The keeping properties of confectionery as influenced by its water vapour pressure

The moisture vapour pressure of a foodstuff, regarded in relation to that of the surrounding atmosphere decides whether loss or gain of moisture can occur and, to a considerable extent, whether the foodstuff can form an acceptable medium for micro‐organisms. It follows that this property has great importance with regard to storage life. The moisture vapour pressure of confectionery has been studied firstly by measuring the vapour pressure/moisture‐content relations of the principal ingredients, namely sucrose, confectioners' glucose and invert sugar, and of some minor ingredients. The resulting information can be combined in the form of a number of formulæ by means of which the moisture vapour pressure of most kinds of confectionery may be calculated from the composition. The figures so obtained agree well with direct measurements made on the individual samples. A wide variation in vapour pressure is observed between different classes of confectionery, these differences resulting in widely different keeping properties and requirements for satisfactory storage.