COMPARATIVE ANALYSIS OF FRESH AND STORED COMMERCIALLY CULTURED BUTTERMILK BY GAS-CHROMATOGRAPHY

The volatile flavor compounds of commercially cultured buttermilk were collected using a Likens and Nickerson steam-distillation-extractor and analyzed by gas chromatography in order to study the flavor changes occurring during a two week storage of this product at 7 ± 2°C. Separation of diacetyl, acetoin, 2,3-butylene glycol, acetaldehyde, and acetic acid was achieved by using a 100/150 mesh Porapak Q column in a gas chromatograph equipped with a flame ionization detector. The column was programmed to operate from 100 to 200°C at the rate of 10°C per minute with a nitrogen carrier gas flow of 45 ml per minute. Tentative identification of resultant peaks was made by comparing the relative retention of the peaks on the chromatograms of ether extracts of the samples and known mixed standards. The number of peaks and total peak areas were used to compare samples on the day of purchase (0 day) and after 15 days storage at 7 ± 2°C. Gas chromatograms of ether extracts of fresh (0 day) samples showed more peaks and a large total peak areas as compared to the chromatograms of the same samples after two weeks (15 days) storage at 7 ± 2°C. © 1979, Oxford University Press. All rights reserved.