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|標題:||Effect of bacterial strains on functional properties and ingredients of of Pu'er tea made by an improved fermentation method|
|摘要:||The purpose of this study was mainly on studying changes in the functional components of Pu'er tea during an improved fermentation method by using bacteria isolated from two famous commercial Pu'er teas (Ta-Huang-In and Ta-Hon-In). The method included mixing isolated strains (R9 and Y11) with tea leaves initially, and then fermented under 60~70 RH% at room temperature for 6 weeks. Changes in tea color, total polyphenol, effects of scavenging superoxide radical , and scavenging DPPH radical during fermentation were investigated. Results showed that the L values of tea broths made by same strain but different fermentation time were not significantly different, however the values of “a”,“b” and ΔE value increased with time. The total polyphenol contents of tea made by either one of the two strains.increased during fermentation Results showed that the tea made by the strain R9 (3285.3 mg/100g) was higher than that (3190.5mg/100g) of Y11. The abilities of scavenging superoxide radical of R9 were 86.05∼92.62%, 90.12∼99.22%, 88.20∼97.89%, 82.49∼98.75%, 83.10∼98.69% and 88.78∼98.18% of those tea fermented for 7, 14, 28, 35 and 42 days, respectively. Similarly, there were 86.05∼92.62%, 90.12∼99.22%, 88.20∼97.89%, 82.49∼98.75%, 83.10∼98.69% and 88.78∼98.18% for Y11, respectively. The abilities of scavenging DPPH radical for all tea in the experiment were corrllated to total polyphenol content, so that the abilities of scavenging DPPH became higher and higher as fermentation time longer. The scavenging DPPH effect of R9 fermented for 42 days was the highest (80.38∼92.59%), and Y11 was the second.|
本研究以15年大黃印及25年大紅印兩種市售普洱茶為樣品，分離篩選菌種並大量培養單一菌種後與茶菁混合進行普洱茶之改良式醱酵，主要探討不同菌種及醱酵時間對普洱茶水萃取物其機能性保健成分變化之影響，包括不同醱酵時間及菌種之醱酵成品其茶湯顏色、總多酚含量、清除超氧離子及DPPH離子能力。結果顯示，茶湯色澤在接種同菌株不同時間之L值並無明顯差異，a值、b值及總色差E值隨醱酵時間增長而增加。接種不同單一菌株於毛茶經醱酵7至42天之總多酚含量隨著醱酵時間增長有增加之趨勢，其中又以R9 之含量 (3285.3 mg/100g) 最高，Y11次之 (3190.5 mg/100g)。清除超氧離子之能力於醱酵第7、14、21、28、35及42天，分別為86.05∼92.62%、90.12∼99.22%、88.20∼97.89%、82.49∼98.75%、83.10∼98.69% 及88.78∼98.18%。清除DPPH離子之能力與總多酚含量有相同之趨勢，亦即隨著醱酵時間之增長其清除DPPH能力越高，於醱酵第42天時為80.38∼92.59% 其中以R9清除率最高，Y11次之。 比較以R9與Y11兩種菌株所進行之改良式醱酵普洱茶與八種市售普洱茶之DPPH離子清除率及γ-胺基丁酸含量，發現在DPPH離子清除率方面，除較易武春茶及大紅印低外，與其他市售品則非常接近；另外R9與Y11兩種改良式醱酵普洱茶之γ-胺基丁酸含量分別為1663.5g/g及1921.3g/g，除比儲藏六年之易武春茶高外，其餘皆低於儲藏八年以上之市售產品，唯其含量均比未醱酵之茶菁含量明顯增加。
|Appears in Collections:||食品暨應用生物科技學系|
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