PREPARATION AND PROPERTIES OF ENCAPSULATED FAT POWDERS CONTAINING SPECIALITY FAT AND ω/PUFA-RICH OILS

摘要

Fat powders with high fat content using three types of fats /oils, namely semi-solid fats like vanaspati, trans free speciality fat, and liquid oils like safflower or flax seed, were prepared by spray drying. The effect of type and quantity of wall materials and additives on total fat and quality of powders were studied and found that casein was effective as wall material to encapsulate maximum fat of up to 75%. Sugar and tricalcium phosphate were found to improve flowability of the powders. The quantity of fat encapsulated depends on type of fat or oil and found that semi-solid fats could be encapsulated at a higher percentage compared to liquid oils. The moisture of powders was 1-2 g/100 g, bulk density 0.3-0.4 g/cc, surface fat 15-19% and angle of repose 50-55°. The powders with bakery fat or spe-ciality fat were lighter (creamish) in appearance compared to those with safflower or flax seed oils, which were light yellow due to the colour of the parent oil. Scanning electron microscopy of fat powders revealed that those prepared with bakery fat or speciality fat and with casein and sugar showed distinct spheres indicating effective encapsulation. Scanning electron microscopy of powders with skim milk powder and also those without added sugar showed aggregation of particles. The powders with PUFA-rich oils had a high proportion of ω-3 and PUFA. Equilibrium relative humidity and storage stability of powders were determined.