Mobility of Lactose in Milk Powders
Abstract
Lactose is the major component of milk powders and is normally found to be in a glassy/amorphous state. During storage, lactose is known to participate in physicochemical processes, including crystallization on the surface and reaction with proteins such as -lactoglobulin. Lactose needs to be mobile to participate in such processes. However, there is a lack of evidence of its mobility in milk powders. In this study, we demonstrate that some of the lactose becomes mobile when milk powders are exposed to humid air an inappropriate storage condition. This mobility is evidenced by peaks in magic angle spinning NMR spectra of milk powders in the range of 3.5 ppm to 4.0 ppm, which stem from lactose molecules displaying considerable rotational mobility. These signals have a longitudinal relaxation time constant T1 similar to that of mobile water according to 2D T1 experiments under magic angle spinning. Furthermore, 2D HSQC magic angle spinning experiments of skim milk powder demonstrate the same fingerprint as that of lactose in the solution, confirming our observations.
Cite
@article{arxiv.2511.06834,
title = {Mobility of Lactose in Milk Powders},
author = {Armin Afrough and Pernille Andersen and Tanja Ninette Angelika Weihrauch and Dennis Wilkens Juhl and Serafim Bakalis and Kirsten Gade Malmos and Thomas Vosegaard},
journal= {arXiv preprint arXiv:2511.06834},
year = {2025}
}