Search

Byline: Anna Heras (1), Alexander Schoch (1), Monika Gibis (1), Albert Fischer (1) Keywords: Malondialdehyde; Lipid peroxidation; High performance liquid chromatography; Thiobarbituric acid test Abstract: A reproducible and sensitive HPLC assay with fluorometric detection for measuring malondialdehyde as an index of lipid peroxidation in dry sausage (salami) has been developed. Following the homogenisation of dry sausage in water, a solution of 5% ice-cooled trichloroacetic acid led to the precipitation of the proteins. The addition of thiobarbituric acid (TBA) (0.02 M) to the filtered mixture and its corresponding incubation (35 min, 100 degC) completed the method. High correlation coefficients (r&gt 0.977), with regard to the distillative TBA test, were obtained. Ratios between the HPLC and the distillation method of 2.23 were found. Also, the effect of the antioxidant BHT and an examination of the distillative classic TBA test have been done. Results indicate that this HPLC method, on account of its simplicity, sensitivity and specificity, may be preferred over the classic TBA test for estimating the rancidity of dry sausage. Author Affiliation: (1) Institute of Food Technology, Department of Meat Technology, University of Hohenheim, 70593, Stuttgart, Germany Article History: Received Date: 05/03/2003 Online Date: 13/06/2003

Because of their antioxidant properties, carotenoids may have beneficial effects in preventing cancer and cardiovascular disease. However, in humans consuming carotenoid-rich vegetables, data concerning the antioxidant effects of carotenoids are rather scarce. A human intervention trial was conducted, therefore, to determine whether a moderately increased consumption of carotenoid-rich vegetables would influence the antioxidant status in 23 healthy men. This short-term feeding study lasted 8 wk during which the men consumed a low carotenoid diet. A 2-wk low carotenoid period was followed by daily consumption of 330 mL tomato juice, then by 330 mL carrot juice and then by 10 g of spinach powder, each for 2 wk. Antioxidant status [water-soluble antioxidants in serum, ferric reducing ability of plasma (FRAP) and antioxidant enzyme activities] and lipid peroxidation (plasma malondialdehyde and ex vivo oxidation of LDL) were determined. In a subgroup of 10 men, lipoprotein carotenoids were measured. The consumption of carotenoid-rich vegetables significantly increased selected carotenoids in lipoproteins but had only minor effects on their relative distribution pattern. Tomato juice consumption reduced plasma thiobarbituric acid reactive substances (TBARS) by 12% (P [is less than] 0.05) and lipoprotein oxidizability in terms of an increased lag time (18%, P [is less than] 0.05). Carrot juice and spinach powder had no effect on lipid peroxidation. Water-soluble antioxidants, FRAP, glutathione peroxidase and reductase activities did not change during any study period. In evaluating the low carotenoid diet, we conclude that the additional consumption of carotenoid-rich vegetable products enhanced lipoprotein carotenoid concentrations, but only tomato juice reduced LDL oxidation in healthy men. J. Nutr. 130: 2200-2206, 2000. KEY WORDS: * vegetable * humans * antioxidant * carotenoid * lipoprotein