Study On Cold Water Solvable Powder Oil With Low Saturation, Low Trans Fatty Acid

Powder oil was widely added in beverage industry such as coffee and milk tea. However, powder oil available had the disadvantage of inferior cold water-solubility, high trans fatty acids and high saturated fatty acids. Less than 65% of saturation was low saturation oil,less than 2% of trans fatty acid was low trans fatty acid oil. The wall materials and preparation technology were investigated to study the emulsion stability,encapsulation efficiency, cold water solvability to develop cold water solvable powder oil with low saturation,low trans fatty acid. The latest detection equipment TurbiScan was used to predict the stability of the emulsion.The formula of cold water solvable powder oil was studied.The common hydrogenated soybean oil was used as core material, four types of protein including soybean concentrate protein, sodium caseinate, whey protein and pea protein were chosen as wall materials. The particle size, emulsion droplet size,encapsulation efficiency, viscosity, stability and solvability were tested. The results showed that the whey protein concentrate(WPC, 6%,w/w) and modified starch NL 100(4%, w/w) were the optimized wall materials. 2% monoglycerides were added to prepare emulsion of 20% solid content,the powder oil was obtained after sprayed which cold water solvability achieved 78.45%, and the encapsulation efficiency was 93.37%.The emulsification process and conditions were studied, molecular distilled monoglycerides(DMG) and lactic acid sodium stearoyl(SSL) were used as the emulsifiers, total addition amount was 2.4%(w/w), the ratio of DMG and SSL was 2:1. Under neutral pH and 35 MPa,the initial emulsion droplet showed the minimum particle size and high stability after homogenized twice. The powder oil solvability in cold water was more than 89% and its emulsion had wide pH stability and a stable state in the weak acid environment after further optimization, the spray dryer inlet air temperature was 180°C, outlet air temperature was 85~90°C, solid content was 30%.The study of core materials of cold water solvable powder oil showed that either high or low melting point of the core materials would affect the solvability of powder oil. A new core material was prepared by Shea olein(SO) and Palm kernel stearin(Palm kernel stearin, PKST)(SO: PKST = 60:40) through transesterification.The obtained powder oil had less than 60% saturated acid,less than 1% trans fatty acid and more than 99% solvability in cold water.Different combination of antioxidants was compared by oven method and accelerated oxidation method(AOM), the results showed that two kinds of natural antioxidants( AP+VE and AP+ROS) were effective in powder oil.Based on the excellent cold water solvable characteristics of the prepared powder oil, its oxidation stability of(IE SO:PKST=60:40) was studied under 60°C storage.The surface oil content and fatty acid composition had no change. Peroxide value was used as the index to predict IE(SO: PKST = 60:40) powder oil’s shelf life and oxidation kinetics model was set up. The results illustrated that(SO: PKST = 60:40) powder oil could be stored at room temperature for 318 days, which achieved the storage performance of the commercial powder oil product. The stability of the emulsion system could delay and protect the core materials of high unsaturated fatty acid from oxidation.The solvability of powder oil in cold water were evaluated. Glass transition temperature was above 65°C, the powder kept the glassy state under room temperature storage. The surface structure of the powder oil observed by scan electron microscope showed the powder particles were integrated, which suggested that the powder protected the core materials well.