Sorting fat from fiction

Prepared Foods, Oct, 2002 by Kellie Fischer

Blending tropical oils--such as palm and palm kernel--with liquid oils is not an ideal option since it increases saturated fatty acid amounts. The original FDA proposal on trans fat rules indicated that claims of "trans fat free" would require the product to have less than 0.5 grams of trans fat and less than 0.5 grams of saturated fat per serving.

Fat Replacement in a Different Sense

Do consumers, who are advised to reduce the amount of trans fatty acids in their diet, expect food products to contain no trans or reduced trans fatty acids? The difficulty of replacing solid, hydrogenated or partially hydrogenated fats with liquid, nonhydrogenated, oils will depend on the application.

Applications requiring shortenings or partially hydrogenated oils rely on the solids content, polymorphism and melting point profiles for formation and stability of the final product. Melting point profiles are affected by fatty acid chain length, degree of saturation, types of fatty acids and isomerization. It is these isomers present (including trans) in vegetable shortenings and margarines that are responsible for the semi-solid state of these products.

Applications where the rate and type of crystallization of the fat is imperative for product performance and stability will be extremely difficult to manage using liquid oil as a replacement (margarines and spreads, chocolate and RTS frosting). Polymorphism of fat is dependent on molecular structure, crystallization conditions, temperature and storage conditions.

A one-to-one replacement of a hydrogenated shortening in a baked good with a liquid oil usually does not work in instances where 1) the fat content is high and 2) the solid fat is critical to maintain structure at certain points in the process or is the required form upon cooling. Examples of this are puff pastry and laminated baked goods. These products rely on shortenings formulated to melt at a very specific point during the baking process and would be greatly affected by a change in composition. Oils and shortenings used to fry doughnuts or french fries must contain enough solids to "set up" upon cooling so sugar can adhere to doughnuts and the products do not leave oil slicks on plates or in containers. The key will be how well the oil processors can customize and blend to obtain similar functionality with different precursors than before; although, as soon as customization is discussed, price will inevitably increase.

Re-Development Process

Since hydrogenation is used to help foods stay fresh on the shelf and/or to obtain a solid fat product, reformulating products that are supposed to be shelf stable will be a challenge. With the increasing number of products developed to withstand longer shelf lives, a change in fat and oil composition that would decrease the shelf life goes against this trend and may force some products back to the refrigerated or frozen distribution channels.

Until adequate substitutions are available, many products may require re-development, defined as a combination of reformulation and processing changes. For example, emulsifier systems may need to be re-balanced or modified, depending on the changes in the fat composition necessary to reduce or eliminate the need for hydrogenation. When fat replacer ingredient "systems" were introduced, many were not easily implemented because they required additional equipment such as shearing devices or other pre-processing requirements to use them.