NATS 1560 Lecture 8: Chapter-8-Food-and-Fermentation
6 Nov 2017
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Milk and dairying: fermentation is the conversion of sugars by bacterial action into carbon dioxide gas and ethyl alcohol, co(cid:449)"s (cid:373)ilk is (cid:1012)(cid:1011)% (cid:449)ater. The (cid:374)ext (cid:373)ai(cid:374) co(cid:373)po(cid:374)e(cid:374)t is lactose sugar, which is a disaccharide combining glucose and galactose (5%). Fat averages at 3. 9% and protein averages at 3. 5%, primarily casein: bacteria invade fresh milk and degrade it. Some bacteria produce lactic acid which makes milk sour: cows produce milk to feed their calves. When calves were weaned, milk production naturally shuts down. But if farmers continue to milk the cow and take calves from their mother earlier, they would get more milk: most milk is pasteurized (20th century)- heated to a high temperature for a few seconds. Almost all milk sold today is also homogenized. This technique stops the cream from separating and rising to the top. Hot milk is blasted through nozzles at high pressure. This breaks down the fat globules into smaller globules.
