キシリトール

外観

白色, 結晶〜結晶性粉末

定義

本品は、次の化学式で表される五価の糖アルコールである。

溶解性

水に易溶。メタノールに微溶。エーテルに不溶。水に極めて溶けやすく、エタノールに溶けにくい。

解説

キシリトール，甘味度は砂糖に匹敵する．白色の粉末．融点93～94 ℃．水に易溶，メタノールに微溶．水に溶解する際に吸熱するため，清涼感ある甘味を与える．人体での代謝にインスリンを必要としないため，糖尿病患者用の甘味料となる．また，虫歯予防のための甘味料として注目されているが，これは口腔内微生物によって代謝されない特性による．綿実殻，バガスなどの農産廃棄物，シラカンバ，アスペンなどの広葉樹材，ササや竹などからアルカリ抽出によってキシランを得るか，蒸煮・爆砕処理によってキシロースおよびキシロオリゴ糖区分を得たのち，これを酵素加水分解して原料であるD-キシロースを得る．

森北出版「化学辞典（第2版）

化粧品の成分用途

保湿.湿潤剤、保水剤、香味剤、消臭剤

効能

賦形剤, 甘味料, 栄養補給剤

製造

D-キシロースを還元して得られる糖アルコールで，天然にはイチゴ，スモモ，カリフラワーなど，多くの野菜や果物に含まれているキシリトール．

商品名

キシリトール (コーアイセイ); キシリトール (ニプロ); キシリトール (光製薬); キシリトール (大塚製薬工場); キシリトール (扶桑薬品工業); キシリトール (扶桑薬品工業); キシリトール (東和薬品); キリット (大塚製薬工場); クリニット (共和クリティケア)

確認試験

(１) 本品の水溶液(1→2)1mLに硫酸鉄(Ⅱ)試液2mL及び水 酸化ナトリウム溶液(1→5)1mLを加えるとき，液は青緑色を 呈するが混濁を生じない．
(２) 本品を乾燥し，赤外吸収スペクトル測定法〈2.25〉の 臭化カリウム錠剤法により試験を行い，本品のスペクトルと 本品の参照スペクトルを比較するとき，両者のスペクトルは 同一波数のところに同様の強度の吸収を認める．

定量法

本品を乾燥し，その約0.2gを精密に量り，水に溶かし， 正確に100mLとする．この液10mLを正確に量り，ヨウ素瓶 に入れ，過ヨウ素酸カリウム試液50mLを正確に加え，水浴 中で15分間加熱する．冷後，ヨウ化カリウム2.5gを加え， 直ちに密栓してよく振り混ぜ，暗所に5分間放置した後，遊 離したヨウ素を0.1mol/Lチオ硫酸ナトリウム液で滴定 〈2.50〉する(指示薬：デンプン試液3mL)．同様の方法で空 試験を行う．
0.1mol/Lチオ硫酸ナトリウム液1mL＝1.902mg C₅H₁₂O₅

純度試験

(１) 溶状 本品5gを10mLに溶かすとき，液は無色澄明で ある．
(２) 塩化物〈1.03〉 本品2.0gをとり，試験を行う．比較 液には0.01mol/L塩酸0.30mLを加える(0.005％以下)．
(３) 硫酸塩〈1.14〉 本品4.0gをとり，試験を行う．比較 液には0.005mol/L硫酸0.50mLを加える(0.006％以下)．
(４) 重金属〈1.07〉 本品4.0gをとり，第1法により操作し， 試験を行う．比較液には鉛標準液2.0mLを加える(5ppm以 下)．
(５) ニッケル 本品0.5gを水5mLに溶かし，ジメチルグ リオキシム試液3滴及びアンモニア試液3滴を加えて5分間放 置するとき，液は赤色を呈しない．
(６) ヒ素〈1.11〉 本品1.5gをとり，第1法により検液を調 製し，試験を行う(1.3ppm以下)．
(７) 糖類 本品5.0gを水15mLに溶かし，希塩酸4.0mLを 加え，還流冷却器を付け，水浴中で3時間加熱する．冷後， 水酸化ナトリウム試液で中和する(指示薬：メチルオレンジ 試液2滴)．更に水を加えて50mLとし，その10mLをフラス コに量り，水10mL及びフェーリング試液40mLを加えて穏 やかに3分間煮沸した後，放置し，酸化銅(Ⅰ)を沈殿させる． 次に上澄液をガラスろ過器(G4)を用いてろ過し，沈殿を温湯 で洗液がアルカリ性を呈しなくなるまで洗い，洗液は先のガ ラスろ過器でろ過する．フラスコ内の沈殿を硫酸鉄(Ⅲ)試液 20mLに溶かし，これを先のガラスろ過器を用いてろ過した 後，水洗し，ろ液及び洗液を合わせ，80℃に加熱し， 0.02mol/L過マンガン酸カリウム液で滴定〈2.50〉するとき， その消費量は，1.0mL以下である．

貯法

容器 気密容器．

乾燥減量

1.0％以下(1g，減圧，酸化リン(Ⅴ)，24時 間)．

強熱残分

0.1％以下(1g)．

化学的特性

The solubility of D-xylitol (D-xylopentan-1.2.3.4.5-pentaol) in water is approximately 1,690 g/L at room temperature. Xylitol is stable under the common processing conditions of foods.
Xylitol is, depending on the concentration, similarly or slightly sweeter than sucrose and noncariogenic.
In the European Union, xylitol is approved as E 967 for a large number of food applications. In the United States, it is approved for use in foods following Good Manufacturing Practice and it is also approved in many other countries.

来歴

Xylitol is equally as sweet as sucrose. This property is of advantage to food processors because in reformulating a product from sucrose to xylitol, approximately the same amounts of xylitol can be used. Because xylitol has a negative heat of solution, the substance cools the saliva, producing a perceived sensation of coolness, quite desirable in some food products, notably beverages. Recently, this property has been used in an iced-teaflavored candy distributed in the European market. As of the late 1980s, 28 countries have ruled positively in terms of xylitol for use in commercial products. Xylitol has been found particularly attractive for use in chewing gum, mint and hard candies, and as a coating for pharmaceutical products. Xylitol has the structural formula shown below, with a molecular weight of 152.1. It is a crystalline, white, sweet, odorless powder, soluble in water and slightly soluble in ethanol and methanol. It has no optical activity.

使用

A polyol substrate for xylitol and sorbitol dehydrogenases.

定義

ChEBI: A pentitol (five-carbon sugar alcohol) having meso-configuration, being derived from xylose by reduction of the carbonyl group.

調製方法

Xylitol occurs naturally in many fruits and berries, although extraction from such sources is not considered to be commercially viable. Industrially, xylitol is most commonly derived from various types of hemicellulose obtained from such sources as wood, corn cobs, cane pulp, seed hulls, and shells. These materials typically contain 20–35% xylan, which is readily converted to xylose (wood sugar) by hydrolysis. This xylose is subsequently converted to xylitol via hydrogenation (reduction). Following the hydrogenation step, there are a number of separation and purification steps that ultimately yield high-purity xylitol crystals. The nature of this process, and the stringent purification procedures employed, result in a finished product with a very low impurity content. Potential impurities that may appear in small quantities are mannitol, sorbitol, galactitol, or arabitol.
Less commonly employed methods of xylitol manufacture include the conversion of glucose (dextrose) to xylose followed by hydrogenation to xylitol, and the microbiological conversion of xylose to xylitol.

一般的な説明

Xylitol is a naturally occurring five carbon sugar alcohol, equivalent to sucrose in sweetness. Xylitol finds applications in the preparation of confectionaries, chewing gum, toothpaste and mouthwashes. Xylitol is a low-energy sweetener with insulin independent metabolism, making it a promising alternative for sugar in diabetic patients. Xylitol is a natural anticaries agent used in the treatment of dental caries, as it is not utilized by cariogenic bacteria creates a starvation effect on them. Xylitol prevents otitis and upper respiratory tract infections. Commercially, microorganisms like bacteria, fungi and yeasts produce xylitol by fermentation.

安全性プロファイル

Very low toxicity by ingestion. When heated to decomposition it emits acrid smoke and irritating fumes. A sugar.

貯蔵

Xylitol is stable to heat but is marginally hygroscopic. Caramelization can occur only if it is heated for several minutes near its boiling point. Crystalline material is stable for at least 3 years if stored at less than 65% relative humidity and 25℃. Milled and specialized granulated grades of xylitol have a tendency to cake and should therefore be used within 9 to 12 months. Aqueous xylitol solutions have been reported to be stable, even on prolonged heating and storage. Since xylitol is not utilized by most microorganisms, products made with xylitol are usually safe from fermentation and microbial spoilage.
Xylitol should be stored in a well-closed container in a cool, dry place.

不和合性

Xylitol is incompatible with oxidizing agents.

規制状況(Regulatory Status)

GRAS listed. Approved for use as a food additive in over 70 countries worldwide, including Europe, the USA and Japan. Included in the FDA Inactive Ingredients Database (oral solution, chewing gum). Included in nonparenteral medicines licensed in the UK and USA. Included in the Canadian List of Acceptable Nonmedicinal Ingredients.