As the world’s demand for fried food continues to expand, there has been a huge increase in manufacturers, restaurants, and cafes producing such foods. From chips and fried chicken to Mars bars, ice-cream and donuts, there is simply no limit to what can be thrown into a deep fat fryer and served up to the public. The demand has never been higher.
Cooking oil quality – what affects it?
There are however some issues with this, particularly around the education of frying, ensuring the products created are of the highest standard and that food safety is always considered. Ever had fish and chips that had a burnt, faintly nasty taste? I bet you have. With this in mind, it is important to understand cooking oil quality and what devices are available on the market to measure it.
Cooking oil, like most things, ages as a result of many factors. With relation to deep frying, these can include what food was fried, the heat at which the oil was heated and the amount of times it was used. In scientific terms, this is referred to as thermal oxidative modification. The quality of cooking oil can also decrease due to time spent at room temperature, causing an oxidation reaction between the air and the oil.
With cooking oil becoming an important tool for many industries, scientists had to come up with a way to measure quality. Research revealed that the most effective way to see how used or old cooking oil is was to test the Total Polar Materials (TPM). In essence, a high level of polar components illustrates that the cooking oil is of low quality and has been used frequently.
There are a number of risks associated with a company using cooking oil that is past its best. A recent Testo study looked at the Frying Oil Quality Curve, which explains each step of the process. As the oil begins to get older, the fried food becomes darker and could feature spotty surfaces. In addition, the fried shell is less crisp and the food absorbs much more oil than usual. This can leave a bitter, unpleasant taste and is also unhealthy due to a higher content of saturated fats. There is also another stage of the degradation of cooking oil. The product produced is hard, oily and the food inside might not even cook properly. This can then cause problems from a food safety point of view. It can also produce a burnt flavour and give off a pungent smell.
Essentially, the more times cooking oil is used and the longer it’s left, the poorer the quality it will be and the lower the standard of the fried product.
Testo 270 Cooking Oil Tester
The improved Testo 270 is latest generation of proven range cooking oil testers. Testo’s 270 allows you to determine the quality of cooking oil faster and more reliably than ever before. To do so, it measures the ‘Total Polar Material’ (TPM) content in the oil, which is a sure indicator of its quality. It then gives a percentage and if the oil is aged an increased TPM value will show.
Cooking oil develops its best potential between 14 and 20% TPM. Using this measurement tool to understand exactly when oil needs replacing also makes sure you aren’t wasting oil. 
You don’t want to be replacing perfectly good oil by changing too frequently as this will increase oil consumption and ultimately costs.
Extensive practical tests by Testo engineers have demonstrated that regular measurement with the Testo 270 reduces the consumption of cooking oil by up to 20 %. Therefore it's not just productivity that will be improved with the Testo 270, but also costs can be significantly reduduced.
The traffic-light alarm system provided by multi-colour backlighting makes it even easier to evaluate the quality of the cooking oil:
Green = TPM content is good.
Amber = TPM value will need changing soon.
Red = TPM value has exceeded safe amount.
FEATURES:
Reliable, robust and easy to clean.
Sensor is embedded in metal and breakage-proof.
Alarm function – 3 colour LED (green, yellow, red).
Display: Max measurement temperature exceeded – minimum measurement temperature not reached.
Dishwasher-Proof TopSafe protection case.
Calibration adjustment facility.
Back-to-back testing without the sensor having to cool down.
Links: Testo 270 Cooking Oil Tester