Acid hydrolysation of starch and formulation of starch microspheres

Sammanfattning: The aim of this diploma work is to investigate the acid hydrolyses of two types of starch, waxy barley and maize starch to be applied for further usage, in rheology studies and formulation of starch microspheres. Modified starch has always been essential in many areas, especially in tablets, where it could be used as a disintegrant. Starch has also been investigated for manufacturing microspheres. In difference from previous work in the pharmaceutical technology (Elfstrand,2006a) ‘’ from starch to starch microsphere’’, where starch microspheres were used for the encapsulation of protein drugs, starch is in this thesis was used to encapsulate yeast cells. According to this diploma work the two starches that are acid hydrolysed have shown different rheological behaviour. The parameters that are found to affect the rheology behaviours of the starches are temperatures during acid hydrolysis, time, and type of starch. Light microscopy shows that waxy barley starch exhibited a regular spherical structure whereas maize starch has spheres with irregular structure and it also shows that morphology of the starches are intact after acid hydrolysis. Waxy barley starch consisting almost of amylopectin, is easy to gelatinize and solubilized in aqueous medium with the method used for heating in this work (microwave Owen). Formulation of starch microspheres is investigated according to the methods described by Elfstrand.Light microscopy is used to discover if there are microspheres produced. Microspheres could be produced by acid hydrolysed waxy barley starch but not from the maize starch.Waxy barley starch is selected for further studies, where yeast cells are encapsulated.There are indications that yeast cells could be encapsulated or at least that the presence of yeast did not disrupt the formation of microspheres. In conclusion, and regarded to this diploma work waxy barley is the more suitable type of starch to be used since granules are easy to swell and solubilize and do form m