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Bread staling: I.—Experimental study
Author(s) -
Willhoft E. M. A.
Publication year - 1971
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740220406
Subject(s) - gluten , starch , moisture , food science , retrogradation (starch) , chemistry , absorption of water , starch gelatinization , chemical engineering , materials science , composite material , amylose , organic chemistry , engineering
Starting with a typical baker's dough, a model system was constructed in order to examine whether moisture re‐distributed itself between the two principal components, gluten and starch, of crumb during ageing. Separation of the components of dough was achieved by ultra‐centrifugation. It was estimated that up to 30% of the moisture associated with the gluten fraction, migrated to the starch during 120 h of storage of the baked system at 25°c. The rate of migration decreased approximately exponentially with time. Moisture from the gluten was also found to migrate to the starch during baking, but at an accelerated rate. The rate of moisture migration in the model system, both at 100 and 25°c, was consistent with a diffusion‐controlled process involving migration of the gluten‐released moisture to the gluten‐starch interface. Experimental results show that staling of bread involves (in addition to the generally accepted retrogradation of the starch) an irreversible modification in the water structure of the gluten, leading to the formation of labile water, which becomes available for absorption by the incompletely gelatinised starch. Since the gluten forms the continuous matrix of the crumb, the modification results in a rigidification or firming process.