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Lipid Oxidation FDSC400
Types of Rancidity Hydrolytic rancidity –Lipase –Free fatty acids provide aroma Oxidative rancidity –Radical oxidation –Aldehydes and other compounds provide aroma
Oxidative Rancidity Part 1: Form lipid hydroperoxides Part 2: Break down lipid hydroperoxides
Oxidative Rancidity Initiation –A radical is formed Propagation –Radicals react and transfer their unpaired electron to other compounds Termination –Two radicals combine to stop the reaction
The Pentadiene Structure RHR H. …Radical Migration
Addition of Oxygen - Propagation - R+O 2 ROO ROO +RHROOH+R.... Each methylene interrupter can lead to three possible lipid hydroperoxides!
Part 2: Hydroperoxide Breakdown (1) (2)
Factors affecting rate Fatty acid composition Temperature Water activity Metal ions Oxygen Light
Antioxidants Metal chelators citrate, EDTA Radical scavengers (primary and secondary) BHA, BHT, tocopherol
Radical Scavenging Antioxidants
e.g.: 3 PUFA Supplemented Yogurt w3 oil water w3 emulsionmilkCulture ingredients Pasteurize Homogenize Pack Ferment Store Pasteurize Store/ship Homogenize
Oxidative Rancidity A mechanistic look at this reaction Go to Slide Show mode and click to begin.
Reactions of Oils and Fats
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Antioxidants. Oxidation of food Oxidation reactions can occur when food is exposed to oxygen in the air. Foods containing fats or oils are at the greatest.
Isabelle Yang Antioxidant Assay Selection. Generally: Oxidation is loss of electrons.
CHEMICAL DEGRADATION Whilst all polymers will be attacked by certain chemicals it is the reactive chemicals in the atmosphere which must be considered.
Fats & Oils AL Chemistry p. 1 Structure & Properties Hydrolysis of Fats & Oils Iodine Value Hardening of Vegetable Oil Hydrolytic & Oxidative Rancidity.
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Benzene and Its Derivatives
Phenolic antioxidation Go to Slide Show mode and click the big red button.
Oxidation/Reduction & Batteries. Oxidation Combining with Oxygen – combustion Gives off energy Oxidation in the body – H 2 O and CO 2 Oxidation in an.
(D) The Chemistry of Cooking and the Oxidation of Food
ADVANCED BIO-FRIENDLY POLYMERS György Kasza Thermal, antioxidative and photochemical stabilization of polymers: low molecular weight versus macromolecular.
Food Chemistry Chapter 17 in Green / Damjii Chapter X in Nuess Chapter X in Oxford Study (no resource in Chang)
The most important structural feature of an atom for determining behaviour is the number of electrons in the outer shell. A substance that has a full.
Lipid Oxidation The overall mechanism of lipid oxidation consists of three phases: (1) initiation, the formation of free radicals; (2) propagation, the.
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Element Elements and Compounds Structure of Atom Compounds A compound is a substance composed of two or more elements, chemically combined with one another.
Chapter 13 Part 2 Benzene and its Derivatives Benzene and its Derivatives.
Aromatic Compounds Aromatic compound: a hydrocarbon that contains one or more benzene-like rings. arene: a term used to describe aromatic compounds. Ar-:
Oxidants and Aging Rolf J. Mehlhorn Lawrence Berkeley Laboratory
Writing & Balancing Equations Types of Reactions.
BETHY NGUYEN CHEMISTRY 12B SPRING, INTRODUCTION Green tea is natural dried leaves of the tea plant, camellia sinensis. Green tea is natural dried.
Effect of frozen storage time and temperature on quality of Atlantic mackerel (Scombrus scomber) Paulina E. Wasik PhD student Matís ohf. & University of.
Types of Chemical Weathering. Carbonation Carbonation- the reaction between calcite and weak acids in rain water and acids in groundwater. Rocks that.
Also called fat – are a family of chemical compounds that are a main part of every living cell.
1 CHM 585 /490 Chapter 12 Additives 2 Chapter 12 Additives Antioxidants UV stabilizers Antistatic Agents Peroxides Lubricants FR Heat stabilizers.
CHAIN POLYMERIZATION Free Radical Polymerization Free radical are independently-existing species that have unpaired electron. Normally they are highly.
UV light H removed 1. Formation of cross-links between fatty acid molecules The carbon chain becomes a radical: INITIATION 2.
Nature’s Chemistry Oxidation of Food.
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Free radicals and Antioxidants. Objectives Basics of Redox Chemistry. Heterolytic and Homolytic fission. Free Radical meaning. Important characteristics.
© 2003 Thomson Learning, Inc. All rights reserved General, Organic, and Biochemistry, 7e Bettelheim, Brown, and March.
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