Classification of Brazilian honeys by physical and chemical analytical methods and low field nuclear magnetic resonance (LF 1H NMR)

This study evaluated the possibility of differentiating the botanical origin of honeys using Low Field Nuclear Magnetic Resonance (LF H-1 NMR). Eighty samples of honey from 8 different botanical sources (eucalyptus, "assa-lipto", oranges, Barbados cherry, cashew tree, "assa-peixe", "cipo-uva" and polyfloral) were analyzed. A close correlation (p < 0.01) was established between the LF H-1 NMR analysis and physical and chemical measurements, including water content, water activity, pH and color. Bi-exponential fitting of the transverse relaxation (T-2) data revealed two water populations in all samples, T-21 and T-22, corresponding to relaxation times of 0.6-1.8 ms and 23-5.4 ms respectively. The observed differences in the relaxation times suggest that these were influenced by the differences in botanical origins. Good linear correlations were observed between the T-2 and T-21 parameters and the physical and chemical data. This study demonstrated that LF H-1 NMR can be a viable technique for use in classifying honeys by their botanical origin. (C) 2013 Elsevier Ltd. All rights reserved.