Discriminatory power assessment of the sensor array of an electronic nose system for the detection of non alcoholic beer aging

Abstract

Ghasemi-Varnamkhasti M., Mohtasebi S.S., Siadat M., Razavi S.H., Ahmadi H., Dicko A. (2012): Discriminatory power assessment of the sensor array of an electronic nose system for the detection of non alcoholic beer aging. Czech J. Food Sci., 30: 236-240.Many chemical changes in beer aroma occur during storage (aging), and monitoring these changes could give guidelines to the brewers how to manage and control the brewing process to obtain the final product with a high stability in flavour after packaging. In this regard, our laboratory aimed at a research into the application of an electronic nose in order to get the fingerprint of the change of non alcoholic beer aroma during aging. Th discriminatory power of the sensor array of this system was evaluated. Principal Component Analysis (PCA) and Soft Independent Modelling of Class Analogy (SIMCA) techniques were used for this purpose. The results obtained can direct us to performing other parts of our project. Considering the discriminatory power of the sensor array used, we can develop the application of a specific electronic nose system by picking up the most effective sensors or ignoring the redundant sensors.Keywords: electronic nose; chemical change; storage; beer; aroma; food; PCA In recent years, the quality of non-alcoholic beers has been fairly improved in such a way that the consumption of such product has become of great interest to the consumers. Brewery industries believe that non-alcoholic beers have a different flavour fingerprint compared with regular beers and many challenges should be addressed to attain an acceptable quality of non-alcoholic beers; for instance, achieving flavour stability is a critical challenge, especially the fact that what occurs with the beers between packaging and consumption (storage period) is usually out of the control in brewery. During storage (aging), flavour stability of non-alcoholic beer is diminished and off flavours are developed in aged beer accordingly. Although some methods exist, such as sensory panel and GC-MS, to evaluate and monitor these changes, due to some drawbacks, the use of other methods to evaluate the beer aroma during aging as fast and accurately as possible seems necessary (Ghasemi-Varnamkhasti et al. 2011, 2012. So, the employment of advanced analytical systems such as the electronic nose could be an option for this purpose. Some valuable works on the beer 237Czech J. Food Sci. Vol. 30, 2012, No. 3: 236-240 quality evaluation (e.g, off flavour detection) by the electronic nose have been reported in literature (Ragazzo-Sanchez et al. 2006). Also, a few works have been reported evaluating the aroma of beer in the aging process with the greatest emphasis having been laid in these studies on alcoholic beers (Lamagna et al. 2004;Sikorska et al. 2007). The knowledge of the aging phenomenon in non-alcoholic beer can be used to develop appropriate technological process improvements to control its particular flavour stability in brewery. This study was aimed at the evaluation of the discrimi...

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