Characterization of different unifloral indian honey varieties based on the physico-chemical and rheological properties

Abstract

Honey is a natural product well known for its nutritive value and being usually used as natural sweetener. India is one of the major honey exporting countries in the world. The present research refers to an investigation of the physico chemical and rheological behavior of four freshly harvested unifloral honey samples collected from different plant sources viz Sunflower (H1), Eucalyptus (H2), Mustard (H3) and Prosopis (H4). Rheological studies were carried out by varying honey samples temperature from 10 to 50 oC. Three different models (Arrhenius, Ostwald-de Waele Power law and Newtonian-I) were investigated. A continuous fall in apparent viscosity (p<0.05) with the increase in temperature was observed for all honey varieties. Moreover no significant changes (p>0.05) in apparent viscosity of honey was observed with the variation in shear rate, indicating their Newtonian behavior. The moisture content present in different honey samples (H1, H2, H3 and H4 was 13.6 %, 17.2 %, 15.5 % and 16.1 % respectively) also had a significant effect (p <0.05) on the apparent viscosity of honey following changes in temperature (10-50 oC). The honey samples having higher moisture content exhibited greater decrease in their apparent viscosity. Power law was found to be the most suitable model (R2 > 99%) in explaining the rheological behavior of honey following the variations in temperature when compared with Arrhenius and Newtonian-I respectively.