ABSTRACT

Contrary to the [regular] thick bread, the thin flatbread is consumed in few countries, which explains the scarcity of published research on this type of bread. The present work aims to investigate experimentally and numerically the effect of different heat flux profiles on temperature field and moisture content in the thin flatbread during the baking process, as well as their effect on the quality of the final baked bread. In order to investigate the effect of different heat flux profiles during the baking process, a machine built on a laboratory scale is used to bake the bread pieces used as samples in this experiment. Heat and mass transfer equations are modeled numerically using the finite difference method. The equations are discretized using the finite difference method and solved using the unconditionally stable transient implicit method implemented in MATLAB. Also, the energy required for baking is measured and compared for different heat flux profiles. Reasonable agreement is observed between the experimental and numerical results. Three different heat flux profiles, namely constant, descending, and ascending profiles, are evaluated experimentally and numerically, and the baked pieces of bread are subjected to sensory evaluation as well as colorimetry. It is observed that the baked bread samples subjected to the ascending profile are of a better quality due to the uniform and proper heating during the baking process. It is also observed that the type of heat flux profile affects the final bread quality and determines the energy consumption of the process.

摘要

与[常规]厚面包相反，很少有国家食用这种薄面包，这解释了已发表的有关这种类型面包的研究的稀缺性。本工作旨在通过实验和数值研究在烘烤过程中不同热通量分布对薄面包中温度场和水分含量的影响，以及它们对最终烘烤面包质量的影响。为了研究烘焙过程中不同热通量分布的影响，使用了实验室规模的机器来烘焙在本实验中用作样品的面包块。使用有限差分法对传热和传质方程进行数值建模。使用有限差分法将方程离散化，并使用MATLAB中实现的无条件稳定瞬态隐式方法进行求解。同样，测量烘烤所需的能量并针对不同的热通量曲线进行比较。实验和数值结果之间观察到合理的一致性。实验和数值评估了三种不同的热通量曲线，即恒定，下降和上升曲线，并对烘焙过的面包片进行了感官评估和比色法。可以看出，由于在烘烤过程中均匀且适当地加热，经受上升轮廓的烤面包样品具有更好的质量。