Psicose

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Psicose
Psicose.png
Names
IUPAC name
(3R,4R,5R)-1,3,4,5,6-Pentahydroxyhexan-2-one
Other names
D-Psicose
Identifiers
23140-52-5 N
ChEBI CHEBI:27605 YesY
ChemSpider 81254 YesY
Jmol-3D images Image
MeSH psicose
PubChem 90008
Properties
C6H12O6
Molar mass 180.16 g·mol−1
Melting point 58 °C (136 °F; 331 K) [1]
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N verify (what isYesY/N?)
Infobox references

D-Psicose (D-allulose, D-ribo-2-hexulose, C6H12O6) is a low-energy monosaccharide sugar present in small quantities in natural products. First identified in wheat more than 70 years ago, psicose is a C-3 epimer of D-fructose, and is present in small quantities in agricultural products and commercially prepared carbohydrate complexes. The sweetness of psicose is 70% of the sweetness of sucrose.[2]

Though the U.S. Food and Drug Administration (FDA) allows Psicose to be used as a food ingredient, Psicose is not permitted in the European Union. [3] In February 2015, London-based Tate & Lyle released its proprietary variant of Psicose, known as Dolcia Prima allulose. The company plans to market it for use in foods and beverages as a low-calorie sugar substitute in beverages, yogurt, ice cream, and baked products.

Two studies into the toxicity of Psicose found that rats fed diets with extremely high levels of d-psicose appeared to suffer harm to the intestinal tract. [4] The studies also found that the relative weights of liver and kidney were significantly higher in the D-psicose group than in the sucrose group.[5] The studies' authors noted, "the effects of long-term feeding of D-psicose must be elucidated prior to utilization as a physiologically functional food." U.S. nutritionist Kantha Shelke seconded these concerns, and warned that "the food marketplace is being used as a test laboratory for this product."[6]

A study sponsored by Psicose producer Tate & Lyle showed that because Psicose is not generally metabolized, its caloric value is significantly lower than table sugar - nearly zero. The company maintains that Psicose can benefit consumers who monitor their sugar intake because it does not impact the glycemic response significantly. A study cited by Tate & Lyle showed that when 25 grams of psicose were ingested compared to 25 grams of sugar, psicose did not raise blood sugar levels above the baseline for two hours after ingestion.[7] [8]

The first mass-production method for psicose was established when Ken Izumori at Kagawa University in Japan discovered the key enzyme, D-tagatose 3-epimerase, to convert fructose to D-psicose in 1994.[9][10] This method of production has a high yield, but suffers from a very high production cost, in the hands of the Kagawa research group.

References[edit]

  1. ^ David R. Lide, G.W.A. Milne, ed. (December 30, 1993). CRC Handbook of Data on Organic Compounds (3rd ed.). CRC Press. p. 4596. 
  2. ^ Chung MY, Oh DK, Lee KW. Hypoglycemic health benefits of D-psicose. J Agric Food Chem. 2012, 60:863-869.
  3. ^ Tate & Lyle unveils Dolcia Prima allulose low-calorie-sugar;http://www.foodnavigator-usa.com/Suppliers2/Tate-Lyle-unveils-Dolcia-Prima-allulose-low-calorie-sugar.
  4. ^ The Study on Long-Term Toxicity of D-Psicose in Rats;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2771247/.
  5. ^ The 90-day oral toxicity of d-psicose in male Wistar rats;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3303479/.
  6. ^ Tate & Lyle unveils Dolcia Prima allulose low-calorie-sugar;http://www.foodnavigator-usa.com/Suppliers2/Tate-Lyle-unveils-Dolcia-Prima-allulose-low-calorie-sugar.
  7. ^ Chung MY, Oh DK, Lee KW. Hypoglycemic health benefits of D-psicose. J Agric Food Chem. 2012, 60:863-869.
  8. ^ Wolever T, Jenkins AJ. A Randomized, Controlled, Crossover Study to Assess the Effects of a Sweetener on Postprandial Glucose and Insulin Excursions in Healthy Subjects. 2015. Glycemic Index Labs. Toronto, ON, Canada.
  9. ^ Itoh H, Okaya H, Khan AR, Tajima S, Hayakawa S, Izumori K (1994). "Purification and characterization of D-tagatose 3-epimerase from Pseudomonas sp. ST-24". Biosci Biotechnol Biochem. 58: 2168–2171. doi:10.1271/bbb.58.2168. 
  10. ^ Itoh H, Sato T, Izumori K (1995). "Preparation of d-psicose from d-fructose by immobilized d-tagatose 3-epimerase." J Fermentation and Bioengineering 80(1): 101–103.