THE STUDY OF CRYSTALLS' FORMATION IN GREEK HONEYS

摘要

Honey is a natural product produced by bees with high nutritional value for human. Sometimes honey crystallizes quickly because of the high carbohydrate content. During the crystallization, aggregates from glucose and fructose are formed. Even though the crystallization of honey does not relate with honey quality, it affects the preferences of the consumers. For this reason packers try to delay the crystallization or to liquefy the crystallized honey. In this work a method to follow the evolution of crystal formation was developed. Also the physicochemical parameters (moisture, acidity, pH, HMF, diastase invertase and sugars) of three kinds of Greek honey were determined and correlated with their crystallization. For this study heather, orange and thyme honey, were used. Initially the absence of crystals was confirmed using a polarizing microscope and then the formation of the crystals during honeys' crystallization was studied. Average time for the heather honey crystallization was 23 days, while for citrus and thyme honey were 49 and 76 days respectively. The aggregation of crystals in heather honey was biggest than the others. Positive correlation was observed between the size of crystals and the time for the liquefaction of honey. The destruction of crystals in heather honey is not always similar to the other monofloral honeys. In thyme this destruction was completed within 72 h at 45 °C, while in heather 128 h. In conclusion the variability of the size of crystals and the time of honey crystallization depends on the honey's botanical origin and its chemical composition.