Effect of temperature on the formation of acrylamide in cocoa beans during drying treatment: An experimental and computational study

Maritza Gil; Pablo Ruiz; Jairo Quijano; Julian Londono-Londono; Yamilé Jaramillo; Vanessa Gallego; Frederic Tessier; Rafael Notario

doi:10.1016/j.heliyon.2020.e03312

Effect of temperature on the formation of acrylamide in cocoa beans during drying treatment: An experimental and computational study

Heliyon. 2020 Feb 10;6(2):e03312. doi: 10.1016/j.heliyon.2020.e03312. eCollection 2020 Feb.

Authors

Maritza Gil^{1

2

3}, Pablo Ruiz^{2

3}, Jairo Quijano², Julian Londono-Londono⁴, Yamilé Jaramillo¹, Vanessa Gallego¹, Frederic Tessier⁵, Rafael Notario⁶

Affiliations

¹ Grupo de investigación de Ingeniería de Alimentos GRIAL. Corporación Universitaria Lasallista. Caldas, Antioquia, Colombia.
² Laboratorio de Fisicoquímica Orgánica, Facultad de Ciencias, Universidad Nacional de Colombia, Sede Medellín AP 3840, Medellín, Colombia.
³ Instituto Tecnológico Metropolitano, Facultad de Ciencias Exactas y Aplicadas, Medellín, Colombia.
⁴ Sosteligroup - Generation Wellness, Kra. 54B N 37 - 25 Rionegro, Antioquia, Colombia.
⁵ Faculty of Medicine - University of Lille, 59655 Villeneuve d'Ascq, France.
⁶ Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain.

Abstract

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.

Keywords: Acrylamide; Asparagine; Chemical food analysis; Cocoa bean; Computational chemistry; Drying; Elimination reaction; Food analysis; Food composition; Reducing sugars; Theoretical computer science.