On-line-monitoring of food fermentation processes using infrared and Fourier-transformed infrared spectroscopy
- How does it work?
- What can it be used for?
- What can it not be used for?
- Related Facilities
- Further Information
|Key words||Fermentation, IR, FTIR, infrared spectroscopy, on-line monitoring, ATR, process control, MIR, NIR, non-invasive|
How does it work?
|Primary objective||Infrared (IR) - spectroscopy offers the possibility to measure substrate conversion or product/ biomass formation directly in food fermentation processes, eliminating the need for additional off-line assays.|
|Working principle|| On-line process control of fermentation processes is often limited to the measurement of chemical and physical parameters like temperature, gas composition or pH. Information on substrate conversion or product/ biomass formation must be obtained by off-line assays. These are time-consuming and bear a risk of process contamination and are therefore performed rather periodically.
Spectroscopic measurements with suitable on-line sensors provide the opportunity to monitor the conversion and formation of a broad variety of biomolecules like sugars, organic acids, alcohols and proteins. The method can be applied to the actual fermentation process and facilitates a nearly real-time detection of the above mentioned biomolecules.
Infrared (IR) – spectroscopy:
IR – spectroscopy is a method that makes use of the specific physical properties of simple to complex molecules in the infrared range of the electromagnetic light spectrum (0.8 – 1000 µm), namely in the near-infrared (NIR, 0.8 – 2.5 µm), the mid-infrared (MIR, 2.5 - 25 µM) and the far-infrared (FIR, 25 – 1000 µm) region. Molecules active in the IR – region possess at least one asymmetrical chemical bond. CO for example has a distinct IR – signal whereas N2 does not. The more complex a molecule is the more signals it exhibits. This results in a specific “fingerprint” of the molecule which allows predictions of a sample composition and the concentration of compounds.
In FTIR – measurements, a broad range of spectral data is collected in a wide spectral range. This leads to an improved signal-to-noise-ratio. After the raw data acquisition, the actual spectrum is evaluated by a mathematical algorithm, the Fourier transform. FTIR – spectrometers are preferentially applied in the MIR or FIR region. In the NIR, conventional IR – spectrometers are widely distributed.
ATR (Attenuated Total Reflectance):
ATR is a sampling technique in which the sample is in direct contact with a reflective crystal surface. The IR – beam is passed through the crystal, resulting in an evanescent wave that extends into the sample for only a few micrometres. This constitutes a huge advantage over conventional transmission measurements, especially for aqueous or highly absorbing samples.
|Important process parameters||overall sensitivity of the detection system (wavelength range, light source, detectors, CO2 adherence to ATR surface, biofilm formation, temperature)|
|Important product parameters||compounds in the fermentation process, sample absorbance|
What can it be used for?
|Products||Liquid products, fermented products (e.g. ethanol or lactic acid fermentations), beverages, food waste|
|Operations||On-line detection, fermentation process control|
|Solutions for short comings||Infrared-on-line-monitoring is needed in food fermentation processes which afford rapid, constant and effective control of the fermentation progress and identification of the included biomolecules. It therefore enhances the quality and safety of the final product , , .|
What can it NOT be used for?
|Products||Non-fermented foods, dry foods|
|Operations||The application of IR/ FTIR online monitoring is restricted in operations that do not provide suitable physical parameters for optical detectors (e.g. high optical density or dispersion). Operations which do not include the turnover of biomolecules/ biomass with additional need of their identification/ quantification may not benefit from this technique.|
|Risks or hazards|
|Modularity /Implementation||Easy implementation in old and new fermentation equipment.|
|Consumer aspects||Since IR/ FTIR spectroscopy provides a method for the online monitoring of industrial processes it is unlikely that consumers are generally aware of the application of this technique. Given the fact that infrared light does not cause any changes in the molecular composition of a product and does not cause the formation or liberation of allergenic or toxic by- products, this application can be viewed as completely harmless for the production of foodstuffs. Furthermore, since it is a non- invasive tool of process control, the need for off-line measurements with a risk of process contamination is reduced, leading to enhanced products safety and freshness .|
|Legal aspects||None to be expected. The method does not influence or alter the product properties.|
Facilities that might be interesting for you
|Institutes||UTCN, DTU Food, University of Vienna|
|Companies||Bartec Benke GmbH, Vital Sensors Technologies, Bellingham & Stanley|
overall sensitivity of the detection system (wavelength range, light source, detectors, CO2 adherence to ATR surface, biofilm formation, temperature) compounds in the fermentation process, sample absorbance Light equipment 2.1.1 physical, chemical conversion other http://www.cta.tuwien.ac.at/; http://www.abe.psu.edu/; companies websites