Effects of fermentation process on sensory characteristics of coffee with different geographical characteristics
學生姓名:
鄭宇君
指導教授:
劉修銘
學 期:
112上
摘 要:
Coffee quality will be affected by genetic characteristics, geographical features and processing methods. The fermentation step is one of the most important in the processing method. Thus, this study explores the changes in sensory characteristics of coffee from different regions after inoculation with yeast. The first study used Coffea Arabica from five production areas and inoculated them with Saccharomyces cerevisiae and Torulaspora delbrueckii using the Natural (NAT) and Pulped natural (PN) methods. The analysis of the persistence of inoculated yeasts, organic acid, and sugar content were carried out in coffee cherry and the analysis of volatile compounds content and
sensory score were carried out in roasted coffee. After the fermentation, S. cerevisiae reached 7.0 Log CFU/g, T. delbrueckiishowed a similar population to the control group. After roasting, pyrrole and furan are compounds that distinguish the type of processing. More furan was observed in NAT sample, while more pyrrole was observed in PN sample. In the sensory analysis part, the groups inoculated with yeast all reached the specialty coffee standard (80 points), while the control group did not (last 80 points). The second study uses low-altitude coffee through yeast inoculation, using three species (S. cerevisiae, T. delbrueckii, and Candida parapsilosis) singly and with co-inoculation for fermentation. S. cerevisiae increased during the fermentation process, while C. parapsilosis grew stably at 5.82-6.41 Log cell/g. All treatments inoculated with T. delbrueckii had similar trends to the control group. FT-IR analysis results show characteristic peaks with OH, CH, C=O groups, chlorogenic acid, and trigonelline. These compounds are all related to the flavor of coffee. The sensory score of the group inoculated with S. cerevisiae was lower than that of the control group, while C. parapsilosis and T. delbrueckii co-inoculated had the highest scores. Yeast can be used to control coffee quality and increase the economic value of coffee beverages. Overall, after inoculation with T. delbrueckii or a combination of inoculations, it has better sensory evaluation in the natural method.
sensory score were carried out in roasted coffee. After the fermentation, S. cerevisiae reached 7.0 Log CFU/g, T. delbrueckiishowed a similar population to the control group. After roasting, pyrrole and furan are compounds that distinguish the type of processing. More furan was observed in NAT sample, while more pyrrole was observed in PN sample. In the sensory analysis part, the groups inoculated with yeast all reached the specialty coffee standard (80 points), while the control group did not (last 80 points). The second study uses low-altitude coffee through yeast inoculation, using three species (S. cerevisiae, T. delbrueckii, and Candida parapsilosis) singly and with co-inoculation for fermentation. S. cerevisiae increased during the fermentation process, while C. parapsilosis grew stably at 5.82-6.41 Log cell/g. All treatments inoculated with T. delbrueckii had similar trends to the control group. FT-IR analysis results show characteristic peaks with OH, CH, C=O groups, chlorogenic acid, and trigonelline. These compounds are all related to the flavor of coffee. The sensory score of the group inoculated with S. cerevisiae was lower than that of the control group, while C. parapsilosis and T. delbrueckii co-inoculated had the highest scores. Yeast can be used to control coffee quality and increase the economic value of coffee beverages. Overall, after inoculation with T. delbrueckii or a combination of inoculations, it has better sensory evaluation in the natural method.
20231004_專題討論_摘要_鄭宇君.pdf