Impact of Humidified Baking on Crust and Crumb Properties of Open Bread during Storage

Abstract

Humidified baking was investigated in the light of producing breads envisaged to have better quality and freshness. Open bread loaves were prepared using the straight dough method where baking was performed with or without humidity at three levels of temperatures of 185, 195 and 205℃, and baking times of 25, 30 and 35 min. Baked breads were evaluated by measuring its crust color and thickness, and bread crumb moisture content and firmness. Humidified baking has no significant effect in enlightening bread crust color (P > 0.05) but significantly reduced the crust thickness (P < 0.001) and increased the initial moisture content (IMC) of bread crumb. The higher IMC of bread crumb led to a higher final moisture content (FMC) of bread during storage and these helped to reduce the firming rate of bread during a 96 h storage especially for the lower baking temperatures and times. Significant differences (P < 0.001) were observed on crust color and thickness, and bread crumb moisture content and firmness as effect of baking temperature and time.Keywords: bread, humidified baking, crust, crumb *To whom correspondence should be addressed. E-mail: chinnl@eng.upm.edu.my IntroductionBaking is an eminent step in a breadmaking process as it highly contributes to the setting and changes of bread's organoleptic and physico-chemical properties. With simultaneous heat and mass transfer processes occurring during baking, dough experiences changes which lead to the transformation of raw dough to bread through a series of physical, chemical and structural transformations which include starch gelatinization, protein denaturation and coagulation, volume expansion, and browning reactions (Mohd. Jusoh et al., 2009;Zanoni et al., 1993).Apart from transforming inedible raw dough to soft, moist and palatable porous bread structure, baking process is also responsible in controlling the moisture content in bread. In conventional baking, the relationship of moisture content is reciprocal to the baking temperature and time (Wagner et al., 2007;Baik and Marcotte, 2002;Faridi and Rubenthaler, 1984). An appropriate amount of moisture content is required in bread to prolong its shelf-life. Higher moisture content is proven to assist in slowing down the rate of crumb firming (Baik and Chinachoti, 2002;Faridi and Rubenthaler, 1984). Crumb firming is the condition which the crumb becomes dry and crumbly resulting in gradual reduction of bread eating properties, or more commonly described as bread staling. The common causes for bread staling are starch retrogradation, proteins and protein-starch interactions and moisture migration (Gomes-Ruffi et al., 2012; Gray and Bemille, 2003). Crumb firming is unavoidable, however it can be slowed down by adding bread emulsifiers, enzymes or hydrocolloids in the bread recipe. Complex interaction between bread emulsifiers and enzymes with the flour components improves bread quality and assists in retarding crumb firming (Gomes-Ruffi et al., 2012;Purhagen et al., 2011). He and Hoseney (1990) and Faridi and Rubentha...