The Impact of Parbaking on the Crumb Firming Mechanism of Fully Baked Tin Wheat Bread

The impact of parbaking on the quality and shelf life of large tin bread baked from 270 g of wheat flour was investigated using a proton nuclear magnetic resonance method combined with techniques that measure at different length scales. With increasing partial baking time, the resilience of fresh partially baked crumb increased because of its more extended amylose and gluten networks. During subsequent storage, the crumb became more firm due to an increased extent of amylopectin retrogradation and moisture redistribution. Although only amylopectin retrogradation was reversed during final baking, a fresh fully baked (FB) bread with reversed crumb softness was obtained. Furthermore, the rate of crumb firming during final storage of FB bread was not higher than that of conventionally baked bread. This was attributed to the high crumb to crust ratio of large tin bread which caused the crumb moisture content to remain sufficiently high despite nonreversible moisture redistribution during intermediate storage.