FoodNet

Experimental cookery

1932

Page 33

Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
To determine the effect of salts found in hard water upon the decom- position of dextrose in fondant, some fondants were made with 10 per cent of dextrose added to sucrose and distilled water. To the solution different salts similar to those found in water were added, the fondants made and stored in a heavy glass container, with a tight-fitting lid. They were kept for two years. Acid calcium phosphate was added to some of the fondant to compare an acid-reacting salt containing calcium with the other calcium salts used. At the end of one year the fondants made with calcium acid phosphate were plastic and kneadable, whereas those made with mag- nesium sulfate, calcium sulfate, and other salts, as well as the control with no salt, were too hard and dry to be kneaded. Here slow hydrolysis from the calcium acid phosphate probably occurred over a long period, but drying out of the fondant was also prevented, which was due to the hygroscopic property of the levulose. If fondant is to be stored for some time before it is molded the fondant made with an acid salt remains soft and plastic, or Keeps better than fondant made without an acid or acid salt. Hydrolysis of sucrose is often spoken of as inversion and the resulting sugar as invert sugar. The reason for this name is found in the effect of invert sugar upon a beam of light. If a straight beam of light is allowed to pass through a solution of sucrose in an instrument called a polariscope, the beam of light is rotated to the right and the sucrose is called dextro- rotary. After the sucrose is hydrolyzed, the ray of light is rotated to the left and the invert sugar is levo-rotary. Because of this inversion of a beam of light, hydrolyzed sucrose is called invert sugar. Dextrose is dextro- rotary and sucrose is levo-rotary. It is due to the fact that levulose rotates EFFECT OF ALKALIES UPON SUGARS 37 the beam of light further to the left than dextrose rotates it to the right that the rotation of invert sugar is opposite to that of sucrose. Hydrolysis o£ sugars by enzymes. Enzymes also bring about hy- drolysis of the disaccharid sugars. Since heat destroys enzymes the reaction must occur at a low temperature. The enzyme invertase causes hydrolysis of sucrose to dextrose and levulose. Maltose is prepared from corn by using an enzyme. Hydrolysis in chocolate creams. Jordan states that the liquefied centers of chocolate creams and other confections are brought about by acids, acid salts, or enzymes. The substance bringing about the hydrolysis is added when the fondant is fairly hard and the softening due to the hydrol- ysis occurs during storage. Paine states that the amount of the acid or acid salt required to bring about inversion imparts a perceptible acid taste to the fondant. Evaporation of liquid from the fondant must be prevented, or the fondant loses water and becomes dry. Then some moisture is neces- sary for hydrolysis to occur. The enzyme, invertase, may be added when the fondant is beaten or when it is molded before dipping. The proper amount of invertase is added for the inversion of the fondant, and accord- ing to Paine this inversion takes place more readily at pH 4.4 to 4.6. To give this acidity citric acid is added in small quantities. Invertase may be used in fondant for chocolate creams, in confections with fruit like cherries and pineapple, and in bonbons.