Sky Journal of Food Science Vol. 6(4), pp. 046-053, August, 2017, Available online http://www.skyjournals.org/SJFS

©2017 Sky Journals

Full Length Research Paper

Roasted barley addition to coffee: detection of the adulterant barley using ultraviolet and infrared spectroscopy

The objectives of this research were to detect the adulterant roasted barley at different concentrations (5 to 20 %w/w) in roasted and ground coffee using ultraviolet and mid infrared spectroscopy. Infrared spectroscopy transmission measurement of medium roasted coffee admixture (5 to 20% w/w barley) showed that the infrared spectra among 5 to 20% w/w barley addition to coffee were not resolved though it was possible to identify infrared spectra peak regions useful to discriminate the roasted barley from roasted coffee using caffeine, lipid amount and existing starch. The ultraviolet spectroscopy analysis showed that it can discriminate pure coffee from adulterated coffee, 5 to 20% w/w barley based on ultraviolet absorbance measurement. In conclusion, ultraviolet spectroscopy analysis resulted in discriminating pure roasted and ground coffee from the adulterated coffee as low as 5% w/w barley addition. Mid infrared spectroscopy analysis could not resolve the addition of 5 to 20% w/ w roasted and ground barley to pure coffee.

Key words: Adulterant, barley, coffee, infrared, spectroscopy and ultraviolet.