Mix Calculations for Ice Cream and Frozen Dairy Desserts
The general objective in calculating ice cream mixes is to turn your formula into a recipe based on the ingredients you intend to use and the amount of mix you desire. The formula is given as percentages of fat, milk solids-not-fat, sugar, corn syrup solids (glucose solids), stabilizers and emulsifiers. The ingredients to supply these components are chosen on the basis of availability, quality and cost. The following table illustrates the relationship between the major components, the main ingredients that supply the major components, and the minor components that are supplied with the major ones for each ingredient.
Component and Ingredients to supply that component (but note that each of these ingredients also supplies the following other components):
Milkfat, supplied by Cream (which also supplies SNF and water) or Butter (which also supplies SNF, water);
Milk solids-not-fat (SNF, or sometimes also called serum solids, S.S.), supplied by any of the following:
- Skim powder (which also supplies water, about 3%)
- Condensed skim (which also supplies water)
- Condensed milk (which also supplies water and fat)
- Sweetened condensed (which also supplies water and sugar)
- Whey powder (which also supplies water)
Water, supplied by Skim milk (which also supplies msnf), or milk (which also supplies fat and msnf), or pure water.
Sweetener, supplied by dry or liquid (which also then supplies water) sucrose or corn syrup solids.
The first step in a mix calculation is to identify for each ingredient we intend to use its components. If there is only one source of the component we need for the formula, for example the stabilizer or the sugar, we determine it directly by multiplying the percentage we need by the amount we need, e.g., 100 kg of mix @ 10% sugar would require 10 kg sugar. If there are two or more sources, for example we need 10 % fat and it is coming from both cream and milk, then we need to utilize an algebraic method.
Computer programs developed for mix calculations generally solve a simultaneous equation based on mass and component balances. To solve simultaneous equations, you need as many independent equations as you have unknowns. For an example of a free on-line mix calculator, see http://www.dairyscience.info/newcalculators/calculator/index.php.
For manual calculations, a method known as the "Serum Point" method has been derived. This method has solved the simultaneous equations in a general way so that only the equations need to be known and not resolved each time.
In standardizing mixes, the composition of the various ingredients used must be known. In some cases the percentage of solids contained in a product is taken as constant, while in others the composition must be obtained by analysis. Information on the various ingredients is given below:
(a) Skim milk - can be determined by analysis or assumed at 9 percent serum solids. Fat (0.01% - 0.10%) should be taken into account if significant.
(b) Dried products, e.g. skim milk powder, whey powder, WPC, milk powder blends, usually taken to be 97 percent solids as they retain some moisture.
(c) Cream - Percent fat usually measured by an acceptable method.
Percent MSNF found by formula as follows: (100 - percent fat) x .09 = % snf (assuming that the "skim milk" contains 9% total solids). Example: In cream testing 30% fat, the percent snf would be (100 - 30) x .09 = 6.3% snf
(d) Milk - Percent fat measured by an acceptable method.
Percent snf may be found same as for cream or by making a total solids test and deducting the percent fat.
(e) Condensed Milk Products - Composition of these products should be obtained by the supplier.
(f) Sweeteners - Sucrose - Dry 100% solids
Sucrose - Liquid 66% solids
Dextrose - Dry 100% solids
Corn Syrup Solids 100% solids
Corn Syrup Liquid 80% solids
Glucose 80% solids
Honey 80% solids
(g) Stabilizers and Emulsifiers (if solid) - Because of the small percentage used may be figured as 100 percent solids.
(h) Egg Products - Fresh whole eggs: 10% fat, 25% solids
Fresh egg yolk: 33% fat, 50% solids
Frozen egg yolk: 33% fat, 50% solids
Dried egg yolk: 60% fat, 100% solids