Characteristic aroma components of British farmhouse cheddar cheese

Aroma components responsible for aroma typical of British Farmhouse Cheddar cheese were studied by aroma extract dilution analysis. Cheese extracts we re prepared by direct solvent extraction, high-vacuum transfer, and class f ractionation. Most aroma-active components of acidic and neutral/basic frac tions have been previously associated with Cheddar cheese flavor. p-Cresol was mainly responsible for a "cowy-barny" note, whereas an intense "soil-li ke" note was due to 2-isopropyl-3-methoxypyrazine. At much lower odor inten sity, 2-isobutyl-3-methoxypyrazine contributed a "bell pepper-like" note. A dditionally, within the same wedge of cheese, the concentrations of p-creso l and 2-isopropyl-3-methoxypyrazine were lower at the narrow end (center) t han at the rind side. Direct addition of p-cresol (greater than or equal to 100 ppb) or 2-isopropyl-3-methoxypyrazine (greater than or equal to3 ppb) in a mild domestic Cheddar cheese resulted in increases in intensities of c owy/phenolic and earthy/bell pepper aroma notes.