Presence of furosine in honeys

Nineteen commercial samples (with a shelf-life of 2 years) and two artisanal samples (freshly collected and stored for 1 year respectively) of Spanish honeys were analysed for pH, protein content and furosine content. Most of the samples had pH values and protein contents within the limits reported in the literature. The presence of furosine was confirmed by comparison of its retention time with that of a furosine standard and by HPLC-MS. The level of furosine in the samples studied ranged from 4.32 to 13.62 g kg(-1) protein. The lowest furosine value was observed in the freshly collected artisanal sample. Heat treatment under severe conditions (90 degreesC for up to 135 min) increased the furosine content from 4.43 to 14.38 g kg(-1) protein. The results show that furosine seems to be a promising indicator to detect overheating during honey manufacture. (C) 2001 Society of Chemical industry.