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

Abstract

Hysteresis phenomena of four basic focd compounds (amylose, amylopedin, casein, and cellulose) were studied affer 9 days eguilibtion in descicators at 2BC. Adsorption experiments starfed from 2% moisture content and desorption from wetted samples with excessive rnoistu~. In starch and prorein, the hysferesk occurred in the middle range of the sorption isotherm in the range of 10 - 90% RH and no hysteresis at the lowest and highest mges of RH. While in cellulose hysteresis started at about 10% RH and was increasing to the saturated RH. Analyses of stratified bound water using sorption isotherm data revealed that from the four samples, the desotption monolayer and secondary bound water fractions were higher than those of adsorption. However, the tertiary bound water fractions of desorption were lower than fhose of adsorption, except from the cellulose sample.