For centuries, people have preserved fruit by mixing it with sugar, making thick jams that last for months without spoiling. Now scientists at the National Institute of Standards and Technology (NIST) have discovered* a fundamental property of mixture behavior that might help extend the life of many things including vaccines, food and library booksand save money while doing it.
In addition to jams, sugars are often used to preserve pharmaceuticals and similar biological materials. There are a number of mechanisms involved, but recently the local stiffening of the preservative was identified as a factor that can increase shelf life. Basically, stiffening the preservative decreases the rattling of the fluids molecules and stabilizes the product, presumably because these rattling motions are intimately involved in spoilingfor instance, in the protein degradation processes that lead to the loss of biological function. Several years ago, the NIST team discovered the practical importance of high-frequency molecular rattling for protein preservation.**
But while sugars and other preservatives such as salts have been used since ancient times, the prediction of how well a preservative works for a specific material has remained more an art than a science. Now, however, the NIST team has developed a relatively accessible measurement method for precisely quantifying the slowing down (or enhancement) of the local rattling motions in preservative formulations and have introduced a general mathematical framework for describing these changes. This should remove much of the guesswork in determining the best way to protect a particular commodity, says Jack Douglas of Polymers Division of NIST.
In the new paper, the team reveals a general pattern of behavior in the change in the rattling motions in mixtures that appears to apply to a variety of materials; these findings promise to be very helpful in the future development of preservatives. The paper al
|Contact: Chad Boutin|
National Institute of Standards and Technology (NIST)