Properties of Spray-Dried Combinations of Milk and Fruits and Vegetables

Abstract

The properties of products made by spray drying purées of 17 different fruits and 16 different vegetables alone or combined with skimmilk were studied. Natural flavors and colors, although proportionately diluted by skimmilk addition, were retained in the freshly dried products. Shelf life (air-pack, room temperature) varied from a few weeks to a year or more among the different products. Loss of color and development of haylike flavor in carrot, pumpkin, and tomato powders in 2-4 wk were attributed to carotenoid oxidation. Apple, banana, pea, prune, and sweet corn products were virtually unchanged after storage for 12 to 18 months. Determined moisture content of samples from 81 products ranged from 1.6 to 6.0%. Monomolecular layer moisture contents derived from desorption isotherms by the Brunauer, Emmett, and Teller (BET) equation ranged from 3.9 to 11.8%. The products varied considerably in bulk density: however, no attempt was made to control this property. Except for the presence of fibrous particles, microscopic appearance of the various powders resembled that of spray-dried milk. © 1967, American Dairy Science Association. All rights reserved.