Effect of the storage temperature on volatile organic compounds and aroma profile of Robiniapseudoacacia honey

In this study we evaluated the trend of volatile organic compounds and aroma profiles of Robinia pseudoacacia honey samples during storage extended for 18 months at three different temperatures (15, 25 and 35° C) by using Solid-Phase Microextraction coupled with Gas-Chromatography Mass-Spectrometry (SPME-GC/MS). The 103 volatile compounds identified belonged to different major chemical classes: aldehydes, alcohols, sulphur compounds, free fatty acids, furans, hydrocarbons, ketones and terpenes. The aromatic profile analyses were also evaluated using an electronic nose and the sensor array was composed of 10 different sensors. A stepwise discriminant analysis was used to determine the best combinations of variables that would separate the 3 storage temperatures. A mixed model was fitted to investigate the effect of temperature and time on the volatile compounds and the aromatic profile. The discriminant analysis resulted in four selected volatile compounds (furans, sulphur compounds, aldehydes, and alcohols) and three selected sensors reactive to aromatic, hydrogen and methane compounds. A consistent increase of furans was observed in honey samples after 4 months and after 14 months for samples stored at 35 and 25° C, respectively. No variations for furans were observed for honey at 15° C. A difference among the three storage temperature was detected for the sensor reactive to hydrogen compounds after 6 months.