ラクトース一水和物

解説ラクトース乳糖ともいう．D-グルコースの4位にD-ガラクトースがβ-グリコシド結合した還元性の二糖．すべてのほ乳動物の乳汁中に5％ 前後含まれており，モクセイ科植物，ナツメヤシなど2，3の植物にも存在する．牛乳から脂肪およびチーズをとった残りの乳清を濃縮して，結晶化させて製造する．α-アノマーの一水和物は融点202 ℃．＋85→＋52.6°(水)．β-アノマーは融点252 ℃．＋34.9→＋55.4°(水)．前者は常温で，後者は93 ℃ 以上で晶出させると得られる．生体中ではUDP-ガラクトースのガラクトシル基がグルコースに転移して合成される．特殊なラクトース酵母で発酵されて乳酸を生じ，各種の乳酸菌の栄養源となる．散薬の希釈剤や錠剤の賦形剤などの薬用，乳製品添加剤，乳酸発酵用などの食用として広く用いられる．

用途培養基剤、食品添加物

使用Lactose is a disaccharide carbohydrate that occurs in mammalian milk except that of the whale and the hippopotamus. it is princi- pally obtained as a cows’ milk derivative. it is also termed milk sugar and it is a reducing sugar consisting of glucose and galactose. its most common commercial form is alpha-monohydrate, with the beta-anhydride form available to a lesser extent. all forms in solution will equilibrate to a beta:alpha ratio of 62.25:37.75 at 0°c. it is about one-sixth as sweet as sugar and is less soluble. it functions as a flow agent, humectant, crystallization control agent, and sweetener. it is used in baked goods for flavor, browning, and tenderizing and in dry mixes as an anticaking agent.

一般的な説明Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.

There are two anhydrous forms of lactose: a-lactose and b-lactose. The temperature of crystallization influences the ratio of a- and blactose. The anhydrous forms that are commercially available may exhibit hygroscopicity at high relative humidities. Anhydrous lactose is produced by roller drying a solution of lactose above 93.5°C. The resulting product is then milled and sieved. Two anhydrous a-lactoses can be prepared using special drying techniques: one is unstable and hygroscopic; the other exhibits good compaction properties. However, these materials are not commercially available.

合成方法通过乳酸在加热和减压的条件下进行缩合反应得到。

純化方法-Lactose crystallises from water below 93.5o as the hydrate which can be dried at 80o/14mm. [Horst Recl Trav Chim, Pays-Bas 72 878 1953, Beilst 17 III/IV 3066.]