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Depending on what kind…. ◦ Omega 3 fatty acids (fish oils-EPA, DHA;
plant sources -ALA) ◦ Mono-unsaturated fats (canola and olive oils)
Decreased fat consumption since the 1960’s associated with obesity epidemic—CHO intake has increased dramatically
Glycemic index/glycemic load Consumption via Retail oils-bottles or solid fat in tubs Retail spreads Take away foods/restaurant food Baked goods
Cost and quality
Stability
Crystal structure
Nutrition-saturated fat and cholesterol
Environmental issues
GM
Trans fats
Culinary oils Saturated fat Monounsaturated fat Polyunsaturated fat
(cold pressed)
Olive oil 15 80 5
Avocado oil 12 80 8
Flaxseed oil 8 18 74
Walnut oil 10 21 67
Macadamia nut oil 13 83 4
Hazelnut oil 9 80 11
Hempseed oil 9 12 78
canola oil 8 60 32
pumpkinseed oil 20 30 50
RBD rice bran oil 25 37 38
Hazelnut oil
Walnut oil
Extra virgin Olive Oil
Avocado
Flaxseed
Hempseed
Cold pressed NZ canola-high quality
Low in saturated fats <20%
Adequate essential fatty acids
Low in oxidation products (no rancidity)
Contains other functional ingredients such as antioxidants
Been subject of clinical trials or epidemiological studies
Tastes great so you consume it regularly
In a new study, researchers from the University of Otago, Wellington analysed the data from several international studies examining the links between saturated and polyunsaturated fat and cardiovascular disease. They then applied their findings to the average New Zealand diet, and determined that switching just 5% the daily energy intake from saturated fats to polyunsaturated fats could lead to a 10% decrease in heart disease.
Australian and New Zealand Journal of Public
Health
Volume 37, Issue 4, pages 329–336, August 2013
Fatty acids Coconut Medium chain triglycerides
Butyric 4:00 0 0
Caproic 6:0 1 <2
Caprylic 8:00 9 50-80
Capric 10:00 7 20-50
Lauric 12:00 47 <3
Myristic14:00 16.5 <1
Palmitic16:00 7.5 0
Stearic18:00 3 0
Oleic18:1 cis 6.4 0
Frying is a demanding process
180 degrees Celsius
Polyunsaturated fatty acids deteriorate rapidly
Linolenic (18:3) should be less than 3 %
Natural antioxidants play a part in stability
oxygen, heat, water
VOLATILE
PRODUCTS
Aldehydes
Hydrocarbons
Alcohols
Ketones
Methyl Ketones
Pentyl Furans
Carboxylic acids
Lactones
* potato chips fried
pyrazines
NON-VOLATILE
PRODUCTS
Polar & Nonpolar
Free Fatty Acids
Cyclic Fatty Acids
Dimers
Hydroperoxides
Oxysterols
FATS DECOMPOSITION
PRODUCTS
Parameter Specification How the processor
delivers
Phosphorus < 1 mg/kg or
better still ND
Efficient degumming +
bleaching
Free Fatty
Acids
< 0.05 % oleic
acid
Alkali or physical
refining
Peroxide Value < 1 meq O2/kg good bleaching +
nitrogen sparging
antioxidants
Soaps Traces Citric acid and bleaching
Metals Fe < 0.1 mg/kg
Cu < 0.02 mg/kg
Efficient chelation and
bleaching
Virtually all available frying oils were used ◦ Edible Beef Tallow, Palm, Soy, Cottonseed, then
Canola. Market leader was Chefade (refined tallow)
Cholesterol fears saw the gradual decrease in the use of animal fats-but Chefade was economical and long lasting
Growth in the QSR-McDonalds used Deodorised beef /cottonseed
Tallow replaced by palm
Now palm being replaced by liquid oils
Edible tallow
Refined Tallow
Palm oil or palm olein/HPOl
Cheap imported liquid oils (SBO,canola)
Blends of physically refined oils-high oleic
Rice bran Oil
Retail oils-SBO,SFSO, Rice Bran Oil, Canola, Olive, Avocado, Flaxseed
QSR High oleic acid oils-Frying Oils
Industrial Food Oils-Palm, Coconut, sunflower,canola,cottonseed
Margarines and shortenings (Palm a major constituent)
Brass fittings
Wrongly calibrated thermostats
Long periods of non-use heat left on
Sulphur dioxide in the potatoes
No filtering
Lots of fatty chicken being fried
Fractionate crude tallow at 39 degrees
Alkaline refine and bleach
Hydrogenate 2-3 IV units
Post filter and post bleach with citric acid
Deodorize at 180 degrees
Final colour 5.0 Y0.5R
FFA <0.07%
Add TBHQ,1 ppm silicone, citric AOM 100 hours
Eyres, Food Industry Magazine (1986)
Intake of 1-hour oxidised PUFA appears to activate the endothelium in CAD patients (increase in plasma VCAM-1 levels).
This may be due to increased oxidative stress as indicated by increased plasma peroxides and decreased resistance of serum to oxidation
©University of Otago 2003
Oil type DO temp.
(°C)
DO time
(hours)
C18:2
Degree Isom.
C18:3
Degree Isom.
Soyabean 226 2 0.37% 5.7%
Sunflower 223 2 0.24% ND
Canola 226 2 0.21% 5.1%
Canola 246 2 1.7% 20.8%
Isomerisation level – Industrially Deodorised, Refined, oil samples
Source: Kemeny et.al., JAOCS, 78(9), 973-979 (2001)
Total deodoriser induced trans fats typically 1% or less
Margarines (80% fat) are not made any more –all spreads-fat contents 45-70%
Used to contain 11-15% trans monoenes. Not now
Now contain 20% interesterified saturated fats
Use olive oil, sunflower, soybean ,canola, rice bran oil
Plant sterol spreads a profitable niche
Margarines contain 16% water
Shortenings are dry fats
Most commercial biscuit fats are now anhydrous palm based fats
Commercial pastry fats are predominantly tallow based for performance
Cocoa butter substitutes-palm fractions and shea butter stearine
Compound fats based on hydrogenated palm kernel stearine (high in lauric acid)
Hard fats but melt in the mouth
Nutritional issue is with partially hydrogenated vegetable oils
In USA foods contained fats that had 40% trans
This issue never arose in NZ
Average intake of trans in NZ is 1-2 g per day
Butter and animal fats are sources of natural trans due to ruminant metabolism
Have to be plasticized in special plants for texture
Cake ,biscuits and pastry all require different melting points, solid fat contents and crystallisation properties
Texture deterioration-bloom in chocolate or shortbread
Oxidative rancidity which analyses ?
Hydrolytic rancidity-due to lipase
Analysis
Extraction-free fat or total lipids?
Biggest source of dietary fat in the Western world (45% saturated FA)
No trans fats and adequate EFA
Red palm oil has high levels of Vitamin E and tocotrienols plus carotenoids
Mostly consume RBD palm products with little carotenoids and reduced Vitamin E although contains tocotrienols
A growing nutritional area of study
Polyunsaturated fats are unsuitable for high temperature frying
Polar oxidised material and oxidised tallow atherogenic
The Med diet relies on EV olive oil with high levels of polyphenols
NZ consumes imported oxidised olive oils with depleted polyphenol levels (if any at all)
More than 19,000 scientific papers have been published on omega-3s, including 2,000 randomized, controlled trials in humans. The ability of EPA omega-3s to reduce triglycerides( now on drug register) is well-documented, but because EPA and DHA are an integral and structural component of cells, we are still learning about the full extent of the beneficial health effects they exert.
Two imbalances in food choice
cause damage & disease & death
Prevent the two food imbalances
and prevent the damage & distress
Here’s a simple idea
NZIC oils and fats website www.oilsfats.org.nz
AOCS website
Food NZ