De Vleeschouwer Kristel, Van der Plancken Iesel, Van Loey Ann, Hendrickx Marc E
Laboratory of Food Technology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, B-3001 Heverlee, Belgium.
J Agric Food Chem. 2008 Aug 13;56(15):6460-70. doi: 10.1021/jf8006294. Epub 2008 Jul 3.
The influence of water activity on the formation and elimination reactions of acrylamide was examined by means of multiresponse modeling on two different levels of complexity: basic equimolar asparagine-glucose systems and equimolar potato-based asparagine-glucose systems. To this end, model systems were first equilibrated to initial water activities in the range of 0.88-0.99 (corresponding roughly to the moisture gradient observed in French fries) and then heated at temperatures between 120 and 200 degrees C during different reaction times. For each sample, the concentration of acrylamide, glucose, asparagine, and aspartic acid was measured, as well as the extent of browning. A mechanistic model was proposed to model the five measured responses simultaneously. For both types of model systems, the model prediction was quite adequate, with the exception of the extent of browning, especially in the case of the potato-based model system. Moreover, the corresponding estimated kinetic parameters for acrylamide formation and elimination did not change significantly (based on a 95% confidence level) within the range of water activities tested, nor between the systems in the absence or presence of the potato matrix. The only remarkable difference was observed for the activation energy of acrylamide elimination, which was lower in the presence of the potato matrix, although not always significant. In general, these results confirm the generic nature of the model proposed and show that the influence of different moisture levels on acrylamide formation and elimination is minimal and that the addition of a potato matrix has little or no influence on the kinetic model and corresponding kinetic parameters.
通过多响应建模，在两种不同复杂程度的水平上研究了水分活度对丙烯酰胺形成和消除反应的影响：基本等摩尔的天冬酰胺 - 葡萄糖体系和基于马铃薯的等摩尔天冬酰胺 - 葡萄糖体系。为此，首先将模型体系平衡至初始水分活度在0.88 - 0.99范围内（大致对应于炸薯条中观察到的水分梯度），然后在120至200摄氏度的温度下加热不同的反应时间。对于每个样品，测量了丙烯酰胺、葡萄糖、天冬酰胺和天冬氨酸的浓度以及褐变程度。提出了一个机理模型来同时模拟五个测量响应。对于这两种类型的模型体系，除了褐变程度外，模型预测相当充分，特别是在基于马铃薯的模型体系中。此外，在所测试的水分活度范围内，以及在不存在或存在马铃薯基质的体系之间，丙烯酰胺形成和消除的相应估计动力学参数没有显著变化（基于95%置信水平）。唯一显著的差异是在丙烯酰胺消除的活化能方面观察到的，在存在马铃薯基质的情况下其较低，尽管并非总是显著。总体而言，这些结果证实了所提出模型的通用性，并表明不同水分水平对丙烯酰胺形成和消除的影响最小，并且添加马铃薯基质对动力学模型和相应的动力学参数几乎没有影响。
