Gil Maritza, Ruiz Pablo, Quijano Jairo, Londono-Londono Julian, Jaramillo Yamilé, Gallego Vanessa, Tessier Frederic, Notario Rafael
Grupo de investigación de Ingeniería de Alimentos GRIAL. Corporación Universitaria Lasallista. Caldas, Antioquia, Colombia.
Laboratorio de Fisicoquímica Orgánica, Facultad de Ciencias, Universidad Nacional de Colombia, Sede Medellín AP 3840, Medellín, Colombia.
Heliyon. 2020 Feb 10;6(2):e03312. doi: 10.1016/j.heliyon.2020.e03312. eCollection 2020 Feb.
The aim of this work was to determine the effect of temperature on the formation of acrylamide in cocoa beans during drying treatment by an experimental and computational study, in order to assess the presence of this neoformed compound from postharvest stage. The computational study was conducted on the reaction between fructose, glyoxal from glucose, and on asparagine at the M06-2X/6-31+G(d,p) level, under cocoa bean drying conditions at 323.15 to 343.15 K. The proposed reaction for acrylamide formation consisted of seven steps, which required to progress a via cyclic transition state of the four members. In addition, step III (decarboxylation) was considered to be the rate-determining step. Glucose followed an E1-like elimination and fructose exhibited an E1cb-like elimination. Computational model showed that the reaction of acrylamide formation was favored by fructose rather than glucose. The content of reducing sugars, asparagine and acrylamide in fermented and dried cocoa from two subregions of Antioquia-Colombia, as well as roasted cocoa, were evaluated by UHPLC-C-CAD and UHPLC-QqQ. The concentrations of monosaccharides measured at the end of the fermentation and drying process of cocoa nibs showed greater decreases in the levels of fructose as compared to glucose, supporting the main model hypothesis. Acrylamide formation only occurred in Bajo Cauca due to the presence of both precursors and fast drying time (72 h). Finally, it was possible to find the conditions to which acrylamide can be formed from the drying process and not only from roasting, information that can be used for future control strategies.
这项工作的目的是通过实验和计算研究来确定温度对可可豆干燥处理过程中丙烯酰胺形成的影响，以便评估收获后阶段这种新形成化合物的存在情况。计算研究是在M06 - 2X/6 - 31 + G(d,p)水平下，针对可可豆在323.15至343.15 K干燥条件下，果糖、葡萄糖产生的乙二醛与天冬酰胺之间的反应进行的。所提出的丙烯酰胺形成反应由七个步骤组成，这些步骤需要通过四元环过渡态进行。此外，步骤III（脱羧反应）被认为是速率决定步骤。葡萄糖遵循类似E1的消除反应，果糖表现出类似E1cb的消除反应。计算模型表明，果糖比葡萄糖更有利于丙烯酰胺的形成反应。通过超高效液相色谱 - 电荷气溶胶检测器（UHPLC - C - CAD）和超高效液相色谱 - 三重四极杆质谱仪（UHPLC - QqQ）对来自哥伦比亚安蒂奥基亚两个次区域的发酵和干燥可可豆以及烘焙可可豆中的还原糖、天冬酰胺和丙烯酰胺含量进行了评估。在可可豆粒发酵和干燥过程结束时测得的单糖浓度显示，果糖水平的下降幅度比葡萄糖更大，这支持了主要模型假设。由于两种前体物质的存在以及快速干燥时间（72小时），丙烯酰胺的形成仅发生在考卡山谷下游地区。最后，有可能找出丙烯酰胺可从干燥过程而非仅从烘焙过程中形成的条件，这些信息可用于未来的控制策略。
