Food Engineering Practice Test: Water, Carbohydrates and Dietary Fibre — Flashcards

Drinking water doesn't contain carbohydrates, sugar, fiber, or starches unless it has added flavorings like juice. 
Carbohydrates are naturally occurring compounds made up of carbon, hydrogen, and oxygen. They are the most widespread organic substances and play a vital role in all life. 

There are three main types of carbohydrates:
Sugars: Also called simple carbohydrates, these are the most basic form.
Starches: These are complex carbohydrates, which are made of lots of simple sugars strung together.
Fiber: This is also a complex carbohydrate. 

Monosaccharides are simple sugars made up of three to seven carbons. They can exist as a linear chain or as ring-shaped molecules. 
Polysaccharides are polymers of repeating units of monosaccharides and are also called "glycans". They are macromolecules and have high molecular weight. 

Common disaccharides include lactose, maltose, and sucrose. Lactose is a disaccharide consisting of the monomers glucose and galactose. It is found naturally in milk. Maltose, or malt sugar, is a disaccharide formed by a dehydration reaction between two glucose molecules.

Dietary fiber is a type of carbohydrate that the body cannot digest. It's mainly found in plant cell walls and includes cellulose, hemicellulose, and pectin. 

Dietary fiber can be classified into two categories based on its solubility in water: soluble and insoluble.
Soluble fiber
Attracts water and forms a gel during digestion. This slows the emptying of the stomach, shortens intestinal transit time, and delays the absorption of glucose.
Insoluble fiber
Does not dissolve in water and passes through the digestive tract. It can help add bulk and softness to stools to promote bowel regularity. 
Dietary fiber is the seventh largest nutrient group in the human body, after proteins, fats, carbohydrates, vitamins, minerals, and water.