Determination of volatile compound profiles and physico-chemical analysis of linden and acacia Czech honey

In this study 12 acacia and 12 linden honey samples from the Czech Republic were analyzed with a chemometric and volatile compound profiles approach. The results of electrical conductivity (17.4 and 65.1 mS/m), free acidity (12.5 and 24.5 meq/kg), diastase activity (12.6 and 18.8 DN), colour (21.5 and 47.8 mm Pfund), hydroxymethylfurfural (HMF) (11.5 and 3.5 mg/kg), fructose (45.1 and 36.3 g/100g), fructose + glucose (F + G) (76.7 and 69.3 g/100g) content and fructose/glucose ratio (1.4 and 1.1) showed statistically significant differences (p < 0.05) between acacia and linden honey, respectively. The physico-chemical properties and pollen profiles were in compliance with the description of European monofloral honey, except for acacia honey due to the low proportion of acacia pollen (2.8 − 10.3%). According to volatile compounds analysis by head-space solid phase micro-extraction coupled with gas chromatography − mass spectrometry (HS-SPME/GC-MS), nine key volatile substances were selected from more than 100 volatile compounds present in the analysed samples for evaluation as markers of botanical origin typical of the most common plant nectar sources in the Czech Republic. Further, the non-targeted analysis combined with Principal Component Analysis (PCA) revealed trends and outliers within all chromatography data obtained for 24 honey samples. Cis-linalool oxide and β-linalool have been confirmed as markers of acacia honey, while carvacrol and p-cymenene were found almost exclusively in linden honey. The results demonstrated that the chemometrics with the non-targeted and targeted volatile compounds analysis approach is reliable and accurate for the classification of honey of various botanical origins.