Lactic Fermentation in Traditional Beverages Made from Cereals and Tubers. Process Control Using a Biosensor

Monitoring lactic acid is a critical parameter during the production of fermented foods, as it serves as an indicator of product quality and process control. The use of biosensors offers a simple and cost-effective approach for real-time monitoring in the production chain.

A biosensor based on lactate oxidase (LacOx) was developed to determine lactic acid content in fermented beverages (chicha and pozol). Different membranes were evaluated as immobilization supports, with particular focus on enzyme stability. The system operated at a potential of -0.5 mV, and the amperometric signal was recorded after 10 seconds. Sensor performance was assessed through calibration, sensitivity, and kinetic analysis.

The enzymatic reaction rate was directly proportional to oxygen consumption (mg L⁻¹ O₂ s⁻¹), showing a linear detection range between 0.1 and 2 mM (R² = 0.9986). The sensor demonstrated good sensitivity at 0.1 mM and allowed membrane reuse up to 15 times. Enhanced stability was observed when using a cassava biopolymer as immobilization support. The Michaelis-Menten constant (KM = 340 µM) indicated a high affinity of the enzyme for the substrate.

The developed biosensor provides a reliable, sensitive, and low-cost method for monitoring lactic acid in fermented beverages and represents a practical tool for quality control in the food industry.