Evaluation of DNA extraction methods from green and roasted coffee beans

This paper describes a generic approach to the evaluation of DNA extraction methodology using green and roasted coffee beans as a model commodity. The use of Design-Expert® software was used in the design of experimental work to compare and optimize yields using a variety of commercial DNA extraction kits. The quality of the extracted DNA in terms of PCR inhibitor content is assessed and a judgment made that GeneSpin represents perhaps the best methodology in this instance. Coffee is a major commercial crop and there is the potential for fraudulent adulteration of the more expensive Arabica with Robusta beans. It is demonstrated that the DNA extracted from both green and roasted beans could be used in a PCR–RFLP based analysis to differentiate between Arabica and Robusta types of coffee.