lab-applesensymaticbrowning - Enzymatic Browning...

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Enzymatic Browning Polyphenoloxidase Group Members: Katie Van Camp Pamela Katz Eric Wilson Date Performed: February 25, 2008 FSN 364 Food Chemistry Lab Section 03 Mondays 9-12 a.m. Food Science and Nutrition Department, College of Agriculture Food and Environmental Sciences, Cal Poly, San Luis Obispo
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Introduction Enzymatic browning is caused when fruits, vegetables, and shellfish are cut or bruised, and therefore exposed to air, the enzyme that catalyzes the reaction is polyphenol oxidase (see Figure 1). (Montecalvo, 2000) The enzyme that is responsible for the brown color formation, quinones and meladonins, is tyrosinase. Enzymatic browning is usually an undesirable effect and some ways to stop the action of the enzymes are to inactivate with heat, chemical inhibition (sulfites), removal of oxygen, or the use of reducing agents. This experiment showed the rates of enzymatic browning in various treatments of distilled water, 1% thiourea, ascorbic acid, and 0.1% sodium sulfite. The solutions were then analyzed spectrophotometrically and compared. (Paul Grotheer, 2005) Figure - Enzymatic Browning Reaction Catalyzed by Polyphenol Oxidase Materials and Methods Materials: 2 Granny Smith Apples 1% thiourea Ascorbic acid Sodium sulfite Deionized water Spectrophotometer Buchner Funnel Whatman No. 1 filter paper
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Blender Handheld filter (pneumatic) 150 ml beaker (5) Methods First cut up both Granny Smith apples in to small pieces (1/8 inch), and remove skin.
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