**3. Test conditions**

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

(blue or amber-coloured) tasting glass.

gustatory sensitivity.

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.

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

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

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 olfactory-

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

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

readily available or who are incapable of expressing themselves clearly.

capacity of the candidate on the entire scale of intensities.

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

"The oil sample for analysis shall be presented in standardised tasting glasses conforming to the standard COI7T.20/Doc. No. 5 (Fig. 2).

**Figure 2.** Tasting glass

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.

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

The oil samples intended for tasting shall be kept in the glass at 28 °C ± 2 °C throughout the test (Fig. 3).

Sensory Analysis of Virgin Olive Oils 229


booth allotted to them in an orderly, quiet manner;


the concentration and work of their colleagues.

**4. Technique for tasting of virgin olive oil** 

shall take a short rest before trying again (Fig. 5).

**Figure 5.** The olfactory test during

panel leader accordingly;

2568/91:





The technique applied for tasting is the one described in annex XXI of (EEC) Reg. N.

"the taster shall pick up the glass (Fig. 2), keeping it covered with the watch glass, and shall

Once this stage is completed, he shall remove the watch-glass and smell the sample taking even, slow deep breaths until he has formed a criterion on the oil under assessment. Smelling shall not exceed 30 seconds. If no conclusion has been reached during this time, he

bend it gently fully in this position so as to wet the inside as much as possible.

This temperature has been chosen because it makes it easier to observe organoleptic differences than at ambient temperature and because at lower temperature the aromatic compounds peculiar to these oils volatilize poorly while higher temperatures lead to the formation of volatile compounds peculiar to heated oils. The test room must be at a temperature between 20 and 25 °C.

The morning is the best time for tasting oils. It has been proved that there are optimum perception periods with regards to taste and smell during the day. Meals are preceded by a period in which olfactory-gustatory sensitivity increases, whereas afterwards this perception decreases. However, this criterion should not be taken to the extreme where hunger may distract the tasters, thus decreasing their discriminatory capacity; therefore, it is recommended to hold the tasting session between 10:00 in the morning and 12:00 noon (Fig. 4).

**Figure 4.** Cabins of the test room

The following recommendations apply to the conduct of the tasters during their work.

When called by the panel leader to participate in an organoleptic test, tasters should be able to attend at the time set beforehand and shall observe the following:



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

test (Fig. 3).

temperature between 20 and 25 °C.

**Figure 4.** Cabins of the test room

the time of the test;

The oil samples intended for tasting shall be kept in the glass at 28 °C ± 2 °C throughout the

This temperature has been chosen because it makes it easier to observe organoleptic differences than at ambient temperature and because at lower temperature the aromatic compounds peculiar to these oils volatilize poorly while higher temperatures lead to the formation of volatile compounds peculiar to heated oils. The test room must be at a

The morning is the best time for tasting oils. It has been proved that there are optimum perception periods with regards to taste and smell during the day. Meals are preceded by a period in which olfactory-gustatory sensitivity increases, whereas afterwards this perception decreases. However, this criterion should not be taken to the extreme where hunger may distract the tasters, thus decreasing their discriminatory capacity; therefore, it is recommended

to hold the tasting session between 10:00 in the morning and 12:00 noon (Fig. 4).

The following recommendations apply to the conduct of the tasters during their work.

to attend at the time set beforehand and shall observe the following:

When called by the panel leader to participate in an organoleptic test, tasters should be able


