Effect of cooking on protein oxidation in n-3 polyunsaturated fatty acids enriched beef. Implication on nutritional quality.
The effect of cooking on protein oxidation was investigated in M. Longissimus thoracis of eight Normand cows fed during a 100 days finishing period with two different diets: a conventional diet (concentrate/straw based diet) and a diet rich in n-3 polyunsaturated fatty acids (PUFAs), obtained by addition to the conventional diet of a mixture of extruded linseed and extruded rapeseed. After 11 days storage, at 4 degrees C under vacuum, meat was cooked by applying jets of steam. Three experimental heating treatments were tested: two with constant surface temperatures of 65 and 96 degrees C during 300s, and one with a continuous increasing surface temperature up to 207 degrees C. Protein oxidation was evaluated by the measurement of carbonyls, aromatic amino acids, and free thiols content. The formation of Schiff bases due to the reaction of proteins with aldehydic products of the lipid oxidation was also evaluated. Cooking resulted in a significant increase of carbonyl groups and Schiff bases as well as a significant degradation of tyrosine and tryptophan. Nevertheless, enrichment of the animal diet in n-3 PUFAs had minor effects on protein oxidation induced by cooking which are unlikely to be of nutritional significance.
Gatellier
Ph
P
INRA, UR370, QuaPA, F-63122 St Genès Champanelle, France. pgatel@clermont.inra.fr
Kondjoyan
A
A
Portanguen
S
S
Santé-Lhoutellier
V
V
D000447:Aldehydes / Q000378:metabolism; D024322:Amino Acids, Aromatic / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D002417:Cattle; D003296:Cooking / Q000379:methods; D004041:Dietary Fats / Q000378:metabolism*; D019587:Dietary Supplements; D005229:Fatty Acids, Monounsaturated; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D005260:Female; D006358:Hot Temperature; D008043:Linseed Oil; D015227:Lipid Peroxidation; D008460:Meat / Q000032:analysis / Q000592:standards; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D009753:Nutritive Value; D010938:Plant Oils; D050050:Protein Carbonylation; D000074262:Rapeseed Oil; D012545:Schiff Bases / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000032:analysis; D014364:Tryptophan / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
D000447:Aldehydes; D024322:Amino Acids, Aromatic; D004041:Dietary Fats; D005229:Fatty Acids, Monounsaturated; D015525:Fatty Acids, Omega-3; D009124:Muscle Proteins; D010938:Plant Oils; D000074262:Rapeseed Oil; D012545:Schiff Bases; D013438:Sulfhydryl Compounds; D014443:Tyrosine; D008043:Linseed Oil; D014364:Tryptophan