Invert sugar,—. Inversion,— -SACCHAROSES

If saccharose (molasses) is present, another portion of the defecated and filtered solution is inverted by the usual procedure and the determination of the reducing sugars repeated. From the difference between the results before and after inversion, expressed as invert sugar, the saccharose is calculated by multiplication by 0-95. 

Invert Sugar. Inversion.—We have mentioned the fact that glucose may be obtained by the hydrolysis of cane-sugar. In this hydrolysis not only glucose but also fructose is obtained. Cane sugar is a di-saccharose of the composition C12H22O11. When it is hydrolyzed it splits and is converted into two molecules of mono-saccharoses. One of these molecules is glucose and the other is fructose. 

With products prepared with addition of sugar, determinations of the saccharose and other sugars, i.e. of the lactose and of the invert sugar which may be formed by the inversion of the saccharose, are carried out by the following methods. 

In presence of invert sugar, 50 c.c. of the solution prepared as above are subjected to inversion in the usual way and polarised, the saccharose being calculated by Clerget s formula (see later Raw Sugar). 

Determination of the Sugars.—The principal sugar present is saccharose, but invert sugar is also found—mostly due to inversion of the saccharose during the preparation of the fruits—as well as glucose, which is added directly. The method of determination is as follows ... 

If such rotation is about equal to, or less laevo-rotatory than, that observed in the inverted liquid, only invert sugar is present. In such case, since the invert sugar originally present arises from the inversion of part of the saccharose used in the manufacture, the total quantity of saccharose added is equal to that actually found plus the amount of invert Sugar multiplied by 0-95. 

Colour Reactions.—These are used for the detection of commercial invert sugar and are based on the colorations given by certain substances with methylfurfural and hydroxymethylfurfural, which occur in commercial invert sugar as decomposition products formed from the levulose during the inversion of saccharose by acids. Invert sugar prepared with invertase or by other special methods does not contain these decomposition products and consequently does not give the colour reactions. The most reliable of the latter are as follows ... 

Acid or enzymatic hydrolysis of sucrose, inversion, produces an equimolar mixture of n-glucose and n-fructose known as invert sugar. Invert sugar is used as a food additive substance, usually in the form of syrup (relative sweetness is 95-105% of saccharose sweetness). It also serves as a starting material for obtaining d-glucose and D-fructose, the sweeteners mannitol and glucitol and other substances. 

The above procedure is adopted for the inversion of saccharose solutions of about the concentration indicated with more dilute solutions, inversion may also be carried out by adding 5 c.c. of hydrochloric acid (sp. gr. 1 10) to about 0 c.c. of the solution to be inverted and heating for 15 minutes in a water-bath at 67-70° (see, for instance, determination of sugars in the chapters on milk and on wine). 

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