Solid-Phase Microextraction Method for the Determination of Volatile Compounds in Hydrolysates of Alaska Pollock Frame

The volatile compounds in Alaska pollock frame and Alaska pollock frame hydrolysates were analyzed by solid-phase microextraction and gas chromatography-mass spectrometry for identifying and comparing their flavor characteristics. The optimized SPME extraction conditions were 75 μm carboxen/polydimethyl siloxane fiber, adsorption time of 40 min, and extraction temperature of 65°C. Compared to Alaska pollock frame, Alaska pollock frame hydrolysates have more aromas detected and identified. Numerous volatile compounds were responsible for the overall aroma of Alaska pollock frame hydrolysates, such as 1-penten-3-ol, 2-penten-1-ol, ethyl acetate, methacrolein, 3-methylbutanal, hexanal, octanal, nonanal, 6-methyl-5-hepten-2-one, and so on. However, only a relatively small proportion showed similar composition. Although Alaska pollock frame hydrolysates was prepared by the same raw material, each Alaska pollock frame hydrolysate exhibited its individual flavor characteristics. Thus, the type of enzyme was probably one of the important factors affecting the differences of volatile compound composition and Alaska pollock frame hydrolysate flavor. Compared to other Alaska pollock frame hydrolysates, FPH5 (hydrolysates prepared by mixed enzymes for animal proteolysis) exhibited less fishy odor. It can be used as an effective approach to improve product quality.