May 11, 2016

Understanding the types of sugars and carbohydrates

Carbohydrates, or saccharides using their scientific name, are molecules consisting of rings of carbon, hydrogen and hydrogen atoms. They are important sources of energy for the body and are divided into four main chemical groups in order of size and complexity:

Monosaccharidesgrapes

E.g. glucose, fructose, galactose and xylose. The later two are rarely found naturally on their own but some amounts of free natural glucose (not added) can be found in dried fig, sweet corn, grapes, mango and bananas. Fructose is more commonly found in fruit, such as honey, apples, fig, grapes, pears and some root vegetables. The vast majority of glucose and fructose is added by the manufacture, chief or consumer.

Disaccharidessugar

Sucrose (a fusion of glucose and fructose) is the main component of table sugar. It is the usual sugar added to sweets, candies, sugary drinks, toffees, pastries, cakes, donuts and even processed foods. Sucrose is harvested from sugar cane or sugar beet. Lactose (glucose and galactose) is the common sugar found in milk. People with lactose intolerance lack the enzyme in the gut, which breaks down the bond between glucose and galactose to enable its absorption. Maltose (glucose and glucose) is found in malted drinks, beer and can be found naturally in cereals.

Oligosaccharides

These are intermediate-chain carbohydrates found in artichoke, budock, chicory, leeks, asparagus and onions. They are commonly used as food additives as the give food and drinks a smooth, more substantial texture. The most commonly used oligosaccharide additives include maltodextrins, inulin and oligofructose. They are sometimes referred to as soluble fibre or prebiotics because they are not easily broken down in the small bowel and 90% pass to the large bowel, providing energy for the commensal bacteria.

potatoesPolysaccharides

E.g. starch, amylose, cellulose and pectins. Starch is the most common carbohydrate in the human diet and is contained in many staple foods. The major sources of starch are cereals (rice, wheat, maize, oats, millet, barley) and any foods made from them, such as bread, pasta, chips, cakes and noodles. They are also found in root vegetables, such as potatoes, carrots, cassava, swede, sweet potato, yams and legumes (beans, lentils, soy, peanuts, beans, peas). These complex polysaccharide-containing foods tend to contain other nutrients, such as fibre, proteins, vitamins and minerals; these are not only are healthy for the body, they slow the transit of the food through the gut, slowing the stomach emptying time, and delaying break down and absorption of the carbohydrates. The trouble is, processing these foods often removes many of these healthy elements and increases their breakdown and absorption times thus increasing their glycaemic index.

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