Ketoseja

Ketoseja refer to ketose sugars, a class of monosaccharides defined by a carbonyl group (a ketone) located at carbon 2. In English, the term is ketoses; ketoseja is the plural form used in some languages or contexts.

Ketoses include fructose (a hexose ketose), ribulose and xylulose (pentose ketoses), and dihydroxyacetone (a triose ketose). They can cyclize to form five- or six-membered rings, giving furanose and pyranose forms; anomeric configuration is defined at the ring carbon.

Natural occurrence and metabolism: Ketoses are found in fruits, honey, and as parts of more complex carbohydrates such as oligosaccharides. In metabolism they can interconvert with aldoses through enediol intermediates, and fructose is metabolized to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate in glycolysis.

Chemical properties: Ketoses are reducing sugars because they can tautomerize to aldoses; they can participate in Maillard reactions and browning; they can be detected by chemical tests for reducing sugars like Benedict's or Fehling's test under appropriate conditions.

Industrial relevance and naming: Fructose is the most common ketose in foods; it is sweeter than sucrose and widely used in sweeteners. The production often involves isomerization of glucose to fructose (high-fructose syrup). When writing in English, ketoses is used; ketoseja is the plural in other languages.

---