PROPERTIES OF DEXTRAN AS A CRYOPROTECTANT IN ICE-CREAM

In order to determine the usefulness of dextran as a stabilizer in fro zen dairy products, ice cream mixes with varying concentrations of thi s microbial polysaccharide were prepared and tested by sensory, physic al and mechanical means. Although previous results had shown that aque ous solutions of dextran exhibited remarkably low viscosities, the add ition of dextrans to ice cream mixes resulted in much higher values. T his is thought to result from interactions among dextrans, dairy prote ins and, perhaps, other stabilizers. Dextran addition effectively incr eased the T-g of ice cream mixes, indicative of its value as a cryopro tectant. Also, dextran significantly reduced the sensory perception of 'iciness intensity' in heat-shocked ice cream samples. This resulted from the ability of dextran to slow ice crystal growth during storage and thermal abuse, as indicated by reduced ice crystal size as compare d to a control formulation. However, dextran also produced unwanted fi rmness and melting characteristics in ice cream that could influence c ommercial acceptability.