Dados do Trabalho

Título

ELECTRICAL IMPEDANCE SPECTROSCOPY AS BASIS FOR A NEW METHODOLOGY FOR DETECTION HONEY ADULTERATIONS

Introdução

Quality control for identification of honey adulterations is a very important topic in food safety, specially because honeys are constantly targets of adulterations. A common fraud in honey samples is the addition of syrup composed of water and sugar, with the illicit intention of increasing its volume The traditional analytical methods for quality control, such as chromatography or spectrophotometric methods, are sometimes not efficient for marketing purposes, by demand long time for experimentation and qualify professionals. Recently, our research group has proposed the Electrical Impedance Spectroscopy as a fast and promising technique for quality control in honey. Thus, the objective of this work was to study changes in electrical impedance spectra in pure honey upon addition of sucrose syrup.

Material e Métodos

The honey sample, certified by Federal Inspection Service from the Brazilian Ministry of Agriculture, were purposely adulterated with addition syrup (20%w/w sucrose solution) up to weight percentages of 0, 2.5, 5.0, 10.0, 15.0, 20.0 and 25.0%. Measurements were carried out using a HIOKI electrical impedance analyzer, with an electrode of parallel plate of platinum, which has been adapted to the instrument for measurements in liquids. Additionally, rheology measurements were carried out to support the discussions.

Resultados e Discussão

The results demonstrated that there was a significant change in all spectra profiles due to the syrup additions. The effects indicated that there was a reduction in the electrical resistance of the samples and this is due to the reduction in viscosity and the consequent increase in ionic mobility in the medium. A modeling with equivalent circuits was realized to expand knowledge about the phenomena studied and all presented a correction factor above 0.96 and an error of less than 0.34%, indicating good adjustments. The results obtained demonstrate the potential of measuring electrical impedance as an alternative in the development of methodologies applied to the detection of adulteration in honey by syrup.

Conclusão

The work concludes that the EIS technique showed promise for use as a methodology for detecting adulteration in honey by syrup since the spectrum profiles change significantly due to these additions.