CHAPTER 18: Proteins of Coffee Beans: Recent Advances

Amino acids, peptides and proteins play a central role in coffee cup quality. They interact with carbohydrates during coffee roasting in a process known as Maillard reaction. Although several reports have been published on this matter, information on protein chemistry in the coffee bean is scant. Since 1999 some biochemical and genetic works have introduced new challenges for those working with protein in coffee. The 11S globulin is the main protein of coffee beans – 45% of the total protein – but so far there is no conclusion about its participation in the cup quality. Many questions still exist such as ‘are the several and different peptides formed from the 11S protein cleavage as a result from proteases action?’ A gene coding for a 2S protein is the most expressed gene during the development of coffee bean but the protein accumulates to a lesser extent than the 11S protein. What is its participation in coffee quality? Several proteases were identified in genomic studies; what role do they play in cup quality? We are still far from understanding the whole complexity of coffee beverage quality but we may use genomic and biochemical available data to plan new proteome experiments in order to answer some basic questions regarding the importance of proteins in the quality of coffee beverage.