| Red raspberry has high medicinal value and health care effects.As a by-product of red raspberry processing,red raspberry seeds have the prospect and value of development and utilization.This article studied three extraction methods to extract red raspberry seed oil,in order to determine the best extraction method for red raspberry seed oil.Furthermore,the storage stability,antioxidative and hypolipidemic activities in vitro of red raspberry seed oil were studied.Some major conclusions from this research work are as follows:1.The single factor tests and L9(34)orthogonal test were used to optimize the process parameters of Soxhlet extraction and high-speed-shear-ultrasonic extraction of red raspberry seed oil,and compared with the optimized ultrasonic extraction method.The optimal extraction process parameters of Soxhlet extraction were as follows:the extraction solvent was n-hexane,the crushing degree of red raspberry seeds was 100 mesh,the ratio of liquid to material was 15 mL/g,the extraction time was 1.0 h,and the extraction temperature was 80?,under these conditions the yield of red raspberry seed oil was 19.96±0.52 g/100g.The optimal extraction process parameters of ultrasonic extraction method were as follows:the extraction solvent was n-hexane,the crushing degree of red raspberry seeds was 80 mesh,the liquid-to-material ratio was 11 mL/g,the ultrasonic time was 25 min,the ultrasonic temperature was 30?,and the ultrasonic power was 100 W,under these conditions the yield of red raspberry seed oil was 20.34±0.32 g/100g.The optimal extraction process parameters of the high-speed-shear-ultrasonic extraction of the results showed that:the extraction solvent was n-hexane,the crushing degree of red raspberry seeds was 100 mesh,and the liquid-to-material ratio was 10 mL/g.Intermittent high-speed-shear in ultrasound(10 s of high-speed-shear initiation and 20 s pause for one cycle)extraction for 15 min,the extraction temperature was 40?,the ultrasonic power was 270 W,the high-speed-shear speed was 15000 r/min,under these conditions the yield of red raspberry seed oil is 23.24±0.49 g/100g.2.The physical and chemical indexes of three extraction methods of red raspberry seed oil were determined.The fatty acid composition of three extraction methods was analyzed by GC-MS.The contents of ?-sitosterol and ?-tocopherol in three extraction methods were determined by HPLC.Raspberry seed oil yield,acid value,iodine value,peroxide value,saponification value,palmitic acid,stearic acid,oleic acid,linoleic acid,linolenic acid,arachidic acid,SFA,MUFA,PUFA,UFA,the seed oil of ?-sitosterol and ?-tocopherol content were used as indexes to calculate the comprehensive score three extraction methods,through the principal component analysis to extract the principal component,and the optimal extraction method of raspberry seed oil was obtained.The results showed that the high-speed-shear-ultrasonic red raspberry seed oil had low acid value,low saponification value,low peroxide value and high iodine value;19 fatty acids were detected in red raspberry seed oil,accounting for 98.22%of the total composition of red raspberry seed oil,of which linolenic acid was 29.98%and linoleic acid was 48.07%;The content of ?-sitosterol and ?-tocopherol in red raspberry seed oil extracted by soxhlet extraction were 97.37 mg/100g and 18.88 mg/100g.Two principal components were extracted by principal component analysis,and the variance contribution rates were 52.288%and 47.712%.The high-speed-shear-ultrasonic extraction method got the highest comprehensive score,followed by ultrasonic extraction method and Soxhlet extraction method.The high-speed-shear-ultrasonic extraction method was the best extraction method of red raspberry seed oil.3.Red raspberry seed oil was extracted by high-speed-shear ultrasonic extraction method.The storage stability of red raspberry seed oil was studied by Schaal accelerated storage experiment.The peroxide value,palmitic acid,stearic acid,oleic acid,linoleic acid,linolenic acid,arachidonic acid,SFA,MUFA,PUFA,UFA,content of ?-sitosterol and ?-tocopherol in seed oil,DPPH and ABTS free radical scavenging rate in the storage process of red raspberry seed oil were used as indexes to extract the principal components by principal component analysis and calculate the weight.The results were as follows:The peroxide value increased,palmitic acid,stearic acid and SFA contents increased,and the contents of oleic acid,linoleic acid,linolenic acid,arachidonic acid,MUFA and PUFA decreased during the storage of red raspberry seed oil.The contents of ?-sitosterol and ?-tocopherol in seed oil decreased at first and then leveled off.DPPH and ABTS free radical scavenging were first reduced and then leveled off.Four principal components were extracted by principal component analysis,with variance contribution rates of 63.230%,11.590%,9.855%and 7.698%.Among them,SFA,?-tocopherol,?-sitosterol,stearic acid,peroxide value,palmitic acid,aracic acid,linoleic acid,UFA,PUFA,ABTS free radical scavenging rate and MUFA account for 82.82%of the storage stability of red raspberry seed oil,which were important indexes of the storage stability of red raspberry seed oil.It is predicted that the shelf life of red raspberry seed oil stored at 20? was 336 d.4.Red raspberry seed oil sample solution was preparated by protein adsorption method.Through MTT test,the optimum concentration of HepG2 cells induced by red raspberry seed oil and H2O2 was obtained.The antioxidant activity of red raspberry seed oil was evaluated by determining the survival rate of HepG2 cells,the content of MDA and oxidation-related enzyme activities,such as SOD,CAT and GSH-Px.The lipid lowering activity of red raspberry seed oil was evaluated by the determination of levels of lipid,TG,HDL-C and LDL-C in HepG2 cells.The results showed that the maximum concentration of HepG2 cells induced by red raspberry seed oil for 24 h was 0.284 g/L;the modeled concentration of HepG2 cells induced for 8 h by H2O2 was 0.8 mmol/L.Compared with the model group,the cell survival rate increased by 49.34%,MDA decreased by 75.18%,SOD increased by 32.18%,CAT increased by 156.28%,and GSH-Px increased by 111.55%,all of which showed extremely significant differences,indicating that red raspberry seed oil could reduce the oxidative damage of cells.Compared with the model group,the lipid content in the test group of the experimental group was decreased by 14.10%,TG decreased by 50.76%,HDL-C increased by 48.47%,and LDL-C decreased by 28.89%,all of which showed extremely significant differences,indicating that red raspberry seed oil could reduce the accumulation of intracellular fat. |
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