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ItemAntibacterial activity of Chrysanthemum indicum, Centella asiatica and Andrographis paniculata on Bacillus cereus and Listeria monocytogenes under Low pH StressClassic food preservation methods do not guarantee to inhibit Bacillus cereus and Listeria monocytogenes growth. The application of natural antibacterial agent is an alternative way to control their growth. Asia herbs, Chrysanthemum indicum, Centella asiatica, and Andrographis paniculata were used in this experiment to test their antibacterial activity under low pH stress. Their antibacterial activities of 95% ethanolic crude extracts were tested on B. cereus and L. monocytogenes 10403S under different low pH stress by agar disc diffusion method. The best antibacterial effect on both bacteria was found at low pH stress condition. Lowering pH also acts as one inhibitory effect. The result of in vitro antibacterial effect as inhibition zone at pH 7.0, 6.5, 6.0, 5.5, showed that the inhibition zone diameters of C. indicum extracts were 7.62±1.18. 7.87±2.35, 6.25±3.06 and 9.50±2.14 cm, while the inhibition zone diameters of C. asiatica extracts were 8.75±1.03, 8.75±2.66, 7.75±2.37 and 9.12±1.96 cm and A. paniculata extracts were 9.75±1.75, 5.87±3.52, 8.5±1.23 and 9.33±1.63 against L. monocytogenes 10403S, respectively. Under the same condition, the inhibition zone diameters of C. indicum extracts at 2.12±0.64, 1.37±0.92, 0.93±0.78 and 6.00±3.25 cm, the inhibition zone diameters of C. asiatica extracts at 0.62±0.44, 2.25±0.46, 1.75±0.28 and 6.50±1.60 cm and A. paniculata extracts at 0.87±0.79, 1.25±0.60, 2.00±1.65 and 6.00±1.31, respectively against B. cereus. All 95% ethanolic crude extracts showed more inhibition effect on L. monocytogenes 10403S than B.cereus. However, the promising active antibacterial compounds in all three herbs are needed to be identified. The MBCs of A. paniculata, C. asiatica and C. indicum showed 4, 16 and >32 µl/ml against B. cereus while A. paniculata and C. asiatica showed 16 and >32 µl/ml against L. monocytogenes 10403S.
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ItemBiodegradable human serum albumin nanoparticles as contrast agents for the detection of hepatocellular carcinoma by magnetic resonance imaging(Elsevier, 2014) Waralee Watcharin ; Schmithals, Christian ; Pleli, Thomas ; Koberle, Verena ; Korkusuz, Hudayi ; Huebner, Frank ; Zeuzem, Stefan ; Korf, Hans W. ; Vogl, Thomas J. ; Rittmeyer, Claudia ; Terfort, Andreas ; Piiper, Albrecht ; Gelperina, Svetlana ; Kreuter, JorgTumor visualization by magnetic resonance imaging (MRI) and nanoparticle-based contrast agents may improve the imaging of solid tumors such as hepatocellular carcinoma (HCC). In particular, human serum albumin (HSA) nanoparticles appear to be a suitable carrier due to their safety and feasibility of function- alization. In the present study HSA nanoparticles were conjugated with gadolinium diethylenetriamine- pentaacetic acid (Gd-DTPA) using carbodiimide chemistry. The nanoparticles had a uniform spherical shape and a diameter of 235 ± 19 nm. For better optical visualization in vitro and in vivo, the HSA-Gd nanoparticles were additionally labeled with rhodamine 123. As shown by confocal microscopy and flow cytometry analysis, the fluorescent nanoparticles were readily taken up by Huh-7 hepatocellular carci- noma cells. After 24 h incubation in blood serum, less than 5% of the Gd(III) was released from the par- ticles, which suggests that this nanoparticulate system may be stable in vivo and, therefore, may serve as potentially safe T1 MRI contrast agent for MRI of hepatocellular carcinoma.
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ItemBiofilm production by Zymomonas mobilis enhances ethanol production and tolerance to toxic inhibitors from rice bran hydrolysateMicroorganisms play a significant role in bioethanol production from lignocellulosic material. A challenging problem in bioconversion of rice bran is the presence of toxic inhibitors in lignocellulosic acid hydrolysate. Various strains of Zymomonas mobilis (ZM4, TISTR 405, 548, 550 and 551) grown under biofilm or planktonic modes were used in this study to examine their potential for bioconversion of rice bran hydrolysate and ethanol production efficiencies. Z. mobilis readily formed bacterial attachment on plastic surfaces, but not on glass surfaces. Additionally, the biofilms formed on plastic surfaces steadily increased over time, while those formed on glass were speculated to cycle through accumulation and detachment phases. Microscopic analysis revealed that Z. mobilis ZM4 rapidly developed homogeneous biofilm structures within 24 hours, while other Z. mobilis strains developed heterogeneous biofilm structures. ZM4 biofilms were thicker and seemed to be more stable than other Z. mobilis strains. The percentage of live cells in biofilms was greater than that for planktonic cells (54.32 7.10% vs. 28.69 3.03%), suggesting that biofilms serve as a protective niche for growth of bacteria in the presence of toxic inhibitors in the rice bran hydrolysate. The metabolic activity of ZM4 grown as a biofilm was also higher than the same strain grown planktonically, as measured by ethanol production from rice bran hydrolysate (13.40 2.43 g/L vs. 0.432 0.29 g/L, with percent theoretical ethanol yields of 72.47 6.13% and 3.71 5.24% respectively). Strain TISTR 551 was also quite metabolically active, with ethanol production by biofilm and planktonically grown cells of 8.956 4.06 g/L and 0.0846 0.064 g/ L (percent theoretical yields were 48.37 16.64% and 2.046 1.58%, respectively). This study illustrates the potential for enhancing ethanol production by utilizing bacterial biofilms in the bioconversion of a readily available and normally unusable low value by-product of rice farming.
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ItemChemical profiling of centella asiatica under different extraction solvents and its antibacterial activity, antioxidant activity( 2015) Patchanee YasurinCentella asiatica (L) urban, synonym Hydrocotyle asiatica, is found almost all over the world. This plant is famous in Ayurvedic medicine and used in the management of central nervous system, skin and gastrointestinal disorder. Thus this research had been done to evaluate the effect of solvent extraction (Ethanol, Chloroform and Hexane) of C. asiatica on chemical profile, antioxidant activity and antibacterial activity against some foodborne pathogens. The result showed that all solvents (ethanol, chloroform and hexane) used in extraction showed antibacterial activity against Salmonella enterica Typhimurium U302, S. enterica Enteritidis, S. enterica 4,5,12:I human (US clone), Bacillus cereus and B. subtilis at 50mg/ml concentration. In antioxidant part, ethanolic extract gave highest phenolic content and FRAP value. The results also showed that different extraction solvent gave different chemical profile. Hexane extract C. asiatica showed lowest in both antibacterial and antioxidant activity. Ethanolic and chloroform extract of C. asiatica showed promising potential in both antibacterial and antioxidant activity.
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ItemCombining means-end chain analysis and the portrait value questionnaire to research the influence of personal values on food choicePersonal values can be measured using quantitative or qualitative methods. This paper aims to investi- gate the attribute-consequence-value patterns collected from means-end chain analysis and to examine their relationship to personal value domains from Schwartz value theory measured through the use of the Portrait Value Questionnaire. The study was performed on two product categories, potato chips and orange juice, in which two value segments of opposing value domains were found, Conservatism and Openness to change clusters. There was consistency between means-end chain analysis results and the expected traits of the value domains. The Conservatism cluster embracing security, tradition, and confor- mity values sought financial security through saving money by paying more attention to price and selected familiar brands in order to avoid risks of spending extra money. The Openness to change cluster, which embraced hedonism and stimulation values, emphasized attaining pleasure and enjoyment in life through various consequences that branched out from a number of sensory product attributes. This study illustrates the compatibility between the two instruments. The use of means-end chain analysis con- firmed Schwartz’s definition of values as guiding behavior, and that values are ordered by relative importance.
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ItemComparison of sensory properties of freshly harvested and 1-year storage Thai riceThailand is a major producer and world supplier of rice, both aromatic and non-aromatic varieties. Rice sold as “new crop” shortly after it is harvested generally commands higher prices. The study compared differences in sensory properties of various aromatic (Khao Dawk Mali 105, RD 15, Pathum Thani 1) and non- aromatic (Chai Nat 1, Phitsanulok 2, Suphan Buri 1) rice varieties and differences in fresh rice and rice stored for 1 year. Floral, popcorn, and sewer/animal flavors were found in both rice samples but jasmine rice had higher intense of floral aroma and was the only aroma that decreased overtime. The texture of jasmine rice samples were more adhere to lips, grain to grain, softer and more intense of cohesiveness of mass than non-aromatic rice. There were three attributes; residual, toothpacking, sweet, from nineteen attributes were not different between jasmine and non-aromatic rice and not changed overtime. Most of the texture attributes were not changed after one year of storage except cohesiveness of mass and starchy mouthcoating that reduced after storage. There were not a significantly differences for most of the flavor attributes except musty flavor between jasmine and non-aromatic rice samples within the same testing year such as grain, straw-like, starch, popcorn flavor, sweet, overall sweet, bitter and metallic. The changes of the flavor like grain and straw-like were decreased from their original intense; while, musty flavor and bitter taste were increased.
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ItemDetection of hepatocellular carcinoma in transgenic mice by Gd-DTPA- and rhodamine 123-conjugated human serum albumin nanoparticles in T1 magnetic resonance imagingNanoparticle (NP)-based contrast agents that enable high resolution anatomic T1-weighted magnetic resonance imaging (MRI) offer the prospect of improving differential diagnosis of liver tumors such as hepatocellular carci- noma (HCC). In the present study, we investigated the possibility of employing novel non-toxic human serum albumin nanoparticles conjugated with Gd-DTPA and rhodamine 123 (Gd-Rho-HSA-NPs) for the detection of HCC by T1-weighted MRI. In addition, the influence of surface coating of the NPs with poloxamine 908, which al- ters the absorptive behavior of NPs and changes their distribution between the liver and tumor was examined. MRI of transgenic mice with endogenously formed HCCs following intravenous injection of Gd-Rho-HSA-NPs revealed a strong negative contrast of the tumors. Contrasting of the HCCs by NP-enhanced MRI required less Gd as compared to gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid-enhanced MRI, which current- ly provides the most sensitive detection of HCC in patients. Immunohistochemical analyses revealed that the Gd-Rho-HSA-NPs were localized to macrophages, which were – similar to HCC in patients – fewer in number in HCC as compared to the liver tissue, which is in agreement with the negative contrasting of HCC in Gd-Rho- HSA-NP-enhanced MRI. Poloxamine-coated NPs showed lower accumulation in the tumor macrophages and caused a longer lasting enhancement of the MRI signal. These data indicate that Gd-Rho-HSA-NPs enable sensi- tive detection of HCC by T1-weighted MRI in mice with endogenous HCC through their uptake by macrophages. Poloxamine coating of the NPs delayed the tumor localization of the NPs.
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ItemDetermination of suitable palate cleanser for spicy tom yum soup( 2014) Kamolnate KitsawadPalate cleansers are required in sensory tests as they help improve the accuracy for sensory responses especially for foods containing strong flavour. The objective of this study is to determine a suitable palate cleanser that can be used to relief spiciness in a Thai dish, tom yum soup. The untrained judges rated the spiciness of three levels of spicy tom yum soups before and after using five palate cleanser strategies, water, bread, unsweetened milk, 10 percent sucrose and nothing. One palate cleanser strategy was used per session, thus the judges performed a total of five sessions. All of the palate cleanser strategies have shown to exhibit the ability to relief spiciness of the tom yum soups where milk was most effective Thus, using milk as a palate cleanser strategy follow by a water rinse is considered to be one of the appropriate palate cleanser choices for spicy soup.
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ItemDevelopment of corn silk as a biocarrier for Zymomonas mobilis biofilms in ethanol production from rice straw( 2016) Tatsaporn Todhanakasem ; Rashmi Tiwari ; Pornthap ThanonkeoZ. mobilis cell immobilization has been proposed as an effective means of improving ethanol production. In this work, polystyrene and corn silk were used as biofilm developmental matrices for Z. mobilis ethanol production with rice straw hydrolysate as a substrate. Rice straw was hydrolyzed by dilute sulfuric acid (H2SO4) and enzymatic hydrolysis. The final hydrolysate contained furfural (271.95 ± 76.30 ppm), 5-hydroxymethyl furfural (0.07 ± 0.00 ppm), vanillin (1.81 ± 0.00 ppm), syringaldehyde (5.07 ± 0.83 ppm), 4- hydroxybenzaldehyde (4-HB) (2.39 ± 1.20 ppm) and acetic acid (0.26 ± 0.08%). Bacterial attachment or biofilm formation of Z. mobilis strain TISTR 551 on polystyrene and delignified corn silk carrier provided significant ethanol yields. Results showed up to 0.40 ± 0.15 g ethanol produced/g glucose consumed when Z. mobilis was immobilized on a polystyrene carrier and 0.51 ± 0.13 g ethanol produced/ g glucose consumed when immobilized on delignified corn silk carrier under batch fermentation by Z. mobilis TISTR 551 biofilm. The higher ethanol yield from immobilized, rather than free living, Z. mobilis could possibly be explained by a higher cell density, better control of anaerobic conditions and higher toxic tolerance of Z. mobilis biofilms over free cells.
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ItemEffect of drying process on the production of 5-hydroxymethylfurfural in citrofortunella microcarpa at two different maturity stages(International Cooperation and Development Fund, 2015) Teeradate Kongpichitchoke ; Hsu, Jue-Liang ; Huang, Tzou-ChiCitrofortunella microcarpa is a well-known citrus fruit as a good source for flavonoids and antioxidant compounds in peels and seeds. However, they are leftover from juice industry. 5-Hydroxymethylfurfural (HMF) is well-recognized for its dominant role in immunology field, and commonly found in thermal-processed products. Thus, this study aimed to first time report HMF discovery from dried C. microcarpa waste. A conventional hot air drying method was used to determine the effects of drying temperatures (30 - 70 °C) and times as well as the maturity stages of C. microcarpa on HMF production. Liquid chromatography-tandem mass spectrometry (LC-MS") and nuclear magnetic resonance (NMR) were used to characterize the produced HMF. The results showed that HMF production was positively correlated with drying temperature and drying time. Furthermore, the mature fruits produced significantly higher HMF levels than immature fruits. The highest amount of HMF (0.86 mg/g dry weight) was obtained from drying mature fruit at 70°C for four days.
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ItemEncapsulation of protease from Aspergillus oryzae and lipase from Thermomycess lanuginoseus using alginate and different copolymer type( 2016) Thu, Truong Thi Mong ; Wunwisa KrasaekooptAlthough the application of enzymes in food as a food processing aid and enzyme supplement is ofinterest and widely used, the enzymes can be easily deactivated or lose their activity due to many causessuch as pH and moisture as well as through the introduction of incompatible ingredients during foodprocessing and storage. These problems can be solved by the encapsulation technique, especially in a gelmatrix. The influences were studied of the alginate concentration, types of copolymer and their con-centrations on the bead size, encapsulation yield (EY), encapsulation efficiency (EE), leakage and theretention of enzyme activity during storage period of encapsulated protease from Aspergillus oryzae andlipase from Thermomyces lanuginosus beads. A solution of purified protease or lipase was encapsulated incalcium alginate-chitosan beads (CACB), calcium alginate-xanthan gum beads (CAXB) and calciumalginate-maltodextrin beads (CAMB) using the extrusion method. Increasing the alginate and copolymerconcentrations in the solution increased the bead size, EY, EE and the retention of enzyme activity duringthe storage period and reduced leakage of both the encapsulated protease and lipase. In addition,different types of copolymer significantly (p0.05) affected these properties of both encapsulatedenzymes. Furthermore, protease encapsulated using 2.0% alginate and 0.2% chitosan provided the highestEY (81.7%) and EE (77.2%) with a bead size of 1.85 mm and 8.1% leakage. The retention of encapsulatedprotease activity and the shelf-life of encapsulated enzyme which was expressed as half-life, the timerequired for the enzyme activity to decrease by half (thalf life) were 75.8% and 27.2 wk, respectively afterstorage at 4C for 10 wk. For lipase, encapsulation using 2.0% alginate and 0.4% xanthan gum providedthe highest EY (42.5%) and EE (43.9%) and the bead size and leakage were 1.81 mm and 6.2%, respectively.The retention of encapsulated lipase activity and the thalf lifewere 77.9% and 27.8 wk, respectively afterstorage at 4C for 10 wk. CACB was a suitable complex polymer for encapsulating protease while CAXBwas suitable for lipase. EY and EE values of CACB-protease were higher than those of CAXB-lipase.Therefore, the encapsulation method, gelling conditions and interactions between carriers and lipaseshould be further studied.
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ItemFermentation of rice bran hydrolysate to ethanol using Zymomonas mobilis biofilm immobilization on DEAE-celluloseBackground: The major challenges associated with the fermentation of lignocellulosic hydrolysates are the reduction in the operating cost and minimizing the complexity of the process. Zymomonas mobilis biofilm has been emerged to resolve these complexities. Biofilm has been reported to tolerate to the toxic inhibitors and easily manipulated toward the cell recycle through the cell immobilization. Results: Z.mobilisZM4 and TISTR 551were able to develop biofilms onDEAE cellulose under the differences in the morphologies. Z. mobilis ZM4 developed homogeneous biofilm that brought DEAE fiber to be crosslinking, while Z. mobilis TISTR 551 developed heterogeneous biofilm in which crosslinking was not observed. Ethanol production under batch and repeated batch fermentation of rice bran hydrolysate containing toxic inhibitors were compared between these two biofilms. TISTR 551 biofilm produced the maximum yield (YP/S) of 0.43 ± 0.09 g ethanol/g glucose (83.89% theoretical yield). However the repeated batch could not be proceeded due to the bacterial detachment. Z. mobilis ZM4 biofilm produced the maximum yield (YP/S) of 0.177 ± 0.05 g ethanol/g glucose (34.74% theoretical yield) in the batch culture and the biofilm remained intact to proceed along the repeated batch. The highest ethanol yield (YP/S) in the repeated batch of Z. mobilis ZM4 was 0.354 ± 0.07 g ethanol/g glucose (69.51% theoretical yield). Conclusions: Homogeneous biofilm structure of Z. mobilis provided more recycle beneficial over the heterogeneous biofilm structure for the ethanol production from lignocellulosic hydrolysate.
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ItemFreeze–thaw stability of edible oil-in-water emulsions stabilized by sucrose esters and Tweens( 2015) Suwimon Ariyaprakai ; Kanitha TananuwongThis work aimed to investigate freeze thaw stability of 20 wt% coconut oil (CtO) and corn oil (CnO)- in-water emulsions stabilized by 1 wt% of various types of sucrose esters and Tweens. Sucrose esters composed mainly of sucrose monostearate (S1670), sucrose monopalmitate (P1670), sucrose monolaurate (L1695), Tween 20 (TW20), Tween 60 (TW60), and Tween 80 (TW80) were used. After all emulsions were frozen at 20 ± 2 C and thawed to room temperature, their stability was analyzed from visual appearance, optical micrographs, amounts of destabilized oil, and average particle sizes. The CtO emulsions stabilized by S1670 and P1670 were very stable, the CtO emulsions stabilized by L1695 partly destabilized, and the CtO emulsions stabilized by TW20, TW60, and TW80 mostly destabilized into oil layers separated on top. The excellent stability of CtO emulsions stabilized by S1670 and P1670 was also confirmed from similar thermograms obtained from differential scanning calorimeter after three cooling–heating cycles (40 C to 40 C to 40 C at 5 C/min). It was proposed here that S1670 and P1670 affected the interfacial fat crystallization and their interfacial layers protected CtO emulsions against partial coalescence. Differently for the case of CnO emulsions, the CnO droplets remained liquid during freezing. All CnO emulsions stabilized by any emulsifiers destabilized by coalescence since these small surfactants could not provide enough interfacial barriers.
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ItemGallic acid content in taiwanese teas at different degrees of fermentation and its antioxidant activity by inhibiting PKCδ activation: in vitro and in silico studies( 2016) Teeradate Kongpichitchoke ; Chiu, Ming-Tzu ; Huang, Tzou-Chi ; Hsu, Jue-LiangTeas can be classified according to their degree of fermentation, which has been reported to affect both the bioactive components in the teas and their antioxidative activity. In this study, four kinds of commercial Taiwanese tea at different degrees of fermentation, which include green (non-fermented), oolong (semi-fermented), black (fully fermented), and Pu-erh (post-fermented) tea, were profiled for catechin levels by using high performance liquid chromatography (HPLC). The result indicated that the gallic acid content in tea was directly proportional to the degree of fermentation in which the lowest and highest gallic acid content were 1.67 and 21.98 mg/g from green and Pu-erh tea, respectively. The antioxidative mechanism of the gallic acid was further determined by in vitro and in silico analyses. In vitro assays included the use of phorbol ester-induced macrophage RAW264.7 cell model for determining the inhibition of reactive oxygen species (ROS) production, and PKCδ and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit (p47) activations. The results showed that only at a concentration of 5.00 μM could gallic acid significantly (p < 0.05) reduce ROS levels in phorbol ester-activated macrophages. Moreover, protein immunoblotting expressed similar results in which activations of PKCδ and p47 were only significantly (p < 0.05) attenuated by 5.00 μM treatment. Lastly, in silico experiments further revealed that gallic acid could block PKCδ activation by occupying the phorbol ester binding sites of the protein.
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ItemIn-vitro antibacterial activity screening of herb extracts against foodborne pathogenic bacteria from Thailand( 2015) Patchanee Yasurin ; Sasiwan Piya-IsarakulHerbs have been used as traditional medicine since the ancient times as primary health care for local people. This experiment was aimed to study the individual antibacterial activity of six Thai local herbs (Tradescantia spathacea, Andrographis paniculata, Eleocharis acicularis, Acacia concinna, Phyllanthus niruri, and Tinospora cordifolia) against six foodborne pathogenic bacteria (Escherichia coli ATCC25822, Samonella enterica Typhimurium U302 (DT1046), S. enterica Enteritidis (human), S. enterica 4,5,12: i-(human) US clone, Bacillus cereus, and Listeria monocytogenes 10403S) under five extractions (95% ethanol, chloroform, hexane, sterile distilled water, and autoclaving at 121°C 15 PSI for 15 minutes). Agar disc diffusion method was used to evaluate antibacterial activity. The results showed that 95% ethanol and chloroform extraction gave the highest antibacterial activity of all herb extracts against all bacteria. The range of antibacterial activity is between 7.0 mm to 10.5 mm. The highest antibacterial activity was chloroform extract of T. cordifolia against S. enterica Typhimurium U302 (DT1046). The range of MIC and MBC is between 32 µl/ml to 256 µl/ml. These results showed the promising of antibacterial activity of six Thai local herbs which are stepping stone for further application like food industry, pharmaceutical industry, and cosmetic industry.
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ItemIn-vitro Individual Antibacterial Activity Of Thai Red Curry Paste Ingredients Against Salmonella Enterica Enteritidis (Human) And Listeria Monocytogenes 10403s( 2015) Patchanee Yasurin ; Treuktongjai SaenghirunaThai red curry paste consists of herbs which have potential to be natural antibacterial agents. Therefore 7 herbs of Thai curry paste ingredients; Chili (Capsicum annuum), Kaffir lime (Citrus hystrix), Cumin (Cuminum cyminum L.), Shallot (Allium ascalonicum L.),Garlic (Allium sativum), Lemongrass (Cymbopogon citrates), and Galangal (Alpinia galangal), were investigated for their individual antibacterial activity againt Salmonella enterica Enteritidis (human) and Listeria monocytogenes 10403S by agar diffusion method Agar under 3 extraction3; water, UHT coconut milk and fresh coconut milk. In-vitro antibacterial screening results, fresh coconut milk extraction showed the highest potential in inhibiting S. enterica Enteritidis (human), in all herbs and the highest antibacterial activity was found in garlic; 01.00 ± 0.18 cm, using water extraction. For L. monocytogenes 10403S, the highest antibacterial activity was found in lemon grass using fresh coconut milk extraction; 0.90 ± 0.12 cm. The minimum inhibitory concentration (MICs), using broth dilution method, of all herbs were between 80 to >160µl/ ml. The minimum bactericidal concentrations (MBCs) of all herbs under three extractions, using broth dilution method, showed >160µl/ml in both bacteria. The herbs in Thai red curry paste ingredient showed the significantly promising antibacterial activity against food-borne pathogen, S. enterica Enteritidis (human) and L. monocytogenes10403S.
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ItemInterfacial and emulsifying properties of sucrose ester in coconut milk emulsions in comparison with TweenIn this study, sucrose esters were presented as a promising alternative to petrochemically synthesized Tweens for application in coconut milk emulsions. The interfacial and emulsifier properties of sucrose ester (SE), mainly sucrose monostearate, had been investigated in comparison with Tween 60 (TW), an ethoxylate surfactant. The interfacial tension measurement showed that SE had a slightly better ability to lower the interfacial tension at coconut oilewater interface. These surfactants (0.25 wt%) were applied in coconut milk emulsions with 5 wt% fat content. The effects of changes in pH, salt concentration, and temperature on emulsion stability were analyzed from visual appearance, optical micrograph, droplet charges, particle size distributions, and creaming index. Oil droplets in both SE and TW coconut milk emulsions extensively flocculated at pH 4, or around the pI of the coconut proteins. Salt addition induced flocculation in both emulsions. The pH and salt dependence indicated polyelectrolyte nature of proteins, suggesting that the proteins on the surface of oil droplets were not completely displaced by either added nonionic SE or TW. TW coconut milk emulsions appeared to be thermally unstable with some coalesced oil drops after heating and some oil layers separated on top after freeze thawing. The change in temperature had much lesser influence on stability of SE coconut milk emulsions and, especially, it was found that SE emulsions were remarkably stable after the freeze thawing.
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ItemInvestigating the Effect of Cold Soak Duration on Phenolic Extraction during Cabernet Sauvignon FermentationThe impact of increasing cold soak (CS) duration (0, 1, 4, 7, and 10 days at 10 °C) on the extraction of phenolic compounds during the CS period and primary fermentation as well as the final composition of Cabernet Sauvignon wine was investigated. The results showed that CS duration had no effect on hydroxycinnamate and flavonol extractions. Greater amounts of gallic acid, (+)-catechin, (−)-epicatechin, and total tannins were extracted with increasing CS duration, with differences maintained during bottle aging. Anthocyanin extraction and color density increased with longer periods of CS; however, by the end of primary fermentation, as well as three months’ bottle aging, there were no significant differences due to CS duration. The wines made with seven and 10 days of CS had higher seed tannin contributions and total tannin compared to the non-CS wine, which could potentially result in increased astringency.
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ItemMicrobial Biofilm in the industry( 2013) Tatsaporn TodhanakasemBiofilms represent negative and positive attributes in the industries. Biofilm is a functional consortium of microorganisms attached to either biotic or abiotic surfaces and embedded under the extracellular polymeric substances (EPS). Spoilage and pathogenic microorganisms can develop biofilms on food industrial surfaces that can lead to food spoilage and disease transmission when the inappropriate clean up and control have been applied in the food industies. However, single and mixed species of microbial biofilms also represent tremendous advantages in bioprocesses and waste treatments. Biofilm reactors have been employed in order to improve the productivities, stability of the processes and reduce the production cost. To understand biofilm, numerous direct and indirect experimental approaches have been used to study the biofilms. Molecular genetics approaches have led to study on the process of biofilm development in order to understand its genetic regulations.
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ItemMicroencapsulation of Litsea cubeba Essential Oil in β-Cyclodextrin Using Paste and Co-Precipitation Methods( 2014) Elizei, Pooyan Shakouri ; Wunwisa KrasaekooptMicroencapsulation of Litsea cubeba essential oil (LCEO) with β-cyclodextrin (BCD) was carried out using the paste and co-precipitation methods at various oil concentrations and ratios of LCEO to BCD adapted from a central composite design to determine the effect of these factors on the microencapsulation efficiency, microencapsulation yield, surface oil and recovery of the finished product. In addition, the effect of different levels of water activity and temperature on the oxidative stability of the powder was investigated. Treatment 4 using the paste method with 90% LCEO and a ratio of LCEO to BCD of 15:85 was found to be more efficient compared to samples produced by the co-precipitation method. This condition provided an oil loading of 102 mg.g-1 of powder, 74.7% microencapsulation yield, 71.9% microencapsulation efficiency, 94.8% recovery of LCEO powder and surface oil with 4.08 mg.g-1 of powder. Statistical analysis indicated that the temperature and water activity had significant effects on the peroxide value. Moreover, there was an interaction between these two factors. The LCEO powder had higher oxidative stability with the lowest peroxide value of 4.9 meq.kg-1 when it was stored at 10 °C and a water activity of 0.53 whilst the accelerated conditions of 50 °C and a water activity of 0.64 resulted in the highest peroxide value (13.6 meq.kg-1) and lower oxidative stability. It was notable that except for the samples stored at a water activity of 0.64 and temperatures of 30 and 50 °C, the other samples did not exceed the limit for the peroxide value of 10 meq.kg-1 which is the acceptable limit for edible vegetable oils.