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|Title: ||文旦皮精油之成分組成及其乳化物對S. aureus及E. coli的抗菌活性之探討|
Study on Constituents of Pummelo Peel Oil and Antibacterial Activity of It's Emulsion for S. aureus and E. coli
|Authors: ||Yu-Hsin Lin|
|Contributors: ||NTOU:Department of Food Science|
pummelo;essential oil;antibacterial activity
|Issue Date: ||2011-06-30T07:42:28Z
|Abstract: ||摘要 利用蒸氣蒸餾萃取文旦果皮之精油，並以GC-MS分析其成分組成，共鑑定出33個化合物，主要成分為limonene（940.07 mg/g），其次為myrcene（23.65 mg/g），次之為β-pinene（13.53 mg/g）。在自體酵素試驗，文旦果皮於30 oC反應15天，並以水蒸餾法萃取精油，其萃取率明顯的由2.50下降至2.04%，而精油中主要碳氫萜烯類化合物由911.68降低至828.19 mg/g，主要含氧萜烯類化合物由9.46增加至12.43 mg/g。然而利用蒸氣蒸餾萃取，於50 oC反應2天的文旦皮精油，其萃取率亦明顯的由2.48下降至1.64%，精油中主要碳氫萜烯類化合物由原來的982.15減少至864.35 mg/g，而主要含氧萜烯類化合物則由10.95增加至13.92 mg/g。 以未經均質（0 rpm）的精油乳化物（0.1、0.2及0.4%）對S. aureus及E. coli 的抗菌效果皆隨著精油濃度的增加而提高。濃度為0.4%時比控制組分別降低了1.03及0.85 Log CFU/mL。以24000 rpm轉速均質之精油乳化物對S. aureus及E. coli的抑制效果皆高於13500 rpm。然而經24000 rpm均質之精油乳化物對E. coli的抗菌效果比未均質的高，MIC值可由0.49降低至0.25%，明顯提高其抑制E. coli之效果。精油乳化物（0.1、0.2及0.4%）經微射流1次及3次循環處理後，粒徑大小平均分別為1383.5及216.6 nm。然而以0.4%精油乳化物經1次循環處理後對S. aureus之抑制效果最佳，比控制組降低了1.13 Log CFU/mL。以相同濃度之乳化精油經1次及3次循環處理後對E. coli亦具有明顯的抑制效果，且比控制組分別降低了1.12及1.16 Log CFU/mL。且經微射流1次循環處理後可提高低濃度（0.1%）之精油對S. aureus及E. coli 的抗菌效果，比控制組分別下降0.88及1.02 Log CFU/mL。 僅添加水溶性幾丁聚醣（DA=54.8%）的抗菌效果隨著濃度的增加而上升，濃度於500 ppm時，對S. aureus具最佳抑制效果，比控制組降低了1.12 Log CFU/mL。然而水溶性幾丁聚醣濃度為1000 ppm時，E. coli的菌數則比控制組降低了1.07 Log CFU/mL，因此明顯的表示幾丁聚醣對S. aureus的抑制效果高於E. coli。於0.4%的文旦皮精油乳化物（經 24000 rpm均質）中添加不同濃度之幾丁聚醣（100、300、500及1000 ppm）相較於僅含幾丁聚醣及精油乳化物的抗菌效果，對S. aureus及E. coli之抑制效果皆具明顯的增加，分別以300及500 ppm時，比控制組降低了2.40及2.55 Log CFU/mL。在不同pH值時，文旦皮精油乳化物（0.4%）對S. aureus的抑制率則隨著pH值上升而增加，而幾丁聚醣（300 ppm）於pH 5.5下對S. aureus及E. coli 之抑制率高於pH 7.4及8.5。然而在pH 7.4時，將300 ppm之幾丁聚醣添加入0.4%之文旦皮精油乳化物對此兩株菌種皆具最佳的抗菌效果，其抑制率分別為99.48和99.06%。|
Abstract Pummelo peel oil was extracted by steam distilation and the constituents were analyzed by GC-MS. There were thirty-three compounds identified from the essential oil. The main compound was limonene (940.07 mg/g), the second was myrcene (23.65 mg/g), and the third was β-pinene (13.53 mg/g). In order to find the effect of endogenous enzymes on composition of pummelo peel oil, the oil was extracted by water distillation after reacting with endogenous enzymes for 15 days at 30oC. The yield of the essential oil decreased from 2.5 to 2.04%. The amount of hydrocarbon monoterpenes in the essential oil decreased from 911.68 to 828.19 mg/g, while the oxygenated terpenes increased from 9.46 to 12.43 mg/g. If the pummelo peel oil was extracted by steam distillation after reacting with endogenous enzymes for 2 days at 50oC, the yield of the essential oil significantly decreased from 2.48 to 1.64%. The hydrocarbon monoterpenes in the oil decreased from 982.15 to 864.35 mg/g and the oxygenated terpenes increased from 10.95 to 13.92 mg/g. The antibacterial effect of emulsified pummelo peel oil (without homogenization) on S. aureus and E. coli increased as the concentration of the oil raised. The plate counts of S. aureus and E. coli were lower (1.03 and 0.85 CFU/mL, respectively) than the control when 0.4% essential oil was used. The antibacterial effects of emulsified pummelo peel oil, which had been homogenized at 24000 rpm, on S. aureus and E. coli were higher than that homogenized at 13500 rpm as well as that without homogenization for E. coli. The MIC (minimum inhibitory concentration) value for E. coli decreased from 0.49 to 0.25%. The mean partical size of the emulsified pummelo peel oil was 1383.5 nm after being homogenized with 1 time of microfluidizing treatment. The size decreased to 216.6 nm while the microluidizing treatment increased to 3 times. The inhibitory effect of S. aureus was the best when 0.4% emulsified pummelo peel oil was homogenized with 1 time of microfluidizing treatment, of which the plate count of S. aureus was 1.13 Log CFU/mL lower than the control. The same concentration of emulsified pummelo peel oil also had significant inhibitory effect on E. coli after the essential oil was homogenized with 1 and 3 times of microfluidizing treatments, of which the plate counts of E. coli were respectively 1.12 and 1.16 Log CFU/mL lower than the control. The emulsified pummelo peel oil with lower concentration (0.1%) could increase its inhibitory effects on both S. aureus and E. coli after the essential oil was homogenized with 1 time of microfluidizing treatment, of which the plate counts of S. aureus and E. coli were respectively 0.88 and 1.02 Log CFU/mL lower than the control. The antibacterial effect raised by adding water-souble chitosan (DA=54.8%) alone when the concentration increased. The inhibitory effect on S. aureus reached to the maximum when the concentration of water-souble chitosan was 500 ppm, of which the plate count of S. aureus was 1.12 Log CFU/mL lower than the control. The plate count of E. coli was only 1.07 Log CFU/mL lower than the control as the concentration of water-souble chitosan increased to 1000 ppm; hence, the water-souble chitosan exhibited higher inhibitory effect on S. aureus than on E. coli. The 0.4% emulsified pummelo peel oil (homogenized at 24000 rpm) adding different concentrations of water-souble chitosan (100, 300, 500 and 1000 ppm) was found to have higher antibacterial effect than both water-souble chitosan and emulsified pummelo peel oil without adding chitosan. The inhibitory effects on S. aureus and E. coli increased significantly when 300 and 500 ppm of water-souble chitosan was added in 0.4% emulsified pummelo peel oil. The plate counts of S. aureus and E. coli were respectively 2.40 and 2.55 Log CFU/mL lower than the control. As for the pH effect, the inhibitory percentage of S. aureus for the 0.4% emulsified pummelo peel oil increased as the values of pH raised. The water-souble chitosan (300 ppm) had higher inhibitory percentage for S. aureus and E. coli at pH 5.5 than at pH 7.4 and 8.5. The 0.4% emulsified pummelo peel oil which had been added with 300 ppm water-souble chitosan showed the best inhibitory effects on both bacteria when the value of pH was 7.4. The inhibitory percentages were 99.48 and 99.06% for S. aureus and E. coli, respectively.
|Appears in Collections:||[食品科學系] 博碩士論文|
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