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Dynamic Mechanical Analysis for Glass Transitions in Long Shelf‐Life Bread
Author(s) -
HALLBERG L.M.,
CHINACHOTI P.
Publication year - 1992
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1992.tb11299.x
Subject(s) - glass transition , dynamic mechanical analysis , moisture , materials science , viscoelasticity , shelf life , composite material , hardening (computing) , water content , thermal analysis , thermal , polymer , chemistry , food science , thermodynamics , layer (electronics) , geology , geotechnical engineering , physics
Dynamic Mechanical Analysis (DMA) showed three thermal transitions in meal, ready‐to‐eat (MRE) bread, resulting in various degrees of change in the viscoelastic property. The moisture‐dependent transition at an extremely low temperature (‐90°C to – 50°C) was due to humcctants added, while that at a higher temperature T1 was possibly due to ice melting and the polymer components. T1 increased from ∼−10°C at 29% moisture to ∼ 150°C as moisture decreased to 2%. This correlated with hardening of the sample. A moisture independent transition at ∼ 10‐15°C by DMA was identified as a melting process of lipids (shortening). During storage, the magnitude of tan 8 peak decreased but its peak temperature did not change. No evidence of any network could be observed by DMA throughout 3 yr storage.