| Abstract
| - ε-N-Pyrrolylnorleucine was determined in different fresh food products to study its presence as anormal component of food proteins. Twenty-two different products were screened: cod, cuttlefish,salmon, sardine, trout, beef, chicken, pork, broad bean, broccoli, chickpea, garlic, green pea, lentil,mushroom, soybean, spinach, sunflower, almond, hazelnut, peanut, and walnut. Foods werehomogenized, their proteins were precipitated with trichloroacetic acid and hydrolyzed with 2 NNaOH for 20 h, and the ε-N-pyrrolylnorleucine content was determined by capillary electrophoresis.The ε-N-pyrrolylnorleucine, which was identified by HPLC/MS in sardine muscle hydrolysate, rangedin the 22 foods analyzed from 0.24 to 6.36 μmol/g. This concentration was correlated with the proteincontent of the food (r = 0.687, p = 0.00041). In addition, the ε-N-pyrrolylnorleucine/lysine ratio wasfound to be a function of the lipid, iron, and protein contents of the food (r = 0.881, p< 0.0001) andwas directly correlated with lipid and iron contents and inversely correlated with the protein content.These results are in agreement with the oxidative stress origin proposed for ε-N-pyrrolylnorleucineand suggest that the ε-N-pyrrolylnorleucine/lysine ratio is a characteristic of each food. In addition,ε-N-pyrrolylnorleucine seemed to be a normal component of many fresh food products, in which itmay be acting as a natural antioxidant. Keywords: ε-N-Pyrrolylnorleucine; fishes; meats; vegetables; nuts; capillary electrophoresis; naturalantioxidants; amino−carbonyl reactions; oxidative stress
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