Inline control of yoghurt fermentation process using a near infrared light backscatter sensor. (July 2020)

• Record Type: Journal Article
• Authors: Arango, Oscar; Trujillo, Antonio José; Castillo, Manuel
• Is Part Of: Journal of food engineering. Volume 277(2020)
• Publication Date: 2020-07
• Subjects: Yoghurt fermentation -- Milk coagulation -- Optic sensor -- pH monitoring -- Inulin; Food industry and trade -- Periodicals; Food -- Analysis -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Analyse -- Périodiques; Aliments -- Recherche -- Périodiques; 664.005
• DOI: 10.1016/j.jfoodeng.2019.109885
• Languages: English
• ISSNs: 0260-8774

Abstract

Abstract: In industrial yoghurt production, continuous process monitoring using pH meters is a cumbersome and non-appropriate technique. The objective of this study was to evaluate the suitability of an optical sensor as a new method for the inline control of yoghurt fermentation. Tests were conducted with three fat and three inulin concentrations and fermentation was monitored simultaneously using an inline light backscatter sensor, pH-meters and a rheometer. A mathematical model that correlates the near infrared light backscatter ratio with the pH, at real time during milk fermentation, was developed. The model was calibrated and successfully validated at the different experimental conditions, predicting the evolution of pH from 5.2 to 4.6 with determination coefficient values higher than 0.993 and standard error of prediction values between 0.02 and 0.11 pH units. The results demonstrated that this is a promising method for the inline control of pH in industrial yoghurt production. Highlights: A promising method for in-line monitoring of yoghurt fermentation is presented. The method is based on using a non-destructive, non-intrusive inline optical sensor. Near infrared light backscatter was correlated with pH during fermentation evolution. The method predicted yoghurt pH from 5.2 to 4.6 with SEP between 0.02 and 0.11 pH units. The model would need to be calibrated for specific production conditions in yoghurt plants.