Pro Tip: By knowing which fats and oils properties need to be analyzed, bakers can avoid using ingredients that are already oxidized and take better care of the ones they use.
Once in a while, bakeries receive a load of bulk fat that has an off-flavor. This would be the start of rancidity. So why be concerned about rancidity? That’s because over the course of your product shelf life, this rancid oil will further oxidize to create unpleasant off-flavors.
The way to prevent this is to receive fats that have not been oxidized and to store your fats in a place with little temperature fluctuation.
Liquid canola or corn oil is high in unsaturated fatty acids. Although unsaturated fatty acid makes the oil healthier, highly unsaturated oils are prone to fast oxidation and quality deterioration during processing, handling and storage. Oil quality deteriorates by hydrolysis, oxidation and polymerization of the oil.
Here are some quality metrics you can use:
- Peroxide Value measures the amount of oxidation that has occurred to the fat/oil. This value will indicate the rancidity of the oil and how soon it would go rancid. For most fats and oils, the peroxide value should not be above 3 milliequivalents of active oxygen per kilogram of oil.
- Acid Value measures the FFAs that have been released during hydrolysis. The p-Anisidine value, or AV, is a measure of the secondary oxidation products that are formed by breakdown of the primary oxidation products during extensive oxidation. AV is strongly correlated with overall oil odor intensity. Refined oil should have an AV of less than 5.
The good news is that there are food labs around the world that could run these tests for you. To learn more details on these tests, check out our BAKER certified module on Fats and Emulsifiers. Also, click on our fat specification sheet on BAKERpedia to further understand your oil specs.
For hard fats like butter and shortening, quality is dependent upon the amount of saturation and water content.
- Moisture determination measures the actual water content is important. Through titration with Karl Fischer reagent, it reacts quantitatively with water.
- The Penetrometer method measures consistency. This method provides an arbitrary measure of the firmness of plasticized fats by measuring the distance a given weight will penetrate the fat in a certain period of time. The firmness of fat is related to the composition and character of the fat, to the temperature of the test sample at the time of measurement, and to the previous history of the test sample.
- The Iodine Value of fats and oils is a measure of the unsaturation of fats and oils. It is expressed in terms of percentage of iodine absorbed.
- Melting point analysis measures the temperature at which a column of hard fat turns into liquid fat.
- Smoke point analysis will indicate the temperature at which the fat will smoke, flash or burn. This is an AOCS method Cc 9a-48
You may not need all these analyses in your fat receiving program, but understanding which property is the most important to you will help streamline your QA program.
Lin Carson, PhD, is the founder and chief executive officer of Bakerpedia. You can connect with her on LinkedIn.