Modification Of Conjugated Linolenic Acid And Effects On Oxidation,Biological Activity In Vitro

Conjugated Linolenic acid (CLnA) refers to a group of octadecatrienoic acids with threeconjugated double bonds. It has attractted a great attention in the scientific research community forits excellent biology activity, such as intense antioxidation, losing weight, boosting high-densitylipoprotein and ringing prostaglandin secretion, lowering blood pressure, anti-prothrombin,anti-inflammatory and so on. But Conjugated Linolenic acid has poor oxidation stability. It will becompletely oxidated in a few hours at the room temperature, which greatly affects the product’sshelf life and limits its application.In order to solve this problem, we modified Conjugated Linolenic acid to protect CLnA fromtwo methods of encapsulating and esterifying. At the same time, we researched the effects tooxidation stability and the possible mechanism after the two method modification of CLnA. Thenwe got some primary evaluation for the two methods and the effects of two methods on ConjugatedLinolenic acid, such as structure, morphology, dispersibility, releasing in vitro, scavenging activity,cell activity in vitro.For the esterifying modification, we chose glycerine, glycol, PEG-400, catechin andproanthocyanidins these five polar molecules to modify Conjugated Linolenic acid. The reactionwas carried out under DCC agent and mild conditions. Then we got different ester derivates andisolated them into pure monoester, and all these pure ester derivates were characterized by UV,FT-IR,1HNMR. This research was stated in the Chapter Two. In the third chapter, the oxidationstability and water-dispersibility of different ester derivates were researched, and the antioxidationof each ester was also investigated by scavenging activity on inductive free radicals withspectrophotometric methods, in this chapter taking O-2· as an example. The studies on digestionunder lipase and cell activity in vitro were carried out for farther researches on biological activityof each ester derivate. We found that the oxidation stability of ester derivates were increased byvarying degrees, and the enhance range has been greatly related to the molecules’ polarity. Thecatechin and proanthocyanidins have bigger molecules’ polarity, and their oxidation stability arebetter. Water-dispersibility of different ester derivates were increased varying degrees, some canform emulsion and soluble directly in water. All the results demonstrated that esterifying modification can enhance oxidation stability and antioxidation stability, at the same time, esterderivates had not affect CLnA activity in vitro.For the encapsulating modification in the Chapter Four, we chose β-cycldextrin asmicrocapsule material and got the β-cycldextrin-CLnA complex with high encapsulation efficiencyof CLnA. The result of oxidation stability demonstrated that oxidation stability of β-cycldextrin-CLnA was improved greatly. Pure CLnA had been oxidated90%in30minutes at50degree in theair; the β-cycldextrin-CLnA complex still had70%remainder after12days under the sameconditions. We found the β-cycldextrin-CLnA complex were flaked solids with1μm length and50nm thickness. The study on digestion under pepsase indicated that CLnA could release instomach without any effect. These also mean that the method of encapsulating modification withβ-cycldextrin as microcapsule has good application value. In a word, all the results demonstratedthat the two methods of encapsulating and esterifying modification both are valuable for CLnAapplication.At last, we systematically summed up the contents of the study and prospected the researchof its production and wide application in daily life.