Scanning electron microscopy (SEM)
A Jeol 6100 scanning electron microscope operating at 30 kV was used to determine the microscopic morphology of the samples. Chorizos were divided in two parts for SEM analysis: the casings, and the chorizos without casings. Samples were pretreated by means of freezing to 193.15 K for 4 h followed by freeze-drying in a lyophilizer (Telstar-Cryodos, Spain) for 1 day.