Chapter 4 Carbohydrates (plant-derived energy nutrients)

carbohydrate

one of the three macronutrients a compound made up of carbon, hydrogen, and oxygen, that is derived from plants and provides energy

glucose

the most abundant sugar molecule, a monosaccharide generally found in combination with other sugars; it is the preferred source of energy for the brain and an important source of energy for all cells

photosynthesis

the process by which plants use sunlight to fuel a chemical reaction that combines carbon and water into glucose, which is then stored in their cells

simple carbohydrate

commonly called sugar, can be either a monosaccharide (such as glucose) or a disaccharide

monosaccharide

the simplest of carbohydrates, consisting of one sugar molecule, the most common form of which is glucose

disaccharide

a carbohydrate compound consisting of two sugar molecules joined together

fructose

the sweetest natural sugar, a monosaccharide that occurs in fruits and vegetables, also called levulose or fruit sugar

high fructose corn syrup

a highly sweet syrup that is manufactured from corn and is used to sweeten soft drinks, desserts, candies, and jellies

galactose

a monosaccharide that joins with glucose to create lactose, one of the three most common disaccharides

lactose

a disaccharide consisting of one glucose molecule and one galactose molecule. It is found in milk, including human breast milk also called milk sugar

maltose

a disaccharide consisting of two molecules of glucose. It does not generally occur independently in foods but results as a by product of digestion also called malt sugar

fermentation

a process in which an agent causes an organic substance to break down into simpler substances resulting in the production of ATP

sucrose

a disaccharide composed of one glucose molecule and one fructose molecule, sucrose is sweeter than lactose or maltose

complex carbohydrate

a nutrient compound consisting of long chains of glucose molecules such as starch glycogen and fiber

polysaccharide

a complex carbohydrate consisting of long chains of glucose

starch

a polysaccharide stored in plants, the storage form of glucose in plants

glycogen

a polysaccharide the storage form of glucose in animals

dietary fiber

the non-digestible carbohydrate parts of plants that form the support structures of leaves stems, and seeds

functional fiber

the non-digestible forms of carbohydrates that are extracted from plants or manufactured in a laboratory and have known health benefits

total fiber

the sum of dietary fiber and functional fiber

soluble fibers

fibers that dissolve in water

viscous

having a gel like consistency viscous fibers form a gel when dissolved in water

insoluble fibers

fibers that do not dissolve in water

gluconeogenesis

the generation of glucose from the breakdown of proteins into amino acids

ketosis

the process by which the breakdown of fat during fasting states results in the production of ketones

Ketones

substances produced during the breakdown of fat when carbohydrate intake is insufficient to meet energy needs. Ketones provide an alternative energy source for the brain when glucose levels are low

ketoacidosis

a condition in which excessive ketones which are acidic lower the pH of blood, altering basic body functions and damaging tissues

salivary amylase

an enzyme in saliva that breaks starch into smaller particles and eventually into the disaccharide maltose

pancreatic amylase

an enzyme secreted by the pancreas into the small intestine that digests any remaining starch into maltose

maltase

a digestive enzyme that breaks maltose into glucose

sucrase

a digestive enzyme that breaks a sucrose into glucose and fructose

lactase

a digestive enzyme that breaks lactose into glucose and galactose

insulin

the hormone secreted by the beta cells of the pancreas in response to increased blood levels of glucose, it facilitates the uptake of glucose by body cells

glucagon

the hormone secreted by the alpha cells of the pancreas in response to decreased blood levels of glucose it causes the breakdown of liver stores of glycogen into glucose

hypoglycemia

a condition marked by blood glucose levels that are below normal fasting levels

glycemic index

the system that assigns ratings (or values) for the potential of foods to raise blood glucose and insulin levels

glycemic load

the amount of carbohydrate in a food multiplies by the food’s glycemic index, divided by 100

added sugars

sugars and syrups that are added to food during processing or preparation

enriched foods

foods in which nutrients that were lost during processing have been added back, so that the food meets a specified standard

fortified foods

foods in which nutrients are added that did not originally exist in the food or which existed in insignificant amounts

nutritive sweeteners

sweeteners such as sucrose, fructose, honey, and brown sugar, that contribute calories (energy)

nonnutritive sweeteners

manufactured sweeteners that provide little or no energy (also called alternative sweeteners)

acceptable daily intake

an FDA estimate of the amount of a nonnutritive sweetener that someone can consume each day over a lifetime without adverse effects