Preparation And Properties Of Chia Seed Oil Microcapsules

Chia seed oil is a new kind of functional oil,which is rich in polyunsaturated fatty acids.It is the source of omega-3 fatty acids for the human body.However,its properties are not stable and lipid oxidation occurs easily in contact with oxygen,light,humidity,and heat,which leads to certain limitations in its application in the food industry.Microencapsulation can effectively delay the oxidation of chia seed oil and the loss of nutritional value of the oil during processing,transportation and marketing.In this paper,sodium caseinate and D-lactose hydrate were used as wall materials,and chia seed oil was used as core materials.The microcapsules of chia seed oil were prepared by the freeze-drying method and the corresponding process optimization was carried out.The basic physical and chemical properties,storage stability and the slow-release kinetics of chia seed oil were studied.(1)The preparation technology of Chia seed oil microcapsules was optimized with the embedding rate of microcapsules as the evaluation index.The results showed that the optimum parameters for microencapsulation of Chia seed oil were as follows: wall material ratio(sodium caseinate: D-lactose hydrate)1.1:1,the concentration of solid content 31.32%,mass ration of the wall to core 2.34:1.Under these conditions,the encapsulation rate of Chia seed oil microencapsulation was 90.65%.(2)Chia seed oil microcapsules were prepared with the best technological parameters,and the basic physical and chemical properties of the microcapsules were determined.The results showed that the microcapsules had a small average particle size,uniform dispersion,low moisture content,good fluidity,smooth surface,low viscosity,high solubility,and good thermal stability.The microcapsules have irregular geometry and compact structure,and there are some projections and small pores on the surface wall.(3)FT-IR analysis showed that the main characteristic absorption peaks of chia seed oil and composite wall material were shown on the spectrogram of microcapsule products,but the intensity was weakened,indicating that the composite wall material had a good encapsulation effect on chia seed oil.The X-ray spectra show that a new diffraction peak has appeared and a polymer of sodium caseinate-D-lactose hydrate-chia seed oil has been formed.DSC analysis shows that when the temperature reaches131.17℃,microcapsules undergo thermal decomposition and have good thermal stability,which can basically meet the general food processing conditions.The analysis of the fatty acid composition of chia seed oil before and after embedding showed that the contents of linoleic acid and α-linolenic acid in chia seed oil did not change much,and the content of unsaturated fatty acid was still rich.The results showed that the fatty acid composition and relative content of Chia seed oil microcapsules prepared by freeze-drying had no significant effect on the functional characteristics and nutritional value of Chia seed oil.(4)The changes of POV values of chia seed oil microcapsules under different storage temperatures were analyzed.Meanwhile,the oxidation kinetics and shelf life prediction of Chia seed oil microcapsules were conducted according to the Arrhenius and Vant ’Hoff empirical formulae.The results showed that the shelf-life of chia seed oil and its microcapsules at room temperature was 219 days and 105 days,respectively,under the storage condition of room temperature(25℃),indicating that the shelf life of Chia seed oil could be effectively extended by microcapsule technology.(5)The microcapsule products were stored at different temperatures,humidity,and p H conditions for 16 d.The core material retention rate was measured at different time points.The results showed that the core material retention rate was not conducive to the high temperature and humidity environment,and the core material release was better under the conditions of strong acid or alkali;After fitting by Avrami’s formula,R2 were all greater than 0.98,indicating a good fitting degree.Release types under different storage conditions were determined by analyzing release mechanism parameters and release rate constant.(6)In vitro digestion model was used to study the release behavior of chia seed oil microcapsules in vitro.During the whole digestion process,the release rate of microcapsules reached 81.73%,and the release rate of microcapsules in the intestinal fluid was significantly higher,which ensured the release of most chia seed oil in the intestinal tract and effectively improved the bioavailability of Chia seed oil in the human body.