An electronic tongue taste evaluation: Identification of goat milk adulteration with bovine milk

Abstract

a b s t r a c tAn electronic tongue with 36 cross-sensibility sensors was built allowing a successful recognition of the five basic taste standards, showing high sensibility to acid, salty and umami taste substances and lower performance to bitter and sweet tastes. The taste recognition capability was afterwards tested in the detection of goat milk adulteration with bovine milk, which is a problem for the dairy industry. This new methodology is an alternative to the classical analytical methods used to detect caprine milk adulterations with bovine milk, being a simpler, faster and economical procedure. The different signal profiles recorded by the e-tongue device together with linear discriminant analysis allowed the implementation of a model that could distinguish between raw skim milk groups (goat, cow and goat/cow) with an overall sensibility and specificity of 97% and 93%, respectively. Furthermore, cross-validation showed that the model was able to correct classify unknown milk samples with a sensibility and specificity of 87% and 70%, respectively. Additionally, the model robustness was confirmed since it correctly or incorrectly classified milk samples with, respectively, higher and lower probabilities than those that could be expected by chance.

Sensory intensity assessment of olive oils using an electronic tongue

“…The type of sensors and polymeric membrane compositions (relative percentage of additive, plasticizer and PVC) were selected based on a previous work [31] considering the satisfactory signal stability over time (%RSD o5%, for 5 min signal record) and repeatability (0.5% o %RSDo15%, for three solutions with the same concentration at three levels ranging from 1 Â 10…”

Practical procedure for discriminating monofloral honey with a broad pollen profile variability using an electronic tongue

“…The membrane additives and plasticizers used in the polymeric membranes preparation were selected taking into account the sensor performance, especially the signal stability and repeatability in time of the sensor responses towards basic standard taste substances (salty, sweet, bitter, acid and umami), as previously shown by Dias et al [30]. These sensor arrays were homemade and their cost only concerns the price of reagents and materials.…”

Evaluation of healthy and sensory indexes of sweetened beverages using an electronic tongue

“…In this study, a drop-by-drop technique was applied to prepare each membrane. Type of sensors and relative compositions were chosen based on a previous work [22] since, globally, they enable good signal stability in time (%RSD < 5%) and repeatability (0.5% < %RSD < 15%) towards the basic standard taste compounds (e.g., sweet, acid, bitter, salty and umami). Further details on membrane composition of each sensor can be found in Sousa et al [24].…”

“…The broad range of applicability of electronic tongues (E-tongue) within the food field, including direct analysis (e.g., milk, fruit-beverages, beer, wine) [19][20][21][22] or after sample pretreatment steps, such as dilution or extraction procedures (e.g., olive oils, honey and cereal-based solid foods) [23][24][25][26][27], may be attributed to the capability of these devices in recognizing and measuring basic taste compounds (e.g., acid, bitter, salty, sweet and umami) that has been previously demonstrated for multi-sensor systems based on lipid polymeric membranes [22,[28][29][30]. In some cases, sample pre-treatment, like dilution, dissolution and/or extraction with a hydro-ethanolic solvent, is useful either to obtain a liquid sample, to minimize viscosity issues or to obtain a conductive solution, rich in tastant-related substances that can be recognized and measured by the E-tongue.…”