engleski

Rheological properties of sucrose model solutions with pectin and cellulose at low temperatures

The knowledge of rheological properties is important for conduction of processes in food production and achieving specific properties of food. The different carbohydrates are important ingreadiants of many food Products. The aim of this paper was to investigate the influence of soluble dry solid content, insoluble dry solid content and shear rate on rheological properties of sucrose model solutions at low temperatures before and during freezing. Model solutions were made from different mass weights of sucrose (20%, 30% and 40%) and different combinations of model solution of 30% sucrose with addition of pectin (0, 2% and 0, 4% (71% esterification)) and cellulose (1%, 2%, 3% and 4%). Measurements were conducted by rotational viscosimeter with refrigeration unit. Dependance of shear stress and shear rate at 0°C and 5°C ; at constant shear rate by continuing and scale cooling were measured. Results showed that all examined model solutions of pure sucrose at 0°C and 5°C had newtonian caracter. Pectin and cellulose addition in sucrose model solutions increase viscosity and it becomes pseudoplastic. The shear of investigated solutions was conducted at higher cooling temperatures at scale coling, while at continous cooling the temperatures were lower.

rheological properties, model solutions, low temperatures, sucrose, viscosity

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