Evaluation of Biogenic Amine and Free Fatty Acid Profiles During the Manufacturing Process of Traditional Dry-Cured Tuna

The aim of this study was to investigate the changes in the formation of biogenic amines and free fatty acids occurring during the manufacturing process of a traditional dry-cured product based on yellowfin tuna, Thunnus albacares (protected geographical indication-Mojama) and how the different processing stages could affect food safety aspects. The biogenic amines profile was determined by HPLC-DAD, following the official methodology, and free fatty acids were quantified by GC-MS. Histamine levels found in all stages of the manufacturing process did not exceed the maximum limits established in the European Commission (100-200 mg/kg) and US Food and Drug Administration (50 mg/kg) regulations. Other biogenic amines, such as cadaverine and putrescine, were detected at low level or below the limit of detection. Yellowfin tuna filets could be classified as lean fish flesh, presenting 1.18% fat on average. An increment in the free fatty acid fraction was evidenced along the manufacturing process, ranging from 10.37% of the total lipids in fresh loins to 16.88% in the dry-cured filet product. The results indicated that the traditional manufacturing process of mojama, consisting of salting and drying tuna loins kept at a controlled temperature, promoted a moderate lipolysis phenomenon, and the formation of free fatty acids with high proportions of unsaturated fatty acids, likely arising from the lipolysis of muscle phospholipids.