30C-19 |
Bioavailability of carnosine from beef |
Y. PARK1, G. D. Brannan, and E. A. Decker. (1) Department of Food Science, University of Massachusetts, Chenoweth Lab, Amherst, MA 01003 Carnosine (b-alanyl-L-histidine) is a dipeptide found in the muscle foods. Carnosine has been postulated to numerous biological roles including inhibition of oxidative reactions. The objective of this research was to determine how beef influenced blood plasma carnosine concentrations in human subjects. The study was conducted with 18 individuals between the ages 18-30. Food devoid of meat products was given to the subjects so they did not consume carnosine for 48 hours prior to the test. Subjects fasted for 12 hr and then had blood withdrawn prior to a meal containing 200 g of ground beef. Additional blood samples were collected over the following 24 hr. Blood samples were centrifuged to isolate plasma. Plasma was heat treated in the presence of perchloric acid and resulting supernatant was filtered through 0.45mm syringe filters. Filtrate was derivatized with o-phthaldehyde and carnosine concentrations were determined by HPLC. Carnosine ability to inhibit the oxidation of low-density lipoprotein was also evaluated using conjugated dienes and tryptophan fluorescence as oxidation markers.. The cooked ground beef used in the study contained 52% water, 24% protein, 22% fat and 124 mg carnosine/100 g beef. No plasma carnosine was detected in subjects before the consumption of the beef. Carnosine (10.4 mg/L plasma) was detected in plasma immediately after beef consumption. Plasma carnosine concentrations continued to increase with a maximum (32.7 mg carnosine/L plasma) being recorded 3.5 hr after consumption. Carnosine concentrations then decreased until no carnosine could be detected at 5.5 hr post consumption. Carnosine was found to inhibit copper promoted oxidation of low-density lipoprotein at concentrations found in blood plasma. These results indicate that dietary carnosine is absorbed into plasma after the consumption of beef. Since carnosine has several potential health benefits, evidence of its bioavailability suggests that it could be suitable as a functional food ingredient.
Session 30C, Food Chemistry: Proteins
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