| Since 2015,central and local documents have advocated to increase the proportion of ten woody oil crops such as Xanthoceras sorbifolium Bunge in the edible oil structure.Subsequently,the planting area of Xanthoceras sorbifolium Bunge oil in my country has expanded rapidly.The oil yield of Xanthoceras sorbifolium Bunge Seed oil is higher than 60%,which has extremely high edible and health value.However,because Xanthoceras sorbifolium Bunge oil also contains 6%-10%erucic acid,some animal experiments show that erucic acid can hinder mitochondria and peroxisome metabolism,causing liver enlargement,cardiac fibrosis and other diseases.Therefore,the high erucic acid content has become the biggest obstacle to the use of Xanthoceras sorbifolium Bunge oil as an edible and health-care vegetable oil.At present,the method for reducing erucic acid in commercially available rapeseed oil is achieved by breeding canola varieties,and no erucic acid has been detected in other edible vegetable oils except rapeseed oil on the market.As a woody plant,the cultivation method of low erucic acid in the herb rape can not provide an effective reference,and the physical properties of erucic acid are similar to other components in the oil.The current feasible solution can only be considered without destroying its basic components and in the case of function,the erucic acid was removed from the Xanthoceras sorbifolium Bunge seed oil by physicochemical methods.This article is the first attempt to reduce the erucic acid in Xanthoceras sorbifolium Bunge seed oil through chemical methods and use green and natural food additives,and test the results of each experimental group.The specific content is divided into the following parts:(1)In the first chapter,the distribution,planting,and production of Xanthoceras sorbifolium Bunge,the basic characters and characteristics of Xanthoceras sorbifolium Bunge seed oil,and the functions of its main components were reviewed.And the current methods to achieve low erucic acid are summarized,and the research problems and the methods to solve the problems are proposed.(2)Using green natural food additives citric acid,gallic acid and lipase to reduce erucic acid in Xanthoceras sorbifolium Bunge seed oil by single-factor experiment and research on response surface optimization.It was found that when the concentration of citric acid was 0.1,the reaction temperature was 40℃,and the reaction time was 1.5 h,the reduction effect of erucic acid in Xanthoceras sorbifolium Bunge Seed oil was the best,and the total fatty acid content of erucic acid was 5.17%.When the concentration of gallic acid was 0.1,the reaction temperature was 30℃,and the reaction time was 1.5 h,the reduction effect of erucic acid in Xanthoceras sorbifolium Bunge seed oil was the best,and the clearance rate of erucic acid reached 16.73%.It is also the best reaction conditions for the three kinds of reagents;when the lipase concentration is 1.5%,the reaction temperature is 35℃,the reaction pH=6,and the reaction time is 20 h,the reaction effect is the best.The total fatty acid content was 5.42%.The results of gas chromatography(GC)showed that citric acid has the best removal effect on long carbon-chain fatty acids,and it may have a certain preference for it and have certain application value;while the total peak area of fatty acids in the gallic acid group(GA group)Compared with the crude oil,the total peak area of the GA group was reduced by 28.87%on average,and the reaction effect on long carbon chain fatty acids was small,and the specificity was not obvious;the total fatty acid peak area in the lipase group(CR group)was reduced to 1 of the original peak area,that is,lipase hydrolyzes and frees fatty acids in Xanthoceras sorbifolium Bunge oil in large quantities,which is related to the strong preference of Candida rugosa for short-chain fatty acids in oils,so the use effect is not ideal.(3)On the basis of the experimental results,the physicochemical properties of XBS,CA,GA and CR groups were tested.Through rheological experiments,it was found that Xanthoceras sorbifolium Bunge Seed oil exhibited shear thinning behavior,and the viscosity of different Xanthoceras sorbifolium Bunge seed oil experimental groups showed consistency with the thixotropic ring area in the thixotropy experiment and the results of the Arrhenius I model data.The fitting results of the Bingham I model also showed good correlation,and the dynamic viscoelasticity measurement showed that the storage modulus(G’)and loss modulus(G")before and after treatment with Fructus A.The size of G’ and G" in each experimental group were XBS>CA>GA>CR group.The results showed that the addition of green additives in the three reaction systems would cause changes in fatty acid composition in Xanthoceras sorbifolium Bunge seed oil,and the change in the gallic acid group was not obvious;the viscosity of the citric acid group decreased,which may be related to the reduction of long carbon chain fatty acids;The addition has a great influence on Xanthoceras sorbifolium Bunge seed oil,which reduces the molecular weight of the fruit,the entanglement and interaction between the molecules become smaller,and the viscosity decreases the most.FTIR was used to determine the structural characteristics of each group of Xanthoceras sorbifolium Bunge seed oil to observe some structural changes before and after treatment of Xanthoceras sorbifolium Bunge seed oil,which indirectly indicated that the change of its components was consistent with the removal effect of erucic acid.(4)In this chapter,the antioxidant capacity of Xanthoceras sorbifolium Bunge seed oil before and after removal of erucic acid(XBS,CA group,GA group and CR group)was tested to explore the changes of its antioxidant activity.The experiment found that it has certain scavenging ability to DPPH free radical,ABTS free radical,hydroxyl free radical and superoxide anion free radical,and also has certain reducing ability to iron ion.The results showed that compared with XBS,the antioxidant capacity of each group did not change significantly,but increased slightly,which may be related to the antioxidant capacity of the three green natural food additives.In this paper,the effect of citric acid in the erucic acid process of Xanthoceras sorbifolium Bunge oil is the best,but due to the lack of current research in this area,the selection of green natural reducing agents in the erucic acid process of Xanthoceras sorbifolium Bunge fruit seed oil still needs to be carried out.A large number of experiments are carried out to screen the reagents that have specificity or even specificity with erucic acid,so as to achieve the purpose of being edible,and provide a reliable basis for the cultivation and industrial development of Baiyin Xanthoceras sorbifolium Bunge. |
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