optimization of headspace solid-phase microextraction for the analysis of volatile compounds of high-fat dairy powders

Optimization of main extraction parameters of the headspace solid-phase microextraction (spme) method for two high-fat dairy powders with distinctly different volatile profiles was performed with response surface methodology. while cream powder (60% fat content) has a weak odor, enzyme-modified cheese powder (emc) (35% fat content) is known with its intense flavor generated by high degrees of proteolysis and lipolysis. extraction time, extraction temperature, and agitation speed were selected as optimization factors. eight different volatile compounds isolated from cream powder and ten volatiles detected in emc powder in varied molecular weight, boiling temperature, and organic classes were selected as optimization responses to express the overall extraction efficiency and volatile profile of powders. optimization was performed to obtain the highest extraction efficiency for each response. it is suggested to use the spme conditions at 56.2 °c for 70.8 min with 250 rpm for the isolation of volatiles in cream powder whereas the extraction temperature, time, and agitation speed were optimized for emc powders as 53.4 °c, 63.2 min, and 250, respectively.