【作者】 李蕾；

【导师】 胡小松； 赵广华；

【作者基本信息】 中国农业大学 ， 农产品加工及贮藏工程， 2005， 硕士

【摘要】 大蒜绿变有两种形式,人们最为熟悉的是腊八蒜,这种绿色素作为腊八蒜的主要呈色物质,经过几千年的传统饮食习俗已验证其安全性,具有作为一种天然色素开发价值。本论文对这种绿色物质形成机理的进行了初步研究,并取得了一定的进展。实验结果如下: (1)大蒜浸泡绿变同酸的种类有关,只有乙酸溶液可导致大蒜绿变,而与浸泡液的pH值无关;乙酸可以致使大蒜绿变,原因是乙酸不仅可以导致大蒜细胞膜通透性增大幅度最大,同时它具有影响大蒜内部结构的完整性;参与大蒜绿变前体物质在整个蒜瓣分布上没有差异,绿变从茎盘开始的主要原因是由于茎盘破损处是浸泡液渗入的一个首选入口。 (2)初步建立了毛细管气相色谱法测定大蒜中蒜氨酸组分的方法,大蒜样品中的蒜氮酸衍生物在该条件下得到了较好的分离;白蒜样品中ACSO含量明显高于绿蒜样品,这是一个值得注意的现象,推测ACSO参与了大蒜绿变反应;白蒜中PeCSO含量略高于绿蒜样品。从本实验结果无法直接得出蒜氨酸与大蒜绿变之间的关系,还需要进一步研究。 (3)对新蒜采取三种不同贮藏温度处理,对大蒜中硫代亚磺酸酯含量和蒜泥滤液吸光值进行了多点监测,研究硫代亚磺酸酯与大蒜绿变能力之间的关系。结果表明,大蒜绿变能力同硫代亚磺酸酯含量呈正相关关系,由此推测硫代亚磺酸酯是参与大蒜绿变反应重要物质,其含量决定了大蒜的绿变能力。同时研究乙酸浸泡期间大蒜硫代亚磺酸酯含量的变化,分析硫代亚磺酸酯与大蒜绿变程度之间的关系。试验得出,硫代亚磺酸酯含量与大蒜绿变程度的呈线性负相关关系,推测在大蒜中前体物质——蒜氨酸含量一定的条件下,绿色素形成的越多,作为反应中间体的硫代亚磺酸酯参与转化越多,最终表现在它的含量随大蒜绿变程度增加而降低。这就进一步说明硫代亚磺酸酯参与了大蒜绿变反应。但是国内外对此相关研究还很少,具体作用机制还有待进一步研究。大蒜在低温贮藏过程中,第十五天之后蒜素含量有很好的升高趋势,这为提高大蒜中蒜素含量的研究建立了理论依据,为其提取加工提供了生产建议。 (4)在对不同生理时期大蒜氨基酸组成的研究中,白蒜浸泡至完全变绿的过程中,其中丙氨酸含量增幅程度最大,与大蒜浸泡绿变试验结果有相同的趋势,是一个值得注意现象;但其余的氨基酸则表现出与大蒜浸泡绿变试验结果相反的试验结果。从本实验结果无法直接得出氨基酸与大蒜绿变之间的关系,还需要进一步研究氨基酸在大蒜绿色素形成过程中的具体变化机理。更多还原

【Abstract】 The greening of garlic has two cases, one that people known best is Laba garlic. The green pigment in greening garlic is safe, because it has been proved by diet habitude of several thousand years. And this green pigment has a value to be exploited as a natural pigment. This study has preliminarily researched mechanism of this green pigment formation, and obtains some advances. The results were summarized as follows:(1) Garlic drench greening related to the sort of acid. Only could acetic acid cause garlic greening, and the garlic drench greening did not relate to the pH value of acid solution. The reason of acetic acid could cause garlic greening was not only acetic acid could maximal improve the permeability of pericellular membrane, but also acetic acid impact the completeness of some inner cellularity. The distribution of precursors of garlic greening was homogeneous in the whole garlic cloves. The main reason of garlic greening from the bottom was that the breakage part of bottom was the first choice entrance of drench liquid entering garlic cloves.(2) A method for quantitative analysis of alliin by GC has been preliminarily established. Derivant of alliin in garlic examples were separated very well in this testing condition. The content of ACSO in white garlic was higher than green garlic significantly, and it was worth to pay attention to this phenomenon. And speculated that ACSO participated in the reaction of garlic greening. The content of PeCSO is little higher than green garlic. It could not get the relationship between alliin and garlic greening in this study, and it need to further studies.(3) This study monitored thiosulfinates content of garlic and absorbance of filtrate of garlic puree during storage adopted at three different temperatures. The aim is to research the relationship between thiosulfinates and the ability of garlic greening. Experimental result indicated that there was a positive correlation relationship between greening ability of garlic and thiosulfinates content, so suggesting that thiosulfinates play a role in garlic greening and thiosulfinates content determines the ability of garlic greening. And a drench greening test was carried out for studying the relationship between thiosulfinates and greening percent of garlic. Experimental result indicated that a linear negative correlation relationship between greening percent of garlic and thiosulfinates content, so speculating that the formation of the green pigment of the garlic is much more and thiosulfinates as a intermediate reactant in the garlic become decreased more on the basis of alliin content being definite. During storage at low temperature, allicin content had a ascend tendency after 15 days, which established fundamental basis for research of increasing allicin content and make a good productive suggestion for extracting allicin.(4) In the researches of garlic amino acid composition in difference physiology periods, the content of alanine increased highest. The study of garlic drench greening had the same tendency. It was worth to pay attention to this phenomenon. But the content of amino acid in this study was opposite with the results in the study of garlic drench greening. It could not get the relationship between amino acid and garlic greening in this study directly, and it need to further studies on the specific mechanism.更多还原