The identification of the relationship between chemical and electrical parameters of honeys using artificial neural networks $ Katarzyna Pentoś a , Deta Łuczycka a , Radosław Wróbel b a Institute of Agricultural Engineering, The Faculty of Life Sciences and Technology, Wroclaw University of Environmental and Life Sciences, pl. Grunwaldzki 24A, 50-363 Wroclaw, Poland b Institute of Machine Design and Operation, Wroclaw University of Technology, Lukasiewicza 7/9, 50-371 Wroclaw, Poland article info Article history: Received 21 November 2013 Accepted 10 August 2014 Keywords: Mathematical modeling Honey quality Electrical parameters measurement Sensitivity analysis Variable contributions abstract A number of significant scientific studies have confirmed the health benefits of honey. Due to the high price of natural honey, it is a common target for adulteration which reduces its medicinal value. Adulteration detection methods require specific laboratory equipment and are very expensive. The development of measurement techniques enables the measurement of electrical characteristics of strained honey. Honey electrical parameters can possibly be used for its quality assessment. The identification of the relationship between chemical and electrical parameters of honeys and analysis to determine if there are frequency-dependent changes, can help in developing of that group of methods. The aim of this research was to determine how the chemical parameters of certain honeys influence the dielectric loss factor and the permittivity of strained honey measured in various frequencies. Another aim was to determine whether the percentage influence of certain chemical parameters of honeys on electrical characteristics significantly depends on frequency value. The research was based on neural network models and sensitivity analysis. The percentage influence of certain chemical parameters on electrical characteristics significantly depends on frequency value. & 2014 Elsevier Ltd. All rights reserved. 1. Introduction Honey is a natural, liquid food product produced by honeybees (Apis mellifera) from nectar of plants or from honeydew. In the European Union the composition and manufacture of honey is regulated by Community Directive 74/409/EEC [1]. Since ancient times, honey has been known, for its significant therapeutic effects in medicine. At present, honey composition and the influence of its various compounds on human health is the subject of many studies. It follows immense health benefits of honey as an antibiotic, anticancer, anti-oxidative, antibacterial and preserving activity, resulting in positive effects on the immune system [2,3]. Natural compounds of honey are carbohydrates, amino acids and proteins, volatile compounds, vitamins and minerals [4]. Health benefits of honey are very well-known and recently, the demand for natural honey has increased [5,6]. In the case of therapeutic and medicinal applications, the quality and origin of honey is of great importance. Natural honey which is properly processed and stored is an expensive product and therefore, it is more and more common target for adulteration. The adulteration leads to reducing or depriv- ing nutritional and therapeutic value from honey. Adulteration of honey can occur by feeding bees with sugar (cane sugar) or adding inexpensive sweeteners such as corn syrups, high fructose corn syrups, invert syrups or high fructose inulin syrups. Furthermore, honey can be adulterated by mixing many varieties of honey or declaring false information concerning geographical origin. The expensive honeys, which are considered to have the most significant therapeutic effects, are the largest target for adulteration [7,6]. Another example of negative honey processing is overheating. It is necessary to heat up the honey during the packaging process. However, heating up to a temperature exceeding 40 1C causes a significant decline in the quality of the honey. Storage temperature of 70–80 1C destroys diastase and invertase within less than 24 h [8]. Heating up to temperature 85 1C causes amylase activity loss [9]. Many various methods for the assessment of honey authenti- city can be used. The first method employed to determine the botanical origin of honey was pollen analysis (microscopic method). Chromatographic and spectroscopic methods are used as well. Measurements of the humidity, ash content, conductivity, acidity, enzymatic activity and many other parameters are taken [6]. For most of these methods, specific and very expensive laboratory equipment is required and therefore they can’t be commonly used. Methods for the assessment of honey authenti- city based on measurement of electrical characteristics can be a Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/cbm Computers in Biology and Medicine http://dx.doi.org/10.1016/j.compbiomed.2014.08.008 0010-4825/& 2014 Elsevier Ltd. All rights reserved. $ This is a special focus paper published in connection with the 2nd International Conference on Biomedical Engineering and Biotechnology (iCBEB 2013), held in Wuhan, China, October 11-13, 2013. E-mail address: katarzyna.pentos@up.wroc.pl (K. Pentoś). Computers in Biology and Medicine 53 (2014) 244–249