Download Beneficial Effects of Omega-3 Polyunsaturated Fatty Acids

The concern with n-3 Lipid Oxidation
Alexandria B. Marciante
Dr. Steve Talcott
• Used as an additive in food products and
supplements to support metabolic functioning
and prevention of diseases, including cancer and
cardiovascular disorders.
• A highly nutritive and beneficial n-3 fatty acid is
omega-3 polyunsaturated fatty acids.
• Can be used for treatment of depression and
schizophrenia.
(Polyunsaturated fatty acids)
• Result from low temperature acclimatization and transfer
to sea water, to form fish oils
• Two most common and most nutritive types are long-chain
eicosapentaenoic fatty acid (EPA) and docosahexaenoic
fatty acid (DHA)
• Most effective in the case of fatal cardiovascular disease
and prevention of progression in some stages of cancer
• Essential for growth and energy, organ differentiation, and
immune function.
Long-chain Fatty Acids
• Although these have many benefits and are
essential for growth and health, the debate to use
these in food systems is challenging.
• The longer the chain and the higher the degree of
unsaturation in a fatty acid, the less energy is
needed for lipid oxidation; which is caused by a
catalytic event and has negative effects.
The oxidative deterioration of lipids containing a number
of carbon-carbon double bonds.
•Has an initiation, propagation, and termination sequence
• Initiation: caused by a catalytic event (light,
temperature, air, etc.)
• Propagation: cocktail of radicals formed, including
peroxyl radicals and reactive oxygen species (ROS),
causing another initiation step
• Termination: addition of oxidation inhibitors (like
antioxidants) that terminate propagation
The chemistry of why degree of unsaturation influences the
rate of lipid oxidation.
• Initiation step
•Hydrogen is abstracted in the presence of initiator
• alkyl radical formation allows radical delocalization across
the double bond
• Propagation step
• addition of oxygen to the alkyl radical to form the peroxyl
radical which has higher energy than alkyl
• peroxyl radical abstract H from another PUFA to produce
LOOH and a new alkyl radical
• Termination
• interaction of two free radicals to form non-radical species
Detecting volatile by-products
• Thiobarbituric Acid (TBA) reactive substances
are used to detect aldehydes in a variety of
food products, using malondialdehyde (MDA)
• Gas chromatograph can be used for further
analysis to quantify ketones, peroxides,
alcohols and other by-products
• Lipid oxidation can result in the production of
off flavors and smells that are undesirable to
consumers.
• Oxidation can also interfere with normal
metabolic functioning and can be toxic from the
formation of free radicals.
• Reduction in nutritional value of lipidcontaining food products.
Protection of PUFA’s from light and heat damage
• Provides more prolonged shelf life by using
encapsulating agents like milk protein, gelatine,
modified starch, etc. and is determined based
on capacity to stabilize and protect the oil from
degradation during processing and storage
conditions
• Freeze-drying is the most cost effective
method
Anti-oxidative compounds
• Compounds known to function as scavengers in 1
and 2 oxidation processes
•Vitamin E
•Carotenoids
•Flavanoids
•Anthocyanins
•Phenolic compounds
•Factors affecting degree of anti-oxidative power
includes polarity and solubility of food system
Protecting food systems from lipid oxidation
• Radical scavenging
• Metal chelation
• Oxygen scavenging
Commercially
• Studies have been done to prepare Omega-3
PUFAs as a 4:1 (16%:4%) ratio of refined fish oil
with corn oil as a way to decrease lipid oxidation
• Antioxidants were also used (butylated
hydroxytoluene and butylated hydroxyquinone
with alpha-tocopherol.
• This increased stability during contact with air
and temperature fluctuations
Using modified atmosphere packaging (MAP)
• Oxidation is especially problematic in meat
because of the pro-oxidants present
• MAP resulted in:
•Better quality
•Increased shelf life
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