|Abstract or Summary
- The unique flavor of high quality Swiss cheese is difficult to
reproduce in commercial market cheese. Swiss cheese flavor has
never been duplicated or thoroughly understood. New techniques and
advances in flavor research have enabled better definition and understanding
of food flavors. Therefore, it was desirable to make a detailed
investigation of Swiss cheese flavor.
Neutral volatile flavor compounds were isolated from Swiss
cheese fat by low-temperature low-pressure distillation. The compounds
were separated by temperature programmed gas chromatography.
Direct analysis of cheese fat and whole cheese from four
domestic and two imported good flavored cheeses by gas entrainment
and on-column trapping provided a further means of isolation of volatile
flavor compounds in Swiss cheese. Gas chromatography in conjunction
with rapid scan mass spectrometry and relative retention
time data were used to identify compounds.
Compounds positively identified by the distillation and on-column trapping techniques were as follows: methanol, ethanol, 1-propanol,
1-butanol, 2-pentanol, trans-2-hexene-1-ol, 2-phenylethanol, acetaldehyde,
2-methyl propanal, 2-methyl butyraldehyde, benzaldehyde,
phenylacetaldehyde, acetone, butanone, 2-pentanone, 2-hexanone,
2-heptanone, 2-nonanone, 2-undecanone, 2-tridecanone, 2-pentadecanone,
hexane, octane, 1-octene, nonane, 1-nonene, dodecane,
pentadecane, toluene, α-pinene, methyl acetate, methyl hexanoate,
methyl octanoate, methyl decanoate, ethyl propionate, ethyl butanoate,
ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl dodecanoate,
butyl acetate, 3-methyl butyl acetate, γ-valerolactone, γ-dodecalactone,
δ-octalactone, δ-decalactone, δ-dodecalactone, dimethyl sulfide,
diacetyl, benzothiazole, o-dichlorobenzene, 1, 2, 4-trichlorobenzene,
di-isobutyl adipate, and chloroform.
Compounds tentatively identified include an aromatic hydrocarbon,
pinane, α-fenchene, ethyl benzene, a di-methyl benzene,
methyl benzoate, 2-phenyl-2-methyl butane, 5-methyl-5-ethyl decane,
3-methyl butyl octanoate, 2, 5-dimethyl tetra decane, methyl
vinyl ether and 2-methyl propenal.
The concentration of selected volatile compounds identified by
the on-column trapping technique were determined by relating their
peak heights to known quantities of compound. Average concentrations
calculated from the mean values for all the six cheeses and
expressed in parts per million were as follows: dimethyl sulfide. 0.107; diacetyl, 0.8; acetaldehyde, 1.4; acetone, 1.6; butanone, 0.3;
2-methyl butyraldehyde, 0.42; 2-pentanone, 0.98; 2-heptanone, 0.45;
ethanol, 16.3; 2-butanol, 0.3; 1-propanol, 2.9; 1-butanol, 0.7; methyl
hexanoate, 1.5; and ethyl butanoate, 0.6.
Liquid-liquid partition chromatography and gas chromatography
were utilized to determine quantitatively the major free, fatty acids in
the six Swiss cheeses. 2-Methyl butyric acid was detected in all
cheeses and varied from 9.0 to 100.0 mg/kg cheese. The other
isomeric acid, 3-methyl butyric, was detected in only two cheeses.
Formic acid was detected in only one cheese. No n-valeric or
2-methyl propionic acids were detected.
A synthetic Swiss cheese flavor was prepared utilizing the data
obtained in this investigation and that available in the literature for
free amino acids. A satisfactory reproduction of Swiss cheese flavor
could be achieved only if the mixture contained free fatty acids, volatile
constituents, and free amino acids and was adjusted to the pH of