The Research On Aqueous Extraction Of Sesame Oil And Protein With Tween

Sesame seeds,had rich fat and protein,was one of the important oil crops in China.Aqueous extraction could simultaneously get sesame oil and sesame protein,which was vital significant to improve comprehensive utilization of sesame and increase supply of plant protein resources.Based on the problems of emulsification and protein recovery,we used tween 20 to optimize extraction process.And we combined tween with a small amount of protease to study product yields and product quality and screened appropriate enzyme species and the concentration;compared the basic physical and chemical properties and oxidative stability of sesame oils obtained by different preparation ways and determined flavor components of sesame oil by GC-MS.The results of the study were as follows:(1)PH,solid-liquid ratio and extraction time had a significant impact on sesame oil and sesame protein by aqueous extraction.The addition of tween 20,tween 60,or tween 80 could significantly increase the oil extraction yield,but the effect on the extraction of sesame protein was not significant.Through orthogonal experiment,the optimum conditions were obtained:pH11,solid-liquid ratio 1:6,extraction time 30 min,tween 20 concentration was 1%.Under these conditions,the extraction yield of oil and protein were 60.97 ±2.43%and 63.53 ± 1.79%,respectively.(2)The yield of sesame oil extraction was higher than that of the single use of tween 20 or protease when simultaneous addition of tween and a small amount of alkaline protease(150 or 300 IU/g).This indicated that tween 20 and protease had synergetic effect on the extraction of sesame oil.And the yields of sesame oil were respectively 67.16±1.79%and 69.13 ± 1.57%,both of which were significantly higher than that of tween 20(62.32 ± 1.52%).The yields of sesame protein were respectively 62.11 ±1.78%and 63.36±1.34%,which were similar to that of tween 20.Whether or not the protease was added,tween 20 had a poor effect on the extraction of roast sesame.(3)Isoelectric precipitation and ultrafiltration methods were respectively used to recover sesame protein.The recovery rate and the purity of protein decreased sharply with the increase of amount of protease.When the same amount of protease was used,the purity of the recovered protein of acid precipitation method was significantly higher than that of the ultrafiltration method.Although a small amount of protease with tween 20 could not improve the yield of sesame protein,it could improve the partial functional properties of sesame protein:such as solubility,oil absorption,emulsifying and foaming properties.A small amount of Alcalase 2.41(150IU/g)combined with tween20 was the optimal method for the extraction of raw sesame oil and protein by taking oil extraction,protein recovery and functional properties into consideration.(4)Four methods were used respectively to prepare sesame oil ?(raw sesame oil extracted with tween20 and small Alcalase2.4L protease),oil ?(raw sesame oil extracted with more Alcalase 2.4L protease),oil ?(toasted sesame oil extracted with more Alcalase2.4L protease 1)and oil ?(raw sesame oil extracted with solvent).By comparison of the physical and chemical properties,there was no significant difference in the content of water and volatiles of the four oils.Oil ? was darker than the other three kinds of sesame oil;The acid value of oil ? was significantly lower than those of other three oils;peroxide value of Oil ? and oil IVwere higher;oxidation induction time of oil ? was the longest,oxidation induction time of oil ? was the shortest.The comparison on sesame phenol content:oil ?was highest,oil ? and oil ? was second,oil? was lowest;the comparison on tocopherol content:oil ? and oil ? were highest,oil ? was second,oil ? was lowest.The difference of antioxidant content in lipids could explain the difference of oxidation stability.The flavor components of four sesame oils were analyzed,and the results showed that hydrocarbons,aldehydes and alcohols were higher in the sesame oil content;22 volatile compounds were identified in oil ?;34 volatile compounds were identified in oil ?;22 volatile compounds were identified in oil ?;oil ? contained four kinds of pyrazine compounds that did not exist in oil ? and oil ?.