Water Sorption by Dried Dairy Products Stabilized with Carboxymethyl Cellulose

The difficulty in spray drying mixtures of fruit juices or flavorings, insoluble proteins, whey solids, and sucrose that have been stabilized by the addition of small amounts of carboxymethyl cellulose or other food grade gums cannot be attributed to unique water sorption capacities. Such products sorb water in quantities reflecting the water sorption capacities normally exhibited by the components of the mix. Sorption isotherms for mixtures primarily of whey solids and soy flour, were not affected appreciably by earboxymethyl cellulose in the mix. A composite sorption isotherm constructed for a dried milk-orange juice product from data obtained separately for the orange juice solids, milk solids, sucrose, and earboxymethyl cellulose was similar to the experimental sorptiou isotherm for the dried product. These data and observations during drying can be rationalized with the theory that hydrocolloid stabilizers increase the intermolecular structuring of water which reduces its rate of diffusion and evaporation during terminal stages of drying.