Wondrak G, Pier T, Tressl R
Institut für Biotechnologie, Technische Universität, Berlin, Germany.
J Biolumin Chemilumin. 1995 Sep-Oct;10(5):277-84. doi: 10.1002/bio.1170100504.
Several authors have reported on high-sensitivity measurement of oxygen-dependent low-level chemiluminescence (CL) from Maillard reactions (MR), i.e. nonenzymatic amino-carbonyl reactions between reducing sugars and amino acids (also referred to as nonenzymatic browning). Here we report for the first time, that light from Maillard reactions can be seen by the human eye and also can be photographed. In parallel with visual perception and photography CL was monitored by means of a CL-detection programme of a liquid scintillation counter (LSC, single photon rate counting). CL emission spectrum was recorded by a monochromator-microchannel plate photomultiplier arrangement. CL intensity from reaction of 6-aminocaproic acid with D-ribose (200 mg each) in 5 mL H2O at pH 11 at 95 degrees C was high enough for visual perception after adaptation to absolute darkness. Reaction in dimethylsulphoxide (DMSO) exhibited strongly enhanced CL (10 mg each in 5 mL were sufficient for visual detection) and could be photographed (15 minutes' exposure, ASA 6400); all characteristics of Maillard specific CL (O2-dependence, no CL from nonreducing sugars, inhibition by sulphur compounds) remained. Visual detection of CL and measurement by LSC were in full concordance. The CL emission spectrum showed two broad peaks at around 500 nm and 695 nm. Fluorescence emission of the brown reaction mixture matched the blue-green part of the CL emission spectrum. Emission of visible light during Maillard reactions may partly originate from oxygen-dependent generation of excited states and energy transfer to simultaneously formed fluorescent products of the browning reaction.
几位作者报道了对美拉德反应（MR）中氧依赖型低水平化学发光（CL）的高灵敏度测量，即还原糖与氨基酸之间的非酶促氨基-羰基反应（也称为非酶促褐变）。在此，我们首次报道，美拉德反应发出的光肉眼可见，也可以拍照。在视觉感知和拍照的同时，通过液体闪烁计数器（LSC，单光子速率计数）的CL检测程序监测CL。通过单色仪-微通道板光电倍增管装置记录CL发射光谱。6-氨基己酸与D-核糖（各200mg）在5mL水中，pH为11，95℃反应产生的CL强度在适应绝对黑暗后高到足以被肉眼感知。在二甲基亚砜（DMSO）中的反应表现出强烈增强的CL（5mL中各10mg足以进行视觉检测），并且可以拍照（曝光15分钟，ASA 6400）；美拉德特异性CL的所有特征（对氧的依赖性、非还原糖不产生CL、被硫化合物抑制）均保留。CL的视觉检测和LSC测量结果完全一致。CL发射光谱在约500nm和695nm处显示出两个宽峰。棕色反应混合物的荧光发射与CL发射光谱的蓝绿色部分匹配。美拉德反应过程中可见光的发射可能部分源于氧依赖型激发态的产生以及能量转移到同时形成的褐变反应荧光产物。
