每周分子 | Molecule of the Week

Original ACS 美国化学会 ACS美国化学会 2022-07-01

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每周分子：D-阿洛酮糖

Molecule of the Week: D-Psicose

D-阿洛酮糖更为有名的名称是D-allulose, 是一种稀有的天然单糖。D-阿洛酮糖是一种己酮糖，与常见的单糖(如：葡萄糖和果糖)具有相同的最简式，是果糖的差向异构体。D-阿洛酮糖的对映异构体L-阿洛酮糖在自然界中尚未被发现，但已经被人工合成出来。

早在1915年，D-阿洛酮糖被称为D-假果糖。德国化学家H. Ohle和F. Just在1935年确定了它的结构并将其重新命名为D-阿洛酮糖。1942 年，美国纽约糖业实验室(New York Sugar Trade Laboratory)的F. W. Zerban和纽约城市大学布鲁克林学院的Louis Sattler将其从商业销售的甘蔗糖蜜中分离出来。当时，D-阿洛酮糖被认为不能发酵，因此被认为没有什么实用价值。

文献中报道的D-阿洛酮糖的物理形态有所不同，如，被描述为58°C或109°C的粘性液体或白色结晶固体。这些差异可能归因于化合物结晶困难。在≈1.0 kg/L时，它极易溶于水。(葡萄糖在≈900 g/L溶解，果糖在 ≈4 kg/L溶解。)

D-阿洛酮糖的甜度是蔗糖(食糖)的 70%，但它只有蔗糖约10%的营养能量(卡路里)值。因此，D-阿洛酮糖正在被开发作为蔗糖和人造甜味剂的替代品。它最初是由玉米制成的；但是在今年，食品配料初创公司Bonumose(美国弗吉尼亚州，夏洛茨维尔)和药物服务公司Novasep(法国，里昂)合作，通过酶法，利用纤维素、淀粉或它们的衍生物来制造D-阿洛酮糖和另外一种低热量糖D-塔格糖。

D-阿洛酮糖信息速览

CAS 登记号	551-68-8
SciFinder命名	551-68-8
分子式	C₆H₁₂O₆
摩尔质量	180.16 g/mol
外观	白色晶体或粘稠液体
熔点	见正文
水溶性	≈1.0 kg/L

D-阿洛酮糖危害信息

非有害物质或混合物。

【关于每周分子】

自2001年以来，“每周分子”已成为广受欢迎的栏目。多数分子由读者推荐。每个结构都经由科学家审查，并以3-D和平面图像的形式显示，同时附有该分子简介。可以通过美国化学文摘社 (CAS) 提供的SciFinder中的CAS REGISTRY获取“每周分子”的更多信息。CAS REGISTRY中的每条物质信息都展示了物质的CAS登记号、索引名、通用名、商品名、书目信息等其他更多信息。发送邮件至motw@acs.org推荐您感兴趣的分子吧。

D-Psicose, also widely known as D-allulose, is a natural but rare monosaccharide. It is a ketohexose that has the same empirical formula as common monosaccharides such as glucose and fructose. It is epimeric with fructose at the 3-position. Its enantiomer, L-psicose1, is unknown in nature but has been synthesized..

Known as early as 1915 as D-pseudofructose, German chemists H. Ohle and F. Just determined its structure in 1935 and renamed it D-psicose. In 1942, F. W. Zerban at the New York Sugar Trade Laboratory (New York City) and Louis Sattler at Brooklyn College (NY) isolated it from commercial cane molasses. At the time, it was deemed to be unfermentable and therefore of little practical value.

The physical state of D-psicose is variously reported in the literature as a viscous liquid or a white crystalline solid with a melting point of 58 °C or 109 °C. These discrepancies are probably attributable to the difficulty of crystallizing the compound. At ≈1.0 kg/L, it is extremely soluble in water. (Glucose dissolves at ≈900 g/L, fructose at ≈4 kg/L.)

D-Psicose is 70% as sweet as sucrose (table sugar), but it has only ≈10% of the nutritional energy (calorie) value. As a result, it is under development as a replacement for sucrose and artificial sweeteners. It was originally produced from corn; but this year, food-ingredient startup Bonumose (Charlottesville, VA) and drug-services company Novasep (Lyon, France) teamed up to manufacture D-psicose and fellow low-calorie sugar D-tagatose2 from cellulose, starch, or their derivatives via an enzymatic process.

D-Psicosefast facts

CAS Reg. No.	551-68-8
SciFinder nomenclature	D-Psicose
Empirical formula	C₆H₁₂O₆
Molar mass	180.16 g/mol
Appearance	White crystals or viscous liquid
Melting point	See text
Water solubility	≈1.0 kg/L

D-Psicose hazard information

Not a hazardous substance or mixture.

About Molecule of the Week

MOTW has been a popular feature on ACS website since 2001. Many molecules are suggested by our website visitors. Every structure is reviewed by a scientist and displayed in 3-D and flat images with a brief description. Each week’s molecule also links to a sample record from the CAS REGISTRY, which is searched using SciFinder. Each record displays the registry number, index name and synonyms, bibliographic information, and more. Send us a molecule suggestion at motw@acs.org.

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