Maryam Jalili - Assistant Professor, Food Technology and Agricultural Products Research Center, Food, Halal and AgriculturalProducts Research Grou, Standard Research Institute (SRI),

The freshness of food is of great importance to the consumer. To investigate the effect of longtermstorage on the physicochemical properties of honey, ۶ polyfloral samples were stored atambient temperature for ۱۲ months and their chemical properties including,hydroxymethylfurfural, diastase number, sugar content (glucose, fructose, and sucrose), andproline were determined periodically (۳ month interval). The hydroxymethylfurfural and sugarscontent were determined by high performance liquid chromatography. Results showed thatdramatic changes were observed after ۹ and ۱۲ months storage in the chemical and biochemicalcharacteristics of honey samples. The average values of determined specifications of ۶ honeysamples after ۱۲ months were as follows: hydroxymethylfurfural ۷۴.۲±۰.۱ to ۷۵۳.۵±۱.۲ mg/kg,diastase ۳.۲±۰.۵ to ۱۸.۱±۰.۲, Proline ۲۱۹.۳±۱.۶ to ۵۰۷.۰±۲.۲ mg/kg, glucose from ۱۵.۶±۱.۲ to۲۵.۴±۱.۲ (%), fructose ۱۸.۳±۱.۷ to ۲۷.۶±۱.۳ (%), and sucrose ۰.۴±۰.۳ to ۴.۲±۰.۵ (%).The current study revealed that hydroxymethylfurfural values in all of the samples were higherthan standard limit after one year storage. Although sugars, proline, and diastase showed a widerange of variation in entire polyfloral honey samples during long-term storage, some of themwere still in accordance with the standard range recommended by the Codex Alimentarius.Therefore these specifications cannot be used to determine the freshness of honey since: ۱) theirinitial levels in honey samples are very different (depends on the type of honey and otherfactors), ۲) their changing behavior during storage is not consistent; which make themunreliable parameters for determining the freshness of polyfloral honey

Honey, Diastase number, Long-term storage, Proline, sugars,hydroxymethylfurfural (HMF)