engleski

Effects of concentration and temperature on rheological properties of some hydrocolloids

Natural and synthetic hydrocolloids, or gums, find significant use in the food industry to control rheological properties of many convenient food products. They are normally used in low concentrations, ranging from 0.05%, or less, to about 5%, and do not usually contribute to the nutritional value, taste, or aroma of the finished product. In this study, flow behaviour of six selected hydrocolloids (carrageenan, carboxymethylcellulose, guar gum and three types of pectins) was evaluated. Measurements of rheological properties of hydrocolloid dispersions (0.1-1%, depending on the type of hydrocolloid) at low temperatures were performed using a rotational viscosimeter. Dispersions of all hydrocolloids had pseudoplastic behaviour, at all given concentration. Ostwald-de Waele's model was used to evaluate their rheological properties. The temperature dependency of the apparent viscosity was investigated using the Arrhenius model.

hydrocolloids; rheological properties; low temperatures

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