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Tuesday, May 22, 2012

Dissecting a label

Ensconced in popular culture is this knee jerk reaction of chemophobia. That's this inherent assignment of a threatening nature to items named with the scientifically accurate chemical names. "Natural foods" advocates dissuade people from eating items with ingredients you "can't pronounce". This reaction is the butt of spoofs like the Dihydrogen Monoxide Research Center. A little interpretation of chemistry can take a lot of the fear out.

The Lactaid milk label. 

Closer up to the label.
Take, for example, my recent purchase of milk. Being normal (that is, not lactase persistent), I purchase lactose-free milk: an amazing product of modern food chemistry. If you recall, lactose is a milk sugar found in almost all milks, and it is broken down by the enzyme lactase. Well, you can just add lactase to milk, and viola, no more lactose.

But the enzyme is not the only ingredient in this carton. Being an enriched milk with calcium (not really sure why they do this), the added calcium is of the form calcium phosphate - basically the same stuff found in bone. But this stuff is only soluble in acid - and you can't add acid to milk without it coagulating (that's how paneer is made, by curdling milk with acid). So, the calcium phosphate is added as a very fine powder which will dissolve into free calcium when it hits the stomach acids.

To keep it in suspension, the milk has to be thicker - that's where carrageenan and guar gum come in. These are hydrocolloids - things that form gels with water. Carrageenan is extracted from seaweed, and guar comes from a bean. Together, these are added in such a low concentration that the milk stays liquid, but is thickened enough to keep things in suspension.

There you have it, nothing too scary about this label. Or even on the other side.

Another rBST denial.
I suspect that the atrocious use of passive voice here is written in fear of pointing out that this inordinate fear of growth hormones in cows contaminates the milk. Because it materially does not. Growth hormone induces an increase in milk yield, but chemical analyses demonstrate that this milk is not significantly different from untreated cows. So the whole "no hormones" schtick is primarily aimed at maintaining an easily manipulated emotional response.

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