Electromagnetic fields effects on microbial growth in cocoa fermentation: A controlled experimental approach using...

Area of Science:

• Food Science and Technology
• Microbiology
• Biophysics

Background:

• Optimizing cocoa bean fermentation is key to enhancing sensory and nutritional qualities.
• Electromagnetic fields (EMF) offer a potential method for precise control of fermentation conditions.
• Understanding EMF effects on microbial kinetics is crucial for process optimization.

Purpose of the Study:

• To evaluate the impact of oscillating magnetic fields (OMF) on the growth kinetics of key microbial communities in Collections Castro Naranjal (CCN 51) cocoa beans.
• To determine the suitability of different growth models (Gompertz, Baranyi, Logistic) for describing microbial responses to OMF.

Main Methods:

• Cocoa beans were exposed to varying OMF strengths (0-80 mT) for 1 hour using a Helmholtz coil.
• Viable populations of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast (Y) were quantified via colony-forming unit (CFU) counting.
• Microbial growth data was analyzed using Gompertz, Baranyi, and Logistic models.

Main Results:

• The Logistic model accurately described LAB and yeast growth under OMF, while the Baranyi model fit AAB growth.
• OMF exposure resulted in lower maximum specific growth rates (μmax) for all microbial groups compared to controls.
• Acetic acid bacteria showed the highest average growth rate at 5 mT, and yeast exhibited the lowest at 80 mT.

Conclusions:

• Oscillating magnetic fields significantly influence the growth kinetics of cocoa bean fermenting microorganisms.
• OMF exposure leads to reduced microbial growth rates and extended lag phases, demonstrating its potential for controlling fermentation.
• Specific microbial groups exhibit differential responses to OMF, suggesting targeted applications in cocoa fermentation.