The sensors for vision, hearing and touch have been developed for several years. The need for sensors capable of mimicking the senses of smell and taste have been felt recently in food industry, environmental monitoring and several industrial applications. By intelligent integration of multitudes of technologies like chemometrics, microelectronics and advanced soft computing, human olfaction has been successfully mimicked by such new techniques called machine olfaction. Implementation of electronic nose which reduce the cost of maturity evaluation, help determining optimum maturity based on the quality. Basically, this device is used to detect and distinguish complex odor at low cost. Commercial techniques have some difficulties. E-Nose provides a non-invasive and rapid method of objective aroma measurement. This book deals with the basic and working principle of E-nose and it's components and application in various fields of food processing sector and also previous work done using E-nose have also been discussed.