Utilization of FT-NIR spectroscopy to check acidity of various types of cheeses

Abstract

Background: Monitoring the acidity of cheese is an important control mechanism in various stages of manufacture, including aging. Acid development in cheesemaking is essential to cheese flavor, texture, and safety. Objective: The aim of the work was to develop and validate calibration models by using NIR spectroscopy, which allows for the monitoring of changes in cheese acidity (pH and titration acidity) during cheese ripening. Methods: Cheeses were analyzed by an FT-NIR spectrometer. Each of the samples was analyzed three times, and for calibration, an average spectrum was used. A partial least-squares regression was used to develop calibration models. The constructed calibration models were validating by full cross-validation. Results: Calibration models were created with a high correlation coefficient for the following cheese pH levels: blue cheese (0.966), Olomouc curd read smear cheese (0.984), and fresh goat cheese (0.980). Results of the calibration of titratable acidity are functional for fresh goat cheese (0.953) and mozzarella (0.999). Conclusions: The results of these new calibration methods showed the possibility of NIR technology for the fast determination of pH and titratable acidity. Highlights: Detection of cheese acidity using FT-NIR spectrometry enables rapid evaluation of the process of lactic acidification in particular cheese technological operations, including the maturing of cheeses.