Mathematical modeling the kinetics of freezing/thawing of the bread dough with fibres

Abstract

More and more consumers are interested in fiber enriched bakery products, but market is lacking commercial fibers that are meeting needs of bakery industry and consumer taste. The objective of this research is to present the mathematical analysis of the influence of different commercial fibers (originating from sugar beet pulp Fibrex, and Jerusalem artichoke inulin HPX and GR) in dough at the level of 0 %, 5 % and 10 %, on kinetics of freezing and thawing. Dough freezing/thawing kinetics was determined at -28 ̊C and +30 ̊C, respectively. Fibers type and quantity are influencing the slope of freezing curve but not the trend of the freezing curve. Related to the control, the presence of fibers in dough prevents the formation of the solid phase. Freezing/thawing process of dough is defined by the Fourier's equation and tested with three approximations. Experimental data correspond the best to unsteady temperature profile, with introduced value of t 2 referring to the phase transformation, proved by determination coefficient. At freezing/thawing the highest determination coefficient is experienced with 10 % of inulin GR (0.975 and 0.985), and the lowest with 10 % of fibrex (0.946 and 0.951). Pertinent data point at the possibility of mathematical interpretation of freezing/thawing processes, at defined temperatures, that is of a particular interest for the bakery practice, thus positively contributing to automatization and computing of the freezing and thawing process at the temperatures experienced in the bakery industry. © 2012 University of Bucharest.