Chemical Composition of Food Flashcards
Proximate components (7)
- water (moisture)
- proteins
- fats (lipids)
- carbohydrates (sugar, dietary fiber)
- vitamins
- minerals (collectively as ash)
- Known to have a chemical composition of Cx(H20)y
- Contributes to sweetness, chemical reactivity, polymer functionality
Carbohydrates
carbohydrates are divided as:
simple (sugars)
complex (polysaccharides)
simple carbs: sugars (4)
monosaccharides disaccharides oligosaccharides sugar alcohols (polyols)
complex carbs: polysaccharides
digestible
dietary fiber
single sugar unit
monosaccharides
- known as blood sugar
- mild sweet flavor
- essential energy source
glucose
- sweetest of all sugars
- found in fruits and honey
- most common sweetener used in soft drinks, cereals, etc
fructose
- hardly taste sweet
- rarely exists as a single sugar unit
galactose
disaccharides
-Pairs of monosaccharides
-Combined by condensation,
separated by hydrolysis
Maltose
- glucose + glucose
- not abundant
- produced upon starch breakdown
Sucrose
-fructose + glucose
-Bears a sweet taste (fruit,
vegetables and grains)
-table sugar that is refined
from sugarcane and/ or sugar beets
Lactose
- Galactose + Glucose
- Known as milk sugar
- Primary carbohydrate of milk
Oligosaccharides
- Short-chain sugars made of monosaccharides
- 3- 10 sugar units
Raffinose, Stachyose and Verbascose
-Composed of Galactose, Glucose and Fructose -Found in seeds (legumes) -Cannot be enzymatically broken
-Non-sugar carbohydrates ༝ Chemical composition resembles one part (CHO) one part alcohol ༝ Commonly used as sweetener ༝ Erythritol, Xylitol, Mannitol, Sorbitol, Isomalt, Maltitol, Lactitol
Sugar alcohols (Polyols)
More than 10 sugar units
Digestible Polysaccharides
Major source of carbohydrates in the human diet
༝ Stored in plant cells
༝ Occurs as “granules”
Starch
Partially hydrolyzed starch in which glucose chains are reduced
༝ Hydrolysis can be done by heat or by enzymes
Dextrins
Found only in meats and animal tissues (liver and muscles)
Allows for breakdown to produce energy
Glycogen
Types of polysaccharides that are indigestible
༝ Can be fermented by colonic bacteria
Dietary Fiber
- resp for the woody texture of plants
- contributed to the characteristic aroma and taste of wood
Lignins
- Principal component of plant cell walls
- Responsible for the structure of vegetables and its crisp texture
Cellulose
- Heterogenous branched polymers found in plant cell walls
- Composed of uronic acids (sugar acids) and sugars
Hemicellulose
