Changes in Free Fatty Acids during Ripening of Idiazabal Cheese Manufactured at Different Times of the Year

Abstract

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 ripening. Total amounts of free fatty acids (FFA) after 180 d of ripening were significantly higher in winter than in spring or summer. The major FFA in winter were C10:0 (3363 μmoles/kg), C4:0 (3309 μmoles/kg), C18:1 (3187 μmoles/kg), and C16:0 (2602 μmoles/kg). The amounts of all FFA in cheese decreased as the cheese-making period progressed from winter to summer with C10:0 exhibiting the largest decrease (72.1%) and C18:1 the smallest decrease (22.8%). The amounts of FFA shorter than C12:0 were significantly higher in winter than either in spring or summer. The percentage of volatile (C4 to C8), medium (C10 to C14), and long-chain FFA (≥C16) changed during ripening: in winter and spring volatile FFA increased from 15% (d 1) to 30% (d 90 and 180) of the total, while long-chain 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 cheeses were different from summer cheeses. Acetic acid increased during the first 90 d of ripening to a final concentration of 26,500 μmoles/kg, the amount of which was independent of the time of the year.