Fermentation of Green Coffee Bean (Coffee Arabica) with Lactic Acid Bacteria and Characterization of Its Biochemical Properties

Abstract

Coffee is one of the most popular beverages in the world. In this study, lactic acid bacteria, Lactobacillus delbrueckii YC KCCM11945P (YC), Streptococcus thermophilus Y2 KCCM11946P (Y2), and Streptococcus thermophilus R2 KCCM11947P (R2) were isolated from Korean traditional food

doenjang, and/or cheonggukjang. Using these strains, green coffee bean was fermented with various water or bacteria inoculation concentration based on sensory evaluation. The water optimization concentration (w/w) was 50% for YC, 50% for Y2, and 15% for R2, respectively. The optimization of bacteria concentration for coffee fermentation was 3.2 x 108 CFU/g coffee for YC and Y2, 6.4 x 108 CFU/g coffee for R2. The fermentation time was found though bacterial growth during fermentation, which was fixed for 12 h. Regular coffee and fermented coffee were analyzed by total phenol and flavonoid contents, antioxidant activity (DPPH, ABTS), angiotensin converting enzyme inhibition activity, and the amount of trigonelline, caffeine, and chlorogenic acid determined by reverse-phase HPLC. Fermented coffee increases 1.2 times and 1.5 times in total phenol and flavonoid content. Fermented coffee improves 2 times of SC50 in DPPH, and 1.3 times in ABTS, and 1.7 times of IC50 in angiotensin converting enzyme. In an analysis of HPLC, content of chlorogenic acid (CGA) increases 1.3 times in fermented coffee than regular coffee, but trigonelline and caffeine were the same in regular coffee and fermented coffee. Additionally, to increase the flavor, cinnamon and pine needle extract added with green coffee bean during fermentation. Fermented coffee with cinnamon or pine needle also showed the similar results of fermented coffee, which improved more functionality than regular coffee.