2.3. Sensory analysis

For sensory analysis, the fruit samples were kept under controlled conditions. The tasting panel consisted of tasters trained over the last 5 years, in which training sessions were conducted for the recognition and rating of the characteristic visual and tactile attributes of the fruit (Bettini et al., ¹⁹⁹⁸). All panelists were regular orange consumers. The panel consisted of 16 judges (8 women and 8 men), aged 25 to 70 years. Between 8 and 12 tasters are required for each test, although it is wise to keep some extra tasters in reserve to cover possible absences (COI/T.20).

In the training sessions, olfactory and taste tests were performed with prepared artificial aromas (Le nez du vin. Jean Lenoir). These were always aromas related to the fruit to be tasted, and taste tests that prepared different scales of acidity and sweetness, among others. The training sessions were held weekly.

The tastings took place in a suitable room which, in addition to being odor‐free, must be sufficiently insulated and comfortable, and must be under controlled ambient temperature as mentioned above. The evaluation was conducted from 10:00 a.m. to 1:00 p.m. in individual booths with controlled lighting and temperature. At each tasting, two oranges for each of the samples were placed on white plates and presented to the panel. The fruits were removed from cold storage, equilibrated to room temperature and placed as random samples of whole, intact fruit for tasting by the panelists. Each sample was identified by a random three‐digit code, and all samples were of uniform size. The order of the samples for each panelist was randomized, and they were provided with water and invited to drink after each sample tasted (Baxter et al., ²⁰⁰⁵). Depending on the harvest dates, one or two different varieties were tasted. When more than one variety was tested, the taster had a repeated sample as a control system for the taster himself/herself.

The tasting session was carried out by means of the tasting sheet, which made it possible to establish the sensations conveyed by the fruit during the sensory analysis (Baxter et al., ²⁰⁰⁵). Tasters were also provided with the material necessary to be able to peel and cut the fruit. Each tasting session was divided into four different parts, in which the visual, tactile, gustatory and olfactory phases were evaluated (Chen & Nussinovitch, ²⁰⁰¹). In each of the phases, an evaluation was made in order to have a complete characterization of the orange (Lotong et al., ²⁰⁰³).

Using a colorimetric scale (Pointer & Attridge, ¹⁹⁹⁷) that we have adapted to the colors of citrus fruits from the Mediterranean climate zone, we studied the color of both the peel and the flesh of the samples. In the taste phase of orange, it is interesting to study the balance between sugar and acidity, on which the assessment of bitter and astringent taste depends, as reported in the article by Baxter et al. (²⁰⁰⁵), in order to have joint knowledge of the parameters.

To prepare for the sensory evaluation, the panelists, in preliminary sessions using commercial and experimental fruit samples, generated the sensory descriptors in the final sensory test. They were asked to score each sample using the tasting sheet developed. The panelist evaluated the samples using a category scale, assigning each descriptor a score from 1 (low intensity of the attribute) to 9 (high intensity of the attribute). The attributes were ranked as follows:

In the meeting that took place at the end of each tasting session, the tasters presented their scores, opinions and points of view, without modifying in any case the data that had been noted on the tasting sheet. The consensus was obtained from the report on each of the samples.

This study was approved by the Research Ethics Committee of the Universitat Politècnica de València (UPV), and informed consent was obtained from each subject prior to their participation in the study.