FSN 125 Lecture Notes - Lecture 2: Granola, Glycerol, Corn Syrup
9 Nov 2017
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Food composition: (% of water, carbs, protein, fat, minerals/vitamins) Milk (lactose) has little structure, while carrot (cellulose/fiber) has a lot of structure (despite similar % water) Ex: grilling burgers -> water moves to atmosphere, meat is cooked, sugars are caramelized (from muscle) Ex: cake -> leavening, starch and protein form network (gluten: holds air cells in place, liquid -> mechanical solid, water is an ingredient. Water works as a reaction medium, heating medium, participates in reactions, and is being lost. Practice: if you have 60 g moisture & 40 grams solids (carbohydrates + proteins + fats + (cid:2872)(cid:2868)(cid:3034) (cid:3046)(cid:3042)(cid:3039)(cid:3031) = (cid:2871)(cid:2870) = 150% moisture db (for dehydration) For mold to grow, water is needed; bread will mold faster than lettuce. In lettuce, water is being held; doesn"t allow mold to grow. Correct definition: water activity is a measure of the energy status of the water in a system.
