Rheological properties of Canadian maple syrup

摘要

Rheological properties of five grades of Canadian maple syrup, namely Canada No. 1 - Very Clear; Canada No.1 - Clear; Canada No.1 - Medium; Canada No.2 -Amber; and Canada No.3 - Dark were studied. The effects of temperature varying from 5 to 55 deg Cand soluble sugar concentration varying from 66 to 75°Brix on the rheological properties were investigated. Grade, temperature, and concentration influenced the apparent viscosity of maple syrup. The Dark grade had the highest viscosity whereas the VeryClear grade had the least viscosity. The other grades of maple syrup, namely Clear, Medium, and Amber had medium viscosity with no statistical difference (p<5%) between them. Maple syrup was predominantly Newtonian as the flow behavior index was close to unity. Apparent viscosity of the maple syrup samples ranged from 0.035 to 0.651 Pa s for all the different grades within the range of temperatures studied. Increasing temperature decreased the apparent viscosity of maple syrup. The effect of temperature on the viscosity of maple syrup was modeled using the Arrhenius model. The activation energy for the temperature change varied from 43.97 to 44 86 kJ/mol. Increasing concentration of maple syrup increased the non-Newtonian behavior of the syrup.