Abstract
In the current study, the Central Composite Design was applied to optimize HS-SPME extraction in order to detect 2,3,5,6 tetramethyl pyrazine in isomalt contaning milk chocolate. The optimal conditions for the three experimental responses influencing SPME efficiency were 10 min, 40 min and 57 °C for equilibration time, extraction time and extraction temperature, respectively. SPME fibers coated with 100 m polydimethylsiloxane coating, 65 µm polydimethylsiloxane/divinylbenzene coating, 75 µm carboxen/polydimethylsiloxane coating and 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane on a StableFlex fiber were investigated. The preparation conditions of the chocolate samples were also evaluated by measuring their effects on the coating composition of the head space. The SPME fiber coated with 50/30 µm divinylbenzene/carboxen-polydimethylsiloxane provided the highest extraction efficiency, especially when the samples were extracted at 60 °C for 30 min under dry conditions. Eighty-one blends were extracted and experimentally detected most of which have been formerly stated as odor-active components.