Page 32 - FoodFocusThailand No.154 January 2019

SPECIAL FOCUS
SPECIAL FOCUS
Quick Quality Control oF
Olive Oil

with UV/VIS Spectroscopy

True extra virgin olive oil is touted for its health
benefits as it is rich in vitamin E, antioxidants
and monounsaturated fatty acids. UV/
VIS spectroscopy provides a fast analytical
method for the classification of olive oil quality
according to international standards and is able
to reliably unveil product falsification.

What causes olive oil quality to differ?
Olive oil of low quality contains substances that are formed as a result
of degradation processes, and, unlike high quality olive oil, absorbs
UV light within the spectral range of 200 – 300 nm. This discrepancy
is explained by the presence of unsaturated fatty acids with differing are achieved within seconds. The equations necessary for the
chemical structure and UV absorbance characteristics in the higher parameter calculations according to the IOC quality classification
quality olive oil, where degradation compounds are hardly present. can be defined easily. Limits can be set up for each calculated
Such difference provides the basis for the spectrophotometric test parameter so that deviations are clearly displayed on the
examining the quality of olive oil: low absorption between 200 – 300 touchscreen.
nm is a measure of high quality extra virgin oil, while high absorption Furthermore, automation with the cuvette changer greatly
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reflects an olive oil of lower quality. increases productivity by allowing for the unattended analysis of
up to 7 olive oil samples, including a blank. Where many different
Easy and fast verification of olive oil quality using olive oil samples need to be analyzed, software facilitates the
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UV/VIS spectroscopy measurement workflow and management of results. Results are
The International Olive Council (IOC) defined three key criteria that securely stored in the database and can be unambiguously tagged
must be met before an olive oil is branded as extra virgin. The criteria in order to differentiate between varying olive oil qualities. Individual
are based on the extinction coefficient K at four different wavelengths tolerance levels automatically support immediate result assessment,
(232 nm, 266 nm, 270 nm and 274 nm). This is illustrated by the UV/ and control charts enable trend analysis of samples over a defined
VIS spectra for two oils of different qualities in Figure 1. The spectrum period of time. In addition, UV/VIS spectra can be individually
of the extra virgin oil (blue) shows a notably weaker absorption in the annotated, results re-evaluated or re-calculated if required and
200 to 300 nm range compared to the olive oil with no quality declaration reports can be individualized according to customer preferences.
(green). The quantitative evaluation and assessment of the individual
K values in accordance with the IOC norms confirm the olive oil
declaration. ข้อมูลเพิ่มเติม / Additional Information
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Spectrophotometer is the ideal instrument for determining the 1 METTLER TOLEDO’s UV5 spectrophotometer
quality of olive oil. Due to the new technology , measurement results 2 METTLER TOLEDO’s FastTrack™ technology
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3 METTLER TOLEDO’s CuvetteChanger
4 METTLER TOLEDO’s LabX® UV/VIS software
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