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FAQ
Typical
Consumer Technical
Quality Assurance
Answers
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What
is canola oil ?
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Canola is a rapeseed variety ( Brassica napus or Brassica campesteris
) which oil component of seed contain less than 5% erucic acid and the
solid component less than 30 m mol of
glucosinolates per gram of air dry oil free solid (GLC method of the
Canadian Grain Commission).
Rapeseed is mainly grown in Canada, France,
Denmark, Poland, UK, India and China. In Western countries, oil for edible
use is controlled by legislation at a level of 5% erucic acid (C22 :1)
maximum whereas rapeseed oil with high levels of erucic acid (40% minimum
) isfor industrial use only.
Canola oil contains very low levels of saturated fat
and high levels of monounsaturated fat. Saturated fats raise cholesterol
levels in the blood and promote clogging up of blood arteries leading to
heart attack while it has been proven that monounsaturated fat reduces bad
cholesterol levels. This leads scientists worldwide to believe that canola
oil is one of the healthiest vegetable oil available.
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| What
is ‘good’ and ‘bad’ cholesterol ? |
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Cholesterol is distributed throughout the body by lipoproteins
(cholesterol carriers) in the blood. Lipoproteins refers to a chemical
compound made of fat and protein. There are two kinds, the low density
lipoprotein (LDL) which have more fat than protein and high density
lipoprotein (HDL) which have more protein than fat.
LDLs carries away cholesterol from the liver through
the bloodstream. When excessive LDL levels are registered, they form a
hard deposit called plaque, that attaches itself to the walls of the
arteries. When an artery of the heart is blocked, a heart attack occurs.
If an artery to the brain is clogged, then a stroke occurs. Therefore LDL
cholesterol is often referred to as the ‘bad’ cholesterol.
HDLs acts like a little vacuum cleaner and picks up
excess fat. HDL carries cholesterol away from the arteries and back to the
liver where it is eventually sent to the intestines to be discharged from
the body. Therefore HDL cholesterol is also known as the ‘good’
cholesterol because a high HDL level seems to protect against heart
attack.
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Table 1. Comparison of dietary fats of
various vegetable oils
| Fatty
acid content normalized to 100 percent (%) |
|
Dietary Fat
|
Saturat- ed Fat |
Polyunsaturated Fat |
Monounsaturated Fat |
|
Linoleic1 |
Alpha - Linoleic2 |
| Canola Oil
Sunflower Oil
Corn Oil
Olive Oil
Soya Bean Oil
Palm Oil
Coconut oil |
6%
11%
13%
14%
15%
51%
92% |
26%
69%
61%
8%
54%
10%
2% |
10%
0%
1%
1%
7%
0%
0% |
58%
20%
25%
77%
24%
39%
6% |
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What
are saturated, monounsaturated and polyunsaturated fat ?
What
is the significance of these fats to health ?
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Basically, all fats or oils (triglycerides) are built up from combinations
of fatty acids. These fatty acids combine with one glycerin molecule to
form one triglyceride unit. Saturated fatty acid contains the maximum
quantity of hydrogen atoms. Saturated fats are solid at room temperature
and they are more stable than unsaturated fats.
A fatty acid is unsaturated when there are places on the
carbon atom that are unoccupied by hydrogen. When one pair of hydrogen
atoms is missing, it is called monounsaturated. When more than one pair of
hydrogen atoms is missing, it is called polyunsaturated. Monounsaturated
fatty acids which are more stable than polyunsaturated fatty acids will not
oxidize as quickly especially during cooking.
Saturated fatty acids is found mainly in palm oil,
coconut oil, meat and dairy products. High consumption of saturated fat can
raise the cholesterol levels in the blood, clogging up arteries, thus
risking a heart attack or stroke.
Polyunsaturated fatty acids is found in vegetable oils
such as corn, soybean, sunflower, safflower, cottonseed, as well as most
nuts. It can help our bodies remove newly formed cholesterol, thus keeping
cholesterol levels low. However, while they lower ‘bad’ LDL
cholesterol, they also reduce ‘good’ HDL cholesterol .
Monounsaturated fatty acids, which is abundant in canola
and olive oil, reduces cholesterol levels and should make up the bulk of
fat in the diet. Medical diet research has proven that monounsaturated fat
are healthier than polyunsaturates because they maintain the ‘good’ HDL
cholesterol and gets rid of the ‘bad’ LDL cholesterol.
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What
are essential fatty acids (EFA) ?
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Most fatty acids can be synthesized in the body, but a few polyunsaturated
fatty acids cannot be produced at all or are only made in small
insufficient amounts. Since the human body cannot function properly
without them and must be obtained from food, these are known as essential
fatty acids (EFAs).
Essential fatty acids can be divided into two groups :
Omega -3 fatty acids – The two most important
types, Eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA)
are formed in the body from alpha-linoleic acid . Omega- 3 fatty
acid has been found to reduce the process of atherosclerosis (the building
up of plaque on the artery walls). Prostaglandins derived from Omega-3
fatty acids regulate the immune system, inhibit blood clotting and have
anti-inflammatory effects. It is postulated that multiple sclerosis, a
disease characterized by disturbances in the nervous system and myelin
breakdown during brain maturation results from deficiency of Omega-3 fatty
acids. Canola and soybean oil are good sources.
Omega-6 fatty acids – The most important types
are linoleic acid and gamma-linoleic acid (GLA).
Linoleic acid is necessary for growth & development of infants,
reproduction and essential for healthy skin. Prostaglandins produced from
GLA have a beneficial effect on the immune system, circulation and
menstrual cycle. Sunflower, corn, soybean and safflower
oil are good sources.
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1. |
Oil Extraction
Historically, many processes were used to recover oil
from seeds, but the two most common procedures are expeller pressing and
solvent extraction.
Expellers are still used throughout the world
on a wide variety of oleaginous materials having high oil contents (e.g.
corn germ, sunflower, cottonseed etc.) but their use for soybeans (
having relatively low oil content of 18-20 %) has greatly diminished.
Solvent extraction process to produce crude oil
generally consist of three parts
(i) preparation of
oilseeds – involves cleaning & crushing of oilseeds/ corn germ into
flakes to facilitate oil extraction
(ii) extraction of oil from
the flakes
(iii) reclamation of solvent from
the oil and meal
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2 |
Refining of crude oil to produce refined bleached
& deodorized oil. This processing step consist of :
Chemical or physical refining - to remove free fatty acids,
phosphatides and gums, coloring matter, insoluble matter, settlings and
miscellaneous unsaponifiable materials from the triglycerides.
Bleaching – an adsorption treatment to further reduce remaining
impurities in refined oil so that the finished oil will be of acceptable
color and taste.
Deodorization – the final process step to improve the odor,
taste, color and stability of oils by the removal of undesirable
substances. This includes FFA, various flavor and odor compounds
classified largely as aldehydes, ketones, alcohols , hydrocarbons and
compounds formed by heat decomposition of peroxides and pigments. |
| How
is oil quality measured ? |
A number of analytical tests are done in setting up specifications for
fats and oils to meet customer’s quality requirements. The most common
are as follows:
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a. |
Free Fatty Acids (% FFA)
Free fatty acids are fatty acids that are not tied onto a glycerin
molecule.
The FFA content in oil can be easily determined by the
titration of a known amount of oil sample with NaOH solution (AOCS
method Ca 5a-40 ). The result is reported as percentage of free oleic
acid.
% FFA indicates the care and control exercised during
processing. It is an indication of fresh oil/fat quality. In a
well-refined shortening or oil (which does not contain emulsifier) the
typical free fatty acid level should be less than 0.05%.
With used oils/fats, it is an indication of the amount
of hydrolysis that has taken place. Free fatty acids are the result of
reaction of water and fats at frying temperatures. Very high levels of
free fatty acids (e.g. about 3-4%) can result in excessive smoking and an
unsatisfactory flavor.
Factors that affect the rate of free fatty acid development in frying
:
- amount of moisture from food that goes into the frying system
- Temperature of the frying oil/fat.
- presence of burnt food crumbs in the oil/fat
- the rate of oil/fat turnover (replacement with fresh frying oil/fat)
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a. |
Free Fatty
Acids (% FFA)
Free fatty acids are fatty acids that are not tied onto a glycerin
molecule.
The FFA content in oil can be easily determined by the
titration of a known amount of oil sample with NaOH solution (AOCS
method Ca 5a-40 ). The result is reported as percentage of free oleic
acid.
% FFA indicates the care and control exercised during
processing. It is an indication of fresh oil/fat quality. In a
well-refined shortening or oil (which does not contain emulsifier) the
typical free fatty acid level should be less than 0.05%.
With used oils/fats, it is an indication of the amount
of hydrolysis that has taken place. Free fatty acids are the result of
reaction of water and fats at frying temperatures. Very high levels of
free fatty acids (e.g. about 3-4%) can result in excessive smoking and an
unsatisfactory flavor.
Factors that affect the rate of free fatty acid development in frying
:
- amount of moisture from food that goes into the frying system
- Temperature of the frying oil/fat.
- presence of burnt food crumbs in the oil/fat
- the rate of oil/fat turnover (replacement with fresh frying oil/fat)
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b. |
Iodine
Value (IV)
The Iodine Value is an index of the number of double
bonds in fat. It is a term that can quantify the degree of unsaturation
of fat. IV is reported in terms of the grams of iodine that will react
with 100g of fat or oil under specified conditions.
Iodine value (AOCS method Cd 1-25 or Wijs
Method ) is obtained by reacting fat with known amount of excess
halogen, iodine or iodine chloride. The reduction of the excess halogen
with KOH and titration with standard sodium thiosulfate using starch
solution as free iodine indicator determines the amount of iodine
consumed by the fat. The results are expressed as the number of grams of
iodine absorbed by 100g of sample, irrespective of the halogen
combination used.
Different types of oil have different IV. Therefore IV is a useful
means to check for the type of oil and contamination with other types of
oil.
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c. |
Peroxide
Value (PV)
PV is an index to indicate the amount of oxidation a fat has
undergone. When oil becomes oxidized, it first develops hydroperoxides.
The extent of oxidation is measured by the amount of free iodine the
oxidized fat can liberate from KI. The results are expressed as peroxide
value (PV) the miliequivalents of iodine formed per kg of fat (AOCS
Method Cd 8-53 ). Freshly deodorized oil should have zero PV
PV as a measure of oxidation for unheated fats is useful for
determining fat quality after processing and storage. With a fat or oil
processed correctly and quickly from good quality oils, the fresh
peroxide value will be practically zero . Peroxides will develop to a
certain extent during storage before use, with the quantity depending on
time, temperature and exposure to light and air.
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e. |
Color
Besides having a crystal clear clarity, a good refined oil should have
a colour as low as possible. Colour of RBD oil is very critical in the
production of mayonnaise and salad oils. Therefore the more colourless
the oil is, the better the oil quality.
Color of oil is usually measured by the Lovibond tintometer (AOCS
method Cc 13b-45)
Comparing the color of the oil in a glass tube at a standard depth
with color of several glass standards does this. Most oils only require a
combination of yellow and red glasses. The analyst selects the closest
red glass, which is the easiest color to match and then selects a yellow
glass with 10 times the color value. The color of measured oil is
customarily reported as Red Index / Yellow index.
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f. |
Smoke Point
Smoke point is the temperature at which smoking is first detected in a
laboratory apparatus protected from drafts and provided with special
illumination (AOCS Method Cc 9a-48)
The smoke point of fatty materials is a measure of thermal stability
of fats and oils when heated in contact with air. Lower than normal smoke
point imply the presence of too much residual non-triglyceride impurities
such as FFA, monoglycerides and other volatiles.
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g. |
Cold Test
This test is to ensure that all the wax in the oil (especially corn
& sunflower oil) have been removed completely in the winterising
process. Wax causes the oil to turn cloudy in cold temperature. This is a
critical test when oil is exported to countries that experiences winter.
Cold winter temperature may cause the wax in the oil to crystallise
resulting in a blur appearance. Soybean oil and canola generally do not
contain much wax. As such, a positive cold test may indicate that there
is a cross contamination of the oil either with corn/ sunflower
oil.
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h. |
Shelf
Stability Test
This is an accelerated method to determine how stable the RBD oil is
during storage. The colour of the RBD oil is measured after incubation in
the oven at 100 C for 2 hours. This reading is correlated to the change
in colour anticipated afer a few weeks of storage at room temperature.
The higher the colour reading is, the less stable the oil is during
storage.
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i. |
Filter
test
This is to check for impurities in the oil. 50 ml of oil is forced
through 1 micron filter paper using vacuum suction. The filter paper is
then inspected later to see if there are dark stains on it.
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| What
causes rancidity ? |
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Off-flavor /odor of fat/oil resulting from the reaction of fat/oil with
oxygen in the air is referred to as rancidity. This reaction occurs
at the double bonds or points of unsaturation.
Products containing a higher proportion of unsaturated
fatty acids are more prone to oxidation. This is owing to the more
unstable double bonds; oxygen will more readily react at these points of
instability. However proper processing techniques can minimize this
tendency.
Factors contributing to the oxidative deterioration of
fats and oils
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Oxygen (in air )
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Amount of surface area of fat that is exposed to air
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Light (UV)
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Duration of exposure (time)
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Temperature (Heat)
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Prooxidant metals (e.g copper and iron) which will
catalyze oxidation
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Presence of antioxidants which retards oxidation
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| What
are the precautions that needs to be followed to prevent oil oxidation ? |
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Generally, precautions that needs to be followed are as follows :
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Limiting atmospheric oxidation by minimizing contact
of oil with air (e.g. nitrogen blanketing ) at ambient temperatures and
avoiding all contact with oxygen (vacuuming) at very high temperatures
e.g. deodorization.
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keeping the process time at elevated temperatures as
short as possible.
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Avoiding, removing and inactivating trace metals
(e.g. copper alloys and high temperatures common iron ) with prooxidant
effect.
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Avoiding exposure of oil to light.
Although these precautions are readily stated,
implementing them in commercial operations is not so simple.
Practices to be avoided in transporting or handling the
oil includes allowing oil to fall through air and sucking, whipping or
bubbling air through the oil.
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| What
are the factors that causes the deterioration of finished oil quality ? |
Factors most likely to affect the quality of finished oils to such an
extent that they would require reprocessing (recycling) or be used as a
industrial sub-quality product include :
- Contamination from atmospheric adulterants
Atmospheric adulteration is avoided by storing the oil in completely
closed tanks
- Internal contamination from water and soaps
Finished oils held in storage tanks can be contaminated by water
leaking from steam or cooling coils. Moisture in the oil can promote
hydrolysis, particularly at elevated temperatures resulting in an
increase in % FFA content. Proper maintenance of coils is necessary.
- Overheating
Overheating of bulk stored oil is undesirable because soaps and
pro-oxidant metals are much more active at elevated temperatures. Storage
tanks for finished oil should be equipped with automatic temperature
controllers to prevent overheating.
- Exposure to air and oxygen
Oxidation has the most detrimental effect on the quality of finished
oils held in bulk storage. The usual procedure involves nitrogen
blanketing (i.e. replacing oxygen with nitrogen ) where the finished oil
is delivered from the deodorizer to the storage tank under a complete
nitrogen blanket. The nitrogen blanket is maintained by a pressure system
controlled by a regulator
Resistance to oxidation : Crude oil > Partially processed oil >
Finished oil
Oil stores best as crude oil. Refined bleached & deodorized oil
(finished oil) is more susceptible to oxidation than other stages in
processing. For this reason, the finished oil should be stored only for
brief periods.
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| How
does Soon Soon assure the quality of oils ? |
Soon-Soon is committed to assure the quality of oils/oil products to meet
customer requirements by performing quality evaluation on every process
step involving:
- Incoming Raw material - oilseeds & packing material
- Storage of Raw Material
- Storage of refined oil
- On line processing (QC)
- Delivery – quality testing, tanker inspection and issuing of COA
- After sales – A team of QA Inspectors doing after sales ‘Quality
Survey’ at Supermarkets.
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| Facility |
Function / Tests conducted |
| 1.
Central lab
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Chemical
Analysis - PV, FFA, Moisture
Physical Analysis - Color, Filter Test, Cold test,
Clarity,
Shelf Stability Test |
| 2.
Instrumentation Lab |
NIR-
Iodine value, GC – Fatty Acid Content, Rancimat- OSI
AAS –Heavy metal analysis, NMR –Solid Fat Content |
| 3.
Microbiology lab |
Total
Aflatoxin Count for incoming oilseed |
| 4.
Food Research Center |
Intensive
R & D programs |
| 5.
Pilot Plant |
Process
investigation & new product development |
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