Fructooligosaccharide
Encyclopedia
Fructooligosaccharides also sometimes called oligofructose or oligofructan, are oligosaccharide
fructan
s, used as an alternative sweetener
. FOS exhibits sweetness levels between 30 and 50 percent of sugar in commercially-prepared syrups. It occurs naturally, and its commercial use emerged in the 1980s in response to consumer demand for healthier and calorie-reduced foods.
degradation or transfructosylation processes.
FOS can be produced by degradation of inulin, or polyfructose, a polymer of D-fructose residue
s linked by β(2→1) bonds with a terminal α(1→2) linked D-glucose. The degree of polymerization of inulin ranges from 10 to 60. Inulin can be degraded enzymatically or chemically to a mixture of oligosaccharides with the general structure Glu-(Fru)n (GFn) and Frum (Fm), with n and m ranging from 1 to 7. This process also occurs to some extent in nature, and these oligosaccharides can be found in a large number of plants, especially in Jerusalem artichoke and chicory. The main components of commercial products are kestose (GF2), nystose (GF3), fructosylnystose (GF4), bifurcose (GF3), inulobiose (F2), inulotriose (F3), and inulotetraose (F4).
The second class of FOS is prepared by the transfructosylation action of a β-fructosidase of Aspergillus niger
on sucrose
. The resulting mixture has the general formula of GFn, with n ranging from 1 to 5. Contrary to the inulin-derived FOS, not only is there β(1→2) binding but other linkages do occur, however, in limited numbers.
Because of the configuration of their osidic bonds, fructooligosaccharides resist hydrolysis by salivary and intestinal digestive enzymes. In the colon they are fermented by anaerobic bacteria. In other words, they have a lower caloric
value, while contributing to the dietary fiber
fraction of the diet. Fructooligosaccharides are more soluble
than inulins and are, therefore, sometimes used as an additive to yoghurt
and other (dairy
) products. Fructooligosaccharides are used specially in combination with high-intensity artificial sweeteners, whose sweetness profile and aftertaste it improves.
s, onion
s, chicory
root, garlic
, asparagus
, barley
, wheat
, jícama
, and leek
s. Some grains and cereals, such as wheat, also contain FOS. The Jerusalem artichoke
and its relative yacón
have been found to have the highest concentrations of FOS of cultured plants.
in Japan for many years, even before 1990, when the Japanese government installed a "Functionalized Food Study Committee" of 22 experts to start to regulate "special nutrition foods or functional foods" that contain the categories of fortified foods (e.g., vitamin-fortified wheat flour), and is now becoming increasingly popular in Western cultures for its prebiotic
effects. FOS serves as a substrate for microflora in the large intestine, increasing the overall gastrointestinal tract
(GI Tract) health. It has also been touted as a supplement for preventing yeast infections.
Several studies have found that FOS and inulin promote calcium absorption in both the animal and the human gut. The intestinal microflora in the lower gut can ferment FOS, which results in a reduced pH. Calcium is more soluble in acid, and, therefore, more of it comes out of food and is available to move from the gut into the bloodstream.
FOS can be considered a small dietary fibre with (like all types of fibre) low caloric value. The fermentation of FOS results in the production of gases and acids. The latter provide some energy to the body.
, E. coli and many Clostridium
species, which are considered less-friendly bacteria in the gut. These species are responsible mainly for the gas formation (hydrogen and carbon dioxide), which results after ingestion of FOS. Most people can eat 5-10 grams of FOS without gaseous discomfort, whereas others have problems with 1 gram. The estimated optimal dose for adults is around 5-10 gram/day.
warned parents of babies that a major European Baby-Formula brand made in New Zealand does not comply with local regulations, (because it contains fructo-oligosaccharides (FOS)) and urged them to stop using it.
Oligosaccharide
An oligosaccharide is a saccharide polymer containing a small number of component sugars, also known as simple sugars...
fructan
Fructan
A fructan is a polymer of fructose molecules. Fructans with a short chain length are known as fructooligosaccharides, whereas longer chain fructans are termed inulins...
s, used as an alternative sweetener
Sugar substitute
A sugar substitute is a food additive that duplicates the effect of sugar in taste, usually with less food energy. Some sugar substitutes are natural and some are synthetic. Those that are not natural are, in general, called artificial sweeteners....
. FOS exhibits sweetness levels between 30 and 50 percent of sugar in commercially-prepared syrups. It occurs naturally, and its commercial use emerged in the 1980s in response to consumer demand for healthier and calorie-reduced foods.
Chemistry
Two different classes of fructooligosaccharide (FOS) mixtures are produced commercially, based on inulinInulin
Inulins are a group of naturally occurring polysaccharides produced by many types of plants. They belong to a class of fibers known as fructans. Inulin is used by some plants as a means of storing energy and is typically found in roots or rhizomes...
degradation or transfructosylation processes.
FOS can be produced by degradation of inulin, or polyfructose, a polymer of D-fructose residue
Residue (chemistry)
In chemistry, residue is the material remaining after a distillation or an evaporation, or to a portion of a larger molecule, such as a methyl group. It may also refer to the undesired byproducts of a reaction....
s linked by β(2→1) bonds with a terminal α(1→2) linked D-glucose. The degree of polymerization of inulin ranges from 10 to 60. Inulin can be degraded enzymatically or chemically to a mixture of oligosaccharides with the general structure Glu-(Fru)n (GFn) and Frum (Fm), with n and m ranging from 1 to 7. This process also occurs to some extent in nature, and these oligosaccharides can be found in a large number of plants, especially in Jerusalem artichoke and chicory. The main components of commercial products are kestose (GF2), nystose (GF3), fructosylnystose (GF4), bifurcose (GF3), inulobiose (F2), inulotriose (F3), and inulotetraose (F4).
The second class of FOS is prepared by the transfructosylation action of a β-fructosidase of Aspergillus niger
Aspergillus niger
Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus. It causes a disease called black mold on certain fruits and vegetables such as grapes, onions, and peanuts, and is a common contaminant of food...
on sucrose
Sucrose
Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...
. The resulting mixture has the general formula of GFn, with n ranging from 1 to 5. Contrary to the inulin-derived FOS, not only is there β(1→2) binding but other linkages do occur, however, in limited numbers.
Because of the configuration of their osidic bonds, fructooligosaccharides resist hydrolysis by salivary and intestinal digestive enzymes. In the colon they are fermented by anaerobic bacteria. In other words, they have a lower caloric
Calorie
The calorie is a pre-SI metric unit of energy. It was first defined by Nicolas Clément in 1824 as a unit of heat, entering French and English dictionaries between 1841 and 1867. In most fields its use is archaic, having been replaced by the SI unit of energy, the joule...
value, while contributing to the dietary fiber
Dietary fiber
Dietary fiber, dietary fibre, or sometimes roughage is the indigestible portion of plant foods having two main components:* soluble fiber that is readily fermented in the colon into gases and physiologically active byproducts, and* insoluble fiber that is metabolically inert, absorbing water as it...
fraction of the diet. Fructooligosaccharides are more soluble
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
than inulins and are, therefore, sometimes used as an additive to yoghurt
Yoghurt
Yoghurt, yogurt or yogourt is a dairy product produced by bacterial fermentation of milk. The bacteria used to make yoghurt are known as "yoghurt cultures"...
and other (dairy
Dairy
A dairy is a business enterprise established for the harvesting of animal milk—mostly from cows or goats, but also from buffalo, sheep, horses or camels —for human consumption. A dairy is typically located on a dedicated dairy farm or section of a multi-purpose farm that is concerned...
) products. Fructooligosaccharides are used specially in combination with high-intensity artificial sweeteners, whose sweetness profile and aftertaste it improves.
Food sources
FOS is extracted from fruits and vegetables such as bananaBanana
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....
s, onion
Onion
The onion , also known as the bulb onion, common onion and garden onion, is the most widely cultivated species of the genus Allium. The genus Allium also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion The onion...
s, chicory
Chicory
Common chicory, Cichorium intybus, is a somewhat woody, perennial herbaceous plant usually with bright blue flowers, rarely white or pink. Various varieties are cultivated for salad leaves, chicons , or for roots , which are baked, ground, and used as a coffee substitute and additive. It is also...
root, garlic
Garlic
Allium sativum, commonly known as garlic, is a species in the onion genus, Allium. Its close relatives include the onion, shallot, leek, chive, and rakkyo. Dating back over 6,000 years, garlic is native to central Asia, and has long been a staple in the Mediterranean region, as well as a frequent...
, asparagus
Asparagus
Asparagus officinalis is a spring vegetable, a flowering perennialplant species in the genus Asparagus. It was once classified in the lily family, like its Allium cousins, onions and garlic, but the Liliaceae have been split and the onion-like plants are now in the family Amaryllidaceae and...
, barley
Barley
Barley is a major cereal grain, a member of the grass family. It serves as a major animal fodder, as a base malt for beer and certain distilled beverages, and as a component of various health foods...
, wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
, jícama
Jícama
Pachyrhizus erosus, commonly known as Jícama , Yam, and Mexican Turnip, is the name of a native Mexican vine, although the name most commonly refers to the plant's edible tuberous root. Jícama is one species in the genus Pachyrhizus. Plants in this genus are commonly referred to as yam bean,...
, and leek
Leek
The leek, Allium ampeloprasum var. porrum , also sometimes known as Allium porrum, is a vegetable which belongs, along with the onion and garlic, to family Amaryllidaceae, subfamily Allioideae...
s. Some grains and cereals, such as wheat, also contain FOS. The Jerusalem artichoke
Jerusalem artichoke
The Jerusalem artichoke , also called the sunroot, sunchoke, earth apple or topinambour, is a species of sunflower native to eastern North America, and found from Eastern Canada and Maine west to North Dakota, and south to northern Florida and Texas...
and its relative yacón
Yacón
The Yacón is a perennial plant traditionally grown in the Northern and Central Andes from Ecuador to Argentina for its crisp, sweet-tasting tuberous roots. The texture and flavour are very similar to jicama mainly differing in that yacon has some slightly sweet resinous and floral undertones to...
have been found to have the highest concentrations of FOS of cultured plants.
Health benefits
FOS has been a popular dietary supplementDietary supplement
A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to supplement the diet and provide nutrients, such as vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet...
in Japan for many years, even before 1990, when the Japanese government installed a "Functionalized Food Study Committee" of 22 experts to start to regulate "special nutrition foods or functional foods" that contain the categories of fortified foods (e.g., vitamin-fortified wheat flour), and is now becoming increasingly popular in Western cultures for its prebiotic
Prebiotic (nutrition)
Prebiotics are non-digestible food ingredients that stimulate the growth and/or activity of bacteria in the digestive system in ways claimed to be beneficial to health. They were first identified and named by Marcel Roberfroid in 1995. As a functional food component, prebiotics, like probiotics,...
effects. FOS serves as a substrate for microflora in the large intestine, increasing the overall gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
(GI Tract) health. It has also been touted as a supplement for preventing yeast infections.
Several studies have found that FOS and inulin promote calcium absorption in both the animal and the human gut. The intestinal microflora in the lower gut can ferment FOS, which results in a reduced pH. Calcium is more soluble in acid, and, therefore, more of it comes out of food and is available to move from the gut into the bloodstream.
FOS can be considered a small dietary fibre with (like all types of fibre) low caloric value. The fermentation of FOS results in the production of gases and acids. The latter provide some energy to the body.
Side-effects
All inulin-type prebiotics, including FOS, are generally thought to stimulate the growth of Bifidobacteria species. Bifidobacteria are considered "friendly" bacteria. This effect has not been uniformly found in all studies, both for Bifidobacteria and for other gut organisms. FOS are also fermented by numerous bacterial species in the intestine, including KlebsiellaKlebsiella
Klebsiella is a genus of non-motile, Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. It is named after the German microbiologist Edwin Klebs...
, E. coli and many Clostridium
Clostridium
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle...
species, which are considered less-friendly bacteria in the gut. These species are responsible mainly for the gas formation (hydrogen and carbon dioxide), which results after ingestion of FOS. Most people can eat 5-10 grams of FOS without gaseous discomfort, whereas others have problems with 1 gram. The estimated optimal dose for adults is around 5-10 gram/day.
NZ NZFSA regulation
The Food Safety AuthorityEuropean Food Safety Authority
The European Food Safety Authority is an agency of the European Union that provides independent scientific advice and communication on existing and emerging risks associated with the food chain, created by European Regulation 178/2002....
warned parents of babies that a major European Baby-Formula brand made in New Zealand does not comply with local regulations, (because it contains fructo-oligosaccharides (FOS)) and urged them to stop using it.