Changes in free fatty acids during ripening of idiazabal cheese manufactured at different times of the year

Lipolysis was studied in cheeses manufactured from raw ovine milk in winter , spring, and summer, with no starter culture added, up to 180 d of ripenin g. Total amounts of free fatty acids (FFA) after 180 d of ripening were sig nificantly higher in winter than in spring or summer. The major FFA in wint er were C-10:0 (3363 mu moles/kg), C-4:0 (3309 mu moles/kg), C-18:1 (3187 m u moles/kg), and C-16:0 (2602 mu moles/kg). The amounts of all FFA in chees e decreased as the cheesemaking period progressed from winter to summer wit h C-10:0 exhibiting the largest decrease (72.1%) and C-18:1 the smallest de crease (22.8%). The amounts of FFA shorter than C-12:0 were significantly h igher in winter than either in spring or summer. The percentage of volatile (C-4 to C-8), medium (C-10 to C-14), and long-chain FFA (greater than or e qual to C-16) changed during ripening: in winter and spring volatile FFA in creased fi om 15% (d 1) to 30% (d 90 and 180) of the total, while long-chai n FFA decreased from 55% (d 1) to 40% (d 180) of the total. In contrast, in summer, the percentages of volatile and long-chain FFA after 180 ripening d were 25 and 50% of the total, respectively. We concluded that winter chee ses were different fi om summer cheeses. Acetic acid increased during the f irst 90 d of ripening to a final concentration of 26,500 mu moles/kg, the a mount of which was independent of the time of the year.