NO₃, NH₄H₂PO₄, NH₄H₂PO₄/Mg(NO₃)₂) to eliminate the matrix effects in the direct determination of Cd, Cu and Zn in food-stuffs by solid sampling-electrothermal atomic absorption spectrometry was compared. The alternative analytical lines were used for determination of Cu (327.4 nm) and Zn (307.6 nm) in order to allow the introduction of reasonably high sample mass into the furnace. Mixed modifiers containing palladium were useful to eliminate the matrix effect in Cd determination. For Cu and Zn determination the application of Pd shows satisfactory analytical performance. In the determinations of Cd and Zn the phosphate containing modifiers shows elimination of matrix effects only when applying them to a partially pyrolysed sample (at 400 °C). The achievable limits of detection for Cd, Cu and Zn in solid samples were 0.279 ng g⁻¹; 0.020 μg g⁻¹ and 2.04 μg g⁻¹, respectively.     

Purification, characterization, and production of β-mannanase from Bacillus subtilis TJ-102 and its application in gluco-mannooligosaccharides preparation

A novel β-mannanase-producing strain, Bacillus subtilis TJ-102, was identified and characterized. Response surface method was applied to improving and enhancing the enzyme production. The optimized media components were obtained: 45.25 g/L konjac, 9.29 g/L Na₂HPO₄·12H₂O, 2.60 g/L CaCO₃, 1.0 g/L (NH₄)₂SO₄, 0.3 g/L KH₂PO₄, 1.0 g/L NaCl, 1.0 g/L MgCl₂·6H₂O, and 0.01 g/L FeSO₄. Under these conditions, the β-mannanase activity could achieve 205.3 U/mL in a 7-L fermentor. Then, β-mannanase was 7.39-fold purified by salting out, ultrafiltration, anion-exchange, and size-exclusion preparative chromatography with a recovery of 21.41 % and a specificity of 125.36 U/mg proteins. β-Mannanase was stable below 65 °C and pH 5.0–8.0, which exhibited excellently enzymatic efficiency in the preparation of gluco-mannooligosaccharides (GMOS) by hydrolyzing konjac flour. The GMOS yield of 57.76 % has been achieved with 8.71 % of mannose and 14.49 % of glucose, demonstrating the potential use of β-mannanase in food industry.     

Evaluation of Gelation and Solubility of Bovine Plasma Protein Isolates

Gelation and solubility of bovine plasma protein isolates prepared from liquid plasma using different acids (HCl, H₃PO₄, H₂SO₄) and bases (NaOH, Na₂CO₃) were evaluated and compared to commercial plasma. Protein recovery was over 90%. Solubility at 1% (w/v) was low in pH range 4.0 to 5.5 but similar to commerical plasma in pp range 5.5 to 8.0 (p < 0.01). All isolates gelled at a concentration o 6.0%. Only isolate H₃PO₄-Na₂CO₃ and commercial plasma gelled at a minimum concentration of 4.0%. This concentration decreased to 2.4% for the same isolate when 0.025M Ca⁺⁺ ion was added.     

Determination of the betaine content of feed ingredients using high‐performance liquid chromatography

A series of studies was conducted to establish a methodology for the accurate and efficient determination of betaine in different feed ingredients. The final methodology involves an extraction step in which the feed sample is heated for 3 h in a methanolic KOH solution using a Goldfisch apparatus. Impurities are removed by the addition of activated charcoal and concentrated (36%) HCl. After centrifugation the extractant is passed through a strong cation exchange resin (Dowex 50W‐X12, H⁺). The betaine retained in the column is eluted with 1.5 N HCl. A 2 ml aliquot of the elute is air dried and reconstituted with 1 ml of deionised water. HPLC separation with a cation exchange column (Partisil SCX‐10) is used for the separation of betaine from other compounds. The mobile phase is kept constant at 50 mM KH₂PO₄ in water, and eluted compounds are detected by UV absorbance (200 nm). The flow rate is maintained at 1.5 ml min^?1. This assay is very accurate over the range of betaine concentrations from 15 to 650 µg ml^?1, with a lower detection limit in feeds of approximately 500 µg g^?1 when 4 g of sample is extracted. Recovery assays done with standard betaine hydrochloride and hard red wheat resulted in a consistent recovery of 80%. Betaine content was quantified in several feed ingredients, including alfalfa (1.77 mg kg^?1), wheat (3.96 mg kg^?1), wheat middlings (4.98 mg kg^?1) and poultry meal (0.77 mg kg^?1). Betaine in corn and soybean meal was not detectable by this method, even when 16 g of sample was used (<125 mg kg^?1). Betaine present in several feed ingredients should influence choline supplementation to animal feeds and may have implications for human health. © 2002 Society of Chemical Industry     

Influence of Chemical Pretreatment on the Dissolved Organics in Poplar Alkaline Peroxide Mechanical Pulping Effluent

The components of the effluent from the chemical pretreatment of poplar alkaline peroxide mechanical pulp (APMP) were analyzed in this study. The main dissolved organics were low-molecular weight (LMW) lignin, oligosaccharides, and monosaccharides. The lignin and sugar concentrations in the effluent obtained using different chemical pretreatment conditions and chemical dosages were analyzed using ultraviolet (UV) spectroscopy. This analysis provided a theoretical basis for the subsequent treatment and utilization of APMP effluent. The experimental results showed that the dosages of NaOH, H₂O₂, and Na₂SiO₃ in the chemical pretreatment process affected the lignin and sugar concentrations in the effluent and that different chemicals had differing degrees of influence. The degree of influence exhibited the following order: NaOH>H₂O₂>Na₂SiO₃. More specifically, the dosages of NaOH and H₂O₂ had stronger influences on the lignin and sugar concentrations than that of Na₂SiO₃. Indeed, the Na₂SiO₃ dosage hardly affected the lignin and sugar concentrations in the effluent, but Na₂SiO₃ could stabilize the chemical pretreatment system and improve the reactive efficiency of NaOH and H₂O₂. The pretreatment temperature and time also affected the organic components, and the influence of the temperature was stronger than that of time.     

Salmonella typhimurium Attached to Chicken Skin Reduced Using Electrical Stimulation and Inorganic Salts

Chicken skins inoculated with Salmonella typhimurium at 1 × 10⁸ CFU/mL were subjected to chemical or electrical treatments (4 mA/ cm² current, 1 kHz frequency and 50% duty cycle) for 10 min in 1% sodium chloride (NaCl), sodium carbonate (Na₂CO₃), or trisodium phosphate (Na₃PO₄ 12H₂O or TSP). Salmonellae on chicken skins and in treatment solutions and rinsing water were enumerated with microbiological platings. Chicken skin was also examined using scanning electron microscopy.S. typhimurium attached to skins were reduced by 90% after electrical treatments in 1% NaCl, Na₂CO₃, or TSP, while the reduction ranged from 34% to 76% in groups treated by the salts alone.     

Phosphate bonded wood composite products from invasive <Emphasis Type="Italic">Acacia</Emphasis> trees occurring on the Cape Coastal plains of South Africa

The feasibility of manufacturing phosphate bonded wood composite board products from four locally occurring invasive acacia tree species (Acacia cyclops, A. saligna, A. mearnsii and A. longifolia) was studied using a formulated magnesium oxide (MgO) and monopotassium phosphate (KH₂PO₄) binder system. The optimization for the manufacturing process was studied using a central composite statistical design, whereupon the following factors were considered, i.e. KH₂PO₄: MgO ratio, the fly ash content as partial replacement for the binder and the wood content as a ratio of wood to the total inorganic content. A fitted response surface plot was used to show the effect of the main factors and their interactions on the measured board properties. A response surface model was developed to predict the parameters leading to the best board properties. All physical properties evaluated met or exceeded the minimum requirements for low density particleboards. The results showed that the variables considered have significant effects on the physical properties of the boards. The optimum composite manufacturing process for making durable products within the scope of the studied species was found to be a KH₂PO₄/MgO ratio of 1.66, an ash content of 2.7% and a wood/inorganic ratio of 0.96 for the selected wood species.     

Influence of calcium and phosphorus, lactose, and salt-to-moisture ratio on Cheddar cheese quality: pH buffering properties of cheese

The pH buffering capacity of cheese is an important determinant of cheese pH. However, the effects of different constituents of cheese on its pH buffering capacity have not been fully clarified. The objective of this study was to characterize the chemical species and chemical equilibria that are responsible for the pH buffering properties of cheese. Eight cheeses with 2 levels of Ca and P (0.67 and 0.47% vs. 0.53 and 0.39%, respectively), residual lactose (2.4 vs. 0.78%), and salt-to-moisture ratio (6.4 vs. 4.8%) were manufactured. The pH-titration curves for these cheeses were obtained by titrating cheese:water (1:39 wt/wt) dispersions with 1 N HCl, and backtitrating with 1 N NaOH. To understand the role of different chemical equilibria and the respective chemical species in controlling the pH of cheese, pH buffering was modeled mathematically. The 36 chemical species that were found to be relevant for modeling can be classified as cations (Na⁺, Ca²⁺, Mg²⁺), anions (phosphate, citrate, lactate), protein-bound amino acids with a side-chain pKa in the range of 3 to 9 (glutamate, histidine, serine phosphate, aspartate), metal ion complexes (phosphate, citrate, and lactate complexes of Na⁺, Ca²⁺, and Mg²⁺), and calcium phosphate precipitates. A set of 36 corresponding equations was solved to give the concentrations of all chemical species as a function of pH, allowing the prediction of buffering curves. Changes in the calculated species concentrations allowed the identification of the chemical species and chemical equilibria that dominate the pH buffering properties of cheese in different pH ranges. The model indicates that pH buffering in the pH range from 4.5 to 5.5 is predominantly due to a precipitate of Ca and phosphate, and the protonation equilibrium involving the side chains of protein-bound glutamate. In the literature, the precipitate is often referred to as amorphous colloidal calcium phosphate. A comparison of experimental data and model predictions shows that the buffering properties of the precipitate can be explained, assuming that it consists of hydroxyapatite [Ca₅(OH)(PO₄)₃] or Ca₃(PO₄)₂. The pH buffering in the region from pH 3.5 to 4.5 is due to protonation of side-chain carboxylates of protein-bound glutamate, aspartate, and lactate, in order of decreasing significance. In addition, pH buffering between pH 5 to 8 in the backtitration results from the reprecipitation of calcium and phosphate either as CaHPO₄ or Ca₄H(PO₄)₃.