Changes in the major free fatty acids in Serra cheese throughout ripening

Changes in the concentrations of the free fatty acids (FFA) containing an even number of carbon atoms in Serra cheese were monitored using a two-way factorial design over a ripening period of 35 days throughout the cheesemaking season. Both time variables had statistically significant effects at the 5% level on the concentrations of FFA. The concentration of stearic acid increased significantly to 351 mg kg^-1 (fat basis) only during the first week of ripening. Concentrations of palmitic and oleic acids increased significantly during all stages of ripening and approximately doubled during the 35-day ripening period to reach levels of 425 and 453 mg kg^-1 respectively. Concentrations of butyric, caprylic, lauric and myristic acids were approximately constant during the first week and increased significantly thereafter up to 285, 17, 94 and 59 mg kg^-1, respectively, at 35 days. The concentrations of caprylic and myristic acids increased five-fold in 35 days, the concentration of butyric acid increased three-fold, and the concentration of lauric acid almost doubled during the same period. The concentrations of caproic, capric, linoleic and linolenic acids increased significantly to 48, 121, 188 and 126 mg kg^-1, respectively, only after 21 days of ripening. The concentration of linoleic acid doubled in that time period, while increases in the concentrations of caproic, capric and linolenic acids were much smaller. The concentrations of butyric, caproic and palmitic acids in cheeses manufactured in February were statistically lower than those in cheeses manufactured in May. The principal FFAs throughout ripening were, according to chain length and degree of saturation, butyric (short-chain), capric (medium-chain), palmitic and stearic acids (saturated long-chain), and oleic (unsaturated long-chain). Saturated and unsaturated long-chain FFA were present at the highest concentration at all stages of ripening. It is concluded that lipolysis in Serra cheese proceeds slowly to total FFA concentration of 2167 mg kg^-1 (fat basis) by 35 days of ripening.