Automatic pH-Controlled Thermal Modulation Unit for Yoghurt Production

Yoghurt, a widely consumed fermented dairy product, requires precise control of incubation and cooling conditions to ensure optimal fermentation and product quality. Small and medium-scale yoghurt manufactures often face challenges in maintaining consistent temperature and pH during fermentation, leading to inconsistencies in texture, flavor, and acidity. This study addresses the problem by developing a pH-controlled automatic thermal modulation unit. The system was designed with a goal to integrate incubation and cooling in a single system. Process simulation was used to ascertain uniform air velocity and temperature distribution. The expert pH controller monitors the fermentation conditions during yoghurt production by maintaining incubation temperatures at 40°C and once set pH is attained, the system automatically switches from incubation mode to cooling mode. The system rapidly cooled yoghurt to 4°C within 90 min halting further lactic acid production. Experimental results demonstrated uniform temperature distribution across the chamber, allowing uniform fermentation and preventing temperature-related inconsistencies in the final product. Various textural, chemical and sensorial parameters showed significant enhancement in yoghurt produced in the automated system compared to traditionally produced yoghurt. The developed system offers several advantages by seamlessly integrating automation with both incubation and cooling processes, like reducing the overall process time, minimizing handling and operational complexities, which helps to prevent defects such as uneven texture and excessive acidity. Additionally, the system's adaptable design allows it to be customized for other fermented dairy products, providing a versatile, automated and efficient solution for small to medium-scale dairy producers.