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.

Gel time studies in activation of polyester resins

Gelling times of polyester resins with varying quantities of catalyst and accelerator were studied and the results reported in this communication.

On sun-drying of Bombay duck

Sun-drying of Bombay duck by hanging on scaffolds gave better products than those obtained by drying them in trays. Optimum rate of drying and quality of dried product were obtained when the fish were suspended at the rate of 50 to 60 per meter length of the rope. The quality of the raw material as affected by the delays in different hauls in the fishing trip was reflected in the dried products also.

Investigations on wooden floating materials: the loss of buoyancy under continuous immersion in water and the rate of its redemption by drying

A wooden fishing float under immersion in water for long periods is liable to absorb water, the quantity of water absorbed possibly being dependent upon the physical factors like the specific gravity and the inherent property of the material, the time of soaking and the pressure acting on it. Consequently a wooden float is likely to become heavy and loss its original buoyancy. However, when the float is removed from water and dried, the lost buoyancy is regained on complete drying. The present paper is an attempt to elucidate these two important characteristics of some of the chief wooden floating materials used on the West Coast of India.

Freeze drying of fishery products: Part IV - Biochemical changes occurring in prawn muscle during freezing, freeze drying and prolonged storage of the freeze dried product

The changes occurring in water and salt extractable protein and non-protein fractions in prawn muscle of different species during freezing, freeze drying and subsequent prolonged storage have been studied. There is no denaturation of water extractable proteins, whereas salt extractable proteins were rendered insoluble to the extent of 21% due to freeze drying. The freeze dried products remained in good edible condition for 32 months of storage up to which storage characteristics were followed.

Freeze drying of fishery products: Part V - Storage characteristics of ready-to-serve freeze dried foods

Behaviour of freeze dried ready-to-serve fish based food preparations during prolonged storage at room temp has been studied and reported in this paper. Storage life of such products under the conditions employed in this study can be reckoned in years at our ambient temps.

Preparation of mussel meat by drying

The paper describes a simple and cheap process for the preservation of mussel meat by drying. The method involves blanching the mussel meat shucked from purified live mussels in 5% boiling brine for 5 min followed by drying to moisture of 10 to 15%. The product stored in glass bottles or polythene bags suitably sealed, has a storage life of about six months after which the organoleptic qualities begin to deteriorate. No preservative is used at any stage of processing and the yield of the product is approximately 20%. The major type of spoilage during storage is brown discoloration. Spoilage due to insect infestation is also common unless packed properly.

Comparative efficiency of different surfaces for drying fish

The efficiency of four different drying surfaces, namely, cement platform, palmyrah leaf mat, aluminum tray and stretched net for drying fish were studied using sciaenids, mullet and perch. All the drying surfaces were found to be equally efficient. The cheaper and locally available palmyrah leaf mat or stretched net can replace costly cement platform and aluminium tray for efficient drying of fish.

Effect of cooking and drying on carbonyls of oil sardine

Changes in the total as well as major individual carbonyls of oil sardine during steam cooking, oven drying, sun drying and freeze drying are presented. Carbonyls extracted with hexane were converted to their 2:4 dinitro phenyl hydrazone (DNPH) derivatives and were separated into major classes by column chromatography on celite/magnesia. Individual carbonyls were then identified by capillary gas chromatography of the DNPH derivatives. Dehydration and heating increase the carbonyl production from highly unsaturated fish lipids. The carbonyls produced react with other muscle constituents leading to complex changes. The influence of the mode of dehydration on these different aspects and their net effect on flavour are discussed.

Effect of water washing on biochemical and gel characteristics of minced meat from croaker fish (Johnius gangeticus)

Quality of analog fishery products invariably depends on the gel characteristics and nutritional status of minced meat. With an objective to find out the effect of water washing on kamaboko gel, the minced meat from Croaker fish was washed for four times (5 minutes each) using chilled water at a temperature of 8-10°C. Results reflected noticeable improvement in folding test and SSN% of kamaboko with essential decrease in fat content, water soluble proteins, expressible water and quality parameters like NPN, VBN, TMA, FFA and PV denoting superior gel quality than control sample after repeated washing. The results indicated that there was a definite improvement in functional properties such as gel forming ability, expressible water content of the croaker minced meat essential decrease in fat content, water soluble proteins, expressible water and quality parameters after each wash, but two washes of 5 minutes duration each was necessary to achieve satisfactory results.

A solid-state dye-sensitized solar cell based on a novel ionic liquid gel and ZnO nanoparticles on a flexible polymer substrate.

This paper describes a new strategy to make a full solid-state, flexible, dye-sensitized solar cell (DSSC) based on novel ionic liquid gel, organic dye, ZnO nanoparticles and carbon nanotube (CNT) thin film stamped onto a polyethylene terephthalate (PET) substrate. The CNTs serve both as the charge collector and as scaffolds for the growth of ZnO nanoparticles, where the black dye molecules are anchored. It opens up the possibility of developing a continuous roll to roll processing for THE mass production of DSSCs.

Application of gel-casting to the fabrication of 1-3 piezoelectric ceramic-polymer composites for high-frequency ultrasound devices

A modified gel-casting technique was used to fabricate a 1-3 piezoelectric ceramic/polymer composite substrate formed by irregular-shaped pillar arrays of small dimensions and kerfs. This technique involves the polymerization of aqueous piezoelectric (PZT) suspensions with added water-soluble epoxy resin and polyamine-based hardener that lead to high strength, high density and resilient ceramic bodies. Soft micromoulding was used to shape the ceramic segments, and micropillars with lateral features down to 4 m and height-to-width aspect ratios of ∼10 were achieved. The composite exhibited a clear thickness resonance mode at approximately 70 MHz and a k eff ∼ 0.51, demonstrating that the ceramic micropillars possess good electrical properties. Furthermore, gel-casting allows the fabrication of ceramic structures with non-conventional shapes; hence, device design is not limited by the standard fabrication methods. This is of particular benefit for high-frequency transducers where the critical design dimensions are reduced. © 2012 IOP Publishing Ltd.

Composite electrospun gelatin fiber-alginate gel scaffolds for mechanically robust tissue engineered cornea.

A severe shortage of good quality donor cornea is now an international crisis in public health. Alternatives for donor tissue need to be urgently developed to meet the increasing demand for corneal transplantation. Hydrogels have been widely used as scaffolds for corneal tissue regeneration due to their large water content, similar to that of native tissue. However, these hydrogel scaffolds lack the fibrous structure that functions as a load-bearing component in the native tissue, resulting in poor mechanical performance. This work shows that mechanical properties of compliant hydrogels can be substantially enhanced with electrospun nanofiber reinforcement. Electrospun gelatin nanofibers were infiltrated with alginate hydrogels, yielding transparent fiber-reinforced hydrogels. Without prior crosslinking, electrospun gelatin nanofibers improved the tensile elastic modulus of the hydrogels from 78±19 kPa to 450±100 kPa. Stiffer hydrogels, with elastic modulus of 820±210 kPa, were obtained by crosslinking the gelatin fibers with carbodiimide hydrochloride in ethanol before the infiltration process, but at the expense of transparency. The developed fiber-reinforced hydrogels show great promise as mechanically robust scaffolds for corneal tissue engineering applications.

Spray drying: An alternative synthesis method for polycationic oxide compounds

Synthesis of polycationic compounds by the spray-drying technique is an interesting alternative in the domain of aqueous precursor synthesis methods. Spray drying yields high quality samples with good reproducibility. The possibility of scaling up for production of large quantities with fast processing time is well established by the commercial availability of powders of various compositions. In this paper, we have discussed the advantages and limitations of this method and demonstrated its interest by synthesizing a few polycationic compounds selected for their attractive properties of thermoelectricity [Bi1.68Ca2Co1.69O 8, La0.95A0.05CoO3 (A=Ca, Sr, Ba)] or magnetoresistance [La0.70A0.30MnO3 (A=Sr, Ba)]. We have confirmed the quality of these samples by reporting their structure, magnetic and transport properties. © 2010 Elsevier Ltd All rights reserved.