Identification of Pure and Adulterated Honey Using Two Spectroscopic Methods

Abstract

Honey is a natural sweet substance which is often mixed with other liquids for health purposes or as a sugar substitute in variety of food. Due to high commercial profit, many fraudulent acts have been around to add other substances to pure honeys. This study used two spectroscopic methods which are the laser induced fluorescence (LIF) and Fourier Transform Infrared (FTIR) spectroscopy to differentiate pure and corn syrup adulterated honeys based on sugar content. LIF used a 405 nm diode laser as the excitation laser. Samples of 27 were prepared for this study. They composed of 15 pure honey and 2 non honeys, and 10 adulterated honeys which we coded from A to Q.. Non honey samples were pure date syrup and corn syrup which coded as K and L. The sugar contents were measured manually using a brix refractometer which resulted the honey sugar contents range of 69.5 % to 78 %. The peak wavelengths observed range from There is R2 = 0.80 correlation between peak wavelength of fluorescence colours to sugar contents. The results showed that the peak wavelengths range from 490.9 nm to 641.3 nm. LIF was able to differentiate between the pure honeys than the adulterated or mixed ingredient honeys except for sample C. The differences of FTIR spectrums were shown by honey samples which was not given corn syrup adulteration, where the difference begins to be seen clearly at the wave number range 1150 cm-1 to 650 cm-1.