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. In February 2015, London-based Tate & Lyle released its proprietary variant of psicose, known as Dolcia Prima allulose.[3] 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."[3]

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.[2] 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 g of psicose were ingested compared to 25 g of sucrose, psicose did not raise blood sugar levels above the baseline for two hours after ingestion.[6]

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.[7][8] This method of production has a high yield, but suffers from a very high production cost.

References[edit]

  1. ^ Lide, David R.; Milne, G.W.A., eds. (30 Dec 1993). CRC Handbook of Data on Organic Compounds (3rd ed.). CRC Press. p. 4596. 
  2. ^ a b Chung, Min-Yu; Oh, Deok-Kun; Lee, Ki Won (1 Feb 2012). "Hypoglycemic health benefits of D-psicose". J Agric Food Chem (ACS) 60 (4): 863–869. doi:10.1021/jf204050w. PMID 22224918. 
  3. ^ a b Watson, Elaine (25 Feb 2015). "Tate & Lyle unveils Dolcia Prima allulose low-calorie-sugar: ‘We believe this will change the food and beverage landscape forever’". foodnavigator-usa.com. William Reed Business Media SAS. 
  4. ^ Yagi, Kanako; Matsuo, Tatsuhiro (Nov 2009). "The Study on Long-Term Toxicity of D-Psicose in Rats". J Clin Biochem Nutr (The Society for Free Radical Research Japan) 45 (3): 271–277. doi:10.3164/jcbn.08-191. PMID 19902016. 
  5. ^ Matsuo; Ishii, Reika; Shirai, Yoko (Mar 2012). "The 90-day oral toxicity of D-psicose in male Wistar rats". J Clin Biochem Nutr (The Society for Free Radical Research Japan) 50 (2): 158–161. doi:10.3164/jcbn.11-66. 
  6. ^ Kendall C, Wolever T, Jenkins A et al. "A Randomized, Controlled, Crossover Study to Assess the Effects of a Sweetener on Postprandial Glucose and Insulin Excursions in Healthy Subjects". May 2014. Glycemic Index Laboratories. Toronto, ON, Canada.
  7. ^ Itoh, Hiromichi; Okaya, Hiroaki; Khan, Anisur Rahman et al. (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. 
  8. ^ Itoh, Hiromichi; Sato, Tomoko; Izumori, Ken (1995). "Preparation of D-psicose from D-fructose by immobilized D-tagatose 3-epimerase". J Fermentation and Bioengineering (Elsevier B.V.) 80 (1): 101–103. doi:10.1016/0922-338X(95)98186-O.