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    ผลการเปรียบเทียบฤทธิ์ในการต้านแบคทีเรียของส่วนประกอบในพริกแกงแดงในสูตรจําลองแกง ป่าและแกงกะทิต่อเชื้อ Salmonella Enterica 4,5,12:i:- (human) US clone
    (คณะอุตสาหกรรมเกษตร สถาบันเทคโนโลยีพระจอมเกล้าเจ้าคุณทหารลาดกระบัง, 2012-09) พัชนีย์ ยะสุรินทร์
    จากการศึกษาฤทธิ์ต้านเชื้อแบคทีเรียของส่วนประกอบหลักของพริกแกงซึ่งประกอบด้วยสมุนไพรเจ็ดชนิด คือ พริก (Capsicum annuum), มะกรูด (Citrus hystrix), ยี่หร่า (Cuminum cyminum L.), หอมแดง (Allium ascalonicum L.), กระเทียม (Allium sativum), ตะไคร้ (Cymbopogon citrates), และ ข่า (Alpinia galangal) ในสูตรจําลองแกงป่า และ แกงกะทิกับเชื้อ Salmonella Enterica 4,5,12:i:- (human) US clone โดยใช้วิธี agar diffusion method ลงบนอาหาร เลี้ยงเชื้อ Sallmonella Shigella ภายใต้การสกัด 3 สภาวะ โดยใช้การปรุงแบบอาหารในครัวเรือน คือ แกงป่าใช้น้ําในการ สกัด แกงกะทิใช้กะทิยูเอชที และ กะทิสดในการสกัด ผลจากสารสกัดทั้งสามชนิด แสดงให้เห็นว่าแกงกะทิที่ใช้กะทิสดใน การสกัดมีศักยภาพสูงสุดในการยับยั้งเชื้อ S. Enterica 4,5,12:i:- (human) US clone โดยในกระเทียม และ เม็ดยี่หร่าพบ ฤทธิ์ต้านแบคทีเรีย 0.90 ± 0.14cm ในแกงกะทิที่ใช้กะทิยูเอชที พริกแห้งให้ฤทธิ์ต้านแบคทีเรียที่สูงที่สุดคือ 0.93±0.12cm และในแกงป่าในพริกแห้ง และ หอมแดงให้ฤทธิ์ต้านแบคทีเรียคือ 0.80 ± 0.00cm ในการหาค่าความเข้มข้นต่ําสุดที่ สามารถยับยั้งเชื้อ (MICs) โดยใช้วิธี broth dilution method, กระเทียมและผงยี่หร่าพบ160 µl/mlใน แกงกะทิโดยใช้กะทิ สด พริกแห้งในแกงกะทิโดยใช้กะทิยูเอชทีพบ80µl/ml ส่วนในแกงป่าพริกแห้งพบ80 µl/mlและหอมแดงพบ 160µl/ml ส่วนประกอบพริกแกงแสดงให้เห็นฤทธิ์ต้านแบคทีเรียที่มีแนวโน้มอย่างมีนัยสําคัญต่อ S. Enterica 4,5,12:i:- (human) US clone ชี้ให้เห็นว่าพริกแกงเป็นอาหารที่มีสารออกฤทธิ์ในการป้องกัน
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    A study of feasibility to utilize lignocellulosic biomass as materials for biodiesel production
    (The International Academic Forum, 2013) Patchanee Yasurin
    Lignocellulosic biomass is a renewable, inexpensive, and abundant resource with high potential for biofuel production to implement the sustainable energy energy worldwide. The bottleneck of biofuel production is the recalcitration of ligoncellulosic biomass to fermentable sugars. Searching for a novel cellulase, a biocatalyst is one of major challenges to promote biofuel production with economic and environmental friendly. Natural microorganism is the great source of cellulase production. Therefore the objective of this research is to identify thermophilic, rapid, efficient cellulose-degrading bacteria from organic fertilizer, rice field, activated sludge, and rain forest in Thailand. More than 300 isolates were screened at 45°C on carboxy-methyl-cellulose (CMC)-containing media to observe the cellulase activity. Using standard filter paper assay, only 9 isolates (S3-10, S3-20, L2-S1, L2-S2, S3-7, L3-S1, L11-S2, L11-S3, and L11-S4) showed high total cellulase activity among other isolates. All isolates then were cultured in media containing 4 different carbon sources; CMC, filter paper, untreated rice straw, nutrient broth (NB), to see effect of substrates on cellulase production. It showed that L2-S2 in Dubois salts media with rice straw could induce high total cellulase activity to 25.57 umole/mg-protein while L11-S3 in NB could induce the highest total cellulase activity to 27.92 umole/mg- protein. Therefore untreat rice straw and NB represented as an effective inducer for cellulase production. A portion of the 16srDNA genes of cellulase positive isolates were amplified and sequenced, then BLASTed to determine species. The results showed that most of isolates are Bacillus sp.
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    The antimicrobial and shelf-life study of vegetable sanitizer from herbal extracts and Acacia concinna(Willd.) D.C’s pod water
    In the past 3 years, the Centers for Disease Control and Prevention (CDC) reported that there were at least 7 outbreaks in fresh produces, for example; Escherichia coli O121 in raw clover sprouts (2014), E. coli O157:H7 in ready-to-eat salads (2013), and Salmonella Saintpaul in cucumbers (2013). The cleaning of fresh produces is the first step in order to prevent foodborne outbreak. Therefore, this experiment aims to study and develop the shelf life of vegetable sanitizer from Thai herb crude extracts including Cymbopogon citratus (Lemongrass), Citrus hystrix (Kaffir lime), Chrysanthemum indicum (Chrysanthemum) and Acacia concinna (Willd.) D.C’s pod (Som-poi) water compared with 2 commercial brands namely Jirada and Veggie. To achieve this goal, antibacterial activity and shelf-life study were determined by antimicrobial efficiency experiment using total plate count. In this study, the vegetable sanitizer was prepared by adding 1.5% of each 0.2 g/ml crude extracts into Som-poi’s pod water and then sterilized at 121 ºC for 15 minutes. Lactuca sativa (Lettuce) using as vegetable model was soaked in 1 % of the vegetable sanitizer in water for 20 minutes before determination antibacterial activity of the vegetable sanitizer every 2 weeks for 10 weeks. Surprisingly, the results showed that the highest percentage of antimicrobial efficiency was 99.70±0.13. Although the percentage of antimicrobial efficiency decreased significantly after the 6th week; however, antimicrobial efficiency of the vegetable sanitizer remained higher than 90% up to 10 weeks. There was no significant difference of antimicrobial efficiency among 2 commercial brands and the vegetable sanitizer for 8 weeks. In conclusion, the results illustrated hat the vegetable sanitizer from Thai herbal extracts and A. concinna (Willd.) D.C’s pod water was excellent in antibacterial activity as well as a commercial brand however it could be more value in terms of a green vegetable sanitizer.
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    Effect of ohmic pretreatment on tissue integrity and extraction yield of Chinese chives (Allium tuberosum) leaf oil
    Chinese chives (Allium tuberosum Rottl.) are known for its antimicrobial and antioxidant properties. However, extract from Chinese chives was not commercially available due to very low extraction yield of the conventional method, steam distillation. This study focused on effect of ohmic pretreatment at different electric field strengths on tissue integrity and extraction yield of Chinese chives leaf oil. The field strength was varied at E = 0, 25, 50, 75 and 100 V/cm. For all treatment, the cut-off temperature was fixed at 60 °C. The tissue integrity was determined by an electrical conductivity disintegration index (Z) and viable staining using neutral red dye. It was found that as the field strength increased, Z value increased indicating a higher degree of tissue damage. The highest degree of tissue damage (Z ~ 0.8) was obtained when E > 75 V/cm were applied. The viability test showed agreeable results to the Z values. More red cells were observed at the lower field strength. At E = 25 v/cm, the amount of viable cells were comparable to the control (fresh tissue) while there was almost no viable cell left at E > 75 V/cm. When ohmic pretreatment at E = 75 V/cm was applied prior to 2.5 h of steam distillation, the extraction yield was increased from 0.12+0.01% to 0.16+0.02% by fresh leaf weight or about 33%. Thus, ohmic pretreatment was suggested to increase the permeability of any biological materials prior to extraction process in order to enhance the extraction yield.
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    Antioxidant activity of Allium tuberosum Rottl. ex Spreng under different extraction methods
    The Bang-Phae organic vegetable grower community enterprise group, Ratchaburi province is one of the big Chinese chives (Allium tuberosum Rottl. ex Spreng) grower in Thailand. However, some Chinese chives did not meet standard and were sorted out. The Chinese chives essential oil, which contains many new and known bioactive compounds, is valued product from sorted out Chinese chives. Therefore, this experiment was aimed to study the antioxidant activity of Chinese chive extracts using 17 different extraction conditions (Steam distillation for 1.0, 2.0, 2.5, 3.0 hour; Ohmic pretreatment with steam distillation for 1.0, 2.0, 2.5, 3.0 hour; 95% ethanol, hexane, oil extract using dry, fresh, freeze Chinese chives). The ferric reducing antioxidant potential assay was used to evaluate antioxidant activity of Chinese chive extracts. The results showed that the highest antioxidant activity was 1.756 ± 0.008 µmol Fe2+/ mg sample of freeze Chinese chives extracted with hexane. The antioxidant activity was vary from 0.098 ± 0.005 - 1.756 ± 0.008 µmol Fe2+/ mg sample depend on the extraction condition.