The Study On The Preparation Of Oil Powder By Kafirin And Its Action Mechanism

In this study,soybean oil powder was prepared by spray drying using kafirin and sodium caseinate as wall materials.Based on the embedding rate index,the single factor and Box-Behnken response surface experiment were carried out to optimize the preparation conditions of oil powder.The prepared oil powder was analyzed by gas chromatography,fourier transform infrared spectroscopy,differential scanning calorimetry,scanning electron microscopy and oxidative stability,and we compared it with commercially available products in terms of sensory quality,basic physical and chemical properties,particle size distribution and instant solubility.The experimental research results were as follows:(1)The yield of kafirin by conventional solvent extraction was 6.54%.The optimal preparation process of soybean oil powder was obtained by response surface experiment as follows: the ratio of kafirin to soybean oil was 2.3:1,sodium caseinate content was 5 g/L,and the inlet air temperature was 110 °C.Under such conditions,the embedding efficiency of oil powder was 40.15%.(2)Gas chromatographic analysis showed that the main fatty acid of soybean oil was linoleic acid,followed by stearic acid and palmitic acid.The loss of unsaturated fatty acid composition of the encapsulated soybean oil was less than 3%,indicating that the microencapsulation process did not affect the fatty acid composition of the soybean oil.Fourier infrared spectroscopy analysis of the core material and the wall material revealed that the characteristic peaks appeared in the microcapsules,confirming the formation of the embedding structure.Differential scanning calorimetry analysis showed that the microcapsules had higher endothermic peak than kafirin and sodium caseinate,which provided good thermal stability for soybean oil.Scanning electron microscopy showed that the particles were approximately spherical,and most of the particle surfaces were concave and shriveled,and there were almost no cracks or fissures.The oxidative stability results showed that the peroxide value of unencapsulated soybean oil was almost 2.7 times as much as that of encapsulated soybean oil after storage for 42 days at room temperature(25 °C).This result suggested that the soybean oil was well protected in microcapsules and the oxidative stability of soybean oil was enhanced significantly after encapsulation.(3)The comparison study results of the self-made products and the commercially available products in terms of the sensory evaluation and physical and chemical indicators,the particle size and instant solubility analysis showed: the self-made powder product had good sensory quality;the moisture content was lower than that of the commercially available products,the solubility was over 95%,and water solubility was good.The particles of the self-made product were looser and the bulk density was smaller;the angle of repose was slightly higher,but it could meet the requirements of fully automatic production(<40°),indicating that the quality of the self-made products had reached the general market level.The average particle size of the self-made product was 10.45±0.67?m,which is within the range of the required particle size(<40?m)of the microcapsules in the food industry,but the particle size range was larger and the distribution interval was not concentrated.The instant solubility of self-made product did not exceed the commercial products,but was relatively close to the degree of dispersion of the general commercial products.