Study On The Activating Of Alliinase In Improving The Allicin Yield

Garlic, Allium sativum L., is the perennial herb of lily family. The sulphide in the garlic has distinct effect of pharmacology such as tumour-cunteracting, vein-protecting, blood sugar-reducing and so on. The garlic alliinase (EC 4.4.1.4) catalyzes the synthesis of allicin, which is the main functional flavor component of fresh garlic. The producing of volatile compounds of garlic highly depends on the activity of alliinase, so it is of great significance to study the properties of alliinase. Alliinase was purified successfully from fresh bulbs by using various steps including PEG8000 method, affinity chromatogram on ConA-sepharose. The effect of different metal ions, glycerin, glucose, L-cysteine, pyridoxal phosphate on alliinase was studied. The conversion ratio of alliin in broken garlic was studied by the method of HPLC. The factors of advancing conversion ratio of alliin were confirmed. The main study results was as follows:1.Main factors affecting the alliinase activity. It showed that most metal ions had effect on alliinase, among of which activation effect of Mg2+, Fe3+, Ca2+, Fe2+, Mn2+ were obvious. Mn2+ was the strongest factor and could advance 2.84 times. The activation was better with the existence of polyhydric compounds such as glycerin, glucose, sucrose. Cu2+ was the inhibitive factor. Acetic anhydride and L-cysteine were the inhibitive factors of alliinase activity. Pyridoxal phosphate was the activation factor.2.Aalliin conversion ratio in broken garlic. The qualitative and quantitative determination of alliin in the garlic was studied by HPLC method. The alliin content of garlic was 0.823%, 0.730%, 0.156% respectively extracted by three enzyme inactivation methods, including microwave, boiled water and chilled organic solvent. The conversion ratio of alliin in the broken garlic was 77.0% in one day. The conversion ratio of alliin could be improved obviously from 76.5% to 87.5% by adding 5 mmol/L pyridoxine phosphate to the broken garlic (detected in 30 minutes). The conversion ratio of alliin could be improved 33.3% by adding 0.1 mmol/L Mn2+ to the broken garlic (detected in 30 minutesr). This method reached to a higher precision (0.83%) and recovery (97.6%) and can be applied to determine the alliin content in garlic.