Fats and Oils Lab Report

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Running head: FATS AND OILS
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Fats and Oils Lab Report
By June Saxton
8/5//2013
Introduction
In this lab, we will look at different types of fats and oils and evaluate them as to
color, odor and flavor and examine what causes them to become rancid. We will also discuss the
differences between different types of fats and oils and their nutritional value.
Materials and Methods
The ingredients that were used for this sensory lab were safflower oil, olive oil, lard,
butter and crusty French bread. The safflower oil and olive oil were placed in a small glass and
smelled and then swallowed. The lard and butter were spread on a piece crusty French bread and
then tasted and smelled.
Results
Type of Fat
Source
Color
Odor
Flavor
Safflower Oil
Hollywood Brand made
Light
fresh
Mild and
(Enriched Expeller
Boulder, Colorado
Yellow
Olive Oil
Gem Brand made in New York
Apple
(Cold Pressed Extra
with olives from Italy, Spain,
Green
Virgin)
Tunisia, Turkey, and Argentina
harmonious
Pressed)
fruity
Fresh and rotund
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Lard
Morrell Brand made in Morrell,
(Hydrogenated)
Indiana
White
Neutral
Bland but with
smooth mouth
feel
Butter
Great Value brand distributed
(Sweet Cream)
Yellow
Sweet and
Creamy, smooth
by Wal-Mart Corporation in
slightly
sensation on the
Bentonville, Arkansas
salty
pallet
(Conforti, 2008) & (The Olive Oil Source, 2013)
Safflower Oil
Olive Oil
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Butter
Lard
Discussion
There are two types of rancidity; hydrolytic and oxidative. In hydrolytic rancidity the
chemical bonds are broken down into the properties of water (oxygen and hydrogen) and with
the aid of the enzyme lipase produce free fatty acids and glycerol. These free fatty acids only
produce off flavors and colors in fats with short-chained fatty acids such as butter. Fats with
long-chained fatty acids require the presence of oxygen to produce off colors and flavors. This
the oxidative reaction mentioned earlier. It is more likely to occur in the presence of heat, light or
metals. The more highly unsaturated the fat, the more susceptible it is to oxidative rancidity
(Bennion & Scheule, 2010).
Highly saturated fats tend to be more stable because in order for a fat to become rancid it
must contain a free fatty acid. Therefore a monounsaturated fat only with only one double bond
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has a better keeping quality than a polyunsaturated fat with two or more double bonds (Bennion
& Scheule, 2010).
Some steps that can be taken to prevent rancidity are: storage at refrigerator temperatures
away from light, moisture and air, use colored containers to keep out the light, vacuum
packaging to keep out the air and adding natural or synthetic anti-oxidants (Bennion & Scheule,
2010).
Antioxidants act as oxygen interceptors in the oxidative process to provide a hydrogen
atom to satisfy the extra free radical causing the chain reaction which produces rancidity to be
broken. Those used commercially are BHA, BHT, TBHQ and propyl gallate.
The natural antioxidants found in common vegetables oils are vitamin C, beta carotene
and Vitamin E.
A synergist is a substance such as Vitamin C which binds the metals present naturally in
some foods to prevent them from catalyzing the oxidation process. This breaks the chain reaction
that produces rancidity.
Lard is the fat from a pig. It may be rendered or unrendered. Unrendered lard is pure
pork fat trimmed off the meat. Rendered lard is pork fat that is melted down, filtered and
clarified and then refrigerated for storage. Rendered lard can also be processed by bleaching,
hydrogenating, emulsified and preservatives added (Cooks, Info., 2011).
Butter is a pure animal fat made from cream which has been churned to separate the fat
from the liquid (Cooks Info., 2012). Margarine is made from hydrogenated vegetable oils, liquid
vegetable oils, milk, buttermilk or whey plus additives such as Vitamin A and D, artificial colors,
salt and preservatives are also allowed (Bennion & Scheule, 2010).
Cooking oils are refined to process the natural oils from vegetables to remove any
FATS AND OILS
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substances that contribute to off flavor, texture, undesirable color and to standardize them (Vora,
2010). They may also be refined into solid fats by hydrogenation (Bennion & Scheule, 2010).
Extra Virgin Olive Oil is made from fresh good quality olives and processed without
excess heat, additives or solvents. Light olive oil refers to olives oils that are light in taste, aroma
and color. They have the same caloric value as EVOO (The Olive Press, 2013).
Some fats are healthier than others. Olive oil is a mono-saturated fat which has been
shown to have a favorable impact on blood lipids. Soybean oil is an omega-3 polyunsaturated fat
which has been associated with decreased risk of coronary heart disease and hypertension. Butter
is a saturated fat which has been associated with coronary heart disease and high cholesterol.
Therefore, it is appears to be more healthy to consume more mono-unsaturated and polyunsaturated fats than saturated fats (Bennion & Scheule, 2010).
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References
Bennion, M., & Scheule, B. (2010). Introductory foods. (13th ed.). Upper Saddle River, NJ:
Pearson Prentice Hall.
Conforti, F. D. (2008). Food selection and preparation, a laboratory manual. (2nd ed.).
Blackwell Pub.
Cooks Info. (2011, February 18). Lard. Retrieved from http://www.cooksinfo.com/lard
Cooks Info. (2012, November 13). Butter Retrieved from http://www.cooksinfo.com/butter
The Olive Oil Source. (2013). Olive oil tasting terms. Retrieved from
http://www.oliveoilsource.com/page/olive-oil-tasting-terms
The Olive Press. (2013). About olive oil. Retrieved from
https://www.theolivepress.com/learn/about-olive-oil/
Vora, S. (2010, October 25). The truth: About refined cooking oil. Retrieved from
http://blog.sejalvora.com/2010/10/25/the-truth-about-refined-cooking-oil/
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