Evaluation of honey in terms of quality and authenticity based on the general physicochemical pattern, major sugar composition and delta C-13 signature

Ensuring the authenticity of honey remains a top issue for scientists, since no reliable method has been developed so far to simultaneously detect all types of honey adulteration. Consequently, the development of simple, fast, accurate and accessible analytical tools that may provide complementary data for assessing the honey authenticity, is encouraged. In this work a complete investigation in terms of general physicochemical properties (water content, Brix, electrical conductivity, free acidity, pH and 5-hydroxymethylfurfural (HMF) content), major sugar composition (fructose, glucose, sucrose and maltose) and delta C-13 signature of honeys from beekeepers and commercial honeys of different botanical origin (acacia, polyfloral, honeydew, sunflower, rape and linden) and various industrial syrup adulterants was performed. The aim was to generate reliable information in the process of honey evaluation linked with compliance or not with the quality standards, detecting additions of C4 plants sugar syrups (e.g. cane and corn) and confirming the botanical origin. Multivariate statistical methods, such as hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied as exploratory methods in order to examine the possible grouping of samples according to their quality. Correlations between the analyzed parameters were also performed. Stable carbon isotope ratio analysis (SCIRA) based on achieving the differences between the delta C-13 values in honey and its extracted protein fraction, allows to estimate the degree of adulteration of honeys with sugar syrups produced from C4 plant sources (corn and cane), while the general physicochemical parameters, major sugar composition and HMF content represents important tracers for honey quality control appreciation. Present results showed that parameters like delta C-13 values of protein extracted from honey, glucose content, ratio between fructose and glucose, and electrical conductivity were significantly different, depending on the botanical origin of honeys.