Volatile composition and aroma-active compounds of farmhouse Idiazabal cheese made in winter and spring

Abstract

Volatile composition and aroma compounds of Idiazabal PDO cheeses made in winter and spring were compared. In these seasons flock management differs: concentrate and conserved forages are fed in winter whereas a part-time grazing system is used in spring. Commercial cheeses from ten farmhouses were analysed during ripening. Acids, carbonyl compounds, esters, and alcohols were the main volatiles in both seasons. The shift from winter to spring management led to a higher proportion of esters and alcohols, and a lower proportion of ketones and aldehydes. More than 30 odour-active compounds were identified by olfactometry with butanoic acid, ethyl butanoate, ethyl hexanoate and 2-heptanone being the principal ones. Coinciding with fresh pasture grazing in spring, the odour impact ratios of esters and alcohols increased, indicating that spring cheeses might have more intense fruity and sweet overtones in comparison with winter cheeses.