Optimisation of supercritical fluid extraction of astaxanthin from Penaeus monodon waste using ethanol-modified carbon dioxide

Some studies demonstrated that astaxanthin surpasses the antioxidant benefits of beta-carotene, zeaxanthin, canthaxanthin, vitamin C, and vitamin E. Penaeus monodon (Tiger shrimp) is one of the most valuable traded crustacean products in which astaxanthin can be found in its by-products. The extraction of thermolabile compound like carotenoids at lower temperatures through supercritical carbon dioxide (SC-CO2) can reduce the potential isomerization and degradation of the extraction product. In this study, astaxanthin had been extracted using SC-CO2 with 15% (v/v) ethanol as an entrainer and the recovered astaxanthin was analyzed using High performance liquid chromatography (HPLC). A central composite design (CCD) was employed to study the effect of three SC-CO2 parameters namely temperature (X1) from 40 to 80°C, pressure (X2) from 150 to 250 bar and extraction flow rate (X3) from 1 to 3 ml/min on the astaxanthin complex yield, (Y1) and free astaxanthin content, (Y2). The nonlinear regression equations were significantly (p0.9261), which had no indication of lack of fit. The results indicated that a combined set of values of temperature (56.88°C), pressure (215.68 bar) and extraction flow rate (1.89 ml/min) was predicted to provide the optimum region in terms of astaxanthin complex yield, (58.50 ± 2.62 μg/g ) and free astaxanthin content (12.20 ± 4.16 μg/g) studied

Co-solvent selection for supercritical fluid extraction of astaxanthin and other carotenoids from Penaeus monodon waste

In recent years, astaxanthin is claimed to have a 10 times higher antioxidant activity than that of other carotenoids such as lutein, zeaxanthin, canthaxanthin, and β-carotene; the antioxidant activity of astaxanthin is 100 times higher than that of α-tocopherol. Penaeus monodon (tiger shrimp) is the largest commercially available shrimp species and its waste is a rich source of carotenoids such as astaxanthin and its esters. The efficient and environment-friendly recovery of astaxanthins was accomplished by using a supercritical fluid extraction (SFE) technique. The effects of different co-solvents and their concentrations on the yield and composition of the extract were investigated. The following co-solvents were studied prior to the optimization of the SFE technique: ethanol, water, methanol, 50% (v/v) ethanol in water, 50% (v/v) methanol in water, 70% (v/v) ethanol in water, and 70% (v/v) methanol in water. The ethanol extract produced the highest carotenoid yield (84.02 ± 0.8 μg/g) dry weight (DW) with 97.1% recovery. The ethanol extract also produced the highest amount of the extracted astaxanthin complex (58.03 ± 0.1 μg/g DW) and the free astaxanthin content (12.25 ± 0.9 μg/g DW) in the extract. Lutein and β-carotene were the other carotenoids identified. Therefore, ethanol was chosen for further optimization studies

Intermediate Phases Formed During Synthesis Of β-Tricalcium Phosphate Via Wet Precipitation And Hydrothermal Methods

Beta-tricalcium phosphate (β-TCP) was synthesized using an aqueous wet precipitation method as well as a hydrothermal method. The processing parameters adopted in both methods were maintained to be as similar as possible. The precursor materials reacted in both methods were 0.3 mole of phosphoric acid, H3PO4, and 0.45 mole of calcium hydroxide, Ca(OH)2. The available processing parameters for the precipitation method are much more varied whilst the parameters for the hydrothermal method are much more limited. Hence, the parameters chosen were based on the availability of the parameters to accommodate both methods, viz. the use of the same precursor materials in a stoichiometric ratio of 1.5, a reaction temperature of 70°C, a reaction time of 2 hours, a stirring speed of either 200 or100 rpm, and a stirring duration of 2 hours. The intermediate phases formed upon precipitation were compared. It was confirmed by x–ray diffraction that the powder formed from the precipitation method was monetite and hydroxyapatite, whilst the initial the powder formed from the hydrothermal method consisted of brushite and hydroxyapatite. Thermal analysis was performed on both powders to ascertain the best heat-treatment temperature. Both powders were subsequently subjected to a heat-treatment temperature of 900°C and both were confirmed by x-ray diffraction to be single-phase β-tricalcium phosphate. Scanning electron microscopy was performed on both heat-treated powders and the microstructures observed were found to be distinctly different. The precipitated powder consisted of nano-sized powders that were heavily agglomerated, whilst the hydrothermal powder consisted of a flattened microstructure due to the pressure imposed upon reaction

In-Vitro Apatite Growth On Porous Â-Tricalcium Phoshpate Scaffolds Coated With PHVB

The bioactive properties of polyhydroxybutyrate-co-valerate (PHBV) coated beta-tricalcium phosphate (β-TCP) have been studied invitro. Porous β-TCP scaffolds have been prepared using a template method and sintered at 1450 °C.The bio ceramics were then coated with PHBV solution before being immersed for 6 weeks in a simulated body fluid (SBF)at 37°C.At the end of the immersion time, insignificant changes in the SBF pH value was observed, suggesting good stability against hydrolytic degradation. X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses revealed the presence of apatite.Morphological analysis by SEM showed the formation of apatite crystals in the form of flakes and globular deposits on the scaffold surface.This bonelike apatite indicates good biological activity of the bio ceramics scaffold with PHVB coating suggesting that the composite has potential for bone tissue engineering applications

Small scale integrated renewable energy supply for remote office employing the use of PV source / Nor Salwa Damanhuri … [et al.]

In order to overcome the running-out of the non-renewable sources, world has been introduced to the application of renewable energy. Renewable energy is defined as the energy which is generated from natural resources such as wind, sunlight, water, geothermal and many more. Wind energy is one the way to generate electricity. To utilize wind as energy source, the system need to be installed in the area consist of airflow to run the turbine. Unfortunately, Malaysia is not suitable to implement the wind energy system because lack of strong airflow [1]. Hydropower is also another renewable energy source. Usually, a hydropower is generated from dam. When the dam is constructed, it may generate the electricity at a constant rate and the lake formed from the dam construction can be used for water sports and leisure. However, the drawback of hydropower system is that the dam construction is extremely expensive to build. The dam also invites flooding to the area nearby and will destroy the living in villages and town [2]

Improment in Mechanical Properties Plain Low Carbon Steel Via Cold Rolling and Intercritical Annealing

AbstractIn this paper, a simple modified process is introduced to improve the mechanical properties of plain low carbon steel. The plain low carbon steel sheet with mainly ferrite and minor amount of pearlite starting microstructure was simply cold-rolled to a reduction of 50% and subsequently intercritical annealed at various temperatures. The specimen intercritical annealed at 850°C revealed dual phase ferrite-martensite and exhibited excellent mechanical properties when compared to specimens intercritical annealed at 800°C and 750°C, as well as the as-received specimen

Low temperature In–Bi–Zn solder alloy on copper substrate

In this paper, characteristic of In–32.7Bi–0.5Zn lead-free solder system have been studied. DSC shows that, In–32.7Bi–0.5Zn system alloy give low melting temperature at 72.30 °C. Lowest melting temperature ensures that the solder melts, forms a joint with the substrates, and re-solidifies within the shortest possible process time. Further, the wettability between molten solder and copper substrate was measured at different reflow temperature. The contact angle for In–32.7Bi–0.5Zn solder alloys were decreasing 30.76° to 24.5° as the temperature increased from 100 to 140 °C. A significant increment of contact angle for In–32.7Bi–0.5Zn at 140 °C. The result of spreading area is inversed with the contact angle. Energy-dispersive X-ray analysis indicated two layer of intermetallic compound between the solder and the substrate; Cu5Zn8 and Cu11In9 compound

Formulation Of Nickel Matrix Composite Coating Utilizing Malaysian Quarry Dust As Reinforcement For Tribology And Corrosion Performance

Quarry industries in Malaysia plays a significant and essential role in the development of the country. However, the enviromental concern is currently rising as one of the main challenging issues affecting the natural aggregate and limestone production. According to Sridharan et al. (2006), about 20- 25% of total production in each crusher unit is left out the quarry dust as waste material. Therefore, efforts have been taken to control enviromental pollution arising due to disposal of these industrial wastes by converting them into utilizable raw materials for usable application. Quarry dust is one of the by- product from the crushing process during quarrying activities, which have gained attention to be used for various applications. Recently, the utilization of quarry dust which is high in silica and alumina content have been extended to be used as a reinforcement for metal matrix composites due to high cost of conventional ceramic particles. Therefore, the effect of various compositions of quarry dust on the tribological and hardness properties of nickel matrix composite coatings electrodeposited on tungsten carbide substrate was investigated in this study. This research will contribute to the knowledge on the improvement of tribological and hardness of nickel-quarry dust composite coating electrodeposited on tungsten carbide via various compositions of quarry dust. The findings would be benefited by the cutting tools industries