2.6. Free amino acids analysis
Free amino acid content was determined following the procedure
described byAristoy and Toldrá (1991). Ham samples (Biceps femoris)
were cut, minced and 5 g homogenised with 0.01 M HCl 1:5 (w/v) in a
stomacher (IUL Instruments, Barcelona, Spain) for 8 min at 4 °C. After
centrifugation at 10,000 ×g for 20 min at 4 °C the supernatant was
filtered through glass wool and stored at −20 °C until required. Once
samples were thawed, 250 μL for raw hams and 100 μL for post-salted
or for dry-cured hams, plus 50 μL of an internal standard solution
(norleucine in 0.01 M HCl) were deproteinised using 2.5 volumes of
acetonitrile and then centrifuged (10,000×g, for 5 min).