New methodology based on E-eye for the detection of honey adulteration with Tunisian traditional fraud solution

The honey is considered as natural and based food product that is widely used for many reasons especially as antioxidant food [1]. Honey fraud is a major global problem, with honey being the third most adulterated food product and, given the implications for human health, it is important to detect any adulteration. Nowadays, the heightened interest on the part of consumers involves the importance to develop increasingly efficient analytical methods such as the E-senses (electronic nose, electronic tongue and electronic eye) for rapid analytical assessment [2]. The aim of this study was to assess the pattern of colour pigmentation of the pure Chestnut Honey and the mixture with adulterants, specifically Tunisian traditional fraud solution (sugar, water and lemon). For the trial, different percentages of addition of fraudulent solution (2%, 5%, 25%, 50% and 75%) at different temperature (20°C, 40°C, 50°C, 55°C, 70°C and 100°C) were used. The honey samples were placed on cylindrical container of 6g of product in a measurement chamber, applying a camera for highresolution data acquisition (16 million colors) by using an E-eye (Iris Visual Analyzer 400-Alpha MOS). Three photos were taken for each honey sample, with a white background and lighting only from above. The application of the software available in the instrument (Alphasoft, version 14.0) allowed to group color spectra in the 16-bit range for each RGB coordinate by selecting those present over 1%. To assess the capabilities of this instrument for the discrimination of different color of pure chestnut honey and adulterated honey, the data collected from each group with different percentage of fraud solution at different temperature were submitted to PCA analysis and the Discrimination Index (DI) was calculated. Results showed the high ability of the E-eye to discriminate the different percentages of honey adulteration. At all temperatures, the DI varies from 95% to 98%. Overall, with the increasing temperature, the E-eye was able to identify specific color codes referable to the different percentages of adulteration. Specifically, at 40°C, two color codes were identified useful for detecting the 2% of fraud solution addition (1329 and 1330); at 50°C, one code identified the 5% of adulteration (1346) and one code the 25% (1602); at 55°C two codes were clearly highlighted for the 25% of adulteration (1602 and 1603), one code for 50% (1618) and two codes for 75% (1890 and 1891). The honey heating to 70°C and to 100°C did not produce useful results, indeed at 100°C the color differences related to the percentage of adulteration were reduced. These results determine that the use of the E-eye can be a valid method to identify the adulteration of the honey based on the change of the intensity of the color.