STANDARDIZATION OF FERMENTATION IN HONEY COFFEE ROBUSTA PRODUCTION WITH VARIATION COMPARISON OF INOCULUM AND FERMENTATION DURATION

• Main Author: Natalia Nusaly, Windy
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/49784
• Institution: Institut Teknologi Bandung

Robusta coffee is one type of coffee planted in around 80% of Indonesia's coffee plantation area. In the micro distribution, Robusta coffee farming provides lower income than Arabica coffee farming. Farmers with Arabica coffee farming have greater income than farmers with Robusta coffee farming. To increase the selling price of Robusta coffee, it can be done through the process of improving the quality of Robusta coffee to become good Robusta through improving postharvest processing and increasing the predominant microbial activity that plays an important role in the fermentation process of coffee and improving the quality of Robusta coffee beans produced. The purpose of this study is to isolate and use predominant microbes, conduct filtering microbes that ferment coffee based on enzymatic activity and optimize fermentation. The method used in this study is the isolation and collection of microbes involved in the post-harvest process of Robusta honey coffee. Then microbial screening is done through its enzymatic activity (amylolytic, pectinolytic, cellulolytic and proteolytic). After that the growth curve of the selected microbes is made to determine the age of the inoculum to be used in the optimization process of fermentation. The optimization process of fermentation is carried out with the selected inoculum with the selected variation of the inoculum and the time of fermentation. Optimized coffee green beans with honey are then roasted and cupping tests are performed to determine the quality of the coffee based on the cupping value. The results of isolation by processing honey obtained 13 bacterial isolates (B1, B2, B3, B7, B8, B9, B10, B12, B13, B14, B15, B16 and B18) and 7 yeast isolates (Y1, Y2, Y3, Y4, Y7, Y9 and Y10). Based on the dominance of isolates and enzymatic test results, isolates B3, B12, Y2 and Y3 were selected to be used as starter culture. B3 isolate has pectinase, cellulase and amylase enzyme activity, isolate B12 has protease enzyme activity, Y2 isolate has pectinase, cellulase, amylase and protease enzyme activity, while Y3 isolate has pectinase and amylase enzyme activity. The optimization of fermentation in this study used a variation of the ratio of bacterial inoculums compared to yeast 1: 1, 1: 2, and 2: 1 as well as variations in the duration of fermentation time of 0 hours, 6 hours and 12 hours and in the In group carried out fermentation without the addition of the inoculum. The pH levels in all treatments showed the same pattern, which decreased during the 6 hour and 12 hour fermentation process (pH ~ 4) and increased slowly during the drying process (pH ~ 7). Optimization results generally showed that culture starters (B3, B12, Y2 and Y3) which were added proved to dominate the microbial community in Robusta coffee honey fermentation. During fermentation, the number of microbial compounds increases but the diversity decreases. The highest number of bacterial communities was found in the C1 treatment with variations in the ratio of bacterial inoculums (B3, B12) to yeast (Y2, Y3) (1: 2) and the fermentation time of 0 hours. While the highest number of yeast cells were found in treatment B2 with variations in the ratio of bacterial inoculums (B3, B12) versus yeast (Y2, Y3) (1: 2) and the incubation time period of 6 hours. At 48 hours of drying after the addition of the inoculum, the number of bacterial cells and yeast increased. At 192 hours until the 288th day of drying, the number of microbial communities decreased. At 240 hours to 288 hours of drying only yeast communities are found and the bacterial community is not found. Based on the results of the cupping test, it is known that the use of microbial starter cultures during the optimization process with a ratio of bacteria (B3, B12) to yeast (Y2, Y3) 1: 2, 6 hours duration of fermentation, roasting profile medium (medium grade), grinding profile mediumcoarse (20 mesh) with a brewing temperature of 93 oC can be used as a standard because it has succeeded in producing fine quality Robusta coffee honey with the resulting flavor and aroma profiles, namely corn, caramel, orange, sweet and the cupping score reached 81.75.