Improve functionality, flavor, stability of butter, milkfat fractions.

Temperature-gradient milkfat fractionation produces a range of ingredient milkfats that have enhanced physical properties for specific applications, including cold-spreadable butter and temperature-resistant pastries. Because of the inherent nature of temperature-gradient milkfat fractionation, soluble functional components of butter, including flavors, remain in the melt as crystalline fractions are harvested. Higher-melting fractions are characterized by low-flavor intensities. Lower-melting fractions contain a disproportionate amount of initial butter flavor.

Scientists at the University of Wisconsin (Center for Dairy Research, 1605 Linden Dr., Madison, WI 53706) are developing an expanded understanding of the flavor properties of alkylphenols in butter and milkfat fractions to enhance the functionality of butter and milkfat fractions in food ingredients.

They're developing information on the biochemical origin of alkylphenols in milk and butter by studying alkylphenol precursors and their formation in milk. In addition, they are investigating the oxidative stability of milkfat fractions and determining the effectiveness of antioxidant strategies for extending the stability and flavor quality of milkfat fractions and recombined butters.

To compensate and enhance the flavors in higher-melting fractions, scientists investigated the functionalities of a variety of butter-derived flavor components, including lactones, methylketones and short-chain fatty acids, for their ability to interact with alkylphenol flavors.

The flavor properties of naturally occurring alkylphenols were determined in a variety of media, including water, butteroil, and salt and sugar solutions. At low concentrations-0.1 parts per billion (ppb) to 10 ppb-the phenolic flavors associated with pure compounds are not detectable. Instead, a key butter flavor-enhancing effect appears. These alkylphenols intensify butter flavors when present at appropriate concentrations.

This flavor is different from the umami flavor of monosodium glutamate, we're told. It potentiates umami sensations. Combinations of alkylphenols and other milkfat flavor compounds create enhanced flavors for milk chocolate, baked goods and butter ingredients. Research is continuing on the effects of alkylphenols when they're introduced into foods.

Scientists also have found that high forage or pasture diets fed to cows and sheep contribute much lower levels of the key flavor functional alkylphenol isomers than certain concentrate diets. By selecting the correct feed concentrates, it is possible to enhance specific flavor intensity.

Further information. Robert Lindsay; phone: [phone]; fax: [phone]; URL: http://www.cdr.wisc.edu.