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ItemSensory properties and consumer acceptance of imported and domestic sliced black ripe olivesTable olives are healthy and nutritious products with high contents of monounsaturated fatty acids, phenolics, vitamins, minerals, and fiber. Understanding sensory cues affecting consumer preferences would enable the increase of olive consumption. The objectives of this study were to characterize the sensory properties of commercial sliced black ripe olives from different regions, including California, Egypt, Morocco, Portugal, and Spain, and to examine the preferences of California consumers for sliced black ripe olives. Sensory profiles and preferences for 20 sliced olive samples were determined using descriptive analysis with a trained panel and a consumer test with 104 users and likers of table olives. Aroma and flavor characteristics separated the olives according to country of origin, and were the main determinants of consumer preferences for sliced olives, even though the biggest differences among the samples were in appearance and texture. Total of 2 consumer segments were identified with 51 and 53 consumers, respectively, that both liked Californian products, but differed in the olives they disliked. Negative drivers of liking for both segments included alcohol, oak barrel, and artificial fruity/floral characteristics; however, consumers from Cluster 1 were further negatively influenced by rancid, gassy, and bitter characteristics. This study stresses the need for sound and appealing flavor quality for table olives to gain wider acceptance among U.S. consumers.
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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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ItemProperties and applications of different probiotic delivery systems( 2012) Wunwisa KrasaekooptProbiotic products should contain and maintain viable cells during the product shelf life at least above therapeutic minimum level for the benefit of consumers. Due to their generally poor viability and stability in food products, especially in fermented dairy products, as well as in the host gastrointestinal tract, various microencapsulation techniques for probiotics have been developed in recent years to overcome these issues. This chapter describes the benefit of microencapsulation, various encapsulation techniques used to encapsulate probiotics and the application of encapsulated probiotics in selected food systems. The use of various supporting or encapsulating materials, such as alginate, chitosan and carrageenan is also discussed. Special treatments (such as complexation coating) of capsules for further improving the stability of the probiotics are also described.
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ItemUse of Rice Hull Hydrolyzate in the Cultivation of Lactobacillus acidophilus( 2012) Tatsaporn T. ; Nikapong PuanglamyaiThis project aims to minimize the cost of production of live L. acidophilus by replacing the expensive carbon source in the fermentation medium with the rice hull hydrolyzate and compare the growth efficiency of the microbe in the rice hull formulated medium with the rich medium (de Man Rogosa Sharpe or MRS). Rice hull was hydrolyzed with diluted H2 SO4 and HCl at various concentrations 0.25, 0.5 and 1% v/v at 120 o C for 30 minutes. The hydrolyzate was further overliming with Ca(OH) 2 and filter through the diatomaceous earth. The treatment with 0.5% and 1% HCl provided the reducing sugar of 23.05 and 27.45 g/L which were close to MRS broth of 20.88 g/L. The hydrolyzate from the treatment with 1% HCl was further mixed with MRS in the ratio of MRS: hydrolyzate of 25: 75 and 10: 90 v/v. The MRS mixed with the hydrolyzate in the ratio of 25:75 v/v gave the maximum specific growth rate (µmax ) of 0.437 hour -1 which was comparable to the MRS broth of 0.424 hour -1 . The biomass yield (Yx/s ), dry weight and viable cell number on the formulated medium at 48 hours cultivation were 0.21 g/g, 2.61 mg/ml and 2.07 × 10 8 CFU/ml respectively in comparison to MRS at 48 hours cultivation which were 0.19 g/g, 3.07 mg/ml and 2.19 × 10 8 CFU/ml (viable cell number in MRS represented the maximum level at 9 hours) respectively. The total acidity produced by the culture in formulated medium and MRS were 1.461% and 1.761%. Although, the formulated medium from rice hull hydrolyzate reduced the production cost in term of medium requirement, the time required for obtaining the same amount of viable cells in the hydrolyzate was longer than using MRS as a sole medium.
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ItemNatural antibacterial activity of Thai curry paste in Thai red curry-water base (Kang-Pa) Model on Salmonella enterica 4, 5, 12: i: - (human) and Salmonella enteric Enteritidis (human)( 2013) Patchanee YasurinNatural antibacterial is now a very interesting food safety trend. The investigation on the food having antibacterial activity itself, as functional food, becomes more dynamic. Salmonella sp. is a food pathogen which has been reported its outbreaks frequently in variety of foods. Thai red curry (Kang-Pa) is a Thai cultural dish and become worldwide well-known menu. The Thai curry paste, Thai red curry main ingredients, compose of seven herbs including Capsicum annuum (Red chili), Cymbopogon citrates (Lemongrass), Alpinia galangal (Galangal), Allium ascalonicum L (Shallot), Allium sativum (Garlic), Citrus hystrix (kaffir lime), Cuminum cyminum (Cumin). This study aimed to investigate the potential of Thai curry paste in Thai red curry-water base (Kang-Pa) model as natural antibacterial agent against S. enterica 4, 5, 12: i - (human) US clone and S. enteric Enteritidis (Human). Thai curry paste in-vitro antibacterial activity was evaluated by standard plate count method on SS media every hour for 6 hrs at room temperature. Thai red curry was prepared according to Thai homemade authentic cooking method as it has been served in Thai cuisine. The result showed that the log CFU/ml of S. enterica 4, 5, 12: i - (human) US clone in Kang-Pa was significantly lower than in nutrient broth, as positive control, (P < 0.05) since 2nd - 6th hour: 2nd hr; 5.14±0.06 and 5.44±0.17, 3rdhr; 5.86±0.19 and 6.76±0.28, 4th; 5.85±0.16 and 6.97±0.6, 5th hr; 5.92±0.22 and 6.26±0.27 and 6th hr; 6.88±0.04 and 7.51±0.20 log CFU/ml, respectively. While the log CFU/ ml of S. enteric Enteritidis in Kang-Pa was significant lower than those of positive control (NB) (P<0.05) only at 2nd and 3rd hour: 2nd hr: 5.705±0.199 and 6.370±0.085 log CFU/ml, at 3rd hr: 5.872±0.255 and 6.878±0.177 log CFU/ml, respectively. The t-test has been done by using SAS on log CFU/ml with P < 0.05. Thai curry paste in Kang-Pa model showed promising antibacterial activity against food-borne pathogenic bacteria, S. enterica 4, 5, 12: i - (human) and S. enteric Enteritidis (human).
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ItemNatural antibacterial activity of Thai curry paste in Thai red curry (Kang-Kati) model against Listeria monocytogenes 10403SIn 2012, outbreak-associated strains of Listeria monocytogenes have been reported to CDC. Foods as natural antibiotics itself might be considered as an alternative for food safety. Thai red curry is a Thai cultural dish which has become well-known worldwide for having fresh coconut milk and red curry paste as main ingredients. The main ingredients of red curry paste include various types of herbs: Capsicum annuum (chili), Citrus hystrix (Kaffir lime), Cuminum cyminum L. (Cumin), Allium ascalonicum L. (Shallot), Allium sativum (Garlic), Cymbopogon citratus (Lemongrass), and Alpinia galangal (Galangal). All of the mentioned herbs have been investigated for their antibiotics activity. This project aimed to investigate the antibacterial activity of red curry paste in fresh-coconut-milk-based Thai red curry (Kang-Kati) model on L. monocytogenes 10403S. Thai curry paste in-vitro antibacterial activity was evaluated by standard plate count method on BHI media every hour for 6 hours at room temperature. Thai red curry was prepared by Thai homemade authentic cooking method as served in Thai cuisine. Results showed that the L. monocytogenes 10403S log CFU/ml level in Thai red curry (Kang-Kati) was significantly lower than in nutrient broth, as positive control, (P < 0.05) since 2nd - 6th hour; 2ndhr; 6.28±0.01 and 6.38±0.02, 3rdhr; 6.39±0.04 and 6.91±0.14, 4th; 6.96±0.05 and 7.24±0.10, 5th hr; 7.02±0.05 and 7.38±0.10 and 6th hr; 7.04±0.04 and 7.43±0.03 log CFU/ml, respectively. The t-test has been done by using SAS on log CFU/ml with P < 0.05. The Thai red curry paste in Kang-Kati model showed promising antibacterial activity against food-borne pathogenic bacteria, L. monocytogenes 10403S.
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ItemStability of Orange Oil-in-Water Emulsions Prepared by Multilayer Membranes( 2013) Suwimon Ariyaprakai ; Qi, Wu JaiDue to the small molecular size of orange oil, primary orange oil–in-water emulsion can easily undergo Ostwald ripening destabilization. To improve the stability of orange oil emulsion, multilayer emul- sion was prepared using Citrem as emulsifier and gelatin as coated biopolymer. Firstly, primary emulsion containing 20 wt% orange oil and 0.4 wt% Citrem was produced. Since Citrem was an anionic emulsifier, the primary emulsion had a negative charge of ~ -57mV. Then, the primary emulsion was suspended in 0.5 wt% gelatin aqueous solution at pH 3 with the ratio of primary emulsion to gelatin aqueous solution of 1:1. The gelatin that was positively charged at this pH condition coated around the primary emulsion and double layer emulsion (secondary emulsion) with a ζ-potential value of ~ +20 mV was Produced. The particle sizes of primary and secondary emulsions at various time intervals were detected using a laser diffraction particle analyzer. The results showed that the average particle size (d3,2) of secondary emulsion on the first day was 1.5 (± 0.02) microns and that after storage at room temperature (~25 °C) for 14 days was 1.5 (± 0.02) microns, indicating good emulsion stability. The particle size of the primary emulsion (d3,2) increased from 1.3 (± 0.02) microns to 1.8 (± 0.02) micron, or increased by a factor of 1.4.
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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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ItemMicroencapsulation of Probiotics in Hydrocolloid Gel Matrices: A Review( 2013) Wunwisa KrasaekooptThe use of hydrocolloid gel matrices to encapsulate probiotics is of interest due to their gentle and simplicity of gel formation as well as mild condition used. This technique enhances the viability of entrapped cells during the product shelf life at least above therapeutic minimum level as well as in the gastrointestinal tract to ensure the health benefits of consumers. This review describes the advantages of microencapsulation, hydrocolloid gel matrices such as alginate, carrageenan and whey protein, microencapsulation processes, special treatments for further improvement in encapsulation efficiency of gel matrices as well as food applications of microencapsulated probiotics.
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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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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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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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Itemโอกาสความเป็นไปได้ของการใช้เทคโนโลยีพลังงานชีวภาพในประเทศไทย( 2014) พัชนีย์ ยะสุรินทร์ ; มาลินี ศรีอริยนันท์ในปัจจุบันความต้องการใช้พลังงานทั้งในภาคอุตสาหกรรมและครัวเรือนเพิ่มขึ้นทุกปี จึงต้องพึ่งพาการนำเข้าพลังงานจากต่างประเทศเป็นหลัก พลังงานที่ใช้ส่วนใหญ่เป็นเชื้อเพลิงซากดึกดำบรรพ์ (Fossil Fuels) บทความวิชาการฉบับนี้แสดงให้เห็นถึงสถานการณ์พลังงานและการพัฒนาการผลิตพลังงานชีวภาพ (Biofuel) ของประเทศไทย รวมถึงโอกาสความเป็นและเทคโนโลยีได้ในการผลิตพลังงานชีวภาพ โดยเฉพาะการผลิตไบโอดีเซลจากมวลชีวภาพลิกโนเซลลูโลสที่ได้มาจากวัสดุเหลือทิ้งทางการเกษตรในประเทศไทยและผลิตพลังงานจากกระบวนเมตาบอลิซึมของกรดไขมันในแบคทีเรีย ซึ่งช่วยลดการพึ่งพาการนำเข้าพลังงานจากต่างประเทศ
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ItemReview: antibacterial, antioxidant and chemical profile of centella asiatica( 2014) Supawan Rattanakom ; Patchanee YasurinPlants have been used since ancient times whether as foods/seasoning or medicinal purposes. The used of plants for medicinal purposes can be found almost every parts of the world; from Africa to Europe. Nowadays, there are increasing trends of using natural products. From the discovery that effective life span of any antibiotic is limited. Scientists try to discover alternatives. One of the sources is from plants. As they have an almost limitless ability to synthesize aromatic substances especially plant secondary metabolites. Most of plant secondary metabolites serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Thus this is where the hypothesis of using plants as alternative antimicrobial agents. Not only that, plant also contains phenolic compounds that can be served as natural antioxidants. Interestingly herbs are considered to be one of the alternatives consumers choose to use. In Thailand, Centella asiatica can be found in local market and locally called Buabok. C. asiatica is famous in Ayurvedic medicine for the treatment of leprosy, insanity, asthma, ulcers, eczema, skin tuberculosis, wounds, stomach aches, arthritis, varicose veins and high blood pressure. By that, gathered information of antibacterial, antioxidant and chemical profile of C. asiatica could serve as stepping stone.
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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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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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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.
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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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ItemNumber of hydroxyl groups on the B-ring of flavonoids affects their antioxidant activity and interaction with phorbol ester binding site of PKCδ C1B domain: in Vitro and in silico studiesAlthough flavonoids have been reported for their benefits and nutraceutical potential use, the importance of their structure on their beneficial effects, especially on signal transduction mechanisms, has not been well clarified. In this study, three flavonoids, pinocembrin, naringenin, and eriodictyol, were chosen to determine the effect of hydroxyl groups on the B-ring of flavonoid structure on their antioxidant activity. In vitro assays, including DPPH scavenging activity, ROS quantification by flow cytometer, and proteins immunoblotting, and in silico analysis by molecular docking between the flavonoids and C1B domain of PKCδ phorbol ester binding site were both used to complete this study. Eriodictyol (10 μM), containing two hydroxyl groups on the B-ring, exhibited significantly higher (p < 0.05) antioxidant activity than pinocembrin and naringenin. The IC50 values of eriodictyol, naringenin, and pinocembrin were 17.4 ± 0.40, 30.2 ± 0.61, and 44.9 ± 0.57 μM, respectively. In addition, eriodictyol at 10 μM remarkably inhibited the phosphorylation of PKCδ at 63.4% compared with PMA-activated RAW264.7, whereas pinocembrin and naringenin performed inhibition activity at 76.8 and 72.6%, respectively. According to the molecular docking analysis, pinocembrin, naringenin, and eriodictyol showed -CDOCKER_energy values of 15.22, 16.95, and 21.49, respectively, reflecting that eriodictyol could bind with the binding site better than the other two flavonoids. Interestingly, eriodictyol had a remarkably different pose to bind with the kinase as a result of the two hydroxyl groups on its B-ring, which consequently contributed to greater antioxidant activity over pinocembrin and naringenin.