Supercritical Extraction And Microencapsulation Of Different Gluten Wheat Germ Oils

Using high, medium and low gluten wheat germ as raw materials, wheat germ oilwas extracted by the supercritical CO₂fluid extraction technology. Gas chromatography wasused to analyze the fatty acids composition of different wheat germ oils and themicroencapsulation of wheat germ oil is also investigated. The optimum conditions ofsupercritical CO₂fluid extraction of wheat germ oil, the content difference of higher fattyacids composition among high, medium and low gluten wheat germ oil, the optimumconditions of preparing wheat germ oil microcapsule and sensory performance aftermicroencapsulation were investigated systematically in the work.The main results are as follows:1. The low gluten wheat germs are chosen as raw materials. The influence ofextraction pressure, temperature and time on wheat germ oil extraction rate by the method ofsupercritical CO₂fluid extraction process was investigated. According to the extraction rate,The extraction conditions were optimized by the orthogonal experiment. The optimumconditions for the wheat germ oil extraction were: pressure30MPa, temperature50℃, time2h, and the extraction rate achieved up to11.05%under the optimal technological conditions.2. The gas chromatography method was used to analyze the fatty acids compositionof different gluten wheat germ oil. The results showed that the content of the high unsaturatedfatty acids is the highest in the wheat germ oil extracted by the method of supercritical CO₂fluid technology. Thereinto, the medium gluten wheat germ oil contains the maximumunsaturated fatty acids, followed by the low and high gluten wheat germ oil. The linoleic acid,recognized as the health protection component, is increased as the gluten content from high tolow. That is to say, the low gluten wheat germ oil contains the highest linoleic acid whichcontent can reach up to58.23%; the saturated fatty acid content is decreased when the glutencontent from high to low. It is roughly judged that the low gluten wheat germ can product thebest quality oil which can be used for kinds of new health protection products.3. Choosing the wheat germ oil extracted by the method of supercritical CO₂fluidtechnology as the raw material and embedding rate as the measurement index, orthogonalexperimental design is used to gain the optimal conditions in the process of wheat germ oil microencapsulation by spray drying way. In the process of spray drying, wheat germ oilmicroencapsulation embedding rate can reach up to89.5%under the optimal conditions:soybean isolate protein/maltodextrin1:1, core material addictive amount40%, total solidcontent25%. Soybean isolate protein/maltodextrin affected embedding rate significantly,while core material addictive amount and total solid content have no significant effect on theembedding rate.4. The sensory evaluation of wheat germ oil microcapsule produced by spray dryingway showed that the resultant product met the quality requirements. The SEM of themicrocapsule micro-structure demonstrated that the wheat germ oil is well encapsulated bythe method of spray drying under the optimum conditions.