**2. Sensory analysis of olive oil**

The European Commission (EC) upon issuing the following regulations:


set the objective of establishing and developing the criteria needed to evaluate the chemical and sensory characteristics of oil and virgin olive oil as well as the opportune methodology. The introduction of the *Panel Test* has led to an evolution in the concept of oil quality. The necessary cognitions are set in order to carry out the sensory analysis of virgin olive oil. It tries to standardise the behaviour and procedures of the tasters, who should take into consideration not only the more general indications but also those specific for tasting olive oil. These procedures have led to an evaluation sheet being drawn up by the International Olive Oil Council (IOOC), leading to results being obtained from different *Panels*, in different areas of the same country as well as different countries to be compared.

Since 1991, this methodology has been part of the regulations of the European Commission for classifying oils and is described in detail in Appendix II of the EU Regulation n. 2568/91.

The method, Quantitative Descriptive Analysis (QDA), defines the main attributes of oil, both positive as well as negative. Appearance as colour was not selected as a quality parameter of virgin olive oil, as a specific dark-coloured glass is used. The official evaluation sheet used within the European Union to establish the sensory profile of virgin olive oil is shown below (Fig. 1). The values, expressed as centimetres, are statistically processed to calculate the median of each positive and negative characteristic.


**Figure 1.** Sheet for sensory analysis

224 Olive Germplasm – The Olive Cultivation, Table Olive and Olive Oil Industry in Italy

preset quality standard, etc.

**2. Sensory analysis of olive oil** 

simultaneously (e.g., fresh olive virgin oil from consecutive years), shelf-life studies, correlation of instrumental and sensory properties, studies of the effects of technological processing on the sensory characteristics of a product, quality assurance, certification of a

Another branch of sensory analysis is represented by consumer science. Generally, people eat and drink food because they like it. But, food intake is not completely driven by hedonic motives. Other factors such as market segmentation, advertising, price, packaging, opinions and beliefs play a role too. The sensory perception of sensory quality is an important factor in motivating consumer choice. It derives from the intrinsic properties of the product, perceived by the consumer at the moment of buying (colour, shape, aspect, etc) and subsequently from direct individual experiences (odour, taste). The measurement of liking is necessary before a product is launched onto the market, with substantial capital being needed. This can therefore save investing in a product that may not be liked due to a deficiency of sensory qualities.

The most frequently used method to measure acceptability and preference is the 9-point hedonic scale, developed in 1955 (Jones *et al.*, 1955). The subjects that take part in the sensory

testing are not trained, and should be relatively naive to this kind of task.

The European Commission (EC) upon issuing the following regulations:

Commission Regulation n. 2568/91 of 11 July 1991 (EC Regulation, 1991);

 Commission Regulation n. 2472/1997 of 11 December 1997 (EC Regulation, 1997); Commission Regulation n. 796/2002 of 06 May 2002 (EC Regulation, 2002);

 Commission Regulation n. 1989/2003 of 06 November 2003 (EC Regulation, 2003); Commission Regulation n. 1640/2008 of 04 July 2008 (EC Regulation, 2008); Commission Regulation n. 61/11 of 24 January 2011 (EC Regulation, 2011);

different areas of the same country as well as different countries to be compared.

set the objective of establishing and developing the criteria needed to evaluate the chemical and sensory characteristics of oil and virgin olive oil as well as the opportune methodology. The introduction of the *Panel Test* has led to an evolution in the concept of oil quality. The necessary cognitions are set in order to carry out the sensory analysis of virgin olive oil. It tries to standardise the behaviour and procedures of the tasters, who should take into consideration not only the more general indications but also those specific for tasting olive oil. These procedures have led to an evaluation sheet being drawn up by the International Olive Oil Council (IOOC), leading to results being obtained from different *Panels*, in

Since 1991, this methodology has been part of the regulations of the European Commission for classifying oils and is described in detail in Appendix II of the EU Regulation n. 2568/91. The method, Quantitative Descriptive Analysis (QDA), defines the main attributes of oil, both positive as well as negative. Appearance as colour was not selected as a quality parameter of virgin olive oil, as a specific dark-coloured glass is used. The official evaluation

Sensory analysis is an essential technique to characterize food and investigate consumer preferences. International cooperative studies, supported by the International Olive Oil Council (IOOC) have provided a sensory codified methodology for virgin olive oils, known as the "COI *Panel test*". Such an approach is based on the judgments of a panel of technicians, conducted by a *panel* leader, who has sufficient knowledge and skills to prepare sessions of sensory analysis, motivate judgement, process data, interpret results and draft the report.

Sensory Analysis of Virgin Olive Oils 227

attributes considered, so that the end result is precise and consistent. In addition, they learn

The maintenance of the *panel* is made through continuous training during the entire life of the same *panel*, the check of the sensory acuity of tasters, and exercises that allow the

Every year, every *panel* must assess a number of reference samples in order to verify the reliability of the results obtained and to harmonize the perception criteria; they must also update the Member State on their activity and on composition changes of their group.

"The oil sample for analysis shall be presented in standardised tasting glasses conforming to

The glass shall contain 14-16 ml of oil, or between 12.8 and 14.6 g if the samples are to be weighed, and shall be covered with a watch-glass. Each glass shall be marked with a code

made up of digits or a combination of letters and digits chosen at random.

The test conditions for tasting are described in COI/T.20/Doc. No. 15/Rev. 3:

to use a profile sheet.

**3. Test conditions** 

**Figure 2.** Tasting glass

measurement of *panel* performance.

the standard COI7T.20/Doc. No. 5 (Fig. 2).

**Figure 3.** Heating the samples when in the glass

The *panel* generally consists of a group of 8 to 12 persons, selected and trained to identify and measure the intensity of the different positive and negative sensations perceived.

Sensory assessment is carried out according to codified rules, in a specific tasting room, using controlled conditions to minimize external influences, using a proper tasting glass and adopting both a specific vocabulary and a profile sheet that includes positive and negative sensory attributes. Collection of the results and statistical elaboration must be standardized. The colour of virgin olive oil, which is not significantly related to its quality, may produce expectations and interferences in the flavour perception phase. In order to eliminate any prejudices that may affect the smelling and tasting phases, *panel* lists use a dark-coloured (blue or amber-coloured) tasting glass.

The *panel* leader is the person responsible for selecting, training and monitoring tasters to ascertain their level of aptitude according to (IOOC/T.20/Doc.15/rev.3). The number of candidates is generally greater than that needed in order to select people that have a grater sensitivity and discriminatory capability. Screening criteria of candidates are founded on sensory capacity, but also on some personal characteristics of candidates. Given this, the *panel* leader will personally interview a large number of candidates to become familiar with their personality and understand habits, hobbies, and interest in the food field. He uses this information to screen candidates and rejects those who show little interest, who are not readily available or who are incapable of expressing themselves clearly.

The determination of the detection threshold of the group of candidates for characteristic attributes is necessary because the "threshold concentration" is a point of reference common to a "normal group" and may be used to form homogeneous *panels* on the basis of olfactorygustatory sensitivity.

A selection of tasters is made by the intensity rating method, as described by Gutiérrez Rosales (Gutiérrez Rosales *et al.*, 1984). A series of 12 samples is prepared by diluting a virgin olive oil characterized by a very high intensity of a given attribute in an odourless and tasteless medium (refined oil or paraffin). The *panel* leader sends out the candidate, removes one of the 12 tasting glasses from the series, and places the remaining together; the candidate is called back in the room and is asked to correctly replace the testing glass withdrawn from the series by comparing the intensity of this last with that of the others. The test is carried out for fusty, rancid, winey and bitter attributes to verify the discriminating capacity of the candidate on the entire scale of intensities.

The stage training of technicians is necessary to familiarize tasters with the specific sensory methodology, to heighten individual skill in recognizing, identifying and quantifying the sensory attributes and to improve sensitivity and retention with regards to the various attributes considered, so that the end result is precise and consistent. In addition, they learn to use a profile sheet.

The maintenance of the *panel* is made through continuous training during the entire life of the same *panel*, the check of the sensory acuity of tasters, and exercises that allow the measurement of *panel* performance.

Every year, every *panel* must assess a number of reference samples in order to verify the reliability of the results obtained and to harmonize the perception criteria; they must also update the Member State on their activity and on composition changes of their group.
