Model Studies on Acrylamide Generation from Glucose/Asparagine in Aqueous Glycerol

Abstract

Acrylamide formation from asparagine and glucose in different ratios in neutral glycerol/water mixtures was found to increase with decreasing water activity (0.33 < or = aw < or = 0.71 investigated) and increasing temperature (120 degrees C < or = T < or = 160 degrees C investigated). The initial rate of acrylamide formation was found to be approximately proportional to the asparagine concentration for an excess of asparagine, but less dependent on an excess of glucose. A steady-state concentration of acrylamide was established at 160 degrees C after 1 h for aw = 0.33 (30 microg x L-1 for GLU:ASN = 10:1, 11 microg x L-1 for GLU:ASN = 1:1, and 130 microg x L-1 for GLU:ASN = 1:10) and for aw = 0.47 (15 microg x L-1 for GLU:ASN = 10:1 and 80 microg x L-1 for GLU:ASN = 1:10), suggesting a protection by glucose against acrylamide degradation. The energy of activation, as estimated from the temperature dependence of the initial rate, increased with decreasing aw despite a higher rate of formation of acrylamide at low aw. For high aw, water elimination from a reaction intermediate is suggested to be rate determining. For low aw, the increase in energy of activation (and enthalpy of activation) is accordingly counteracted by a more positive entropy of activation, in agreement with decarboxylation as rate determining at low aw.

Acrylamide kinetic in plantain during heating process: Precursors and effect of water activity

“…Moreover, it is hard to indentify the effect of initial water activity when working in a small a w range (De Vleeschouwer et al 2008, Robert et al 2004, the use here of larger initial water activity range allowed to overcome this difficulty. The increase of the initial formation rate with increasing temperature and decreasing initial water activity was already highlighted in aqueous glycerol asparagine-glucose model system (mobility does not, depend on water content), within an initial water activity range varying from 0.33 to 0.71 (Hedegaard et al 2007). The authors suggested that in higher a w the elimination of water molecule during Schiff base formation was the rate determining step, whereas in lower a w , Schiff base decarboxylation was the rate-determining one.…”

“…Very slight promoting effect of water activity on acrylamide amount was found in an asparagine-glucose model system (De Vleeschouwer et al 2007, De Vleeschouwer, van der Plancken, van Loey, & Hendrickx 2008. The opposite trend was found in aqueous glycerol asparagine model system, revealing a decrease in acrylamide formation with increasing water activity (Hedegaard et al 2007). The same tendency was observed in real food (cake) where acrylamide formation did not occur in a large extent when moisture content was higher than 5% (Elmore et al 2005).…”

“…)), it is difficult to separate the influence of each parameter in acrylamide formation/degradation reactions during frying. In this context, for many studies, experimentations were performed in closed reactor allowing the identification of the impact of each parameter (De Vleeschouwer, Van der Plancken, Van Loey, & Hendrickx 2007, Hedegaard, Frandsen, Granby, Apostolopoulou, & Skibsted 2007. The effect of water activity on acrylamide formation remains unclear and sometimes contradictory, because the experimental procedures and the physical state of the reactants reported in the literature vary considerably.…”

Acrylamide and 5-hydroxymethylfurfural (HMF): A review on metabolism, toxicity, occurrence in food and mitigation strategies

“…Single-response models based on empirical overall reaction kinetics have been extensively used. Acrylamide formation has been thus modeled as a first order reaction (Gökmen & Senyuva, 2006a;Hedegaard, Frandsen, Granby, Apostolopoulou, & Skibsted, 2007), as a pseudo-first order reaction (Amrein, Limacher, Amadò, & Escher, 2006) or as a second order reaction (De Vleeschouwer, Van der Plancken, Van Loey, & Hendrickx, 2006) according to reaction conditions and reactant concentrations. Acrylamide elimination has been usually modeled as a first order kinetics (Biedermann, Biedermann-Brem, Noti, & Grob, 2002;Gökmen & Senyuva, 2006a).…”

Technological Strategies to Reduce Acrylamide Levels in Heated Foods

“…Acrylamide formation is affected by many factors, such as precursors (i.e., reducing sugar and asparagine) concentration, pH, water content and activity, physical state of the food, and process parameters, mainly represented by the heating time and temperature [12, 28,48,57,60,62,69,70,77]. For instance, acrylamide formation is favored by a high heating temperature and time, as well as pH values, a relatively low water content and activity.…”