Cordyceps militaris fermented tea prepared by solid-state fermentation and its antioxidant and antimicrobial activities

• Main Authors: KUO, YUN-CHEN, 郭芸禎
• Other Authors: LIANG, CHIH-HUNG
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/zfy838

碩士 === 東海大學 === 食品科學系 === 106 === Cordyceps militaris is a precious medicinal mushroom which contains rich functional components such as cordycepin, adenosine, cordycepic acid and polysaccharide. It has been used as a source of dietary supplement development materials. Tea leaves contains catechins, alkaloids and other active ingredients that had many physiological functions such as antioxidant, hypolipidemic and accelerates metabolism. Light-emitting diodes (LEDs), a good artificial light, are more efficiency, more safety and have a longer life than the traditional light. Thus, LEDs has been widely used in a variety of plant irradiation in recent years. The aim of this study was the general conditions of Cordyceps militaris fermented tea and the effects of different LED illumination on their functional components, and furthermore to investigate the antioxidant and antibacterial activities of tea, Cordyceps militaris fermented tea (CMFT) and Cordyceps militaris mycelia (CMM). Results showed that the optimal growth conditions for Cordyceps militaris fermented tea were water supplementation at 60% , inoculation volume at 10%, and incubated for 19 days at 25ºC. In addition, different LED wavelength light sources were used to replace fluorescent lamp and the differences of their functional components were compared. Results showed that the biomass of CMFT increased with different LED light sources especially the red LED light (171.26 mg/g dw). Cordycepin get the higher contents in red (0.362 mg/g dw) and green LED light (0.364 mg/g dw), and cordycepic acid get the higher contents in fluorescent (8.86 mg/g dw) and red LED light (8.36 mg/g dw), but here was no significant difference in the contents of adenosine between different light source. In addition, higher concentrations of gallic acid (0.985 mg/g dw) and total catechin (10.79 mg/g dw) were obtained from fluorescent, and red LED light could be higher caffeine (11.70 mg/g dw) and theobromine (0.481 mg/g dw) contents. On the antioxidant activity of tea, CMFT and CMM, as the concentration of 2 mg/mL, The reducing power of hot water extracts was 0.620, 0.668, and 0.515.The scavegling ability of hot water extracts on DPPH radicals was 61.22, 45.77 and 40.32%. The chelating ability of hot water extracts was 74.61, 67.44 and 70.56%. The scavegling ability of hot water extracts on ABTS radicals was 93.98, 93.22 and 30.95%. The reducing power of ethanolic extracts was 0.627, 0.719 and 0.375.The scavegling ability of ethanolic extracts on DPPH radicals was 90.80, 91.30 and 69.41%. The chelating ability of ethanolic extracts was 50.10, 25.76 and 71.22%. The scavegling ability of ethanolic extracts on ABTS radicals was 93.79, 93.55 and 9.74%. As the sample concentration of 100 mg/mL, the antibacterial activity of hot water extracts from tea, CMFT and CMM were as follows. The antibacterial activity against Bacillus cereus was 10.33, 9.33 and 9.00 mm. The antibacterial activity against Staphylococcus aureus was 10.00, 11.33 and 8.67. The antibacterial activity against Escherichia coli was 9.67, 10.33 and 8.33 mm. The antibacterial activity against Salmonella typhimurium was 10.00, 11.33 and 8.33 mm. As the antibacterial activity of ethanolic extracts, the results against B. cereus was 11.67, 11.00 and 10.67. The results against S. aureus was 11.33, 11.33 and 10.67. The results against E. coli was 11.33, 10.33 and 11.00 mm. The results against S. typhimurium was 11.00, 11.33 and 11.00 mm. In conclusion, different LED light wavelength could regulate biomass, bioactive compounds, and their are antioxidant and antibacterial potential in Cordyceps militaris fermented tea. In the future, the adjustment of light wavelengths can be used as the development of the applications of Cordyceps products.