OPTIMIZATION OF SOLID-PHASE MICROEXTRACTION CONDITIONS OF MILK CHOCOLATE

Abstract

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