Some technologies and processes routinely used in research laboratories have shown a high level of accuracy in determining the bitterness and pungency of extra virgin olive oil.
According to a new study published in Food Chemistry, the latest findings could change how these olive oil characteristics are determined, which is currently done with expert tasting panels.
The study suggests that the new technology would not face some of the challenges associated with traditional panel tests – such as cost, time and organization – but would not fully replace them.See Also:Olive Leaves Can Improve Oil Quality, Researchers Find
“Many authors agreed on the controversies associated with the panel test, conducted by a human panel, especially in terms of efficiency and robustness, pointing out the need of setting up a supporting instrumental tool for sensory evaluation,” the researchers wrote.
The virgin olive oil category does not require bitter and pungent attributes to be specified on its labels. However, current regulations allow producers to state the virgin olive oil’s intensity on the label using specific terminology, such as robust, medium, delicate, well balanced or mild.
“Disposing of a fast and efficient analytical method to measure bitter and pungent attributes in virgin olive oil becomes a need to support the sensory panel,” the researchers wrote. “We hypothesize that fluorescence spectroscopy as such could be the fit-for-purpose tool, given that it is selective, fast and solvent free.”
Previous studies have already applied this technique to determine olive oil authenticity, adulteration, discrimination from other edible oils and level of deterioration.
However, no previous study has applied excitation-emission fluorescence spectroscopy to develop prediction models for bitterness and pungency attributes of olive oils.
To explore their hypothesis, the researchers worked with 255 virgin olive oil samples produced from the 2019/20 harvest by the Institute of Agrifood Research and Technology in Spain.
An expert tasting panel certified and recognized by the International Olive Council assessed and graded the samples, determining their pungency and bitterness.
The samples were then used to build and compare partial least squares regressions with the excitation-emission matrix. Regression analysis allowed researchers to determine which variables mattered most and which could be ignored.
The prediction of virgin olive oil bitterness and pungency was determined by measuring the excitation-emission matrix.
“Errors in prediction were always close to the error of the sensory reference method,” the researchers wrote.
According to the scientists, the excitation-emission fluorescence spectroscopy method applied in the study could correctly predict those crucial qualities of virgin olive oils.
“In view of the results, excitation-emission fluorescence spectroscopy has proven to be a suitable tool for bitterness and pungency prediction of virgin olive oils and could become the fit-for-purpose screening tool to support the panel,” the researchers wrote.
They added that the method has several benefits, including its faster speed and lower cost than traditional panels and other methods used to determine olive oil organoleptic qualities.
However, the authors warned their method is not immediately deployable at scale.
“In spite of the satisfactory results, also considering the error of panel’s performance, further research is needed in order to obtain robust regression models,” they concluded. “Besides, a greater number of virgin olive oils samples with a wider range of the attributes of interest would be worth being included, as well as to carry out an external validation of future regression models.”