Suitability of sodium lactate as cryoprotectant and its effect on gel forming ability and protein denaturation of croaker fish surimi during frozen storage

The effect of sodium lactate is compared with sucrose + sorbitol + sodium tri-poly phosphate as cryoprotectant on gel forming ability & protein denaturation of croaker surimi during frozen storage at -20±2°C for 90 days was evaluated. The quality of Croaker surimi with 6% (w/v) sodium lactate was examined in terms of biochemical parameters of muscle protein, thaw drip, gel strength and calcium ATPase activity :.omparing with those of surimi added with sucrose/sorbitol & without additive as control. Both the cryoprotectants minimized the negative effects of frozen storage on physico-chemical traits of myofibrillar proteins which was evident from the biochemical and sensory parameters. The residual Ca2+ ATPase activity and gel strength of surimi with sodium lactate were higher than those of control throughout 90 days of storage. Ca2+ A TPase activity and gel strength found a high positive correlation. From the results, it was found that sodium lactate was equally effective in preservation of croaker muscle protein native structure during frozen storage as the sucrose/ sorbitol and also less sweet without any risk of maillard browning.

Penetration of sodium chloride during prolonged salting of fish

This work deals with adsorption of salt and expulsion of moisture in Synagris japonicus, Sciaenids sp. and Lactarius lactarius during prolonged salting. The fish used in this study were procured fresh and handled immediately. They were gutted, gilled, cleaned well and salted. Results indicated that larger salt proportions and higher temperature of salting both accelerate the rates of absorption of salt and shedding of moisture by fish muscle during salt curing.

Studies on arsenical creosote as a wood preservative for marine structures. Part 2. Observation on leaching, corrosion and resistance to borer attack

A detailed study on arsenical creosote with reference to leaching, corrosion and anti-borer properties was carried out. Results showed that aging had very little effect on the preservative which suggested better fixation of the preservative into the wood. Corrosion of mild steel, galvanised iron, aluminium-magnesium alloy (M57S) and copper panels in the preservative was found to be negligible. Normal creosote and low temperature creosote of Regional Research Laboratory, Hyderabad, both fortified with arsenic trioxide resisted borer damage on wooden panels for a period of over five months in the port of Cochin. The performance of low temperature creosote fortified with arsenic was found to be equally satisfactory when compared to normal creosote fortified in the same manner. A loading of 208.6 Kgs/ml³ for Haldu (Adina cordifolia) and 138 Kgs/m³ for Mango (Mangifera indica) in the case of normal creosote and 177 Kgs/m³ for Mango the case of RRL creosote were found to be sufficient for treating the wood.

Studies on Colombo-curing of mackerel (Rastrelliger kanagurta)

Results of investigations carried out to improve the process of 'Colombo-curing' of mackerel are presented in this paper. Optimum composition of salt and gorujka puli (malabar tamarind, Garcinia cambogea) to be used in the pickle mixture to give a product of good organoleptic and chemical characteristics have been worked out. Sodium benzoate is used as a preservative against the attack of molds, 'red' etc.

Tolerance of Penaeus monodon larvae to cupric sulfate added in bath

Copper is used to deter the growth of bacterial, fungal and protozoan disease organism in fishes. Zoeae (Z SUB-1 ), myses (M SUB-1 ) and postlarvae (P SUB-1 ) were exposed to copper sulfate at concentrations of 0 . 025, 0 . 05, 0 . 75, 0 . 1 and 0 . 2 ppm from 24 to 96 hours. The number of surviving larvae were counted at the end of each 24-hour period and the percentage of survival is determined for each dose level. The LC SUB-50 for each of the larval stages was interpolated from the data whenever possible. Three trials with 2 replicates per trial were conducted. The physico-chemical characteristics of the bath taken before and at the end of the experimental period show insignificant differences between initial and final values in each trial. Results indicate that mortality rates of all larval stages increased with exposure time and that mortality rates of the experimental group is higher than the control. Interpolation of the LC SUB-50 is possible only for the 48-h and 72-h exposure times for both zoeae and myses and for the 48-h exposure time for the postlarvae. This is due to the high survival percentage of the 24-h group and the low survival percentage (below 50%) of the larvae exposed for 96 hours. The 48-hour LC SUB-50 for Z SUB-1 , M SUB-1 and P SUB-1 are 0 . 225, 0 . 350 and 0 . 125 ppm respectively. Postlarvae seem to be more sensitive than either of the 2 larval stages having a lower 48-h LC SUB-50 and a low survival rate after 72 hours. The larvae were observed to lose their balance and were lethargic, producing few swimming movements so that they were mostly confined to the bottom of the aquaria. Moribund larvae observed under the microscope had a faster but weak heartbeat compared to healthy larvae. Slight or complete loss of feeding ability indicated by empty guts and delayed molting of Z SUB-1 to Z SUB-2 were also noted.

Halichondria sulfonic acid, a new HIV-1 inhibitory guanidino-sulflonic acid, and halistanol sulfate isolated from the marine sponge Halichondria rugosa Ridley & Dendy

A new sulfur-containing guanidino derivative, halichondria sulfonic acid (1) showing anti-HIV-1 activity, and halistanol trisulfate (2) with anti-tumor activity have been isolated from the marine sponge Halichondria rugosa Ridley & Dendy collected in the

Application of encapsulated nisin and sodium citrate for shelf life increasing of Rainbow trout (Onchorhynchus mykiss) fillet packaged with MAP and their effect on Staphylococcus aureus

Nisin is a widely used naturally occurring antimicrobial effective against many pathogenic and spoilage microorganisms. It has been proposed that reduced efficacy of nisin in foods can be improved by technologies such as encapsulation to protect it from interferences by food matrix components. The aim of this study was using of spray dried encapsulated nisin with zein in concentration of (0.15 and 0.25 g/kg) and sodium citrate (1.5 and 2.5%) and treatments with both of them to extent the shelf life of filleted trouts packaged by Modified Atmosphere Packaging (45% CO2, 50% N2 ,5% O2) and stored at 4±1 °C for 20 days. Furthermore, to evaluate the antimicrobial efficiency of encapsulated nisin and soudium citrate the trouts fillets was inoculated with Staphylococcus aureus as an index pathogenic bacteria. Assessment of chemical spoilage indexes such as (Proxide value, Thiobarbituric acid, total volatile base nitrogen and pH) , microbial parameters (Total Plate Count, Psychrotrophic count, Lactic acid bacteria count), Staphylococcus aureus cont in treatments which were inoculated with 5 logcfu/g of this bacteria and sensory evaluation of fillets including (smell, color, texture and total acceptability) was carried out in days of 0, 4, 8, 12, 16 and 20. The results revealed that treatment with both exposure of nisin and sodium citrate showed significantly lower chemical spoilage indexes in comparison with controls (vaccum packed and MAP) (P<0.05). Furthermore, (nisin 0.25 g/kg sodium citrate 2.5%) treatment which was exposed to the maximal level used of both materials was significantly the lowest treatment with (Proxide value, Thiobarbituric acid, total volatile base nitrogen and pH) of 9.95 (meq O2/kg) , 1.55 (mgMA/kg), 29.65 (mgN/100g) and 6.65 , respectively and according to the maximal recommended level of this indices , shelf life of fillets in this treatment was esstimated 20 days.The control (vaccum packed) treatment was significantly the highest treatment with (Proxide value, Thiobarbituric acid, total volatile base nitrogen and pH) of 15.17 (meq O2/kg), 3.03 (mgMA/kg), 38.4 (mgN/100g) and 6.95 , respectively and according to the maximal recommended level of this indices , shelf life of fillets in this treatment was estimated 11 days. Also, in microbial point of view (nisin 0.25 g/kg- sodium citrate 2.5%) treatment was the lowest treatment with Total Plate Count, Psychrotrophic count, Lactic acid bacteria count and Staphylococcus aureus count of 6.7, 6.83, 5.25 and 6.04 logcfu/g respectively, and conrol (vaccum packed) treatment was the highest treatment with 9.15, 9.41, 7.7 and 9.01 logcfu/g respectively. According to the lower results of chemical and microbial indices and higher sensory evaluated scores assessed in this research for encapsulated nisin in comparison with free nisin , it was concluded that encapsulation of nisin with zein capsules may improve the efficiency of nisin. The measuremented values of Mass yield, Total solids content of capsules, Encapsulation efficiency, In vitro release kinetics in 200 hour for encapsulated nisin in this study was 49.89, 62, 98.31 and 69% respectively and Encapsulated particle size was lower than 674.21 μm for 90% of particles. As a consequence, nisin , in particular encapsulated nisin, and sodium citrate alone or together with and Modified Atmosphere packaging might be considered as effective tools in preventing the quality degradation of the fillets, resulting in an extension of their shelf life.

Application of combined effect of sodium acetate and nisin on reduction of contamination by Listeria monocytogenes in vacuum packaged grass carp (Ctenopharyngodon idella) fillets kept at 4°C

In this study microbiological , chemical quality and fatty acid composition of grass carp (Ctenopharyngodon idella) fillets treated by dipping in sodium acetate (%1 and %3), nisin (% 0.1 and % 0.2) and combination of sodium acetate and nisin was evaluated during 16 days of refrigerated of 4°C Antilisterial effect of nisin was enhanced with the increased concentration of sodium acetate. At day 12 post storage, Listeria monocytogenese count was higher in the control group than the recommended value, however in sodium acetate and nisin treated samples, the count was lower (5.17-5.91 log cfu/g). With increasing the concentrations of sodium acetate, mesophilic counts were lower. Regarding nisin, better results was obtained by applying %0.1 nisin. Greater inhibition of mesophile bacteria was observed when combination treatment was used. The number of lactobacillus was lower when higher concentrations of sodium acetate and nisin were used. Total Volatile Nitrogen values at the end of the experiment were lower in the samples treated with both nisin and sodium acetate and the better results were obtained in combination treatments. Peroxide (PV) at the end of the experiment was 1.9 meq/kg in control, and the lowest values were observed for the treatments 3(%0 sodium acetate +% 0.2 nisin) and 9(%3 sodium acetate +% 0.2 nisin) between 1.08 and 1.62 meq/kg without significant difference. Thiobarbituric acid (TBA) levels at the end of experiment have been shown to be 0.46 mg malonaldehyde per kg in the control. On the other hand treatments 9 had the TBA values of 0.19 mg malonaldehyde per kg which was significantly lower than that of control. Polyunsaturated fatty acids increased by increasing the sodium acetate doses and instead saturated fatty acids and n-6/n-3 ratio decreased. The ratio of UFA/SFA and also C22:6/C16:0 increased when a higher concentration of sodium acetate has been used. The best result obtained by using 3% of sodium acetate but no such relation with nisin was observed.

Angle-of-attack effects on counter-rotating propellers at take-off

Due to their potential for significant fuel consumption savings, Counter-Rotating Open Rotors (CRORs) are currently being considered as an alternative to high-bypass turbofans. When CRORs are mounted on an aircraft, several 'installation effects' arise which are not present when the engine is operated in isolation. This paper investigates how flow features arising from one such effect - The angle-of-attack of the engine centre-line relative to the oncoming flow - can influence the design of CROR engines. Three-dimensional full-annulus unsteady CFD simulations are used to predict the time-varying flow field experienced by each rotor and emphasis is put on the interaction of the frontrotor wake and tip vortex with the rear-rotor. A parametric study is presented that quantifies the rotorrotor interaction as a function of the angle-of-attack. It is shown that angle-of-attack operation significantly changes the flow field and the unsteady lift on both rotors. In particular, a frequency analysis shows that the unsteady lift exhibits sidebands around the rotor-rotor interaction frequencies. Further, a non-linear increase in the total rear-rotor tip unsteadiness is observed for moderate and high angles-of-attack. The results presented in this paper demonstrate that common techniques used to mitigate CROR noise, such as modifying the rotor-rotor axial spacing and rear-rotor crop, can not be applied correctly unless angle-of-attack effects are taken into account. Copyright © 2012 by ASME.

Hydrolysis and coagulation behavior of polyferric sulfate and ferric sulfate

The hydrolysis behaviors of polyferric sulfate (PFS) and ferric sulfate (FS) under conditions similar to raw wastewater were investigated and the coagulation of biologically pretreated molasses wastewater using PFS and FS was evaluated by studying coagulation efficiency, zeta potential and microscopic surface morphology of flocs. Experimental results show that the hydrolysis behavior of PFS is different from that of FS on the basis of ferron assay. In the case of FS, fast-reacting Fe(III) polymers were the dominant polynuclear species while large fraction of slow-reacting iron polymers is present in PFS. Despite slightly fewer dosages of PFS required as compared to FS, there is no marked difference in the coagulation of molasses effluent between PFS and FS, especially at the optimum dosages. Both coagulants destabilize organic compounds predominantly through charge neutralization-precipitation mechanism. Hydrolysis rate of PFS in synthetic solution is appreciably different from that in raw wastewater. This may due to the effect of sulfate anion introduced as counter-ion as well as depolymerization of larger polymeric Fe(III) species by the organic ligands present in molasses effluent.

Purification and characterization of hydrosoluble components from the sap of Chinese lacquer tree Rhus vernicifera

Continuous gradient elution chromatography (CGEC) was employed to purify and separate enzymes and polysaccharides from the sap of Rhus vernicifera Chinese lacquer tree. There are three different molecules with laccase enzyme activity. Two are enzymes of each other (L1, and L2), whereas the third (RL) is an entirely separate entity. Two polysaccharides (GP1 and GP2) were also found. The Rhus laccase (RL), and isoenzymes L1 and L2, have peak molecular masses of 109,100, 120,000, 103,000 respectively; each has four copper atoms per molecule, and the pI values were 8.2, 8.6, and 9.1, respectively. The structure of the laccases was studied by Fourier-transform infrared (FT-IR) and Matrix-assisted laser desorption/ionization time-of flight (MALDI-TOF) mass spectrometry. The typical amide I (1646 cm(-1)) and amide II (1545 cm(-1)) bands were observed. The results from MALDI-TOF were similar to those from CGEC, but the molecular mass from the MALDI-TOF was significantly different from that obtained from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). (c) 2006 Elsevier B.V. All rights reserved.

Effects of polyaluminum chloride and copper sulfate on phosphorus and UV254 under different anoxic levels

Experimental sediments and water from shallow, eutrophic Dianchi Lakes were treated in a controlled laboratory microcosm using different chemicals under different anoxic levels. This study revealed that the polyaluminum chloride (PAC) was able to inhibit the phosphorus release and decrease the UV254 value at any anoxic level. When the DO concentrations were between 0.76-0.95 mg(.) L-1, the UV(254)value, total phosphorus (TP), and total dissolved phosphorus (TDP) in the water column were decreased by 71.93%, 87.12% and 64.24% respectively. The UV254, TP, and TDP were also decreased by 72.94%, 70.87% and 50.76% respectively at the levels of 4.56-5.32mg(.)L(-1) of DO concentrations. The treatment effects of TP and TDP in the water column using copper sulfate however were not as efficient as the PAC treatment. The UV254 value was increased with the addition of copper sulfate at every anoxic level tested but the chlorophyll-a (Chl-a) content was decreased rapidly and efficiently by copper sulfate more than the treatment by PAC. When the DO concentrations were 0.76-0.86mg(.)L(-1) and 4.75-5.14mg(.)L(-1), the Chl-a concentrations were decreased by 84.87% and 75.07% respectively through copper sulfate treatment. With additions of PAC and copper sulfate, the phosphorus fractions in sediments were shifted forward to the favorable shapes that have little ability of release. The TP concentrations in sediments were increased after treatment via PAC and copper sulfate. Under anoxic conditions, most of the BD-P (Fe-P) to NaOH-P (Al-P) was converted using the recommended PAC dose in BD-P rich sediment. Similar to the PAC, the copper sulfate also could flocculate the exchange phosphorus from sediment to overlying water. Overall though, the effects of copper sulfate treatment were not better than that of the PAC.

GENOTOXIC EFFECTS OF LINEAR ALKYL BENZENE SULFONATE, SODIUM PENTACHLOROPHENATE AND DICHROMATE ON TETRAHYMENA-PYRIFORMIS

DNA in macro- and micronuclei of Tetrahymena pyriformis treated with linear alkyl benzene sulfonate (LAS) and sodium pentachlorophenate (PCP-Na) were determined by microspectrophotometry. The effects on rate of formation of macronuclear DNA extrusion bodies were also studied. We found DNA content of micronuclei in 0.14 ppm LAS and 0.9 ppb PCP-Na was lower than in that of the control, and LAS was able to increase the formation rate of macronuclear DNA extrusion bodies (the formation rate was 54% in 11.3 ppm LAS and 25.6% in 16.7 ppm dichromate). We concluded that 0.14 ppm LAS (below the maximum acceptable toxicant concentration) was genotoxic, whereas 0.014 ppm LAS was not. Dichromate 0.05 ppm and 0.9 ppb PCP-Na, equal to and below the maximum acceptable toxicant concentration, respectively, were potentially genetoxic.