Scavenging Effect And Mechanism Of Tea Extracts On Allicin

Garlic(Allium Sativum L.)belongs to the allium of lily family. Allicin, whose chemicalname is diallyl thiosulfinates, is the main functional substance of garlic. It is generated byalliin under the catalytic action of alliinase after the fresh garlic is crashed. Allicin plays animportant role in food therapy of garlic. Meanwhile, allicin and its derivatives are the mainsource of garlic odor which especially has a long residual time in the mouth after the rawgarlic is chewed. It seriously affects the consumption of garlic and restricts the developmentof garlic industry.Based on the fact that tea can reduce the garlic odor, this experiment studied thescavenging effect of various tea extracts on allicin and the mechanism of the action. The mainresults were as follows:1. Selection of the functional composition in tea: In this experiment, the scavengingeffect of tea extracts in different types, dosages and extraction solvents on allicin wasdetermined. The result showed that the extract of green tea with the dosage of5g, which wasextracted through60%ethanol, had the best effect on seavenging of allicin. As a substancewas further selectively removed from the tea extracts mentioned above, the experiment foundthat the scavenging effect of the extracts without TP on allicin was significantly reduced,which showed that TP playd an important role in the scavenging of allicin. And a positivecorrelation between the content of TP and the scavenging rate of allicin was found.2. Separation and identification of the main functional substances: In this experiment, theTP, which was obtained after rough separation, was separated by polyamide resin. And afteranalyzing through LC-MS, four effective functional substances were identified which wereflavanonol, Epigallocatechin, caffeine and Epicatechin. After determining their scavengingeffect on allicin, the results showed that Epigallocatechin had the best scavenging effect,followed by Epicatechin, and caffeine and flavanonol.3. Kinetics experiments on the scavenging effect of effective functional substances onallicin: The scavenging effect of allicin in different densities, different reaction time and pHvalue of Epicatechin was studied in this experiment. The results showed that the scavengingeffect of allicin was the best when the density was8mg·mL-1, the reaction time was40min, and the pH value was7. And the verification test showed the results as well. It also found thatthere was a linear correlation between the density of Epicatechin and the scavenging rate ofallicin, and the linear equation was y=9.0368x+11.589, r=0.9665.4. The mechanism of scavenging: The study showed that the scavenging effect ofpolyphenols in tea represented by Epigallocatechin and Epicatechin on allicin was obvious.The phenolic hydroxyl of polyphenols could provide hydrogen which could react with allicinto form a new chemical substance to disable the allicin from existing in an unbound state.However, the experiment also proved that the substance was unstable and was easilydecomposed and restored to allicin in the solvents with strong polar.