Fenomena Histeresis Isotermi Sorpsi Air Pada Granula Pati Amilosa Granula Pati Amilopektin, Protein, dan Selulosa

Abstract

Hysteresis phenomena of four basic food compounds (amylose, amylopectin, casein, and cellulose) wete studied after 9 days equilibration in c/escicetors at 280C. Adsorption experiments started from 2% moistutecontent and desorption ft:om wetted samples with excessive moistute. In starch and protein, the hystetesi$ occurred in the middle tenge of the sorption isotherm in the tenge of 10 - 90% RH and no hysteresi$ at the lowest and highest ranges of RH. While in cellulose hysteresis started at about 10% RH and was incteasing to the saturated RH. Analysas of stratified bound water using sorption isotherm data tevealed that from the four samples, the desorption monolayer and secondary bound water fractions wete higher than those of adsorption. However. the tertiary bound water fractions of desorption wete lower than those of edsorption, except from the cellulose sample. Key words: Hysteresis, isotherm, starch, protein, and cellulose