FROZEN FOODS
DEFINITIONS:
-Frozen desserts include: ice cream, low fat ice cream, filled ice cream, sherbet, water ice, frozen stick confections., custards, mousse, frozen yogurt
Frozen desserts can be considered as formulated foods where functional additives are essential to the characteristics of the finished product. Most frozen desserts incorporated air during processing, with the degree of air incorporation ranging widely in different types of frozen desserts and between a given type manufactured by different companies.
A wide range of different frozen desserts are marketed. These include:
1. Ice Cream: Contains not less that 10% milk fat and 20% total milk solids and most weigh not less that 4.5 pounds per gallon (This is equal to 100% overrun). It may contain not more than 0.5% stabilizer. Bulky flavors (nut, chocolate, etc.) may contain not less than 8% milkfat and not less than 16% total milk solids.
2. Ice Milk (Low fat ice cream) Contains not less than 2% or more than 7% milk fat and not less than 11% total milk solids.
3. Sherbet must contain not less than 1-2% milkfat and between 2-5% non-fat milk solids. A sherbet must weigh not less than 6 ponds per gallon and have not less than 0.35% acidity as lactic acid. It must contain 2% citrus fruits, 6% berry fruits or 10% of other fruits. The acidity value is not required for non-fruit flavored sherbets, which do not contain any fruit or fruit juice.
4. Water Ice is similar to sherbet, but does not contain any milk solids. Other standards are the same as for sherbet.
5. Frozen dairy confections (novelties) must contain not less that 13% milk solids and not less than 33% total solids. Overrun can not be more than 10%.
6. Quiescently frozen confections are similar to frozen dairy confections and must contain 17% total solids. They may or may not contain milk solids.
7. Dietary frozen dessert must contain less than 2% fat and not less than 7% total milk solids. It must weigh not less than 4.5 pounds per gallon.
8. Mellorine type products are similar to ice cream, but contain vegetable fat - rather than milkfat. The product must contain not less than 6% fat and not less than 3.5% protein of biological value at least equivalent to whole milk protein. The must weight not less that 4.5 pounds per gallon. Vitamin A must be added to give 40 USP units/gallon.
9. Frozen yogurt contains the same ingredients as ice cream. It contains not less that 3.25% milk fat and not less than 8.25% milk solids not fat. It should have a titratable acidity of not less than 0.5% as lactic acid and must weigh not less than 5 pounds per gallon.
10. Low Fat yogurt contains not less that 0.5% or more than 2.0% milkfat
12. Non fat frozen yogurt contains less than 0.5% milkfat.
Other less common frozen desserts include freezer made shakes (10% NFMS and 3.25-6% milkfat), frozen puddings, frozen mouses, parfait, frappe, aufai, spomoni, sorbet and egg nog ice cream.
INGREDIENTS:
Ice cream and related frozen desserts contain a number of ingredients, which are essential to the properties of the final product. These include: milk fat, milk solids-not-fat, sweeteners, gum stabilizers and emulsifiers. Most ice cream manufacturers purchase a blended combination of stabilizers and emulsifiers.
Stabilizers, generally polysaccharide gums, improve body and melt-down characteristics of the frozen product. Improvement of body is considered to be related to the reported ability of stabilizers to inhibit ice crystal growth. Common stabilizers are generally blends of one or more of the following: guar gum, carrageenan, alginate, xanthan and pectin.
Sweeteners are either pure cane sugar, which gives the best flavor, or blends of cane sugar and corn syrup solids. Corn syrups are made by hydrolysis of starch and are evaluated in terms of sweetness as related to dextrose (glucose). The relative sweetness is reported in Dextrose Equivalents (DE). The higher the DE the greater the sweetening power and the lower the DE the lower the sweetness. Products with low DE have less hydrolyzed starch and have a greater effect on the body of the ice cream. Generally frozen desserts use products with DE values between 32 and 42.
Emulsifiers affect the structure of the air micelle in the ice cream, improve the whipping properties and contribute to the desired dry (not shiny) surface of the ice cream in the product leaving the ice cream freezer.
The manufacture of ice cream involves mixing, pasteurization, homogenization, cool aging, addition of flavors, freezing and hardening.
SHERBETS AND ICES:
Sherbets and ices differ from ice cream in respect to:
Factors Affecting Characteristics
Important factors in the manufacture of sherbets and ices include:
A schematic drawing of a typical ice cream processing operation is shown in the following figure:
The key piece of equipment is the ice cream freezer. Very rapid freezing is essential to provide small ice crystals. The freezer freezes only a portion of the water in the mix and provides a means for the incorporation of air (over run). Ice cream is drawn from the freezer between 18-22F. For a continuous freezer, about 50% of the water is frozen and for a batch freezer, about 35% of the water is frozen. The remainder of the water is frozen in the hardening room at about -10 to -30 F. Incorporation of air during freezing is essential to the desired characteristics of the ice cream. Overrun may range from 20 to 100%. At 100% overrun the ice cream will weigh 4.5 ponds per gallon, which is the legal limit for standard ice cream.