Benedict's Test is used to identify a reducing Carbohydrate.
1 mL of Benedict's Reagent [Sodium citrate, Sodium carbonate & Copper (II) sulfate] was added to 0.5 mL of each sample.
Samples were then heated for 2 min in boiling water, followed by cooling in an ice water bath.
Monosaccharides will be oxidized in the reaction, while the Copper (II) sulfate will be reduced to copper (I) oxide, producing a red precipitate.
Take note that if polysaccharides and disaccharides are heated too long, the glycosidic bond may be broken, resulting in the production of monosaccharides. This may result in a delayed positive for Benedict's test.
All Monosaccharides and some Disaccharides are considered reducing sugars.
Lactose & Maltose are both considered a reducing sugar.
Sucrose is not considered a reducing sugar based on the structure of the Glycosidic bond.
All Polysaccharides are not considered reducing sugars, as they are complex sugars.
Blue colour = No reducing sugars
Green colour = Low level of reducing sugars
Orange colour = Moderate level of reducing sugars
Red colour = High level of reducing sugars
Negative Control = Distilled Water
Positive Control = 1 % (w/v) Glucose
Positive Control = 1 % (w/v) Lactose
Positive Control = 1 % (w/v) Starch
Unknowns Tested = 12
Alphabetical list of Samples:
0% Skim Milk, 2% Milk, 2% Lactose-free Milk, 2%+ Milk (+ Protein), 5% Light Cream, 10% Table Cream, 35% Whipping Cream, Almond Milk, Cashew Milk, Coconut Milk , Oat Milk, Soy Milk
16 сен 2024
