Application of an electronic tongue for evaluating basic gustatory attributes perceived in table olives: qualitative and quantitative approaches

Abstract

[Excerpt] The organoleptic evaluation of table olives aiming their commercial classification according to sensory trade categories, although not being legally required, is recommended by the International Olive Council. This classification is based on the organoleptic evaluation of negative attributes usually found in table olives (and their respective brine solutions), performed by trained sensory panels. However, the training and implementation of such panels is time-consuming, costly and has some drawbacks like the low number of samples that can be assessed per day as well as the intrinsic degree of subjectivity of the evaluations carried out by the trained panellists. Besides the perception of sensory defects (type and intensity), panellists are usually asked, among other characteristics, to assess the intensity of basic gustatory attributes (e.g., acid, bitter and salty), which knowledge is useful for table olives quality control. In this work, and for the first time, the potential use of a home-made electronic tongue for discriminating standard aqueous solutions of chemical compounds (obtained with mineral water and in the concentration ranges used during sensory panels training sessions) that mimic the 3 basic tastes is evaluated: tartaric and citric acids (0.01 to 2 g/L; for acid taste); caffeine and anhydrous quinine (0.01 to 3g/L; for bitter taste); and, sodium and potassium chloride (0.5 to 25 g/L; for salty taste). [...]