1. TRANS FATTYACIDTRANS FATTYACID
PRODUCTION IN DEEP FATPRODUCTION IN DEEP FAT
FRYING OF FROZEN FOOD WITHFRYING OF FROZEN FOOD WITH
DIFFERENT OILS AND FRYINGDIFFERENT OILS AND FRYING
MODALITIESMODALITIES

2. INTRODUCTIONINTRODUCTION
• Foods are essential for the purpose of nutritionFoods are essential for the purpose of nutrition
• In order to prolong the shelf life of food substances,In order to prolong the shelf life of food substances,
foods are preserved e.g canning, drying, freezing andfoods are preserved e.g canning, drying, freezing and
salting. Freezing is a method of preservation wherebysalting. Freezing is a method of preservation whereby
foods are kept in the refrigerator at a temperature belowfoods are kept in the refrigerator at a temperature below
freezing point. During freezing, microbial activities arefreezing point. During freezing, microbial activities are
reduced and some nutritive values are altered. (Ngoddy,reduced and some nutritive values are altered. (Ngoddy,
1985)1985)
• Methods of processing food include: cooking blanchingMethods of processing food include: cooking blanching
and frying. Frying implores the use of fat and oil as aand frying. Frying implores the use of fat and oil as a
medium of heat transfer. (Perkins, 1996)medium of heat transfer. (Perkins, 1996)
• Justification of study.Justification of study.
• Objective of study.Objective of study.

3. • Deep fat frying is a method of frying and theDeep fat frying is a method of frying and the
most complex edible fat and oil application.most complex edible fat and oil application.
• Behaviour of food during frying. While frying,Behaviour of food during frying. While frying,
moisture initially evaporates from the foodmoisture initially evaporates from the food
thereby dehydrating the surface and a crust isthereby dehydrating the surface and a crust is
formed which seals the water keeping the centerformed which seals the water keeping the center
moist and reducing uptake of oil. (Ologunde,moist and reducing uptake of oil. (Ologunde,
2006).2006).
• Factors influencing deep fat frying are theFactors influencing deep fat frying are the
techniques of frying, type of food and its size,techniques of frying, type of food and its size,
age of oil and temperature at which one is frying.age of oil and temperature at which one is frying.
• Frying modalities: these are the techniquesFrying modalities: these are the techniques
employed during frying such as surface frying,employed during frying such as surface frying,
frying at relatively high temperature and frying atfrying at relatively high temperature and frying at
moderate temperature.moderate temperature.

4. • Lipids: they are diverse groups of fattyLipids: they are diverse groups of fatty
substances found in all living organism.substances found in all living organism.
(Ologunde, 2006). Glycerol esters of fatty(Ologunde, 2006). Glycerol esters of fatty
acids which make up 99% of the lipid ofacids which make up 99% of the lipid of
plant and animal origin have beenplant and animal origin have been
traditionally called fats and oils.traditionally called fats and oils.
• Types of oils: Varieties of fats and oilsTypes of oils: Varieties of fats and oils
include; vegetable oils, animal oils,include; vegetable oils, animal oils,
margarines and shorteningsmargarines and shortenings
(Blumenthal,1996)(Blumenthal,1996)
• Effects of lipid to nutrition and healthEffects of lipid to nutrition and health
• Effects of frying on components of lipidsEffects of frying on components of lipids

5. • Fatty-acids, a common name for group ofFatty-acids, a common name for group of
organic acids and are characterized asorganic acids and are characterized as
saturated or unsaturated.saturated or unsaturated.
• Saturated fatty acids are fatty acids that doSaturated fatty acids are fatty acids that do
not contain double bond in their chain e.gnot contain double bond in their chain e.g
Capric acid and Lauric acid.Capric acid and Lauric acid.
• Unsaturated fatty acids contain one or moreUnsaturated fatty acids contain one or more
double bond in their chain. They may bedouble bond in their chain. They may be
further divided into polyunsaturated andfurther divided into polyunsaturated and
monounsaturated. They occur in the CIS ormonounsaturated. They occur in the CIS or
TRANS configuration. (Katan, 1995)TRANS configuration. (Katan, 1995)

6. • TRANSFATTYACIDS: They are formed from theTRANSFATTYACIDS: They are formed from the
unsaturated fatty acids. They are of lower energyunsaturated fatty acids. They are of lower energy
form and have a different physical and chemicalform and have a different physical and chemical
property due to the ability of trans molecules toproperty due to the ability of trans molecules to
pack more tightly.pack more tightly.
• Trans-fatty acids are formed from the partialTrans-fatty acids are formed from the partial
hydrogenation of unsaturated oil.hydrogenation of unsaturated oil.
• Partial hydrogenation reconfigures most of thePartial hydrogenation reconfigures most of the
double bonds that do not become chemicallydouble bonds that do not become chemically
saturated twisting them so that the hydrogen atomsaturated twisting them so that the hydrogen atom
send upon different sides of the chain (Transsend upon different sides of the chain (Trans
configuration ) (Katan, 1995)configuration ) (Katan, 1995)

7. • Influence of Trans-fatty acids on health.Influence of Trans-fatty acids on health.
Trans-fatty acids increase the totalTrans-fatty acids increase the total
cholesterol levels, increase the low lipidcholesterol levels, increase the low lipid
lipoprotein (LDL), and reduce the high lipidlipoprotein (LDL), and reduce the high lipid
lipoprotein (HDL) cholesterol levels.lipoprotein (HDL) cholesterol levels.
(Leibovitz, 1990)(Leibovitz, 1990)
• Presence of Trans-fatty acids in food.Presence of Trans-fatty acids in food.
Trans-fatty acids are naturally present inTrans-fatty acids are naturally present in
the milk and body fat of ruminant such asthe milk and body fat of ruminant such as
cows and sheep (2-5%) of total fats. It iscows and sheep (2-5%) of total fats. It is
also contained in baking shortenings.also contained in baking shortenings.
(Mozaffarian, 2004).(Mozaffarian, 2004).

8. • Materials and equipments food samplesMaterials and equipments food samples
(frozen), frying oil and deep fryer.(frozen), frying oil and deep fryer.
• Sample preparationSample preparation
• Chemical analysis such as determinationChemical analysis such as determination
of iodine value, fatty acid analysis.of iodine value, fatty acid analysis.