Happy Turkey Day!!! Thanksgiving is a celebration of giving thanks for the harvest and of the past year1. Many countries around the world celebrate the harvest season in their own way, but these festivals typically emphasize gathering and feasting of foods and wines drawn from the new crops. It is no surprise that many Americans tend to overeat on Thanksgiving, and some may even think it is their patriotic duty to do so. But this can come at a high price as more people are hospitalized from food-related complications during this season2.
Kombucha is a fermented beverage from Northeast China that has gained popularity in the USA3. The Americas accounted for about 51% of the global Kombucha sales in 20164. Like other fermented food, Kombucha is loaded with beneficial effects like protection against metabolic disease, arthritis, psoriasis, constipation, indigestion, and hypertension5. So simply adding Kombucha to your Thanksgiving dinner may save you from an untimely visit to an urgent care.
Raman spectroscopy is a valuable process analytical technology (PAT) due to its capacity for non-destructive, real-time measurements and its ability to be implemented for online and inline monitoring. We have explored PAT using the B&W Tek PTRam system previously (Glucose and Lactate Monitoring with PTRam). Raman spectroscopy can monitor microbial activity by tracking changes in media components and metabolic products in a bioreactor. In the Kombucha brewing process, microorganisms produce ethanol and acetic acid, the two main components of the drink, from sugar6. In preparation for our Thanksgiving feast we have been brewing Kombucha in the lab, monitoring the process in situ with the PTRam equipped with an immersion shaft with sapphire ball probe, collecting spectra at 15 minute intervals. Figure 1 shows math-treated Raman spectra of 300 to 800 cm-1 region over the first three days of fermentation. This region is comprised of skeletal vibration of carbons and carbon-oxygen bonds of sugar7.Figure 1a
Figure 1 Relative Raman peak height of δ(C2–C1–O1) bending vibration (415 cm-1) of Kombucha broth7 (a), and math-treated Raman spectra of the exponential sugar uptake phase (growth phase).
We can track the fermentation by following the change in these Raman bands over time (Figure 2). The model built using B&W Tek BWIQ yielded an R-Square value of 0.99 for the calibration model and 0.93 for validation data sets over the growth phase.
Figure 2 Calibration model and validation data of glucose concentration at measured and predicted fermentation time.
In this process the PTRam system and Vision software were used for data collection and real-time monitoring. The B&W Tek Portable i-Raman Plus and i-Raman EX (1064 nm laser system) with BWSpec software can also be used. For more information about B&W Tek’s Raman systems, visit https://bwtek.com/technology/raman/.1. Silverman, D.J., 2021. https://www.britannica.com/topic/Thanksgiving-Day (Accessed 11/21/2021). 2. Brueck, H., 2017. https://www.businessinsider.com/why-thanksgiving-emergency-room-visits-spike-doctors-2017-11 (Accessed 11/21/2021). 3. Villarreal-Soto, S.A. et al., 2019. Impact of fermentation conditions on the production of bioactive compounds with anticancer, anti-inflammatory and antioxidant properties in kombucha tea extracts. Process Biochemistry, 83, 44-54. 4. Kombucha – Statistics & Facts, 2021. https://www.statista.com/topics/3513/kombucha/#dossierKeyfigures (Accessed 11/21/2021). 5. Sreeramulu, G., 2000. Kombucha fermentation and its antimicrobial activity. J. Agric. Food Chem., 48, 2589-2594. 6. Villarreal-Soto, S.A., 2018. Understanding Kombucha Tea Fermentation: A Review, Journal of Food Science, 83(3), 580-588 7. Boyaci, I.H, et. al., 2013. Rapid analysis of sugar in honey by processing Raman spectrum using chemometric methods and artificial neural networks. Food Chemistry, 136(2013) 1444-1452.