Summary: | 碩士 === 國立屏東科技大學 === 食品科學系所 === 103 === Most commonly seen drink in the world is coffee and tea. Coffee leaf is an excellent source of health materials and low in caffeine. However, coffee leaf tea is not common probably due to its special earth odor. In this study, we proposed a modified coffee leaf tea manufacturing technology via fermentation to reduce the earth odor, six-carbon alcohols and aldehydes, in the coffee leaf tea. The methyl salicylate content in fresh coffee leaf tea was 13.69 %, but in our coffee leaf tea, it increased to 26.18 % to give an odor of special herbs. Linalool oxide level was 16.35 %, which was more than 2-ethyl 1-hexanol (3.34 %, earth odor). Fresh coffee leaves were found to have 45.29% aldehydes, which were n-hexanal, E-2-hexenal, E, E-2,4-hexadienal, E-2-heptenal, E, Z-2,4-heptadienal, E, E-2,4-heptadienal and E, E- 2,4-nonadienal. Those aldehydes disappeared after fermentation and new aldehydes generated in the coffee leaf tea were furfural, benzaldehyde, and 5-methyl furfural (9.47 %). In addition, a wine odor ketone 2-octanone was produced (3.69 %), an important aroma in coffee leaf tea. In summary, this coffee leaf tea has an herb wine odor, oolong tea roasting odor, black tea sweet odor, and special fermented aroma. Therefore, the coffee leaf tea was aroma belongs to black tea aroma.
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