大蒜素水溶液稳定性及分解产物组成研究

Stability and Decomposition Products of Allicin in the Aqueous Solution

摘要:

大蒜素水溶液的稳定性对大蒜制品的加工极其重要。作者研究了体系温度、浓度、pH值对大蒜素水溶液稳定性以及分解产物组成的影响。研究结果显示：温度或浓度越高，大蒜素水溶液的稳定性越低；温度相对较低或大蒜素浓度较高时，大蒜素的分解产物越趋向于以3-乙烯基-1，2-二硫环己-4-烯和3-乙烯基-1，2-二硫环己-5-烯为主的环状物；反之，产物以二烯丙基二硫醚等直链化合物为主。溶液的酸性越强，大蒜素越稳定。采用氢谱表征了大蒜素与氘代乙酸的氢键作用，采用理论计算，发现大蒜素在酸性溶液中发生质子化后，O（13）与H（5）的键长变长，分子的能量降低，初步揭示大蒜素在酸性溶剂中稳定性更高的原因。

Abstract:

The stability of allicin in an aqueous solution is extremely important for the processing of garlic products. In this paper，the effects of temperature，concentration and pH value on the stability of allicin were investigated. Results show that the higher the temperature and concentration，the lower the stability of allicin in the aqueous solution. When temperature was relatively low or allicin concentration was high，decomposition products of allicin tended to be ring compounds such as 3-vinyl 1，2-disulfide cyclohex-4-ene and 3-vinyl 1，2- disulfide cyclohex-5-ene；conversely，the products primarily contained straight-chain compounds such as diallyl disulfide. The stronger the solution acidity was，the more stable allicin became. For this phenomenon，hydrogen bonding interaction of allicin with deuterated acetic acid was characterized by NMR. Theoretical calculations found that the main bond length between O（13） and H（5） of allicin obviously elongated and the molecular energy decreased in the protonated acid solution，which revealed the mechanism for the higher stability of allicin in an acidic solvent.