And expanding understanding could lead to food formulation with improved flavour impact and nutritional value, suggest the researchers.
"Increasingly detailed scientific knowledge, often at the molecular level, is needed to provide quantitative guidance for the development of innovative foods and food manufacturing processes," Dr. Job Ubbink from Nestlé Research Center told FoodNavigator.com.
Dr. Ubbink explained that the food industry is being challenged with increasing demands on flavour impact, nutritional value, food stability, consumer acceptance and so on, and in order to optimise our food systems and processing routes new rational ways need to be found.
One such example of this kind of research is published in the journal Nature Materials (August 2006) which reports the molecular investigations and mobility of water in amorphous and crystalline trehalose, a sugar found naturally in mushrooms, honey, lobster and shrimp.
"The work we have published on trehalose is rather specific as this molecule possess a number of unique properties," Dr. Ubbink told FoodNavigator.
"In particular, its ability to crystallize into a dihydrate is of interest as during the crystallization, excess water is removed from the amorphous phase, which is thereby further stabilized, as water is a highly efficient plasticiser of amorphous carbohydrates.
"In our article, we provide structural evidence for this mechanism, which also might provide incentives to further explore the use of trehalose and other carbohydrates in bioprotection," he said.
The research, part of NRC's extended program with the University of Bristol on the molecular physics of carbohydrates, used Positron Annhilation Lifetime Spectroscopy to study the free volume in trehalose, and showed that changes in this free volume are directly connected with molecular structure and mobility of water in the crystalline and amorphous states.
"In the case of the barrier properties of amorphous carbohydrate-based foods, this is relatively easy to explain," said Dr. Ubbink. "The more dense we pack the carbohydrate molecules together, the more difficult it is for a permeating molecule (for instance oxygen), to diffuse through the food matrix and then oxidize sensitive compounds."
And so by optimising the molecular packing of carbohydrates, said Dr. Ubbink, scientists can influence and thereby reduce the rate of oxidation of food ingredients such as flavours and polyunsaturated fatty acids (PUFAs).