ABSTRACT
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485 II. Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487 III. Method of Manufacture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
A. Moisture and Moisture Uptake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488 B. Mass Flow Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489 C. Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489 D. Compressibility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490 E. Particle Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491 F. Scanning Electron Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491
IV. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
I. INTRODUCTION
Encapsulation of powders with different components plays a very important role in foods especially for the delivery of bioactive additives (Jackson and Lee, 1991; Duxbury and Swientek, 1992). Compound powders with “soft” cores provide means for protecting sensitive components with pharmaceutical benefits. Protecting loss of active nutrients, such as carotenoid activity during processing, was the essential role reported for the encapsulation
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of beta-carotene (Wagner and Warthesen, 1995). Marine omega-3 fatty acids have been encapsulated in a starch/oil emulsion and spray-dried to provide this protection in food powders (Andersen, 1995). The entrapment of sensitive ingredients within a continuous film or coating protects them from environmental factors such as moisture, air, or light. Encapsulation, however, leads to demonstrable difficulties in handling, owing to changes in bulk properties of the powders. This was particularly true for encapsulated butter oil, where the encapsulated powders showed a propensity for stickiness and lumping (Konstance et al., 1995; Onwulata et al., 1995, 1996). The amount of the core material retained after encapsulation depends on the coating material used (Onwulata et al., 1994). The main purpose of preparing spray-dried fats is to enhance their handling properties and stability during storage, transport, and blending with nonfat ingredients. Butter oil, to be made into a powder, requires a carrier because it contains appreciable amounts of low melting triglycerides. As the amount of fat to be encapsulated increases, the choice of carrier constituents becomes more and more important, as fats on the surface of powders retard flow (Onwulata et al., 1995).
