FOOD CHEMISTRY
CARBOHYDRATES PROTEINS AND LIPIDS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Lactose
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Sucrose
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Glycogen
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Cellulose
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Detailed explanation-1: -If color changes to red, then 1.5 to 2.0 percent sugar is present. And if color changes to brick red, it means that more than 2 percent sugar is present in solution. Negative Benedict’s Test: No color change (Remains Blue). Reducing sugars absent.
Detailed explanation-2: -Benedict’s solution contains copper (II) sulphate and the Cu2+ ions are what give the solution its blue colour. If simple carbohydrates are present these sugars will, when the mixture is heated, reduce the copper and cause a red copper (I) oxide precipitate to form.
Detailed explanation-3: -Lactose, D-ribose, and D-glyceraldehyde would give a positive Benedict’s test. To be a reducing sugar, a disaccharide must contain an anomeric carbon atom that can open up to form an aldehyde functional group, as shown in this disaccharide (answers will vary).