Study On The Preparation Of Hazelnut Oil Microcapsules And Its Hypolipidemic Function

Hazelnut oil is a high-quality,high-end edible oil,rich in unsaturated fatty acids such as oleic acid,linoleic acid and linolenic acid.It has the functions of lowering blood lipids,anti-oxidation and improving cardiovascular diseases.However,its unsaturated fatty acids are not stable,and are susceptible to oxidative deterioration due to the influence of the external environment,and lose their original nutritional value.The preparation of hazelnut oil into powder oil through microcapsule technology not only protects the hazelnut oil from being affected by external environmental factors,improves its stability,but also facilitates processing and production and expands its application range.This thesis takes hazelnut oil as the research object,adopts ultrasonic-assisted molecular embedding method and emulsion polymerization method to prepare hazelnut oil microcapsules.At the same time,its physical and chemical properties and blood lipid-lowering function are measured.The main research results are as follows:（1）In the experiment of using two methods to prepare hazelnut oil microcapsules,the embedding rate was used as the main evaluation index,and the preparation process of hazelnut oil microcapsules was optimized by response surface analysis.The optimal process conditions for preparing hazelnut oil microcapsules by ultrasonic-assisted molecular embedding method are wall material concentration（β-cyclodextrin/H₂O）1:16 g/m L,core-to-wall ratio 1:5 m L/g,embedding time 62 min and The embedding temperature is59.3℃.At this time,the embedding rate of microcapsules can reach 69.18%,and the average yield can reach 59.74%.The best process conditions for preparing hazelnut oil microcapsules by emulsion polymerization are wall-to-material ratio（Gum arabic/Maltodextrin）1:1.7 g/g,solids concentration 18.5%,core-wall ratio1:1.9 g/g,and homogenization speed 9600 r/min,the embedding rate of microcapsules can reach 46.25%,and the average yield can reach64.24%.The microcapsules prepared by the former were compared and selected to study the physical and chemical properties and the function of reducing blood lipids.（2）The measurement results of the basic physical and chemical properties of the microcapsules show that the average particle size of the hazelnut oil microcapsules is 880.4±10.42 nm,the moisture content is 2.85±0.16%,the solubility is 55.95±0.70%,and the density is 0.57±0.06 g/cm^-3.The angle of repose is 42.49±0.53°.Hazelnut oil microcapsules gained 10.2%in a 75%relative humidity environment,and the weight gain rate（8.5%）under a relative humidity greater than 57%indicates that a dry environment is conducive to the storage of the microcapsules.At the same time,optical microscope and scanning electron microscope show that its microstructure is blocky and diamond-shaped,or irregular columnar,and the wall structure is tight and seamless.X-ray diffraction and infrared spectroscopy confirmed the formation of hazelnut oil microcapsules.In addition,thermogravimetric analysis proved that the hazelnut oil microcapsules have good thermal stability.（3）Using Avrami’s formula and Arrhenius formula to determine the retention rate and peroxide value of the hazelnut oil microcapsule core material and the kinetic analysis showed that the release of the microcapsule core material can be significantly reduced at4℃,and the release of the microcapsule core material can be reduced at the same time as it is protected from light and low humidity.The release of the core material.The peroxide value of the hazelnut oil and its microcapsule core material showed that the hazelnut oil can be stored for 49 days at 40℃,and the hazelnut oil and its microcapsules can be stored for13 days and 25 days at 60℃,respectively.According to the empirical formula of Vant’Hoff,it is speculated that hazelnut oil and its microcapsules can be stored for 208 days and 400days,respectively,at room temperature（20℃）.At the same time,a vacuum and dark environment can also delay the oxidation rate of oils and extend the shelf life.The determination of hazelnut oil and its microencapsulated fatty acids by gas chromatography showed that microencapsulation had little effect on the composition and content of fatty acids in hazelnut oil.（4）The artificial simulation of gastrointestinal juice in vitro shows that the hazelnut oil microcapsules can maintain a relatively complete structure in the acidic environment of gastric juice and release a small amount of core material,which is mainly released in weakly alkaline intestinal juice.In the blood lipid-lowering experiment in mice,after comparing the serum Total Cholesterol（TC）and Triglycerides（TG）content of the model group and the normal group,the results showed that the difference was significant（p<0.05）,that is,the model was successful.The results of measuring serum lipid levels in mice showed that low-dose hazelnut oil group and low-and medium-dose hazelnut oil microcapsule group can effectively reduce serum TC and TG levels（p<0.05）,and increase High-Density Liptein Cholesterol（HDL-C）content.At the same time,the different doses of hazelnut oil group and microcapsule group can also significantly reduce the serum Low-Density Lipoprotein Cholesterol（LDL-C）content（p<0.05）,and promote the metabolism of blood lipids in the body.In addition,the observation of cell structure in mouse liver tissue sections by hematoxylin-eosin（HE）staining also verified the above conclusions.