Baking kinetics of muffins in convection and steam assisted hybrid ovens (baking kinetics of muffin...) Melike Sakin-Yilmazer a,⇑ , Tansel Kemerli c , Hilal Isleroglu a , Ozgul Ozdestan a , Gonul Guven b , Ali Uren d , Figen Kaymak-Ertekin a a Ege University, Faculty of Engineering, Food Engineering Department, 35100 Izmir, Turkey b Ministry of Food, Agriculture and Livestock, Izmir Food Control Laboratory, 35100 Izmir, Turkey c Gebze Institute of High Technology, Faculty of Engineering, Chemical Engineering Department, Kocaeli, Turkey d Avrasya University, Faculty of Engineering and Architecture, Food Engineering Department, 61250 Trabzon, Turkey article info Article history: Received 10 April 2013 Received in revised form 4 June 2013 Accepted 15 June 2013 Available online 26 June 2013 Keywords: Acrylamide Steam baking Drying Hybrid oven Kinetic modelling abstract Effects of oven type and baking temperature on acrylamide concentration, surface browning, temperature profiles and drying rates of muffins were investigated. Muffins were baked in convection and steam assisted hybrid ovens at 145, 160 and 175 °C for different baking times. For all oven types, the acrylamide concentration of muffins increased with increasing baking time and temperature (p < 0.05). The forma- tion was considered as the first order reaction kinetics except for the lowest baking temperature at nat- ural convection and steam assisted hybrid ovens. The reaction rate constant, k was found to be in the range of 0.027–0.078 (min 1 ). For the forced convection oven, the effect of baking temperature on acryl- amide concentration followed the Arrhenius type of equation; with activation energy of 36.35 kJ/mol. The minimum drying rate was observed by the steam assisted hybrid oven, at all conditions. Steam assisted baking resulted in lower acrylamide concentration at all baking temperatures, while providing the aver- age moisture content not significantly different. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Since acrylamide has been introduced as carcinogen/mutagen by IARC (1994) and its formation in baked/fried/cooked food had been introduced by Swedish National Food Agency (2002), this finding caused worldwide concern (World Health Organization, 2002). The observed wide variations in levels of acrylamide in dif- ferent food categories as well as in different brands of the same food category appear to result not only from the amounts of the precursors present but also from variations in processing condi- tions (e.g., temperature and time of processing; pH, moisture con- tent, reactant concentrations, nature of food matrix) (Barutcu et al., 2009; Samuelson, 2003; Shaikh et al., 2009; Weiss, 2002). The formation mechanism starting from heat induced reactions between the amino group of asparagine and the carbonyl group of reducing sugars had been given, previously (Mottram et al., 2002; Stadler et al., 2002; Zhang et al., 2005; Zyzak et al., 2003). The level in foods (Ahn et al., 2002; IRMM, 2013; Ono et al., 2003), its toxi- cological properties (EC SCF, 2002; Friedman et al., 1995), its for- mation and degradation kinetics depending on process time and temperature (Claeys et al., 2005a; Claeys et al., 2005b; De Vleesc- houwer et al., 2009; Gökmen and Senyuva, 2006; Knol et al., 2005; Summa et al., 2006; Wedzicha et al., 2005) had been the sub- ject of researches for more than one decade. The kinetic modelling studies of acrylamide formation by Baisier and Labuza (1992), De Vleeschouwer et al. (2006, 2008, 2009), Knol et al. (2005), Martins and Van Boekel (2005) has been shortly reviewed by Isleroglu et al. (2012). Surface colour and the acrlyamide concentration have been cor- related in different foods undergoing thermal process (cooking, baking, ...)(Amrein et al., 2006; Lukac et al., 2007; Mustafa et al., 2005; Pedreschi et al., 2005, 2006; Senyuva and Gokmen, 2005; Surdyk et al., 2004). The correlation was generally confirmed by using CIE L  a  b  colour system parameters. By a research on po- tato chips, a linear correlation has been found between the acryl- amide concentration and the surface colour represented by the redness component a  at frying temperatures of 120, 150 and 180 °C for up to 5 min of process (Pedreschi et al., 2005). In another study, changes in both acrylamide levels and CIE a  parameter of green coffee, wheat flour and potato chips during heating at rela- tively higher temperatures followed a typical kinetic pattern with an initial increase to an apparent maximum followed by a subse- quent decrease (Gökmen and Senyuva, 2006). With the popularity of such recent findings on food components and its direct relation with human health, the society has been in a 0260-8774/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jfoodeng.2013.06.019 ⇑ Corresponding author. Tel.: +90 232 3113039; fax: +90 232 3427592. E-mail address: melike.sakin@ege.edu.tr (M. Sakin-Yilmazer). Journal of Food Engineering 119 (2013) 483–489 Contents lists available at SciVerse ScienceDirect Journal of Food Engineering journal homepage: www.elsevier.com/locate/jfoodeng