# Improved Functions of Fermented Coffee by Lactic Acid Bacteria
###### Abstract  
Coffee is one of the most popular beverages in the world, and at present, specialty coffees are developing for better tastes, flavors, or functions. Fermented coffees also reflect this trend and some brands are commercialized. Unlike general fermented coffees, we tried to ferment coffee extract with several lactic acid bacteria. Finally, we selected three strains that persisted in the coffee extract, and show strong antimicrobial activity, for the fermentation starters. The strains were identified as _Pediococcus pentosaccus_ (KNUT 0384), _Lacticasibacillus paracasei_ (CJNU 1840), and _Laciplantiobacillus plantarum_ (CJNU 0441) based on 165 rRNA gene sequences. During the fermentation process, the total acidities (\(p<0.05\) vs. the control, non-fermented coffee extract) and cell masses increased, which indicates that the bacteria metabolized properly in the extract. Furthermore, the fermented coffee extracts showed increased antimicrobial activities against _Listeria monocytogenes_ (\(p<0.05\) vs. the control) and _Streptococcus mutans_ (\(p<0.05\) vs. the control), increased anti-oxidative activities (\(p<0.05\) vs. the control, except for the KNUT 0384 sample), decreased caffeine content (\(p<0.05\) vs. the control, except for the KNUT 0384 sample), and increased chlorogenic acid content (\(p<0.05\) vs. the control). Taken together, the fermented coffee extracts with the selected lactic acid bacteria could be specialty coffees where several functions are improved when compared with a control coffee extract. f +
Footnote †: journal: Medical  
to 2011 [5]. Developments in out-of-home consumption habits, opportunities provided by online commerce platforms, and the development of creative brewed coffee variants are some of the key reasons propelling the coffee market's expansion. In addition to their social, environmental, and economic sustainability, consumers are also interested in the quality and provenance of coffee goods [6]. Following these trends, roasteries have brought out special coffee products with special effects on health. In general, high-quality coffee cannot be produced using all types of beans; however, specialty coffee production is distinguished by its approach to controlled conditions of production, from plantation to the selection of raw materials and the cultivation of the products through to different processes like fermentation [7]. The constantly increasing demand for specialty coffee has forced researchers to investigate the impact of coffee on human health along with the quality and taste of the specialty coffee, and many researches have proven the beneficial effects of coffee usage, such as it preventing several chronic diseases like type 2 diabetes mellitus, Parkinson's disease, Alzheimer's disease, and liver disease (cirrhosis and hepatocellular carcinoma) [8; 9; 10]. Antimicrobial, antioxidant, and anti-inflammatory responses are among the other beneficial attributes of coffee; these characteristics of coffee are the result of the availability of the bioactive compounds in coffee that make it a functional beverage [2; 11; 12]. There are many bioactive extracts present in coffee brews, and their composition differs depending on the brewing techniques utilized [13]. Over the past decade, almost 1000 coffee phytochemicals have been described with different functional and bioactive properties [14]. Some of the key bioactive compounds found in coffee are phenolic compounds, including chlorogenic acids, polyphenols and derivatives, methylxanthines (such as caffeine, theophylline, and theochromine), diterpenes (like cafestol and kahweol), nicotinic acid (vitamin B\({}_{3}\)) and its precursor trigonelline, as well as magnesium and potassium [13; 15].