The rapid detection of acacia honey adulteration by alternating current impedance spectroscopy combined with 1H NMR profile

Abstract

Honey adulteration is one of the most prominent issues in food production. Herein, the alternating current (AC) impedance spectroscopy combined with 1H NMR profile were used to reveal the adulterants in acacia honey. Variation of electrical parameters such as solution resistance (Rs), double layer capacitance (CD), charge transfer resistance (RCT) and 1H NMR profile for 10%–90% (w/w) syrups or rape honey adulterated acacia honey samples were analyzed. We clearly demonstrate that the difference of the AC impedance between acacia honey and adulterated honey is obvious, and the levels of RCT of acacia honey samples are always smaller than those of syrups and adulterated honey. Furthermore, the relaxation peaks shift toward the lower frequency zone and gradually increase in intensity with increasing proportion of syrup or rape honey. Also, 1H NMR profile can clearly indicate the adulterant and adulteration proportion, supporting the results of the AC impedance spectroscopy measurement. And the effectiveness of impedance measurement can also be proved by principal component analysis. Our results provide new insights into the authenticity identification of acacia honey and prove the AC impedance measurement combined with NMR is a rapid, nondestructive method for honey authenticity verification.