Gas Chromatographic Analysis of Volatile Sulfur Compounds from Heated Milk Using Static Headspace Sampling

Abstract

An investigation was conducted to test the feasibility of using gas chromatography with static headspace sampling as an objective tool to measure milk flavor quality. Heated milk off-flavor was chosen for study. Different strategies were tried for increasing the sensitivity of a commercially available headspace method, including salting out with sodium sulfate, cryofocusing during injection, and applying backpressure to the sampling loop. With the aid of a sulfur-specific detector, the resulting system was sufficiently sensitive to detect the sulfur volatiles, H2S and dimethyl sulfide, at the concentrations found in pasteurized skim milk. Milk that was heated to varying degrees was analyzed, and the analytical results were compared with the intensity of heated flavor as determined by a sensory panel. For skim milk, correlations were moderately strong: Spearman's correlation coefficients for H2S and dimethyl sulfide were .75 and .60, respectively. Correlations were weak for whole milk.

Characterization of volatile compounds in ultra-high-pressure homogenized milk

“…It has been reported that sulfur compounds such as hydrogen sulfide, methanethiol, carbon disulfide, DMS, dimethyl disulfide and dimethyl trisulfide liberated by heat from the exposed sulfydryl groups of whey proteins, primarily b-lactoglobulin, are responsible for the cooked flavor of heated milk (Christensen & Reineccius, 1992;Patrick & Swaisgood, 1976;Simon & Hansen, 2001). Only DMS was detected in our study, probably owing to the mass spectrometric detectors or the SPME technique being insufficiently sensitive to allow the analysis of sulfur compounds at the low levels of concentration produced.…”

Development of volatile sulfur compounds in heat-shocked and pasteurized milk cheese

“…It has been reported that the concentration of H 2 S in milk increases linearly with heating temperature (Christensen & Reineccius, 1992;Hutton & Patton, 1952). H 2 S is produced mainly from sulfydryl groups of sulfur-containing amino acids (cysteine) in b-lactoglobulin (Badings, Van der Pol, & Neeter, 1981;Damodaran, 1996).…”

Anaerobic biodegradation of vegetable oil and its metabolic intermediates in oil-enriched freshwater sediments

“…The carrier gas was zerograde nitrogen, and the flow rate was 10 ml/min. The DMS concentration in the headspace gas was measured by isothermal (120°C) gas chromatography on a 30 m  0.25 mm DB-17 capillary column (J&W Scientific Inc., Folsom, CA) with a flame photometric detector operated in sulfur mode (Christensen & Reineccius 1992). Ultrahigh-purity helium was used as carrier gas at flow rate of 1.0 ml/min with a split ratio of 100:1.…”