In-Line Measurement of Color and Total Phenolics during Red Wine Fermentations Using a Light-Emitting Diode Sensor

Abstract

An in-line color and total phenolic sensor is described to track the color and total phenol evolution during red wine fermentations. The sensor uses multiple light-emitting diodes (LEDs) spanning the ultraviolet and visible spectrum, in particular 280 and 525 nm. The performance of phenolic sensor was evaluated by analyzing fermentation samples collected from multiple red wine fermentations performed during the 2012 season. The study confirmed that the LED phenolic sensor measurements strongly correlate with measurements performed with a reference UV-vis spectrophotometer and that in-line measurements can be made in a practical manner after removal of yeast and pulp with a 2.0 µm filter. The use of a 100 µm path-length flow cell avoids the need for dilution, making in-line measurements possible. The sensor provides in-line measurement on the evolution of the total phenolic content and color extraction patterns during red wine fermentations.

Optoelectronic sensor for measuring ethanol content during grape must fermentation using NIR spectroscopy

“…For continuous flow in-line measurements, inlet and outlet tubes should be coupled to the cuvette. All the results in this work refer to static measurements, but good results are expected in flow measurements if a good filtration system is provided (Shrake et al 2014).…”

The Use of UV-Vis Spectroscopy in Bioprocess and Fermentation Monitoring

“…Phenolic compounds play an important role in the colour, flavour and "mouth feel" attributes of wines [50]. Consequently, the measurement of phenolic compounds during fermentation is important to better understand and control the winemaking process [50,51]. UV-Vis spectroscopy was used to monitor the phenolic composition during winemaking, where models used to predict phenolic compounds were developed using partial least squares (PLS) regression [50,51].…”

“…Consequently, the measurement of phenolic compounds during fermentation is important to better understand and control the winemaking process [50,51]. UV-Vis spectroscopy was used to monitor the phenolic composition during winemaking, where models used to predict phenolic compounds were developed using partial least squares (PLS) regression [50,51]. The accuracy and robustness of the calibration models were evaluated by the authors using the slope and intercept, interclass correlation coefficients and standard error of measurement [50].…”

“…The application of UV-Vis spectroscopy was evaluated as an inline sensor to monitor changes in colour and total phenol concentration during red wine fermentation [51]. The sensor presented by the authors was based on multiple light-emitting diodes (LEDs) (280-525 nm) [51].…”

Turbidity and RI Dependency of a Polymer Optical Fiber-Based Chromatic Sensor

“…Another approach presented by Zhou et al [11] uses filters in the light path between the white LEDs sources and the sample holder instead of different color LEDs. The only in situ and online measurement device found in literature ready for color measurement was presented by Novo et al [12,13] and Shrake et al [14] for wine monitoring. Novo uses the advantages of polymer optical fiber (POF) miniaturization and maneuverability to create four separate air-gap regions between two fiber extremities in a sensor head structure where the wine to be measured will flow.…”