MICROENCAPSULATION PROPERTIES OF GUM-ARABIC AND SEVERAL FOOD PROTEINS- LIQUID ORANGE OIL EMULSION PARTICLES

The comparative suitability of gum arabic (GA), soy protein isolate (S PI), whey protein isolate (WPI), and sodium caseinate (SC) for use as food flavorant encapsulants was investigated in this study by determin ing their ability to form small-sized, physically stable orange oil em ulsion particles by high-pressure homogenization. The resulting emulsi on particles were evaluated for their microstructural properties, phys ical stability, and droplet size distribution as a function of oil con tent and homogenization pressure. SPI-emulsified orange oil droplets w ere most stable and GA-emulsified orange oil droplets were least stabl e against creaming during 10 days of storage at room temperature. Ligh t scattering results revealed that SC was most effective and SPI was l east effective for producing orange oil emulsion droplets of less than or equal to 4 mu m diameter by high-pressure homogenization. Transmis sion electron microscopy images revealed that SPI-emulsified orange oi l droplets were surrounded by the thickest membrane structures but tha t GA-stabilized emulsion particle membranes did not fully surround the orange oil droplets. Statistical analysis revealed a significant inte raction between several independent variables, i.e., encapsulant type and percent oil load, and two of the dependent variables, i.e., drople t size and depth of cream layer. No interaction was observed between e mulsifier/encapsulant type and homogenization pressure at alpha = 0.05 .