Study of Galactooligosaccharides production from dairy waste by FTIR and chemometrics as Process Analytical Technology

Galactooligosaccharides (GOS) production from whey, a relevant by-product of dairy industry, answers to the Circular Economy principle of extending the life cycle of products. Indeed, it allows the reuse of dairy waste to produce prebiotics to be used in functional food preparations. For this purpose, the effective monitoring of GOS production should be performed in real time and by environmentally friendly techniques. Thus, FTIR spectroscopy, combined with different chemometric approaches, has been tested to assess a Process Analytical Technology to follow GOS production from cheese whey. Partial Least Square regression models were reliable for lactose, glucose and galactose determination (Root Mean Square Error of Prediction of 21.9, 11.1 and 12.4 mg mL−1, respectively). Furthermore, Multivariate Curve Resolution – Alternating Least Square models were proposed to describe trends of the reaction components along the process being an interesting alternative to chromatographic determinations. The real time implementation of the proposed approach will provide the dairy industry with a reliable and green Process Analytical Technology for dairy waste reallocation, avoiding sample pre-processing, large use of organic solvents and long times of analysis.