Inactivation of peroxidase, pectinesterase and alkaline phosphatase in polymers as a model for irradiation of dried foodstuffs

This thesis consists of a summary only of 6 refereed scientific papers published in Lebensmittel -Wissenschaft und -Technologie 3, 37-40 (1970); 4, 24-26, 93-96, 158-162, 196-200 (1971); 5, 128-131 (1972).Aqueous solutions containing an enzyme (peroxidase, alkaline phosphatase, pectinesterase) and a polymer (carboxymethylcellulose, soluble starch, poIyvinylpyrrolidone, sodium pectate) were freeze-dried. The systems thus obtained were incubated over saturated salt solutions at various levels of water activity. They were then irradiated by an electron generator. The storage and radiation sensitivity of the enzymes depended on the polymer used in the model, the enzyme concentration, the humidity and the pH.