Novel immobilization technique for food enzymes

Enzyme was introduced for industrial application as early as nineteenth century. Immobilized enzymes have been developed since early 1960s. In recent years, immobilized enzymes have expanded their applications in many fields, food industry in particular, thanks to their superiority over the soluble forms: multiple or repetitive use; easier separation from reaction system; continuous production process; longer half-life and predictable decay rates.;A new immobilization technique has been developed in our lab using a new inert support material. Immobilized enzymes by the new method have a number of salient features of high activity, low cost and large catalytic area in comparison with the traditional immobilized enzymes. This new immobilization technique has potential to be widely applied for other enzymes.;In this thesis, I have established the optimal immobilization conditions for three food enzymes, glucose isomerase, glucoamylase and lactase. The parameters including temperature, pH, protein capacity, and the ratios of cross-linker and adsorption agent have been studied in details. The applications of the consequently produced immobilized enzymes were studied and compared with the current industrial processes.;The novel immobilized glucose isomerase was applied to convert corn glucose into High Fructose Corn Syrup (HFCS) containing higher concentration of fructose than the current HFCS and achieved much better productivity than the existing immobilized glucose isomerases.;Glucoamylase was also immobilized by the method. The differences between soluble and immobilized enzyme were compared. The potential using the immobilized glucoamylase in production of glucose syrup in replacement of liquid glucoamylase in current industrial process was assessed.;Another new application of the immobilization method is to produce low lactose milk using immobilized lactase. A large population of people, especially the Asian, has intolerance to milk because of the lack of lactase in intestines. Pre-treatment of milk with immobilized lactase effectively reduces the milk lactose to an acceptable level for those people.