Extraction Of Unsaturated Fatty Acids From Tussah Pupa Oil And Preparation Of Microcapsules

Antheraea pernyi is mainly distributed in the three eastern provinces,which is rich in resources.However,the utilization rate of tussah pupa resources is less.In order to improve the utilization of tussah pupa resources,this paper extracts the tussah pupa oil through supercritical CO₂（SFE-CO₂）,and then extracts its unsaturated fat acid.Although tussah pupa oil is rich in fatty acids（especially unsaturated fat acids）,it has high utilization value for balanced diet and human functional nutrition,but it is easy to oxidize,difficult to process and transport and other defects.Therefore,this study developed a microencapsulated product of tussah pupa oil unsaturated fat acid that meets the needs of special people through microencapsulation technology.Based on tussah pupa,this study extracts tussah pupa oil by SFE-CO₂technology,and optimizes the process.Three different extraction methods,SFE-CO₂,ultrasonic assisted Soxhlet（UASE）and Soxhlet（SE）,are compared to analyze the quality of the oil and the composition of fatty acids.The urea inclusion method is used to extract its unsaturated fat fatty acid,and unsaturated fat acid is used as the core to prepare a kind of low water content,high solubility,easy digestion Microcapsules with good storage stability.The main research findings are as follows:（1）The main research results of optimizing the extraction of tussah pupa oil:The optimal extraction process for SFE-CO₂extraction of tussah pupa oil is:extraction pressure 30 MPa,extraction temperature 50℃,that SFE-CO₂flow rate 40L/h,extraction time 60 minutes,and extraction rate（28.48±1.02）%.Comparing the extraction rates of the three extraction methods,it can be concluded that SFE-CO₂（28.48±1.02）%>UASE（26.85±1.21）%>SE（25.43±1.32）%.（2）Basic properties of tussah pupa oil:By comparing and analyzing the protein,volatile substances,insoluble impurities,and phospholipid content of tussah pupa oil,it was found that SFE-CO₂has lower protein content,insoluble impurities,and phospholipid content,and better oil purity;Secondly,there is no significant difference in the content of volatile substances among the three extraction methods.Physical and chemical properties of tussah pupa oil:By comparing and analyzing the acid value,iodine value,peroxide value,and saponification value of silkworm pupa oil,it was found that the SFE-CO₂extraction has a minimum acid value of 1.01 mol/g,indicating that its free fatty acid content is relatively low,and the presence of free fatty acids can easily cause oil oxidation;The peroxide value of SFE-CO₂is also lower by 1.12 mmol/kg,and the peroxide value of oil can reflect the degree of oxidation of oil.The three extraction methods have similar convenience in saponification value and iodine value.The total phenolic content and antioxidant activity of tussah pupa oil:SFE-CO₂has the highest total phenolic content of 100.89mg GAE/kg oil;Secondly,the total phenolic content of UASE is 80.78 mg GAE/kg oil;SE has the lowest total phenol content of 40.21 mg GAE/kg oil.SFE-CO₂extraction method has the strongest scavenging capacity for DPPH free radicals and hydroxyl radical,followed by UASE and SE.Therefore,it can be concluded that the quality of tussah pupa oil extracted by SFE-CO₂is better.（3）Fatty acid analysis:through GC-MS analysis,10 fatty acids were identified.The content of unsaturated fat acid extracted from tussah pupa by SFE-CO₂was78.65%,slightly higher than UASE（77.70%）and SE（78.32%）.Optimization of the extraction process of unsaturated fat acid:the best process conditions for the extraction of unsaturated fat acid from tussah pupa by urea inclusion method:when the ratio of fat to urine is 1:2,the inclusion time is 16 hours,and the ratio of alcohol to fat is 1:7,the inclusion effect is the best,and the yield of unsaturated fat acid from tussah pupa is the highest,with a yield of 68.45%.（4）Optimization of microcapsule preparation process:the best process conditions of tussah pupa unsaturated fat acid microcapsule should be:solid content21.26%,core wall ratio(m _{composite wall material}:m _{unsaturated fat acid})2.22:1,wall material ratio(m _lactose:m _chitosan)1:1.93.Under this condition,the embedding rate of tussah pupa unsaturated fat acid microcapsule is 90.14%.Basic properties of microcapsules:high embedding rate,which is conducive to the storage and transportation of microcapsules;The moisture content of the product（3.06±0.23%）indicates a good freeze-drying effect;The solubility（90.15±1.31%）indicates good solubility,which is beneficial for the digestion of microcapsules;The angle of repose is less than 30°,and the fluidity of the microcapsules is good.The average particle size is 5926 nm,and the size range of the composite microcapsules is within the range of particle sizes;Fourier transform infrared spectroscopy showed that chitosan and lactose were good composite wall materials for tussah pupa oil unsaturated fat acid microcapsules.Bioactivity of microcapsules:Simulate the digestion of microcapsules in gastric juice within 0-4 hours,reach 47.67%after 4 hours,simulate the digestion of intestinal juice within 4-9 hours,and basically release unsaturated fat acid of microcapsules in intestinal juice after 5 hours,reach 92.26%,which are well released in gastrointestinal juice.Storage and transportation of microcapsules:Through the storage test,after 10days in the oven,by comparing the peroxide value of unsaturated fat acid of tussah pupa oil and microcapsules,the results show that microcapsules can effectively prevent high-temperature oxidation process.Finally,the use of microcapsule commercial technology to store and transport the unsaturated fatty acids of tussah pupae can solve the problem that it has a good diet but is not easy to process and transport,and is also beneficial to improve the utilization of tussah resources and promote the economic benefits of local tussah resources.In summary,this study aims to improve the extraction rate of tussah pupa oil through SFE-CO₂extraction optimization experiments;Comparative studies have shown that SFE-CO₂oil has better quality,and the fatty acid composition of tussah pupa oil is rich;The microcapsules with low water content,high solubility,easy digestion and good storage stability were prepared with unsaturated fat acid as the core material and chitosan and lactose as the composite wall material.