A New Biological System for Decreasing Cholesterol Content in Foodstuffs through conversion to Pro-Vitamin D and intracellular steryl esters

CLARA NUDEL; ALEJANDRO NUSBLAT; DIEGO NOCEDA; JORGE FLORIN CHRISTENSEN

San Miguel de Tucumán, provincia de Tucumán, Argentina

Congreso; Simposio Internacional de Biotecnología. Aplicaciones en Alimentos, Salud y Medio Ambiente. II Simposio Argentino-Italiano de Bacterias Lácticas.; 2004

CERELA, PROIMI

The cholesterol content of egg and milk is a well-known risk factor of cardiovascular disease. Means to reduce this sterol in the mentioned foodstuffs could impact significantly human nutrition. The non-pathogenic protozoan Tetrahymena thermophila has a unique set of desaturases that convert cholesterol into provitamin D´s, In addition, all these sterols are acylated and stored intracellularly in lipid droplets. Here we present methods by which this system can be utilised to reduce cholesterol in foodstuffs with simultaneously enrichment in provitamin D´s. So far, no method has such properties of reducing cholesterol from food, while enhancing its nutritional value. The use of live Tetrahymena added to milk and egg reduce by half the initial cholesterol contents in a single treatment. Removal of cells leads to a 90 % reduction of all forms of sterols. Treatments with cell free extracts displayed typical transformations rates of cholesterol of 50 ng min-1 mg-1 in milk and 680 ng min-1 mg-1 in egg suspensions. The ratio of vitamin D compounds accumulated can be modified by medium composition. We present evidence that both enzymes are cytochrome b5 dependent and present possible clues for perfecting the system through the use of recombinant DNA techniques. We present evidence that both enzymes are cytochrome b5 dependent and present possible clues for perfecting the system through the use of recombinant DNA techniques.