Effect of Brewing Methods and Time on Secondary Metabolites, Total Flavonoid and Phenolic Content of Green and Roasted coffee Coffea arabica, Coffea canephora and Monsooned Malabar

Coffea arabica, Coffea canephora (robusta) and monsooned malabar are the three types of coffee which are well known and used by most of population in India and all over the globe. For consuming coffee various brewing methods are used worldwide, French press, Espresso, Turkish coffee, being the common. Eleven brewing methods are introduced in the paper for brewing of green coffee, some of which are common for brewing tea.

Among all the mentioned brewing methods, Decoction method showed the best results, as maximum amount of Flavonoids and Phenols were found to be present in green coffee arabica, values being 69.24 mg QE/g of coffee and 108.67 mg QE/g of coffee respectively, whereas, for robusta it was found to be 47.47 mg QE/g of coffee and 93 mg QE/g of coffee respectively. Brewing time is also considered as one of the major factors for coffee brewing, as if the time is too short, all the flavours will not dissolve and if too long, it may dissolve undesirable components as well. An increasing trend was seen in flavonoid and phenolic content in both arabica (TPC up to 84.11 mg QE/g of coffee) and robusta (TPC up to 78 mg QE/g of coffee) along with monsooned malabar (TPC up to 84.88 mg QE/g of coffee) with increase in brewing time. Another factor considered is the solvent used for brewing. A comparison was made between water and alcohol. Both the coffees, green and roasted showed a significant difference in the values when brewed in ethanol and in water.

Results indicate that the brewing methods given may be used along with a variant brewing time depending on its phenolic content. Also, green coffee can be proved a boon with more health benefits as compared to roasted one.