Why does powdered baby formula dissolve perfectly in water, but protein powder (or even chocolate for chocolate milk) usually clump up?
In: Chemistry
One anomer of **Lactose** (alpha-lactose) is often used in food products as a wetting agent to help products dissolve. The alpha-lactose crystals stay separate and hydrate easily.
Baby formula products generally contain lactose to provide carbohydrates – if that lactose is in the alpha anomer, it will dissolve easily.
Protein powders made from whey have much less lactose, so do not have this inbuilt wetting agent, and form dry clumps due to surface tension.
The alpha-lactose anomer can convert to the beta-lactose anomer when exposed to moisture. The beta-lactose forms a agglomeration of lactose crystals, which **clumps** together. This is why lactose-containing products can go hard when exposed to moist air, and become lumps that are much harder to dissolve.
One of my final year chemistry projects (bachelors degree, many years ago) was to see if I could determine the amount of beta-lactose in a lactose sample – this information is really important in the milk-processing industry, who use specialized drying techniques to maximise alpha-lactose crystallization when making lactose and milk powders. I made no headway on the project – I suspected at the time that some sort of IR Polarimetery or X-ray crystallization method might be required, but I didn’t have those sort of resources. It looks like NMR has also been used successfully.
[The measurement of the β/α anomer composition within amorphous lactose prepared by spray and freeze drying using a simple (1)H-NMR method](https://pubmed.ncbi.nlm.nih.gov/21901569/)
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