Model development for fresh baked bread natural and forced cooling
2011
Pastukhov, A., University of Reading (United Kingdom). Dept. of Food and Nutritional Sciences | Danin, V., St. Petersburg State Univ. of Low Temperature and Food Technologies (Russian Federation)
Industrial production of bakery products allows consumers to get fresh bread at any time of the day. However, there are many problems connected with storage and cooling of bread before distributing it to the trading network. Microbiological safety requirements and marketing necessitates the packaging of bread into films after baking. However, this is only possible when the baked bread has cooled. Rate of cooling is, therefore, very critical parameter. Low cooling rates can limit production capacity in a bakery, while higher cooling rates can lead to higher moisture evaporation rate and result in greater weight loss of the product. The moisture distribution in bread at the end of cooling can also result in water condensation on the film, which can accelerate fungal growth. The principal objective of this work is to study the effect of cooling conditions on heat and mass transfer in bread, and asses their influence on product quality. Experiments were carried out with white pan bread which was prepared in a laboratory. Cooling was undertaken in ambient environment (26±2 deg C, RH 50 %) by placing the hot product on a rack, as well as in a climatic cabinet with controlled temperature, humidity and level of convection. A mathematical model based on Fourier's second law for heat transfer and the Fick's second law for the mass transfer was developed to simulate heat and mass transfer processes in the bread during cooling, and validated using experimental data. The model is able to predict mass and volume changes during the ''cooling'' time.
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