Monitoring the effect of inulin, protein, and calcium on milk coagulation phases using a fibre optic sensor

Validation of an Optical Technology for the Determination of pH in Milk during Yogurt Manufacture

Current systems that allow inline pH control in the fermented dairy industry have drawbacks, such as protein adhesion on the non-glass pH probes, measurement distortion, frequent recalibration needs, and sensitivity to extreme pH conditions encountered during clean-in-place operations. Therefore, the objective of this study was to validate the feasibility of estimating the pH of milk during the yogurt making process by using a NIR light backscatter sensor measuring under different fermentation temperatures and milk protein concentrations using a mathematical model that correlates the light scatter signal with pH. Three replications of the experiment with two protein concentrations (3.5 and 4.0%) and two fermentation temperatures (43 and 46 °C) were used to validate this inline pH prediction model. Continuous and discontinuous measurements of pH were collected as a reference during fermentation, simultaneously with the light backscatter data acquisition. Also, the effect of adjusting the initial voltage gain of the light scatter device on the accuracy of the pH prediction model was evaluated. Temperature and initial voltage were the main factors affecting the fitting accuracy of the model. The adjustment of the initial voltage gain improved the pH prediction model fit. The model has been successfully validated for both continuous and discontinuous measurements of pH, with SEP values < 0.09 pH units and CV < 1.78%. The proposed optical inline and non-destructive method was feasible for inline pH monitoring of milk fermentation, avoiding traditional manual pH measurement.

Development and Characterization of Symbiotic Buffalo Petit Suisse Cheese Utilizing Whey Retention and Inulin Incorporation

This study presents the development and characterization of a novel buffalo Petit Suisse cheese, enhanced with symbiotic properties through an innovative whey retention method and incorporating inulin and xanthan gum. The research focused on assessing the cheese's physicochemical properties, shelf life, lactic acid bacteria viability, syneresis behavior, and the impact of varying concentrations of functional ingredients. The addition of inulin and xanthan gum, following a design of experiments, significantly influenced the cheese's texture and consistency. Higher inulin concentrations were associated with increased fermentation activity, as indicated by total titratable acidity, which showed an increase from 1.22% to 1.50% over a 28-day period, and pH levels that decreased from 3.33 to 2.96. The syneresis index varied across trials, with the highest reduction observed in trials with increased xanthan gum concentrations, effectively reducing syneresis to 0%. Lactic acid bacteria viability also showed notable variations, with the highest cell survival percentage reaching 107.89% in formulations with higher inulin and xanthan gum concentrations. These results underscore the importance of inulin and xanthan gum in enhancing the cheese's microbial stability and textural quality. The study concludes that the strategic use of inulin and xanthan gum improves the nutritional profile of buffalo Petit Suisse cheese and optimizes its textural and sensory attributes.