Browsing by Author "Hayward, Stefan"

Now showing 1 - 3 of 3
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    Degradation of proteins and starch by combined immobilization of protease, α-amylase and β-galactosidase on a single electrospun nanofibrous membrane
    (MDPI, 2019-01-31) Cloete, William J.; Hayward, Stefan; Swart, Pieter; Klumperman, Bert
    Two commercially available enzymes, Dextrozyme (α-amylase) and Esperase (protease), were covalently immobilized on non-woven electrospun poly(styrene-co-maleic anhydride) nanofiber mats with partial retention of their catalytic activity. Immobilization was achieved for the enzymes on their own as well as in different combinations with an additional enzyme, β-galactosidase, on the same non-woven nanofiber mat. This experiment yielded a universal method for immobilizing different combinations of enzymes with nanofibrous mats containing maleic anhydride (MAnh) residues in the polymer backbone.
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    Partial characterization of a bacterial acyltransferase enzyme for potential application in dairy processing
    (Stellenbosch : Stellenbosch University, 2014-04) Hayward, Stefan; Swart, Pieter; Stellenbosch University. Faculty of Science. Dept. of Biochemistry.
    ENGLISH ABSTRACT: This study describes: the evaluation of the current, and potential assay methods for the quantification of cholesterol, cholesteryl esters and free fatty acids in milk and the application thereof ; an account of the difficulties associated with the usage of FoodPro® Cleanline, an enzyme preparation used as processing aid, during ultra-high temperature processing of milk ; the development of activity assays which can be used for the kinetic characterization of glycerophospholipid cholesterol acyltransferase, the active enzyme in FoodPro® Cleanline ; the development of an accurate and facile activity assay, and the validation thereof, which can be used for the validation of enzyme activity prior to dosage of milk with FoodPro® Cleanline.
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    Partial characterization of lentil seed lipoxygenases and their impact in wheat (Triticum aestivum L.) bread making
    (Stellenbosch : Stellenbosch University, 2017-03) Hayward, Stefan; Swart, Pieter; Cilliers, Tertius; Stellenbosch University. Faculty of Science. Dept. of Biochemistry.
    ENGLISH ABSTRACT: This study describes: 1. The evaluation of lentil seed flour as an alternative for soybean seed flour; as a source of lipoxygenase during the making of white bread. 2. The development of efficient, and reproducible methods for the purification of lentil seed lipoxygenase from flour. 3. An evaluation of the current methods for the quantification of products from lipoxygenase-catalyzed reactions, and the adaptation of these methods to enable high-throughput screening and kinetic analysis of lipoxygenase. 4. The kinetic and molecular characterization of lentil seed lipoxygenase with specific mention to the down-stream implications when used in the bread-making process. 5. The application of lentil seed extracts, and purified enzyme solutions in baking trials.