Optimization of a portable NIR device for the optical supervision of milk coagulation process

Abstract

The coagulation of milk is the fundamental process in cheese-making, which is based on a gel formation as consequence of physicochemical changes taking place in the casein micelles. Monitoring the whole process of milk curd formation is a dedicated process for dairy researchers and cheese companies. In addition to advances in composition-based applications by means of NIR spectroscopy, researchers are pursuing dynamic applications that show promise especially with regard to tracking a sample in situ during processing The objective of this work is to propose an original portable NIR equipment to supervise the milk coagulation process. The experiments have been carried out on sheep and goat milk, by immersion of the probe directly in the liquid and acquiring spectrum each 1 minute during the 30 minutes of coagulation process. The increasing values of transflected light registered allow identifying, based on PCA analysis, the different kinetics that occur along the gel formation and the time to reach the optimal gel firmness to cut the cur