Ultrasonic treatment of the coffee extract

Abstract

Coffee is one of the most popular beverages in the world. Coffee gives strength, stimulates brain activity and increases concentration. There are many biologically active substances in its composition. Instant coffee is an important coffee product that would benefit on an extended shelf life. The introduction of modern methods of treatment, as the ultrasonic treatment, may be used to increase the shelf life of this kind of products. Ultrasound is a modern method of treatment biological systems. It can help to intensify the extraction process of biologically active substances. Ultrasound can also be used as a method of sterilization. The object of this study was to investigate the improvement the production technology of natural instant coffee using ultrasonic treatment. The affect of ultrasound on the coffee extract was determined by measuring the water activity, caffeine and 5-(hydroxymethyl)-furfural (HMF) content. Ground coffee dissolved in water was subjected to sonication from 1 to 3 minutes and with power varying from 2 to 8 W. Water activity was shown to be reduced with increasing duration and power of sonication. The caffeine content varied with time and processing power. When processing for 1 or 2 minutes, an increase in caffeine content was observed with increasing power. When processing for 3 minutes, there was an increase in caffeine content at a power of 2 to 4 W and a decrease in power from 4 to 8 W. According to this research the possibility of using sonication in coffee extract to improve its quality was concluded due to the achievement of lower water activities and higher caffeine content.