Browsing by Subject "isomaltuloosi"

The scope of the literature review was to define the physical properties and crystallization of amorphous sugars as single substances and mixtures. The purpose of the experimental part was to measure the water sorption, glass transition and crystallization of sucrose, isomaltulose and different mixtures of both. Crystallization and water sorption was measured with Dynamic Vapour Sorptions (DVS) -system, and with a differential scanningcalorimeter (DSC). Water sorption was studied by weighing samples that were stored at different relative humidities (11 - 85 %). Crystal forms were studied with the x-ray diffraction method. The sucrose samples reached a stable-state at relative humidities of 11-33% in one day of storage. The same was true for isomaltulose samples. Mixtures adsorbed more water the higher the relative humidity. Mixture samples reached a stable state in a day of storage at relative humidities of 11 - 44 %. Water sorption was modelled with the BET-model. The glass transition temperature, measured with DSC, of anhydrous sucrose was measured at 57 ºC. The glass transition temperature of anhydrous isomaltulose was slightly lower 47 ºC. The glass tranition temperature of a mixture sample, at 0 % relative humidity, was in between those two, 50 ºC. The glass transition temperature of sucrose was higher than that of isomaltulose after storage at relative humidities of 11 - 33 %. The critical water content of sucrose and mixture was 3, for isomaltulose it was 2 (g water/100 g solid). The critical storage humidity for sucrose was 25 %, for isomaltulose and mixtures it was 20 %. In testing with DSC sucrose was the only sample to crystallize. The higher the storage relative humidity before testing, the lower the crystallization temperature was for all sucrose samples. Crystallization temperature test run with the DVS system showed that sucrose crystallized at lower relative humidity than a mixture. Pure sucrose and mixtures did not share any reflection angles in x-ray diffraction tests, but isomaltulose and mixtures shared many reflection angles. This led to the conclusion that the mixtures contain more isomaltulose crystals than sucrose crystals. Adding isomaltulose to sucrose did not have a large effect on glass transition temperatures. Glass transition temperatures for mixtures were inbetween sucrose and isomaltulose. Isomaltulose however retarded crystallization greatly. The mixture required a significantly higher relative humidity in order to crystallize than either sucrose or isomaltulose.