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Roi Et, Thailand

Namuangruk S.,National Science and Technology Development Agency | Sirithip K.,Roi-et Rajabhat University | Rattanatwan R.,Ubon Ratchathani University | Keawin T.,Ubon Ratchathani University | And 5 more authors.
Dalton Transactions | Year: 2014

The charge transfer effect of different meso-substituted linkages on porphyrin analogue 1 (A1, B1 and C1) was theoretically investigated using density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. The calculated geometry parameters and natural bond orbital analysis reveal that the twisted conformation between porphyrin macrocycle and meso-substituted linkages leads to blocking of the conjugation of the conjugated backbone, and the frontier molecular orbital plot shows that the intramolecular charge transfer of A1, B1 and C1 hardly takes place. In an attempt to improve the photoinduced intramolecular charge transfer ability of the meso-linked zinc porphyrin sensitizer, a strong electron-withdrawing group (CN) was introduced into the anchoring group of analogue 1 forming analogue 2 (A2, B2 and C2). The density difference plot of A2, B2 and C2 shows that the charge transfer properties dramatically improved. The electron injection process has been performed using TDDFT; the direct charge-transfer transition in the A2-(TiO 2)38 interacting system takes place; our results strongly indicated that introducing electron-withdrawing groups into the acceptor part of porphyrin dyes can fine-tune the effective conjugation length of the π-spacer and improve intramolecular charge transfer properties, consequently inducing the electron injection process from the anchoring group of the porphyrin dye to the (TiO2)38 surface which may improve the conversion efficiency of the DSSCs. Our calculated results can provide valuable information and a promising outlook for computation-aided sensitizer design with anticipated good properties in further experimental synthesis. © the Partner Organisations 2014. Source

Siriamornpun S.,Mahasarakham University | Kaisoon O.,Mahasarakham University | Kaisoon O.,Roi-et Rajabhat University | Meeso N.,Mahasarakham University
Journal of Functional Foods | Year: 2012

Marigold (Tagetes erecta L.) flower has long been used as a food colourant and ingredient in human food and animal feed. Drying is one of the most important processes for producing marigold powder. Therefore the effects of different drying processes, namely freeze drying (FD), hot air drying (HA) and combined far-infrared radiation with hot air convection (FIR-HA), on the colour, carotenoids (lycopene, β-carotene and lutein) and phenolic compounds of marigold flowers were evaluated. The results indicate that colour changes were less for FIR-HA dried marigold than after FD and HA drying. Different drying methods resulted in changes in the content of individual bioactive compounds. HA gave the highest content of β-carotene (15.5. mg/100. g dry weight (DW)), while FIR-HA and FD provided the highest levels of lutein and lycopene. The predominant phenolic acids in all samples of marigold are p-coumaric acid, ferulic acid and sinapic acid. Gallic, protocatechuic, caffeic, syringic, p-coumaric and ferulic acid showed the highest content in marigold after FIR-HA drying. These results demonstrate that FIR-HA should be considered as a suitable drying method for marigold with respect to preserving its colour, antioxidant properties and bioactive compounds and provided useful information for industrial production of marigold powder. © 2012 Elsevier Ltd. Source

Photocatalytic degradation (PCD) of polyphenols (gallic acid) from E. camaldulensis leaves on TiO 2/MCM-41 was investigated in order to get rid of substances harmful to aquatic life. The TiO 2/MCM-41 catalysts with titania loading of 2-40% were synthesized by hydrothermal method using rice husk silica and tetraethyl orthotitanate as silica and titania sources, respectively. The obtained catalysts were characterized by XRD, TEM, Zeta potential analyzer, N 2 adsorption-desorption and diffuse reflectance UV spectroscopy. Hexagonal array of MCM-41 was confirmed, but its crystallinity decreased dramatically with titania loading. Zeta potential of TiO 2/MCM-41s surface varied from 2.11 to 6.00 with the increase of TiO 2 from 0 to 100 wt%. Band gap energy of TiO 2 shifted from 394.1 to 425.1 nm after adding 60%MCM-41 (40%TiO 2/MCM-41), facilitating the ease of OH establishment. Gallic acid - a weak acid solution (pK a=4.0) around 27 ppm was favorable to dissolve in water. PCD of gallic acid was carried out on irradiating of 400W of mercury lamp. The results showed gallic acid solution about 10 wt% properly adsorbed on 10%TiO 2/MCM-41 and effectively degraded at pH solution of 9.0. PCD completed at 60 minutes of irradiation time through catalyst concentration of 0.17 g/L and obeyed pseudo-first order. Intermediate products were formic, oxalic, pyruvic, malanic and maleic acids that finally mineralized to CO 2 and H 2O as downstream products. © 2012 Korean Institute of Chemical Engineers, Seoul, Korea. Source

Prachayawarakorn S.,Bangkok Thonburi University | Raikham C.,Roi-et Rajabhat University | Soponronnarit S.,Bangkok Thonburi University
Journal of Food Science and Technology | Year: 2015

Healthy snacks have increasingly been interested in consumers. Puffing technique is an alternative to produce healthy snacks. Effects of ripening stage of banana and steaming time on quality of banana slices obtained from drying process including fluidized bed puffing were investigated. Bananas at the ripening stages 1 and 3 were steamed at 100 °C for 30 s up to 2 min and dried at 90 °C to moisture content of 25 % dry basis (d.b.). The samples were then puffed by fluidized bed dryer at 160 °C for 2 min and dried at the same temperature as the first stage drying. The experimental results showed that shrinkage, drying time, color, glycemic index and textural properties were affected by steaming time and ripening stage. Steaming provided more uniformity of banana color. Steaming positively or negatively affected the degree shrinkage of banana depending on the ripening stage. The banana texture in particular crispiness could be improved by the steaming for the ripening stage 1 banana whilst it did not improve for the ripening stage 3. During steaming, the C-type crystalline structure of banana starch disappeared and thus the value of glycemic index was increased. The ripening stage 1 banana was recommended for producing healthy snack in order to control glycemic response. © 2015 Association of Food Scientists & Technologists (India) Source

Bunnakit K.,Roi-et Rajabhat University | Khampa S.,Mahasarakham University
Pakistan Journal of Nutrition | Year: 2011

This experiment aimed to study the effects of rumen undegradable protein levels on productive performance of Thai Native-Brahman beef cattle. Four yearling Thai Native × Brahman beef cattle with an average Body Weight (BW) of 175.5±18.6 kg were used in a 4 × 4 Latin square arrangement. The treatments were levels of Rumen Undegradable Protein (RUP) in concentrate at 30, 35, 40 and 45%. Concentrates were formulated to contain 14% CP and were fed at 2.0% BW. The results showed that the DM intake, OM digestibility and TVFA increased linearly (p<0.05) while the level of RUP increased. Moreover, the ruminal NH3-N (p<0.01) and BUN linearly decreased, whereas at 45% RUP the ruminal NH3-N concentration increased (quadratically, p<0.01). The bacteria and protozoa populations also increased as the level of RUP increased. However, the bacteria and protozoa populations decreased quadratically (p<0.05) when the level of RUP changed from 40 to 45%. The N retention (g/d) tended to increase with increasing the level of RUP. However, the N retention tended to decrease at the level of 45% RUP. It could be concluded that RUP level at 40% in concentrate had positive effects on productive performances. © Asian Network for Scientific Information, 2011. Source

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