choosing the right oil or fat
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Some criteria for the choice of an oil or fatTRANSCRIPT
Choosing the right oil or fat?
Laurence Eyres FNZIFSTECG Ltd December 2013
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
FAT IS GOOD!!
Cost and quality Stability Crystal structure Nutrition-saturated fat and cholesterol Environmental issues GM Trans fats
Factors affecting decisions
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
Retail culinary oils in NZ
Hazelnut oil Walnut oil Extra virgin Olive Oil Avocado Flaxseed Hempseed Cold pressed NZ canola-high quality
Boutique culinary oils
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
Criteria for healthy oils
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
Saturated vs Polyunsaturated fat in NZ
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
Comparing Coconut oil with MCT oil
MCT oil versus Virgin coconut oil at ambient in NZ
Moisture FFA as oleic acid PV –initial stages of oxidation Melting Point SFC done by NMR
Quality
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
Frying fats
oxygen, heat, water
VOLATILE PRODUCTS
Aldehydes HydrocarbonsAlcohols KetonesMethyl Ketones Pentyl FuransCarboxylic acidsLactones
* potato chips fried pyrazines
NON-VOLATILE PRODUCTS
Polar & NonpolarFree Fatty AcidsCyclic Fatty AcidsDimersHydroperoxidesOxysterols
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/kgCu < 0.02 mg/kg
Efficient chelation and bleaching
Specifications for Frying Oils Courtesy Geoff Webster
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
Perspectives - 1970’s
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
Evolution of frying mediums
High oleic acid oils for stability
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)
Retail, Quick service restaurants and Industrial Food Supply
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
Takeaway audits(“Your fat is breaking down too quick!”)
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)
Processed tallow Chefade
©University of Otago 2003
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
Nutritional concerns with heat abused PUFA
Sources of TFA:T vs Time
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
Retail Spreads
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
Shortenings and margarines
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
Confectionery Fats
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
Trans Fats
Have to be plasticized in special plants for texture
Cake ,biscuits and pastry all require different melting points, solid fat contents and crystallisation properties
Fats for baking
Texture deterioration-bloom in chocolate or shortbread
Oxidative rancidity which analyses ? Hydrolytic rancidity-due to lipase
Analysis Extraction-free fat or total lipids?
Problems with fats in food
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
Palm oil and palm olein
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)
Issues with oxidised oils
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.
Papers on omega-3 (EPA and DHA)
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
Further readings if Interested