【作者】 王伟；

【导师】 乔旭光；

【作者基本信息】 山东农业大学 ， 食品科学， 2006， 硕士

【摘要】 大蒜为百合科葱属多年生草本植物,含有丰富的营养物质且具有抗肿瘤、保护心血管系统、降低血糖等功效。大蒜之所以具有广泛的药理作用,原因在于大蒜含有的生物活性物质-含硫化合物。大蒜破碎后蒜氨酸(S-烯丙基-L-半胱氨酸)在蒜氨酸酶(EC 4.4.1.4)催化作用下生成大蒜素,大蒜素生成产率与蒜氨酸酶的活性调控有密切联系,因此首先围绕大蒜蒜氨酸酶的酶学性质展开研究具有十分重要的现实意义。本试验以大蒜鳞茎为原料,经PEG8000沉淀法、ConA-Sepharose亲和层析柱法分离纯化出蒜氨酸酶用于性质的研究。研究不同金属离子、甘油、L-半胱氨酸、磷酸吡哆醛等对蒜氨酸酶活性的影响,采用HPLC法定量研究了破碎大蒜体系中蒜氨酸转化率,确定了提高蒜氨酸转化率的因素,同时研究了有利于提高蒜氨酸转化率的因素对于大蒜素产率提高程度的研究。主要试验结果如下:1、蒜氨酸酶活性的影响因素分析研究表明大多数金属离子对蒜氨酸酶活性有影响,其中Mg2+、Fe3+、Ca2+、Fe2+、Mn2+对蒜氨酸酶有明显的激活作用,其中Mn2+的激活作用最显著,10mmol/L Mn2+可以将蒜氨酸酶的活性提高2.84倍。金属离子对蒜氨酸酶的激活作用在有甘油、葡萄糖、蔗糖等多羟基化合物存在的条件下效果更好。Cu2+对蒜氨酸酶有抑制作用。醋酸酐、L-半胱氨酸对蒜氨酸酶有抑制作用,辅酶磷酸吡哆醛能提高蒜氨酸酶的活性。2、大蒜破碎体系中蒜氨酸转化率研究采用微波灭酶、水煮灭酶、有机溶剂冷冻灭酶三种方法对大蒜中蒜氨酸进行提取。蒜氨酸的保留时间为3.717 min,测得蒜氨酸的含量为:0.823%、0.730%、0.156%。同时对大蒜破碎放置一天后体系中蒜氨酸的含量进行了分析,测得蒜氨酸转化率仅为77.0%。通过向破碎的大蒜体系中添加5 mmol/L磷酸吡哆醛可以将蒜氨酸的转化率由76.5%提高到87.5%(30min后测定),0.1mmol/L的Mn2+可以将蒜氨酸的转化率提高33.3%。本法达到较高的精密度(0.83%)和回收率(97.6%),适用于大蒜中蒜氨酸含量的测定。更多还原

【Abstract】 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.更多还原