Washington, Feb 13 : Chemists in England and the Netherlands have paved the way to keep those sumptuous boxes of chocolates, and other goodies, looking fresher and tastier - by discovering a substance that could prevent the formation of unsightly white films on the outside of chocolate.

White films, also called "fat bloom," are actually tiny particles of crystalline fat and most often appear on the surface of chocolates that contain nut-based fillings.

Chocolate lovers are often alarmed, and mistakenly think that good chocolates have gone bad.

Although the blooms have been studied for decades, the phenomenon is poorly understood and researchers have had difficulty finding an effective method to reduce their formation.

However, the new study, by Kevin W. Smith and colleagues, crafted a candy-size mechanical model of a chocolate bon-bon using a series of stacked, steel washers.

They layered the bottom of each cylinder with different concentrations of a substance called "antibloom fat" and then filled the top of each cylinder with cocoa butter to represent a chocolate coating.

The scientists showed that increasing the amount of "antibloom" used in the filling slowed the rate of crystal formation, thereby preventing fat bloom.

The study is scheduled for the March 12 issue of the ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

ANI