Processing Ground Coffee (Blending of Arabica and Robusta) and The Quality Changes During Storage

Abstract

Coffee is beverage ingredient that not only popular in Indonesia but also around the world. Because either ground coffee or liquid coffee has a unique flavor which is not contained in other beverage ingredients. Some of ground coffee is derived from seed of Robusta coffee which is dominated plant in Indonesia. Seed of Robusta coffee has superior characteristic and very fast growing. However, seed quality of Robusta Coffee is poor compare with Arabica coffee that contain about 22% of yield and higher caffeine content with approximately 18% of yield. Caffeine content of Robusta Coffee causes taste of Robusta coffee is bitter, otherwise less content of caffeine will make the taste of coffee more delicious. However, the Arabica coffee has higher price due to the production capacity. In addition, changes of physical and chemical content of coffee seed also occur during roasting process. The use of different media such as stainless steel pan and clay pan also influence the taste of ground coffee because temperature during roasting period will affect acidity of steeping coffee. The purpose of this research were finding the best blending ratio between Arabica and Robusta coffee and also finding the media to obtain the maximum taste and flavor which is preferred by consumers, analyzing the characteristic and the quality change during storage temperature in level of 30°C, 35°C, and 45°C in different media packaging that are kraft paper and polypropilen (PP). This research also estimated shelf life of ground coffee through Arrhenius method. Based on organoleptic test, there were significant differences among each treatment. Analysis of moist content, VRS, coffee extract content, and pH also showed significant differences for each treatment. In the other hand, yield of ground coffee showed that there is no significant difference for every treatment. Based on result of hedonic test which is supported by result of moist content, yield, and VRS, there was selected blending ratio between 10% of Arabica coffee and 90% of Robusta coffee using clay roasting media. The best ground coffee was stored during one and a half month through observation in 10 points using kraft paper and polypropilen (PP) at several temperature levels, those are 30°C, 35°C, and 40°C. Some parameters which were measured such as: the change of moist content, (Volatile Reducing Substances), and the degree of acidity (pH). The quality of ground coffee decline during storage period. The result of the research showed that the moist content and pH vale were increasing, whereas VRS content was reducing. The packaging media that decrease quality of ground coffee was PP plastic at 30°C of temperature. Shelf life of ground coffee using PP were 13 months 27 days at 30°C of temperature, 10 months 27 days at 35°C of temperature, and 8 months 15 days at 45°C at temperature. Meanwhile, the shelf life of ground coffee using kraft paper were 3 months 27 days at 30°C of temperature, 2 months 6 days at 35°c of temperature, and 1 month 9 days at 45°C of temperature. Experiment by all parameters which are measured, it is concluded that the best ratio to blend Arabica coffee and Robusta coffee is 10% of Arabica coffee and 90% of Robusta Coffee using clay roasting media and stored by PP at 30°C of temperature. This ground coffee is the best product to be developed.