1. Altering Functional Properties of Fats Using Ultrasound
Jessica Leis
KNH 404

2. Information obtained from the Journal of Food Science, Issue 74
Suzuki, A.,
Lee, J.,
Padilla, S., &
Martini, S. (2010).

3. Main Objective
To find alternative lipid sources to provide the same adequate functional properties for foods previously containing trans fatty acids using power ultrasound techniques to alter fat crystallization

4. Ultrasound Technique
Ultrasound techniques are those that use sound waves using frequency just above human hearing detection, or greater than 20 kHz. Researchers used power ultrasound, or high frequency ultrasound (HIU) at a range of 20 to 100 kHz to examine its ability to change the physiochemical properties of lipid materials
High frequency ultrasound can be used for generating and inducing chemical reactions to alter crystallization behaviors and functional properties

5. Amount of crystallization
Fats Used
Anhydrous milk fat (AMF)
Palm kernel oil (PKO)
All-purpose shortening (Sh)
To Observe:
Hardness
Amount of crystallization
Melting behavior
To determine if these fats would be acceptable lipid substitutes

6. Experimentation Methods & Materials
Crystallization
Misonix S-3000 sonicator operating
at an acoustic frequency of 20 kHz
for 10 seconds using 50 watts of
electrical power
Crystallization kinetics were
monitored throughout
1.Crystallized at a fast cooling rate of 10 degree Celsius per minute at different crystallization temperatures
2. Heated at 80 degrees C (176 degrees F) for 30 minutes to allow for complete triacylglyceride (simple fat containing 3 FA’s esterified to glycerol – most common) melting
3. Placed in crystallization cell and stirred with magnetic stirrer
4. Upon cooling finish, HIU was applied
5. Samples kept under HIU upon final cooling temperature for 90 minutes

7. Experimentation Methods & Materials
Polarized Light Microscopy
(PLM)
Equipped with digital camera
DSC-2910
To determine melting
profile of crystallized
lipids
Observations taken every 5 minutes during 90 minutes
DSC – 7 to 15 milligrams in airtight aluminum pan

8. Experimentation Methods & Materials
TA-XT plus Texture Analyzer
To determine hardness
Samples were compressed at a
constant speed of 5 mm/s using
a compression strain of 25
percent
All experiments were run
3 times. Data was computed
using an accredited software
program
Cylindrical tubes (1 centimeter in diameter) were stored at 5 degrees Celsius for 24 hours before textural analysis
Hardness was defined as the maximum peak force obtained during the first compression

9. Results Crystallization
HIU could successfully induce crystallization and smaller crystal size in AMF, PKO
Sh crystals were significantly smaller
AMF – however, very dependent on supercooling

10. Results Texture – Hardness
PKO hardness decreased the most, followed by AMF and then Sh
Hardness decreased as crystallization temperature increased

11. Melting Profile and Enthalpy
Results
Melting Profile and Enthalpy
Enthalpy - the energy absorbed from the lipid crystals when they melt
AMF: when HIU was applied, the enthalpy of the crystal network formed was higher due to size of crystals (not amount)
PKO: increased upon crystallization conditions for, meaning HIU is promoting crystallization
Sh: no significant changes when HIU was applied

12. Conclusions
The lipid melting profile of a lipid network depends on the amount of crystallized material and the size of the crystals
The higher the melting profile, the better the mouthfeel and palatability
Melting behavior is important for mouthfeel and palatability

13. Conclusions AMF under HIU had a sharper and steeper melting profile
PKO samples under HIU melted faster contributing to a broader melting profile
Sh results were similar to AMF
Indicates a lower percent of solid at a constant temperature
High frequency ultrasound methods have the potential to become an additional processing tool to modifying the textural, structural, and melting properties of lipids to replace trans fatty acids.

14. Trends in the Research
Effect of lipid oxidation/oxidative stability on the quality of the food
Storage time and temperature
Methods to reduce lipid oxidation
Irradiation
Replacement fats
Interesterified fats with trans-free substrates
High intensity ultrasound
Replacing trans fatty acids with alternative substances
Antioxidant effects on lipid stability
Needs to be controlled to enhance and maintain a quality product. For example, in the experiments examining lipid in California almonds and hulless barley kernels, storage time and temperature were key variables in determining the rate of lipid deterioration and its effect on the product.
Reduce the opportunity for the lipids to go rancid.
Addressing health concerns related to heart disease, etc.
The effect of green tea extracts on biscuit lipid fraction oxidation and antioxidants on salmon jerky were examined as having positive effects on maintaining lipid stability and product quality