FDSC 300 Lecture Notes - Lecture 3: Dry Matter, Phosphorus Pentoxide, Vehicle Emissions Control
20 Oct 2017
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Dry matter has nutrition, is easier to transport (16977$) More moisture -> microbial growth, less shelf-stable. Foods are low, intermed, or high in moisture. Water forms (some methods can detect all, some may not) Free water: surround by other water, unattached (basically pure water in chem properties: available for microbes! (more free water, faster spoil) Trapped water (capillary): held physically in vessels, similar to bulk water. Bound water: physically link to polysaccharides/protein -> changed physiochem properties, chemically hydrates, linked to salts -> changed physiochem properties. Do(cid:374)"t (cid:374)eed (cid:373)o(cid:374)ito(cid:396)i(cid:374)g: air-forced (air flow; even temp, hotter) Faster than normal oven: vacuum (less pressure -> lower boil pt -> lower temp for evap, agents: cacl2 (safe), also so3, p2o5, h2so4 (effective) No decomposition (good for sugary products: microwave (vibrate water molecules -> generates heat) Can monitor wt loss during process: need to pre-d(cid:396)y li(cid:395)uid sa(cid:373)ples so does(cid:374)"t boil ove(cid:396, possible lipid ox (wt gain), loss of volatiles, protein and carb break down.
