THE OPTIMIZATION OF WINE COFFEE FERMENTATION WITH VARIATION OF RATIO AND PERCENTAGE OF INOCULUM

• Main Author: Istiqomaril S, Fathya
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/32562
• Institution: Institut Teknologi Bandung

Coffee consumption in Indonesia is increasing every year. There are various types of coffee consumed, one of which popular is wine coffee characterized with unique flavour of wine as a result from the coffee processing method. Wine coffee is processed through dry processing or named as natural process. The procedure for producing wine coffee is different to natural method as it must underwent fermentation stage for about 3 days prior to drying. This research aimed to isolate predominant microorganism in wine coffee fermentation and to optimize its fermentation process using microbial isolates with specific enzymatic traits. Enzymatic assays such as pectinolytic, cellulolytic, amylolytic, and proteolytic were used to screen microorganism isolate, followed by sequencing using 16S rRNA for bacteria isolate and ITS rRNA for the yeast isolate. Growth curve of chosen isolate was then used to determine the age of inoculum to be used for optimization of fermentation process. After fermentation process, coffee beans were roasted and its quality were assessed by means of cupping test. Based on experiment, 8 bacteria (N2, N3, N4, N5, N6, N10, NK, and NP) and 5 yeast (P2, P3, P6, PB and PK) were isolated. Enzymatic assays were conducted for the predominant isolate N10, NK, NP, PB and PK. Based on the assay result, isolate NP and PB were chosen for inoculum. NP Isolate has pectinolytic and cellulosic ability, whereas PB isolate has pectinolytic, amylolytic and proteolytic ability. Based on sequencing and phylogenetic tree construction, isolate NP was identified as Klebsiella sp. and isolate PB was identified as Pichia kudriavzevii. Fermentation optimization was done using various inoculum ratio of bacteria and yeast of 1:5, 1:10, 1:20 and inoculum volume (v/w) of 5%, 10%, and 15%, all with 24 hour fermentation. Measurement in all treatments showed similar pattern of decreasing pH during fermentation (pH ~ 4) and increasing pH in drying process (pH ~ 5). Experiment without the addition of inoculum showed steady pH level until drying process (pH~ 4). Addition of inoculum in all the experiments showed that the isolates were able to grow and dominated microorganism community during fermentation. Cupping test results also showed that 15% (v/w) inoculum addition of bacteria to yeast rasio of 1:10 produced coffee drinks with the highest cupping score of 84,25, and considered as specialty coffee.