Shelf life of shrimp (Penaeus merguiensis) stored in ice (0°C) and partially frozen (—3°C)

Sensory, biochemical and microbiological changes and changes in SDS-PA GE patterns of myofibrillar and sarcoplasmic proteins were studied in shrimp (Penaeus merguiensis) muscle during storage at partial freezing temperature (—3°C; PFS) and in ice (0°C; IS). During PFS up to 20 days there were slight changes in biochemical parameters, apparently no changes in microbiological populations, and no changes in electrophoretic protein patterns. Rapid changes in these parameters occurred in IS over the same period. Sensory assessment of shrimps stored at PFS showed that a considerable increase in prime quality life was possible at this temperature over shrimps in IS. Prime quality life of shrimps in PFS was found to be 16 days, compared with 8 days in IS. Extension of prime quality life was attributed to the significantly slower rate of biochemical and microbiological changes at PFS compared with IS. Changes in sensory properties were associated with changes in some of the chemical properties.     

Nonenymatic Browning, Fluorescence Development, and Formation of Pyrrole Derivatives in Phosphatidylethanolamine/ Ribose/Lysine Model Systems

Browning, fluorescence, and pyrrole formation were determined in 4 mixtures of phosphatidylethanolamine (PE), ribose (RI), and/or lysine (lys) incubated at 60°C to study the contribution of lipid oxidation to food browning when lipid oxidation products are formed in the presence of other food components. The 4 assayed systems (PE/lys, PE/RI, RI/lys, and PE/RI/lys) were also extracted with chloroform‐methanol (2:1) to distinguish between the nonenzymatic browning produced with the amino group of PE and that produced with the amino groups of lys. Under the assay conditions, both the RI and the oxidized products produced in the fatty acid chains of PE contributed to the development of browning in the assayed systems. However, RI and oxidation products of PE exhibited different reactivities for the different amino groups involved in these reactions. Thus, the oxidized lipids reacted with the amino group of PE with preference for the amino group of lys, and this preference was reversed for RI. These results suggest that the contribution of both carbohydrates and lipid oxidation products to food browning may be distinguished. In addition, determination of oxidized lipid/ethanolamine derivatives in phospholipids may be an alternative procedure to evaluate oxidative damage in foods.     

Microscopic characterization of petiole anatomy of Asteraceous taxa of Western Himalaya-Pakistan

Petiole anatomy of 15 species of family Asteraceae was examined which aimed to investigate petiolar anatomical structures for species level identification. Shandon Microtome was used for petiole histological preparations. Both qualitative and quantitative features were studied under microscope which showed significant variation in petiole, collenchyma, parenchyma shape/size, vascular bundles arrangement/size, and vessel elements quantity. Artemisia japonica Thunb., Cirsium vulgare (Savi) Ten., Myriactis nepalensis Less., Seriphidium brevifolium Ling & Y.R.Ling, Taraxacum officinale (L.) Weber ex F.H.Wigg., and Xanthium strumarium L. showed winged petioles. Maximum length and width of upper and lower epidermis was found in Tagetes erecta L. which is 23.05 ± 0.89 μm, 24.9 ± 1.257 μm length and 21.75 ± 1.38067 μm, 22.75 ± 0.467 μm width, respectively. Petioles of Parthenium hysterophorus L. was longest one with 9.85 ± 10.45 μm while A. japonica Thunb. showed highest number of vessel elements. Maximum size of vascular bundles was found in T. erecta L. with 5.05 ± 14.25 μm. Artemisia annua L., C. vulgare (Savi) Ten, Cyanthillium cinereum (L.) H.Rob., Helianthus annus L., M. nepalensis Less., P. hysterophorus L., Senecio chrysanthemoides DC. have trichomes while Tussilago farfara L. has highest number of vascular bundles. All species have angular collenchyma type except M. nepalensis Less., P. hysterophorus L., S. brevifolium Ling & Y.R.Ling, Tagetes minuta L., T. officinale L., S. chrysanthemoides DC., and T. farfara L. Cluster analysis implemented that distinct plant species in cluster. Petiolar anatomical structures and taxonomic key will helpful for distinguishing Asteraceous taxa at genus and species level. This taxonomic significant investigation will also provide baseline to taxonomists for other Asteraceae studies and phylogenetic research.     

Synthesis and Physico-Chemical Studies of Ester-Quat Surfactants in the Series of (Dodecanoyloxy)propyl n-Alkyl Dimethyl Ammonium Bromide

Ester-quat surfactants in the series of (dodecanoyl oxy) propyl n-alkyl dimethyl ammonium bromide referred to here as LC₃Cm (where m is the hydrocarbon chain lengths 8, 12 and 14) were synthesized and characterized by the usual spectroscopic methods (NMR, IR, MS…). Their physico-chemical properties were investigated by surface tension and conductimetric measurements. From surface tension measurements, isotherms and thermodynamic adsorption parameters were determined. The critical micelle concentration (CMC), the degree of counter ion dissociation (α) of micelles in the water and the standard Gibbs free energy $( \Updelta G_{\text{m}}^{0}) $ , of micellization were also determined by conductimetric measurements. The results obtained from both methods were compared to the similar surfactants in the series of quaternary ammonium surfactants. Optical microscopy was also used to study the behavior of anhydrous surfactants and the binary water/surfactant system as a function of temperature.     

“Metakaolin‐Slag‐Clinker Blends.” The Role of Na+ or K+ as Alkaline Activators of Theses Ternary Blends

This article reports on research into the use of solid alkalis (Na₂CO₃ and K₂CO₃) as activators to obtain hybrid cement (cement whose hydration generates a mix of C–A–S–H and (N,C)–A–S–H gels) from a blend of 20% clínker + 40% blast furnace slag + 40% metakaolin. More specifically, the study aimed to determine the effect of activator dosage (5 and 8 wt%) and type of alkaline cation (Na⁺ or K⁺) on the 2‐ and 28‐d mechanical strength of the end materials. The findings showed that the highest mechanical strength values were obtained with 5% Na₂CO₃. According to the XRD, NMR, and SEM/EDX analyses conducted on the reaction products, the alkalinity and solubilized chemical species generated by adding 5% Na₂CO₃ to the system yielded a mix of (N,C)–A–S–H and C–A–S–H cementitious gels as the main reaction products. The secondary reaction products included metastable (3CaO·Al₂O₃·CaCO₃·11H₂O‐type) carboaluminates that evolved into the calcite or vaterite forms of calcium carbonate. When K₂CO₃ was used (instead of Na₂CO₃), a (3CaO·Al₂O₃·0.5Ca(OH)₂·0.5CaCO₃·11H₂O‐type) hemicarboaluminate also formed. The study also revealed that Na⁺ favors coagulation/precipitation more effectively than K⁺, generating gels with a wider range of Qⁿ species.     

Influence of growth time on crystalline structure, conductivity and optical properties of ZnO thin films

This paper examines the growth of ZnO thin films on glass substrate at 350 ℃ using an ultrasonic spray technique. We have investigated the influence of growth time ranging from 1 to 4 min on structural, optical and electrical properties of ZnO thin films. The as-grown films exhibit a hexagonal structure wurtzite and are (002) oriented. The maximum value of grain size G = 63.99 nm is attained for ZnO films grown at 2 min. The average transmittance is about 80%, thus the films are transparent in the visible region. The optical gap energy is found to increase from 3.26 to 3.37 eV with growth time increased from 1 to 2 min. The minimum value of electrical resistivity of the films is 0.13 Ω·cm obtained at 2 min. A systematic study on the influence of growth time on the properties of ZnO thin films deposited by ultrasonic spray at 350 ℃ has been reported.     

Propagation of a Thermoelastic Wave in a Half-Space of a Homogeneous Isotropic Material Subjected to the Effect of Rotation and Initial Stress

The propagation of thermoelastic waves in a homogeneous, isotropic elastic semi-infinite space is subjected to rotation and initial stress, which is at temperature T₀ - initially, and whose boundary surface is subjected to heat source and load moving with finite velocity. Temperature and stress distribution occurring due to heating or cooling and have been determined using certain boundary conditions. Numerical results have been given and illustrated graphically in each case considered. Comparison is made with the results predicted by the theory of thermoelasticity in the absence of rotation and initial stress. The results indicate that the effect of the rotation and initial stress is very pronounced.     

Strength development and lime consumption progress relationship in lime stabilized bentonite samples

Bulletin of Engineering Geology and the Environment - Although soil-lime treatment has been successfully used for a long time, the mechanisms behind the clay soil-lime reaction remain...     

Effect of active films incorporated with montmorillonite clay and α‐tocopherol: Potential of nanoparticle migration and reduction of lipid oxidation in salmon

Fat‐rich fish such as salmon are highly susceptible to lipid oxidation, which affects the quality of the product. The compound α‐tocopherol is widely used as an antioxidant added directly to food or through the incorporation in active packaging besides having activity of vitamin E, which is an essential nutrient to the human body absorbed from food. The objective of this paper was to evaluate the montmorillonite (MMT15A) and α‐tocopherol migration potential and antioxidant effect of chitosan/MMT15A/α‐tocopherol active films on reduction of lipid oxidation in fresh salmon. Chitosan films incorporated with MMT15A (0 and 1 g/100 g) and α‐tocopherol (0, 10, and 15 g/100 g) were applied on the fresh salmon for 8 days. Samples of salmon wrapped in films 3 and 6 (10% tocopherol and 1% MMT15A + 15%tocopherol, respectively) showed the lower values of thiobarbituric acid reactive substances (TBARS) at eighth storage day at 4°C. Film 6 (1% MMT15A and 15% tocopherol) showed better result on reduction in water vapour transmission rate (WVTR) and controlled release of tocopherol. All the films containing MMT15A presented migration of minerals (Mg and Si) for the salmon during the 8 days. Thus, the use of this film for release of active substances is a promising alternative for application as food packaging in order to obtain nutritionally fortified foods and inhibit oxidation reactions.     

Unrevealing the Sources and Catalytic Functions of Phytase with Multipurpose Characteristics

Catalysis Letters - Phytase, a key biocatalyst with multipurpose applied potentialities, and its significant relationship to contemporary industrial apprehensions provide unique physicochemical and...