Using Chemical Sensors for Technological Monitoring of Aroma Development in Chocolate Glaze

The study demonstrates the potential for monitoring the dynamics of chocolate glaze aroma formation during conching using an artificial olfactory system based on an “electronic nose” with polymer- modified piezoelectric gas sensors. The samples were collected from an actual production environment, and mandatory quality control of their standard properties was conducted throughout the chocolate glaze conching process. The digitization and objective monitoring of the aroma development and maturation process were performed using a data matrix (recorded and calculated signals) from a piezoelectric sensor array. The sensor array, the responses of which correlate with specific physicochemical quality indicators of both semifinished products and final goods, was optimized beforehand. Correlations between the results of sensorometric analysis and the physicochemical quality indicators of confectionery glaze were revealed. Informative sensors were selected, with responses enabling the rapid assessment of standard characteristics, such as moisture content (based on the crown ether sensor with a Pearson correlation coefficient of R = 0.91) and acidity (based on the Tween-40 sensor with a Pearson correlation coefficient of R = 0.90–0.91). The most valuable information comes from monitoring the decrease in the amount of nonvolatile compounds, particularly in the total sugar content during conching, using signals from the Triton X-100 sensor (with a Pearson correlation coefficient of R = 0.89). As a criterion for the reproducibility of the qualitative and quantitative composition, we proposed a new digital characteristic of aroma—a set of binary sensitivity parameters from the “electronic nose” sensors—and developed a novel chemometric method for processing data sets for the test samples. The study demonstrates a potential for integrating an “electronic nose” into production for technological control, ensuring compliance with and optimization of recipes, and monitoring the conching process of chocolate glaze based on physicochemical indicators and digital characterization of the most unstable property—aroma. This approach allows for objective and reproducible quality assessment of confectionery products.