Honey business: two key properties of honey

摘要

Recent research examining the behaviour of honey under differing conditions of relative humidity and temperature has significant implications for handlers and processors of honey. At high relative humidity, honey is able to absorb a lot of water, leading to microbial growth as well as handling and mixing problems. At the same time, the erystallisation behaviour of honey is affected by variations in temperature, which, in turn, affects its keeping qualities. Honey producers need to know more about these processes, so research at The University of Queensland, Australia, now provides a valuable insight. Honey is a solution of various sugars and is frequently super-saturated with glucose at normal temperatures. Glucose and fructose (invert sugars) arethe principal sugars in honey, accounting for 33-35 per cent and 38-40 per cent respectively. Fructose content is normally higher than glucose, although some exceptions have been reported. Moisture in honey normally ranges from 16-18 per cent (wet basis). The moisture content in different varieties of honey may be as low as 13 per cent and as high as 29 per cent. Honey is an intermediate moisture food with a water activity of about 0.6 and is therefore shelf stable for a reasonable period of time. Lowwater activity and high osmotic environment do not support microbial growth. The fermentation of honey may occur by some osmophilic yeast if the moisture content is high, but honeys with moisture content less than 18.5 per cent are unlikely to ferment.