In many parts of the world, the day begins with a ‘good cuppa’!! Tea and Coffee are two most consumed beverages world over and for many populations, a good start to the day is provided by a steaming hot cup of tea or a frothy cup of coffee.
The term ‘Green Coffee’ has suddenly crept into the food vocabulary of the world in recent years. Though Coffee as a beverage has been consumed by populations over several centuries, it is as if someone has suddenly rediscovered the ‘Green Coffee’ part of regular Coffee.
Green Coffee bean is the name that is used for immature or unroasted coffee beans which are a pale green color in comparison to the mature bean which has a brownish or reddish color with a tinge of yellow hue sometimes. These immature coffee beans are usually processed for removal of ‘mucilage’ and outer pulp; a waxy layer of outer surface remains intact.
‘Mucilage’ is a glycoprotein and exopolysaccharide, a gluey, thick substance produced by almost all plants and a few microorganisms. It plays an important role in seed germination by storing food and water.
The dried coffee bean, containing both volatile and non-volatile compounds, typically weighs between 300 and 330 mg per bean.
In the middle of the new millennium, Green Caffeine began to be touted as a supreme health and nutritional supplement. The cholorogenic acid content of green coffee has been the focus of many clinical trials; it is being increasingly used in weight-loss health supplements and diet programs for its lipolytic properties.
The contents of Green Coffee
Green Coffee contains volatile as well as non-volatile compounds, alkaloids, amino acids, carbohydrates, lipids and proteins. Caffeine is the most common alkaloid present in both green and roasted coffee and is unaffected by any changes in the maturation of the coffee beans from green to brown. Others like libertine, methylliberine, paraxanthine, theobromine, and theophylline are found in lower percentages; the concentration of theophylline, an alkaloid which is also found in green tea, is substantially reduced in the process of roasting the coffee beans while others remain unchanged.
The facts on the contents of Green Coffee make for interesting reading
• Proteins account for around 12% of the composition of green coffee beans; a majority of these degrade to free amino acids during the maturation process. The degradation is caused by organic acids like chlorogenic acid. Enzymes such as catalase, oxidase and polyphenol make up the other proteins which are equally necessary for the maturation process of green coffee
• Carbohydrates account for nearly 50% of dry weight of the bean but provides no significant contribution to the flavor
• The total lipid content could be from 11.7 g to 14 g per 100 grams of dried coffee. Some of the more prominent lipids in green coffee are amides, arachidic acid, diterpenes, esters, linoleic acid, oleic acid, palmitic acid, stearic acid, triglycerides, and unsaturated long-chain fatty acids.
• The chlorogenic acid found in green caffeine is part of a compound group called phenolic acids, an antioxidant group. More than 70% of this valuable component is lost while roasting; only a residual 30mg per gram remains in the roasted bean.
• The volatile compounds include nitrogen containing molecules which cause an unpleasant odor and taste in the green coffee beans. These compounds sometimes also cause nausea and vomiting on inhalation of the odor. Although green coffee beans retain more antioxidants and vitamins, they cannot be used by themselves for beverage preparation; roasting allows for the molecules to release fresh and pleasant aroma which is more conducive for consumption. However, much of the vitamins and antioxidants are lost in the process of roasting.