Sugars (powerpoint)
Sugars, by weight, are the most common food ingredient. In addition to the obvious effects on flavor, sugars are added for a number of other reasons:
Lower water activity, control moisture migration
Affect colligative properties (freezing point depression, vapor pressure, boiling point)
Contribute to browning
Affect gelation
Affect crystallization
Bulk, dilution of other ingredients
Humectant
Viscosity
Substrate for fermentation
Glucose (Dextrose)
Common crystalline form is the monohydrate
Most common reducing sugar
Exists in multiple forms that differ in reaction rates, solubility, taste, etc.
Less sweet than sucrose
Less soluble than sucrose at temperatures below 103F
Favored energy source for bacteria
Usually added as corn syrup
When you see dextrose in the lower portions of the ingredient label, think about its use as a diluent, for browning or some other non sweet use.
Fructose (Levulose)
Sweeter than sucrose, sweetness decreases with increasing temperature
Open chain form is less sweet than ring form
Reducing sugar
Most commonly added as high fructose corn syrup
Crystalline fructose is expensive but you will find it in some drink mixes
Disappearance data in the US is about 100 lbs/person/year
Sucrose is non-reducing and does not participate in Maillard browning but does carmelize
Sucrose is the predominant sweetener in the world market. In the US, high fructose corn syrup has replaced sucrose in a number of applications.
When sucrose is hydrolyzed to yield glucose and fructose, the product is called invert sugar. This increases sweetness and solubility.
Sucrose is more substantially more soluble than dextrose at room temperature.
Lactose
Added for purposes other than sweetness. Can exist in several forms and may be a cause of moisture uptake and clumping in dried dairy products. In infant formula it is added to mimic mothers' milk. Commonly used for bulk in the single serve packets where the sweetness comes from high intensity sweetners. As a reducing sugar, it may be added to enhance Malliard browning.
Maltose
Disaccharide composed of glucose.
Used in some hard candies
Minor sugars
Galactose
Reducing sugar added to foods only as it is present in fermented dairy ingredients where lactose has been hydrolyzed and glucose used by the microorganisms.
Raffinose and stachyose
Not metabolished until "eaten" by the microflora in the colon. Cause flatulence. Occur in beans.
