Chemical and physical changes in baked products during storage
Abstract
The purpose of this study was determine the mechanism responsible for spontaneous breakage in cracker. The approach was to study the effect of moisture and storage time on the finished cracker as well as on the major components, starch and gluten. Cracker breaking strength was measured as an indication of likely check formation and it was discovered that breaking strength predictably decreased over storage time. Microscopic determinations of proton mobility within the macromolecules paralleled the effect of moisture on breaking strength in that the increase of proton mobility with moisture increase reflected the loss of strength with moisture uptake. Using electron microscopy it was found that volume changes are evident as a result of sorption. Finally, models were developed that predicted moisture movement through the cracker during baking and storage as well as moisture movement through an individual starch granule coated with gluten following a change in environment. The models give us the knowledge that during hydration of cracker, there will be rubbery and glassy regions coexisting on the scale of the cracker as well as on the scale of macromolecules, starch and gluten. The hypothesis supported by this work is that moisture affects the starch and gluten in such a way as to cause an overall weakening of the cracker structure.
Degree
Ph.D.
Advisors
Okos, Purdue University.
Subject Area
Agricultural engineering|Food science
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