the positive attributes required of edible oil used in deep frying applications
TRANSCRIPT
THE POSITIVE ATTRIBUTES REQUIRED OF EDIBLE OIL USED IN DEEP FRYING
APPLICATIONS
Dr. Adel Gabr Abdel-Razek
Fats and Oils Dept., National Research Centre, Cairo, Egypt.
6th International Conference of Food Industries and Nutrition
Division. October 12-15, 2016, Sharm El-Sheikh, Egypt.
• Egypt’s Fats & Oils Profile
Oils and fats are staple products in the diet
of Egyptian consumers.
• ORIGINATED - FRYING FOODS - MIDDLE EAST - TWO
MILLENNIA BEFORE THE BIRTH OF JESUS.
26 October 2016 3
Sautéing Shallow frying Deep frying
Frying is one of the common and principal
methods for food preparation at homes;
restaurants and food ingredient factories.
In this way, oil is not only act as a heat
transfer, but also it interacts with proteins and
carbohydrates in the food matrix and induces
favorable odor and taste.
Heat transfer media
Remove water in food
Source of flavour, aroma
Modify food texture
Make food palatable
Source of vitamins, fatty acids, energy
Provide lubricity between food and fryer
ROLES OF FRYING
CRUST
CORE
Starch degradation
Non
enzymatic
browning
High temperatures
Frying oil thermal
degradation
Beneficial
compounds
degradation
Water vaporization
Atmospheric conditions
Frying oil
oxidation
Frying oil
hydrolysis
Moisture loss
Oil uptake
Key structural
components
changes
26 October 2016 7
Changes in product during DFF
OIL CONTENT IN SELECTED FRIEDFOOD
Food Oil content (%)
Potato chips
Corn chips
Tortilla chips
French fries
Frozen pre-fried French fries
Battered products (chicken, fish)
Breaded products (chicken, fish)
Instant noodles
Doughnuts
30 - 40
33 - 38
22 - 26
12 - 15
4 - 7
14 - 17
13 - 20
18 - 21
15 - 24
FOOD
OIL
UPTA
KE
DEH
YD
RA
TIO
N
WATER
HYDROLYSIS
OXYGEN
OXIDATION
Cyclisation
Polymerization
HIGH TEMPERATURES (150 -190°C)
Isomerization
HEAT
Mono glycerides
Di glycerides
Glycerol
Free fatty acids
Aldehydes
Ketones
Acids
Epoxides
Dimers - trimers
Hydro peroxides
Polar
CompoundsFRYING OIL
Trans fatty acids
Cyclic Compounds
Dimers – trimers
Polymers
26 October 2016 10
Changes in oil during DFF
14
Physical and Chemical changes of oil during deep fat frying
Properties Conditions
Free fatty acid < 0.1%
Peroxide value < 4 meq kg-1
Smoke point > 200oC
Polymer compounds < 1%
Lauric acid content (C12:0) < 1%
Linolenic acid content (C18:3) < 2%
Colour Light yellow
Flavour Bland
SPECIFICATIONS OF FRYING OIL
LIMITS OF USED FRYING OIL
Parameter Conditions
Free fatty acid (FFA) 0.5% (Potato chips, Instant noodles)
1% (Pre-fried French fries)
2 to 2.25% (Coated food)
Smoke point Minimum 170 oC
Polar compounds 25 - 27%
Polymer compounds 10 - 16%
“...As significant amount of frying oil is
becoming part of the fried food, oil
quality and stability is of major
concern to consumers...”
Selection of suitable oil is an
important factor that affects the
quality of fried foods.
22
• NO ideal oil or shortening that satisfies each and every frying application
Types of food products
Frying conditions
Further processing
Storage
Expected shelf life
• Any oil that is selected may compromise of at least these three factors
Ideal Frying
Oil?
Nutrition
Functionality
Cost
Flavor Reversion – Oxidation!?
Ex: Soybean oil flavor reversion
Polyunsaturated fatty acid content
is high: 57-58%.
With 7% or more Linolenic acid C 18:3
Flavor Reversion – Oxidation!?
Ex: Sunflower oil (regular)
Linoleic acid content is high: 65%.
The flavor and taste of refined oil may
revert back to that of the crude oil.
Flavor is changing to slight beany,
which in advanced stages is described as
painty or fishy.
SBO and SFO have poor oxidative
stability and are prone to flavor
deterioration.
Therefore:
Pure Soybean or sunflower oils which have
high amounts of unsaturated compounds are
not suitable for frying.
Strategies to Improve
Oxidative StabilityChoose the right oil or fat for your application
Modification of the fatty acid profile by:
Hydrogenation (TFAs).
Interesterified oils (of oleic oils and saturated fats) are
developed for specific applications
Simple method (blending)
TFAs are out, and often replaced with saturates from palm oil, palm
olein or palm oil fractions.
What can be the Objectives?
Possible blending objectives are categorized as;
Commercial
Technical
Functional
Nutritional
Commercial Basis for Blending!
Increasing availability
Expanding supply sources
Controlling cost
Moderating the retail price
Enhancing / meeting the consumer acceptance
Maximizing value for the components
Technical criteria relate to the following items:
Tailoring for intended applications
Meeting specification / standards
Enhancing functionality
Balancing and / or fine tuning of FA composition
New product development / diversification
Enhancing shelf life
Improving cold stability
Improving consumer acceptance
Handling ( pour ability)
Nutrition relates to food safety and healthfulness;
Natural antioxidants & vitamins
Food nutrition
Trans fats lowering
Balancing Fatty Acids Ratio,
Meeting recommendation / requirements of food laws Meeting
nutritional guidelines such as AHA / WHO guideline for smart
blend ratio of 1:1:1 between SAFA, MUFA & PUFA
Blend of palm olein & SBO (50:50) can satisfy this requirement.
In Egypt the common oils used for frying:
Cottonseed oil ???
Soybean oil
Sunflower oil
Palm olein
One of the usual ways for increasing the oxidative
stability of these oils is blending with other oils that
have less unsaturated compounds [Chu & Kung, 1998].
Palm oil is one of the suitable oils for blending with
other sensitive oils.
Heat-stable frying medium
Good oxidative, hydrolytic and flavour stabilities
Better or similar frying stability with other oils/fats
As a blending oil
Abundance supply
Competitive price
WHY IS PALM OLEIN CHOSEN?
FATTY ACID PROFILES OF SELECTED OILS
FA (%) PO POo SBO CSO CNO CO SFO HOSFO
C12:0
C14:0
C16:0
C18:0
C18:1
C18:2
C18:3
Others
SFA
MUFA
PUFA
-
1.0
46.0
4.0
37.8
10.0
0.5
0.7
51.0
37.8
10.5
0.4
1.2
40.5
4.1
41.5
11.1
0.4
0.8
46.2
41.5
11.5
-
0.1
11.0
3.6
24.7
53.5
6.4
0.7
14.7
24.7
59.9
0.2
0.8
23.4
2.5
16.6
55.4
0.2
0.9
26.9
16.6
55.6
-
0.1
5.1
2.0
60.2
23.6
6.2
2.8
7.2
60.2
29.8
-
0.1
11.0
2.0
27.0
58.5
0.5
0.9
13.1
27.0
59.0
-
0.1
6.8
3.1
36.1
52.8
0.7
0.4
10.0
36.1
53.5
-
-
3.6
2.5
84.3
8.0
0.1
1.5
6.1
84.3
8.1
Stability
(110 oC, h)
27 23 5 5 6 7 5 15
CONCLUSION
BLENDING WITH PALM OLEIN IS A SIMPLE, PRACTICAL AND COMMERCIALLY VIABLE
PROCESS .
BLENDING HELPS IN ENSURING THE CONTINUOUS AVAILABILITY OF FRYING OILS WHILE
ENRICHING THE TECHNICAL, FUNCTIONAL AND NUTRITIONAL ATTRIBUTES OF THE
RESULTANT PRODUCTS.
BLENDING HELPS MODERATING THE RETAIL PRICES FOR THE CONSUMERS BENEFIT.
WITH THE EMERGENCE OF THE FRACTIONATION INDUSTRY, THE AVAILABILITY OF SUPER
PALM OLEIN IS INCREASING WHICH IN TURN WILL FACILITATE AND ENCOURAGE ITS
BLENDING WITH SOFT OILS.
AWARENESS THE EGYPTIAN CONSUMERS WITH THE PHYSICAL PROPERTIES OF THE
PALM OLEIN, TO BE USED AS A PREMIUM FRYING OIL.
