Experimental cookery

A commonly accepted value of dextrose at the present time is about 70 to 75. There is the probability that this is too high and that 50 is a better figure. Levulose is conceded by all to be sweeter than sucrose, but again there is no agreement as to how much sweeter. Some authorities rank it 120 to 125. With the higher figures for the sweetening powers of dex- trose and levulose it would seem that invert sugar should be sweeter than the original sucrose. But the manufacturers of carbonated beverages, to whom this would be beneficial, since they use solutions of sirup, do not think that invert sugar is any sweeter than sucrose, even though 342 units of sucrose yield 360 units of invert sugar or a gain of 5 per cent in weight. Effect of Acid upon Sugars and Hydrolysis of Sugars Strong concentrated acids decompose all the sugars producing humus or caramel substances. The weak acids, malic and citric in fruits, lactic in sour milk, acetic acid, and salts with an acid reaction like cream of tartar, affect, the sugars in different degrees, depending on the particular acid used, the strength of the acid, whether it is heated, and the length of time of heating. The monosaccharids, dextrose and levulose, are not affected to any ap- preciable extent by weak acids. When sucrose is cooked with weak acids it is partially hydrolyzed to dextrose and levulose, but since the invert sugars are not affected by the acid practically no other change takes place. Lactose is only very slowly hydrolyzed by acid to dextrose and galactose. Maltose is less readily affected by acid than sucrose, but is slowly hy- drolyzed to two molecules of dextrose. Sucrose and fondant. Sucrose is very easily hydrolyzed, even by very 36 SUGAR COOKERY weak acids, tlioui^h the addition of water to the sugar molecule cannot be brought about by mixing sugar and water, but may be brought about by enzymes as well as acids. The weak acids used in cookery — lemon juice, vinegar, fruit juices, or the acid salt cream of tartar — all cause sucrose to combine with water forming dextrose and levulose. Hydrolysis takes place more rapidly if the solution is heated. In making fondant with cream of tartar, if the sirup is boiled slowly for a long time, more inversion may take place than when the sirup is boiled quickly with a larger amount of cream of tartar. Compare the length of time required to bring about crystallization in Experiments 7C, 1, and 7C, 2. Hydrolysis of fondant containing cream of tartar occurs during storage though the rate is slow at the storage temperature. Fondant made with cream of tartar and stored in a fairly tight container becomes softer than fondant of the same con- sistency before storage, but without the addition of cream of tartar. The amount of the acid salt to bring about this softening at room tempera- ture imparts a slightly sour taste to the fondant. To many persons this slight acidity improves the flavor. In fondant made with a larger amount of cream of tartar (Experiment 7C, 4), considerable hydrolysis may occur with short storage.