Kestose
Kestose is a class of sugars that belongs to a group of fructooligosaccharides.
Chemical properties
Kestoses are typical fructooligosaccharides, and in its structure, one fructose molecule is combined with sucrose to form a trisaccharide. In the 1-kestose type, the fructose molecule will be connected to sucrose by a glycosidic bond. Different types of kestoses have different lengths of subunits in the chain, for example, 6-kestose has from 10 to 200 fructose residues and is also called levan type fructooligosaccharide. Also, 1-kestose has less than 50 fructose residues in the chain and is also called inulin type fructooligosaccharide.Kestoses are categorized based on their structure into 3 main groups: 1-kestose, 6-kestose, neokestose. The most common of them is 1-kestose which is found in many plants.
Biosynthesis
According to the conditions of the plant cell, kestose biosynthesis occurs in the vacuole. The precursor molecule of kestose is sucrose. The sucrose-sucrose fructosyl transferase enzyme relates a sucrose molecule with a fructose residue to a second sucrose molecule, producing a kestose-1 molecule. Following, the enzyme fructan-fructan 1-fructosyl transferase combines fructose residue from trisaccharides, and by that synthetase longer kestose-1 chain. Respectively, to synthesize 6-kestose chain, the enzyme fructan-fructan 6-fructosyl transferase should combine fructose residue from trisaccharide and that synthesize a longer chain.Food sources
As well as other fructooligosaccharides, kestose can be found in such plants as wheat, onions, asparagus, and banana. Moreover, the plant families of Compositae, Amaryllidaceae, Gramineae and Liliaceae contain kestose along with other fructooligosaccharides in parts of the plant such as fruits, roots, and tubers.| Ingredient | mg/g |
| Acorn Squash | 0.2 |
| Artichoke | 1.5 |
| Carrot | 0.3 |
| Chicory root | 1.7 |
| Garlic | 3.3 |
| Leek | 0.7 |
| Lettuce | 0.3 |
| Shallot | 4.5 |
| Yam | 0.2 |
Industrial production
In the industry, kestose, like other fructooligosaccharides, is produced by transfructosylation reaction of sucrose with the enzyme B-fructofuranosidase, which is obtained from the mold fungus Aspergillus niger.Potential health effects
Prebiotic activity
Kestose as well as many other fructooligosaccharides belong to the prebiotics, i.e. to the substances that have a positive effect on the intestinal microbiome after consuming them in food. In particular, the consumption of kestose mixed with other fructooligosaccharides increases the concentration of healthy probiotic bifidobacteria and decreases the concentration of the Clostridia, bacteria associated with inflammatory processes.Consequently, kestoses complies with the essential criteria required for a prebiotic: 1) they are not digested by enzymes of the mammalian host organism, 2) they have a positive effect on only positive probiotic microorganisms growth, 3) they have a positive effect on the microbiome in general, 4) they have a positive effect on the defense system of host organism.
Consumption with food
Kestose has less caloric value than sucrose, and is not a promoter of tooth decay. Consumption of kestose, as well as other prebiotics, reduces the risk of cancer, hyperlipidaemia and acute gastroenteritis.In particular, kestoses perform their prebiotic function by positively influencing the growth of lactobacilli and bifidobacteria probiotics, which protect the host organism from acute gastroenteritis, which appears when pathogenic microorganisms multiply in the intestines and has symptoms such as diarrhea, vomiting, and pain in the abdomen.