FoodNet

Experimental cookery

1932

Page 373

Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
The factors that affect the texture of the finished product may be grouped as follows: (1) the ingredients used, (2) the proportion of the ingredients used, (3) the kind and amount of baking powder used, (4) the extent of mixing, (5) the temperature of the ingredients when mixed, and (6) the method of mixing or combining ingredients. Doughs and batters may also be considered in relation to their ph^^sical properties. One of the physical properties of batters and doughs which is intimately connected with their structure, and which can be measured, is viscosity. Viscosity of batters and doughs is important enough to repeat the ten factors listed by Ostwald, causing variation in viscosity, which have MECHANICAL TREATMENT 457 been previously mentioned in Chapter I. They are: (1) concentration, (2) temperature, (3) degree of dispersion, (4) solvation, (5) electrical charge, (6) previous thermal treatment, (7) previous mechanical treat- ment, (8) the presence or absence of other lyophilic colloids, (9) the age of the lyophilic sol, and (10) the presence of both electrolytes and non- electrolytes. The ingredients and their proportion. When factors (1) concentra- tion, (8) the presence or absence of other lyophilic colloids, and (10) the presence of both electrolytes and non-electrolytes, are combined, we have a formula or a recipe, in other w^ords the ingredients and their proportion or concentration. Batters and doughs consist of flour and a liquid. Usually some fat and egg are added, though one or the other may be omitted : fat is seldom used in popovers, and baking powder biscuits contain no egg. The proteins and starch of the flour are lyophilic systems. When eggs or milk are added their proteins add other lyophilic colloids. As the concentration or the quantity of the different ingredients in the batter is varied, its properties and characteristics vary, which in turn in- fluences the texture of the finished product. A batter with a high concentra- tion of liquid has a greater fluidity; one with a smaller proportion has a greater viscosity. As the proportion of each ingredient is varied, the finished product is altered accordingly, the kind and extent of the alteration depend- ing upon the particular quality imparted to the batter by the ingredient and upon the proportion of it used. The proportion of liquid used also influences the degree of solvation or hydration of certain constituents of the batter, i.e., the protein and starch. The presence of both electrolytes and non-electrolytes. Baking powder, salt, soda, and cream of tartar belong to the group of electrolytes. Salts affect the imbibition of water by gluten and coagulation by heat. Since baking powders contain different acid salts, it is possible that they may affect, in different degrees, the rate of hydration of the gluten and the total amount of water absorbed. Sugar belongs to the group of non-electrolytes. Its presence in large quantity in a batter affects the structure and also the extent of mechanical treatment needed to obtain a certain type of grain. Mechanical treatment. The extent of mixing a definite batter or dough may alter its viscosity or fluidity, and the texture of the finished product varies with this variation in viscosity.