Fatty acids and proximate composition of eight Thai edible terricolous insects

Fatty acid composition and proximate analysis of eight terricolous insects namely dung beetle (Copris nevinsoni Waterhouse), short tailed cricket (Brachytrupes portentosus Lichtenstein), june beetle (Holotrichia sp.), queen caste (Oecophylla smaragdina Fabricius), weaver ant (Oecophylla smaragdina Fabricius), termite (Termes sp.), longan stink bug (Tessaratoma papillosa), cicada (Meimuna opalifera Walker) were determined. Polyunsaturated fatty acid (PUFA) was the most predominant fatty acid found in all analyzed insects, followed by saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA). The concentration of total PUFA ranged from 213 in cicada to 1514 mg/100 g in dung beetle. There were five PUFAs; 18:3n ? 3, 20:3n ? 6, 20:4n ? 6, 20:5n ? 3 and 22:6n ? 3 detected in the insect samples. Two fatty acids, 20:3n ? 6, and 20:4n ? 6 were found in all analyzed insects, while, 20:5n ? 3 was only detected in dung beetle which lives in herbivore faeces, at concentration of 300 mg/100 g accounted for 13% of total fatty acid. The SFA content in ranged from 234 in termite to 733 mg/100 g in dung beetle. Only one MUFA, 18:1 was detected in the all analyzed insects. The protein content of insects ranged from 37% in queen caste to 54% in dung beetle. The highest amount of carbohydrate (16%) was found in cicada. Lipid contents ranged from 5% in june beetle to 37% in queen caste, while ash contents of edible insects ranged from 2% in queen caste to 12% in june beetle. We suggest that the insect could be considered as a good nutritional food source especially for fat and protein.     

Modeling of combined far-infrared radiation and air drying of a ring shaped-pineapple with/without shrinkage

A ring shape is commonly used for industrial process of pineapple. Unfortunately, there has been no study on modeling of pineapple rings. Therefore we developed the mathematical model of pineapple rings during combined far-infrared radiation and air convection drying to investigate the evolutions of moisture content and qualities. The drying model based on the solution of Fick's law was used to estimate moisture diffusion coefficient (D). The D values with and without taking into account shrinkage phenomenon of dried products were compared. The kinetics of dried pineapple qualities such as color, shear force ratio and shrinkage during drying also were studied. Pineapples were pretreated, cut into rings and dried at far-infrared intensities of 1–5 kW/m² combined with air temperatures of 40–60 °C and air velocities of 0.5–1.5 m/s. The D values were found to increase with increasing intensity and air temperature. The D values with shrinkage consideration were lower than the D values without shrinkage consideration for all drying conditions. The quartic model gave a better fit over the other three polynomial models for describing the color kinetics. The thin layer drying models such as Page, Henderson and Pabis, Logarithmic and Midilli–Kucuk were modified in order to describe shear force ratio (SFR) of dried pineapple. The statistically analyses from this present study indicated that modification of drying models can be used to describe the kinetics of SFR and Midilli–Kucuk's form gave a better fit over the other form. The quadratic model was better than the linear model to predict shrinkage kinetics for all four dimensions (outer radius, inner radius, thickness and volume) of pineapple rings.     

Prevention of hepatitis B in hemodialysis patients using hepatitis B immunoglobulin. A controlled study

In a controlled study, the protection effect of hepatitis B immune globulin (HBIG) was evaluated in patients hemodialyzed for less than one month in two collaborating units. Fifteen randomly selected patients received HBIG at five to eight week intervals throughout the study, and 13 other control patients received no immunoglobulin. During a follow-up period of 14 to 30 months, none of the HBIG-treated and 12 of the control patients developed evidence of exposure to virus B hepatitis, including 10 with HBs Ag antigenemia (p is less than 0.001): five of these remained persistently antigen positive. Evidence of non-B hepatitis was found in 8 HBIG-treated and in 3 non-treated patients. Only two HBIG-treated patients developed active antibodies against hepatitis B surface antigen. Thus, HBIG seems effective in preventing hepatitis B in hemodialysis patients, provided the interval between two injections is not greater than two months. However, prolonged administration of HBIG may impair passive-active immunization to hepatitis B virus.     

Improvement of quality and antioxidant properties of dried mulberry leaves with combined far-infrared radiation and air convection in Thai tea process

Combined far-infrared radiation with hot-air convection (FIR-HA) drying was used for improving colour and antioxidant properties of mulberry leaf tea. Antioxidant properties and phenolic compounds of FIR-HA dried mulberry tea were determined and compared with the commercial product and with fresh leaves. We found that a smaller decrease in L and b values of the FIR-HA dried tea than those of commercial tea was observed. FIR-HA tea was found to have similar colour to fresh leaf while the commercial tea had darker colour. A significant decrease in total phenolic acid content (TPC) and total flavonoid content (TFC) was found in hot-air (HA) dried commercial tea compared to fresh leaves, while TPC in FIR-HA dried tea was significantly increased. Similar results were found in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical activities. However, the results were different for ferric reducing antioxidant power (FRAP). Both teas had lower FRAP values compared to fresh leaves. Eleven phenolic compounds were identified in fresh leaf and in mulberry tea, namely p-coumaric acid, benzoic acid, (+)-catechin, chlorogenic acid, vanillic acid, syringic acid, sinapic acid, protocatechuic acid, ferulic acid, gallic acid and caffeic acid. The total content of phenolic compounds (TPCC) increased in FIR-HA dried samples compared to those of HA dried tea, except for chlorogenic and syringic acids, which were found in greater amounts in HA dried commercial tea. Our results have demonstrated that FIR-HA should be considered as a suitable drying method for mulberry tea with respect to preserving its antioxidant properties and phenolic compounds.     

A parallel coextrusion technique for simultaneous measurements of radial die swell and velocity profiles of a polymer melt in a capillary rheometer

This article proposes a new experimental technique to simultaneously measure radial die swell and velocity profiles of polystyrene melt flowing in the capillary die of a constant shear rate rheometer. The proposed technique was based on parallel coextrusion of colored melt‐layers into uncolored melt‐stream from the barrel into and out of the capillary die. The size (thickness) ratio of the generated melt layers flowing in and out of the die was monitored to produce the extrudate swell ratio for any given radial position across the die diameter. The radial velocity profiles of the melt were measured by introducing relatively light and small particles into the melt layers, and the times taken for the particles to travel for a given distance were measured. The proposed experimental technique was found to be both very simple and useful for the simultaneous and accurate measurement of radial die swell and velocity profiles of highly viscous fluids in an extrusion process. The variations in radial die swell profiles were explained in terms of changes in melt velocity, shear rate, and residence time at radial positions across the die. The radial die swell and velocity profiles for PS melt determined experimentally in this work were accurate to 92.2% and 90.8%, respectively. The overall die swell ratio of the melt ranged from 1.25 to 1.38. The overall die swell ratio was found to increase with increasing piston speed (shear rate). The radial extrudate swell profiles could not be reasoned by the shear rate change, but were closely linked with the development of the velocity profiles of the melt in the die. The die swell ratio was high at the center (～1.9) and low (～0.9) near the die wall. The die swell ratio at the center of the die reduced slightly as the piston speed was increased. Polym. Eng. Sci. 44:1960–1969, 2004. © 2004 Society of Plastics Engineers.     

Use of paraffin impregnated lightweight aggregates to improve thermal properties of concrete panels

In this study, the effect of aggregates impregnated with phase change material (paraffin type) on properties of concrete is investigated. The experimental series consists of two stages. The first stage is to investigate the techniques used to impregnate phase changed material (paraffin type) into lightweight aggregates and the properties of aggregates with paraffin inside (PLA). Two impregnation techniques are introduced, (1) heat only and (2) heat and pressure (autoclaving). Using the obtained results, the aggregate with the highest level of impregnation in the shortest time is selected to use in the concrete production process of the next stage. In the second stage, the properties of concrete mixed with non-paraffin and paraffin impregnated lightweight aggregates (PLA) at different proportions are investigated. The experimental series include density and absorption, compressive strength, thermal storage (and insulation) and sound transmission loss. Results in aggregate level show the increase in specific gravity and the decrease in absorption with paraffin inserted into aggregates. In concrete form, the density, compressive strength and sound insulation are found to increase with the PLA replacement ratio. The sound transmission loss, on the other hand, becomes less efficient with increasing PLA replacement ratio.     

Experimental studies on radial extrudate swell and velocity profiles of flowing PS melt in an electro‐magnetized die of an extrusion rheometer

This article investigates the radial extrudate swell and velocity profiles of polystyrene melt in a capillary die of a constant shear‐rate extrusion rheometer, using a parallel coextrusion technique. An electro‐magnetized capillary die was used to monitor the changes in the radial extrudate swell profiles of the melt, which is relatively novel in polymer processing. The magnetic flux density applied to the capillary die was varied in a parallel direction to the melt flow, and all tests were performed under the critical condition at which sharkskin and melt fracture did not occur in the normal die. The experimental results suggest that the overall extrudate swell for all shear rates increased with increasing magnetic flux density to a maximum value and then decreased at higher densities. The maximum swelling peak of the melt appeared to shift to higher magnetic flux density, and the value of the maximum swell decreased with increasing wall shear rate and die temperature. The effect of magnetic torque on the extrudate swell ratio of PS melt was more pronounced when extruding the melt at low shear rates and low die temperatures. For radial extrudate swell and velocity profiles, the radial swell ratio for a given shear rate decreased with increasing r/R position. There were two regions where the changes in the extrudate swell ratio across the die diameter were obvious with changing magnetic torque and shear rate, one around the duct center and the other around r/R of 0.65–0.85. The changes in the extrudate swell profiles across the die diameter were associated with, and can be explained using, the melt velocity profiles generated during the flow. In summary, the changes in the overall extrudate swell ratio of PS melt in a capillary die were influenced more by the swelling of the melt around the center of the die. Polym. Eng. Sci. 44:2298–2307, 2004. © 2004 Society of Plastics Engineers.     

Optimized Drying of Kaprow Leaves for Industrial Production of Holy Basil Spice Powder

The present study investigated the changes in color, volatile compounds, total phenolic content, total flavonoid content, and antioxidant activity of two holy basil leaves (kaprow in Thai) Ocimum sanctum L. cultivars, kaprow khao and kaprow daeng, after three drying treatments, namely hot air (HA), low relative humidity air drying (LRH), and far-infrared radiation (FIR). Overall, HA dried showed a greater decrease in L values than did LRH and FIR dried for both kaprow cultivars. A significant decrease in total phenolic content (TPC), total flavonoid content (TFC), and ferric reducing antioxidant power (FRAP) was found in hot-air (HA) dried compared to fresh leaves, while TPC, TFC, and FRAP in LRH and FIR dried kaprow were significantly increased. Kaprow daeng and kaprow khao attributes represented by such compounds as β-caryophyllene, methyl eugenol, and eugenol were found to increase during drying. We found that eugenol was a major volatile compound ranging from 18% in HA dried to 23% in FIR dried samples in kaprow khao, whereas methyl eugenol was the main volatile compound in kaprow daeng ranging from 35% in fresh to 49% in FIR dried samples. Our results have demonstrated that LRH and FIR should be considered as a suitable drying method for kaprow with respect to preserving its color, antioxidant property, phenolic compounds, and volatile compounds. The present study has provided useful information for industrial use of kaprow powder production.     

Phytochemicals,vitamin C and sugar content of Thai wild fruits

The objective of the present study was to generate information about the potential health-enhancing properties of selected Thai wild fruits. Nineteen varieties of wild fruits, collected from the natural forest in north-eastern Thailand, were analysed for phytochemicals, anti-oxidant activity, vitamin C and sugar content. The results showed that Diospyros decandra Lour. exhibited the highest content of total phenolic compounds (215 mg GAE/g) and total flavonoid content (187 mg RE/g). Terminalia chebula Retz. had higher anti-oxidant activities than other fruits, as measured by 1,1-diphenyl-2-picrylhydrazyl radical scavenging (99% inhibition) and ferric reducing/anti-oxidant power assays (63 mmol FeSO₄/g). The sum of sugars (sucrose, glucose, fructose and galactose) ranged from 33 to 430 mg/g fresh weight, being dominated by glucose (ranging from 7.5 to 244 mg/g) and fructose (ranging from 5.3 to 193 mg/g). The highest content of vitamin C was found in Phyllanthus emblica Linn. (2.2 mg/g). Thai wild fruits, which were investigated in this study, have been shown to be a novel rich source of phytochemicals.     

Melt strength,local velocity,and elongational viscosity profiles of low‐density polyethylene filaments affected by the die design and process conditions

An experimental arrangement to simultaneously measure the melt strength, velocity profiles, and elongational viscosity profiles across the cross section of a molten filament that emerged from either a circular or slit die for low‐density polyethylene (LDPE) under nonisothermal and isothermal conditions is proposed. The proposed experimental rig was based on a parallel coextrusion technique of colored LDPE melt layers into an uncolored melt flowing from the barrel into and out of a die to form a continuous filament before they were pulled down by mechanical rollers until the filament failed. The experimental rig was also equipped with a high‐speed data‐logging system and a personal computer for real‐time measurements. The results suggest that the draw‐down forces changed continuously with changing roller speed, and the velocity profiles of the melt were not uniform across the LDPE filament during the stretching of the melt. Greater draw‐down forces and local melt velocities were obtained in the slit die or under the nonisothermal condition. The draw‐down forces and velocity profiles in both dies were affected by the volumetric flow rates from the extruder and the roller speeds used, with the effect being more pronounced for the circular die. The elongational viscosity profiles of the LDPE filament were not uniform across the filament cross section and corresponded well to the obtained velocity profiles. The elongational viscosities of the LDPE filament were relatively higher when the filament was extruded and stretched in the circular die and under the nonisothermal condition. The changes in the elongational viscosity profiles were more sensitive to changes in the volumetric flow rate and roller speed in the circular die. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012