Researchers at Hong Kong Polytechnic University (PolyU) have developed a new method for the rapid authentication of edible oils and screening for gutter oil, Metro Daily reported Tuesday.
Gutter oil is waste oil that may contain other substances and is sold as a cheap substitute for cooking oil.
Authentication of edible oils has been a long-term goal in food safety and has become particularly important with the emergence and widespread use of gutter oil in recent years in the Asia-Pacific.
The conventional approach to authentication is labor-intensive and time-consuming, taking a few hours to analyze a sample.
The new method — developed after two years of work by researchers in the Food Safety and Technology Research Centre under the Department of Applied Biology and Chemical Technology at PolyU – uses matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS).
It allows the authenticity of a sample of edible oil to be determined within five minutes, Associate Professor Yao Zhongping said.
The MALDI-MS approach entails simple preparation of a sample, automatic data acquisition and simple data processing.
As different types of edible oils have different MALDI-MS spectral patterns, the authenticity of a sample of edible oil can be determined rapidly by comparing its MALDI-MS spectrum with the spectogram in the established database of the oil that it is labeled as.
Since this method is capable of authenticating edible oils, it also enables a rapid screening out of gutter oil.
Yao said the new method costs only HK$50 (US$6.45) per test, one-tenth of what the traditional method costs.
PolyU researchers have collected the spectrograms of 32 edible oils that are widely consumed locally.
Yao said they aim to increase the number to 1,000 in future.
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