choosing the right oil or fat

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