Bongartz, Annette

Popp, Martin

ZHAW Zürcher Hochschule für Angewandte Wissenschaften

Quality Discrimination of EVOOs                                           Insights from the long-term project: International Olive Oil Award – ZurichM. Popp, A. BongartzZHAW - Zurich University of Applied Sciences, Institute of Food and Beverage Innovation, Wädenswil, SwitzerlandBackgroundFor sensory evaluation of Extra Virgin Olive Oils (EVOOs) withinthe annual “International Olive Oil Award – Zurich” (a long-termproject organized by the Sensory Science Group of ZHAW) theSwiss Olive Oil Panel (SOP) uses a profile sheet based on anextended methodology, which is cross-validated between theSwiss (SOP) and the German (DOP) Olive Oil Panels. Using thismethodology and thereby exceeding a regular Panel Test (EC640/2008) and the verification of the category “extra virgin”,additional descriptors are used to realize a quality-discriminationwithin the category of EVOOs. In particular the attribute “harmony”is responsible for this improvement of the methodologicalapproach. Using “harmony” as a quality-factor, the discriminationbetween “low” up to “premium” quality levels within the category ofEVOOs is possible [1].Practical Approach / Research QuestionsStatistically analyzing projectdata (n = 620, includingdefective, not acceptable andoils with very low quality) ofthe last five years (2009 up to2013) [Figure 1], allowsanswering selected researchquestions and explainingrelations between selectedquality criteria of n = 570 as“extra virgin” confirmed oils.Altogether 88% of these oils were above “average” and showed“high” (20%), “very high” (50%) and “excellent” quality (18%).FindingsA highly significant correlation (p < 0.0001) exists betweenharmony values and the intensity of bitterness (R2 = 0.172) [Figure2]. Until a certain level of bitterness (3 on a 10 cm intensity scale)harmony values augment. Beyond that point an opposite effect isobserved. Almost the same picture can be found for the intensityof pungency (R2 = 0.304) [Figure 3] and the intensity of fruitiness(R2 = 0.506) [no Figure].Contact:Annette Bongartz  / annette.bongartz@zhaw.chZHAW, ILGI, CH-8820 Wädenswilwww.ilgi.zhaw.ch/sensorik / www.oliveoilaward.chFindings (continued)Looking at the different quality levels of n = 570 EVOOs (“low” upto “excellent”), that were evaluated for their fruitiness and at thesame time were characterized as “green” or “ripe” or “green andripe”, there exist certain interdependences. As shown in Figure 4,the higher the quality level, the more as “green” characterized oilsexist.Production criteria as thereare labeling, organic, coldextraction / pressing andmono-varieties seem to haveno impact on qualitydifferentiation within the gradeof EVOOs [Table 2].In no case significant differences regarding harmony could befound within the production criteria.OutlookA better differentiation between olive oils within the grade of EVOOis possible by using insights concerning the relevance of qualitycriteria. Especially the “harmony” value is a good predictor ofdifferent quality levels within the range of EVOOs. Any helpfulinformation towards consumers as well as a serious and objective“Sensory Marketing” of EVOOs should rely on these additionalaspect.Literature:[1] A. Bongartz, D. Oberg: Sensory Evaluation of Extra Virgin Olive Oil (EVOO) Extended to Include the Quality Factor „Harmony“; Journal of Agricultural Science and Technology A1 (2011), 422-435Figure 1: Quality Levels 2009-2013 (%) (n = 620)Figure 2: Harmony values and intensity of bitterness are significantly correlated (R2 = 0.172, n = 570)Figure 3: Harmony values and intensity of pungency are significantly correlated (R2 = 0.304, n = 570)Table 1: Quality description within the range of EVOOs [1]Figure 4: Contribution of «green», «ripe» and «green and ripe» described olive oils in thevarious quality levels (%) (n = 570)Table 2: Overview of EVOOs with specificproduction criteria (n = 570)Quality Level  Description / MeaningNot acceptable0.0  2.4these oils show panel results with various single defects, but no significant median for a defect / there might be partly unknown defects, perhaps totally inharmonious aspects like for example a certain gallic bitterness / on a whole these oils are more virgin than extra virginVery Low2.5  3.4 these oils show many inharmonious aspects / they offer many negative aroma aspectsLow3.5  4.4 these oils show partially inharmonious aspects / they offer only few aroma aspects and as well single negative ones Average 4.5  5.4these oils show no negative aspects at all, but also nothing "exciting" concerning the presence of aroma components / these oils are often overripe and not always perfectly blendedHigh5.5  6.4these oils show various aspects of flavour / they offer an already more complex aroma profile that can be traced back to the variety used or the excellence of the blendVery High6.5  7.4 these oils show a complex aroma profile / they offer a pronounced harmony and persistency as well a good flavourExcellent7.5  10.0these oils show a very complex aroma profile / the offer a very pronounced harmony and persistency and therefore an excellent (premium) flavourProduction CriteriaLabeling PDO/PGI no labeln = 148 422Organic production organic conventionaln = 104 466Cold extraction / pressing cold ex. / pr. regularn = 182 388Mono-varieties mono-varieties blendsn = 282 288

Quality discrimination of EVOOs : insights from the long-term project: international olive oil award – Zurich

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Quality discrimination of EVOOs : insights from the long-term project: international olive oil award – Zurich

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