Development and Assessment of a Batch Type Ohmic Heating System for Milk Processing

Abstract

This study aims to develop and assess the performance of a batch-type ohmic heating system for the thermal processing of cow and buffalo milk, particularly investigating whether the ohmic system affects the nutritional and microbial quality of the milk. An experimental setup was fabricated with a 7-liter capacity, utilizing an agitator as one electrode and the vessel surface as the other. The system was tested for heating milk from 32°C to target temperatures of 75°C and 92°C. Key processing parameters, including agitator speed and applied voltage, were optimized for both milk types. The physicochemical and microbial properties of the ohmically heated milk were evaluated, along with performance metrics such as heating rates, power consumption, and system efficiency. The developed ohmic heating system achieved heating rates of 4.29°C/min for cow milk and 2.85°C/min for buffalo milk. Cow milk demonstrated lower energy consumption, requiring less time and voltage compared to buffalo milk, with system performance coefficients of 58% for cow milk and 50% for buffalo milk. However, fouling on the agitator surface was identified as a challenge for industrial applications. Importantly, the ohmic heating process preserved the nutritional content while effectively reducing microbial load, confirming its potential for dairy processing. In conclusion, the batch-type ohmic heating system exhibited high efficiency and rapid heating capabilities for both cow and buffalo milk, indicating its viability for commercial use. Future research should focus on addressing fouling issues and further optimizing the system, enhancing the overall potential of ohmic heating technology in the dairy industry.