15A-6 |
A rapid method for furosine determination in dairy products by reversed phase HPLC |
O. TOKUSOGLU1, S. Akalin2, and M. K. Unal1. (1) Department of Food Engineering, Ege University, 35100, Bornova,Izmir, TURKEY, Izmir, 35100, Turkey, (2) Department of Dairy Technology, Ege University Faculty of Agriculture, 35100, Bornova,Izmir, TURKEY., Izmir, 35100, Turkey Furosine, produced by the hydrolysis of E-N-deoxy-ketosyl-lysine (Amadori compound), is one of the most commonly used quality markers for evaluating the raw materials, the type and conditions of heat treatment and the storage conditions of dairy products, pasta and eggs. This marker is of primary importance not only from a nutritional point of view but also to recognize quality levels of the same kind of product. The objectives of our study were 1) the effectively quantitative determination of furosine in UHT-processed and pasteurized dairy products (milk, cheese, yogurt) using High Performance Liquid Chromatography (HPLC) with UV dedection 2) the optimization of isocratic elution method for the furosine dedection by HPLC. Twenty-eight dairy products (sixteen direct and indirect UHT-processed and pasteurized milk , two kind of yogurt as whole and skimmed , ten kind of cheeses as both ripened and fresh white and kasar cheeses, cream, mozzarella and processed cheeses) obtained from Pınar A.Ş. and local markets in Turkey. The HPLC profiles of samples were obtained after acid hydrolysis and solid-phase extraction. An optimized isocratic HPLC procedure using Hypersil-ODS column with sodium heptanesulfonate/ acetonitrile/formic acid (79.8/ 20 / 0.2 v/v/v) as a mobile phase and UV dedection at 280 nm was used. Furosine standard (5-25 mikrolt) had linear calibration curves (R2=0.9999). Recovery studies were performed in range 25-125 ng furosine and regression equation was obtained (y=53.152 x + 0.043) (R2=0.9998). Furosine content of pasteurized milk samples varied from 3.82 to 5.91 mg/100g of protein whereas UHT milk was 54.33- 213.45 mg/100g of protein and UHT skimmed milk was 57.98 -63.09 mg/100g of protein. Processed cheeses were contained 234.21-261.33 mg furosine /100g of protein. The method was rapid, objective for identification of furosine that is important quality parameter of end product application in dairy products with heat treatment.
Session 15A, Dairy Foods
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