INVESTIGADORES
CUKIERMAN Ana Lea
artículos
Título:
Residual moisture content and collapse of freeze-dried sugar matrix.
Autor/es:
P. R. BONELLI; C. SCHEBOR; A. L. CUKIERMAN; P. BUERA; J. CHIRIFE
Revista:
JOURNAL OF FOOD SCIENCE
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 1997 vol. 62 p. 693 - 695
ISSN:
0022-1147
Resumen:
Amorphous sugars were prepared by freeze-drying 20% (w/w) aqueous
solutions of lactose, sucrose, trehalose and maltose. The dried samples
were further dehydrated over P2O5 for 1 wk at 25, 35 or 45 C, and the
residual moisture content was determined using oven drying or a thermogravimetric
balance. Results indicated a small amount of residual
moisture (usually 1?2%) which was not removed by the desiccation
treatment for 1 wk at 25 C over P2O5. The dried samples, heated at a
temperature near the published ??anhydrous?? glass transition temperatures
(Tg) exhibited different behavior depending on whether they were
heated in open or sealed vials. Structural collapse, a sharply visible
shrinkage of the matrix, was found in all samples in sealed vials, while
those samples in open vials did not collapse. Thus, removal of the last
amount of residual moisture by heating in uncovered vials increased Tg,
preventing or delaying collapse.