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Submitted to: National Egg Products School Proceedings
Publication Type: Proceedings Publication Acceptance Date: 9/29/2008 Publication Date: 9/29/2008 Citation: Jones, D.R. 2008. Food Crystals: the Role of Eggs. National Egg Products School Proceedings. p.12.1-12.8. Interpretive Summary: Technical Abstract: Sugar, salt, lactose, tartaric acid and ice are examples of constituents than can crystallize in foods. Crystallization in a food product can be beneficial or detrimental and is of particular importance in candy and frozen desserts. The most common crystal in foods is sugar which affects the quality of many products. Grape juice and wine manufacturers have some concern with tartaric acid crystallization. Lactose crystallization can be detrimental in nonfat dry milk. If the crystal reaches a certain state, it will make the dried milk difficult to disperse. Lactose crystals can also form in frozen dairy products if the amount of milk solids is too great leading to a gritty texture. Another common food crystal is salt with a vast market for various size and textures of salt. What role do eggs perform in food crystal formation? Previous discussions have focused on the foaming and emulsification properties of eggs and egg products. Both of these also factor into food crystal formation. In this discussion, we will examine the role eggs play in food crystal formation in both confections and frozen desserts. In candy-making, eggs can contribute to air incorporation, water binding, and product structure. The major role for eggs in the candy matrix is to control sugar crystal growth. Fat and protein helps to reduce the size and number of sugar crystals that form in the candy by interfering with the orientation of the sucrose molecules. Eggs can provide either or both fat and protein in the candy matrix. Examples of crystalline candies would include: fudge, fondant, rock candy and divinity. Divinity candy is a special case for crystalline candies because the sugar crystals are dispersed in a foam. Albumen serves to not only disrupt crystal formation, but serves as a foaming agent helping to give divinity its distinctive texture. The small sugar crystal size and foam texture also serve to enhance the melting quality of the product in the mouth. Too little albumen could lead to a more dense, coarser texture due to the presence of larger sugar crystals and denser foam. The addition of too much albumen could lead to a “chalky” texture due to excessive foam formation for the sucrose syrup. One of the most common frozen desserts to contain eggs is ice cream. The first wholesale ice cream industry in the U.S. developed in Baltimore, Maryland in 1851. Egg yolks are the predominant portion of the egg found in ice creams. Egg yolk is the traditional emulsifier for ice cream. In 1949, Romanoff and Romanoff listed the following egg products as acceptable ice cream ingredients: dried yolks, dried whole egg, frozen yolks, frozen whole eggs, and fresh whole eggs. Also in this book is the following table depicting average percentage of egg solids found in different types of ice creams: Content of egg solids (%) Average commercial brand 0.25-0.50 Vienna ice cream 0.60-1.24 Neapolitan (New York) ice cream 1.42-2.90 With the current standards of identity, these percentages are not allowable, but it is interesting to see how the product has developed over time. The Food and Drug Administration, Department of Health and Human Services has standards of identity for ice cream published in 21 CFR part 135. It states: “…Except in the case of frozen custard, ice cream contains less than 1.4 percent egg yolk solids by weight of the food, exclusive of the weight of any bulky flavoring ingredients used. Frozen custard shall contain 1.4 percent egg yolk solids by weight of the finished food: Provided, however, That when bulky flavors are added the egg yolk solids content of frozen custard may be reduced in proportion to the amount by weight of the bulky flavors added, but in no case is the content of egg yolk solids in the finished food less than 1.12 percent. A product containing egg yolk solids in excess of 1.4 percent, the maxi |
