Electronic nose food industry

E. Kress-Rogers, Sensors for food flavour and freshness electronic noses, tongues and testers. In E. Kress-Rogers and C.J.B. Brimelow (Eds.), Instrumentation and Sensors for the Food Industry, 2nd ed., Woodhead Publishing Ltd., Cambridge, UK, 2001, pp. 553-622, Chap. 19. 

One of the promising directions for the development of innovative analytical method is the use of electrochemical methods whose speed and on-line capabilities nicely address the trends of automation and continuous processing in the food industry. Recently, devices such as electronic nose and electronic tongue have been proposed for the characterisation and authentication of different type of food products, and also for medical and environmental application. 

Electronic nose and electronic tongue are particularly suitable for carrying out rapid and objective sensory measurements, which are important in food industries. 

The electronic nose arrays have today successfully been used in a vast number of applications. The electronic noses are particularly appealing in food analysis since they resemble the traditional way of controlling the quality of foodstuffs. The electronic nose is already applied as a complement to sensory test panels in the food industry for product quality classification. Examples of applications are classification of grains [6] and beer [7]. Examples of other consumables tested are tobacco [8] and perfumes [9]. Applications in other areas such as environmental control and pulp and paper quality are also reported in over five hundred references currently found in the literature on electronic noses. 

The human nose and tongue are excellent quality-control sensors. For example, we can tell whether food is spoiled by its disagreeable odor and taste. Because it s impractical to use humans as sensors in industrial settings, several companies are now developing electronic noses. 

Figure 32.9. The Cyranose 320. The electronic nose may find uses in the food industry, animal husbandry, law enforcement, and medicine. [Courtesy of Cyrano Sciences.]... 

Recent advances in the technology of multisensor arrays and neural computing have made the development of the electronic nose of great interest to the food industry for discrimination between odors (26). Provided the instrument has been calibrated properly, the technique is rapid, nondestructive, and objective. Shen et al. (27) found the electronic nose was capable of measuring changes in volatile compounds associated with lipid oxidation in canola, com, and soybean oils stored under accelerated conditions and Aparicio et al. (28) found the electronic nose could be calibrated to detect rancidity levels in good quahty ohve oil spiked with rancid olive oil. 

Electronic nose technology and analysis of volatiles has long been apphed in the food industry to control the quahty of food products and to determine shelf hves. For example, sensor arrays based on different Sn02 gas sensors can be used to distingiush milk products of different rancidity levels [41]. Standard microbial test prediction of shelf hfe of milk products has a low level of reliability due to relatively poor correlation between microbial counts and actual shelf hfe. Several alternative methods have therefore been developed. One method is based on dynamic headspace capillary gas chromatography analyses of volatiles in mUk followed by MDA analyses. [42]. Principals of this method were later used for development of a faster and simpler test, where the extraction was performed by the SPME technique, the extracts... 

Monitoring the emissions of VOCs has many potential applications in the food industry, since biological materials that are aged, cooked, treated, etc. often release characteristic signature volatiles that can be indicators of the extent of changes in the food product. There has been considerable development of chemical sensors (i.e. electronic noses ) to detect such volatiles. The following examples illustrate how PTR-MS methods can also be used to detect signature volatiles in food research. 

The widest application of electronic noses and tongues is in the food industry in areas as varied as quality control, process operations, taste studies, and identification of flavor and aroma [3]. All of these areas are discussed in this chapter. In addition, electronic noses are finding use in environmental applications such as the analysis of fuel mixtures, identification of toxic wastes, and the detection of oil leaks [2], Electronic tongues are also now being applied in environmental areas such as analysis of natural waters and detection of heavy metals. Both devices are also being more widely used in clinical and pharmaceutical applications, and several of these will be highlighted. 

Currently, electronic noses are mainly applied in the food industry to recognize the freshness of the products, the detection of fraud (source control, adulteration), the detection of contaminants. 

At present spectroscopy, in all its variations, appears the most widely accepted, among analytical techniques for PAT approach in the food industry. However, the main advantage of the electrochemical sensor technology over spectroscopy is that electronic-nose (e-nose) and electronic-tongue (e-tongue) can be tailored to the monitoring process in a way that complementary information nonobtainable with spectroscopy can be acquired. 

The electronic nose has found its most widespread application in the food industry. Using resistometric and other detection systems, ongoing... 

Baldwin EA, Bai J, Plotto A, Dea S. Electronic noses and tongues appUcatitms ftn the food and pharmaceutical industries. Sensors 2011 11 4744-66. 

Electronic noses (e-noses) and electronic tongues are devices already used in pharmaceutical formulations, in different areas of food industry (oil, tee, wine, dairy discrimination taste or smells), as well as in medicine. Applications in the field of environmental analysis start to emerge. 

One analytical tool that has been proposed in recent years to address the need for routine quality testing in the food industry is the electronic nose (e-nose). An e-nose instrument has an array of weakly specific chemical sensors. Unlike most existing chemical sensors, which are designed to detect specific chemicals, sensors in an electronic nose are not specific to any one chemical (5). 

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