Abstract: This study investigated the effect of vacuum impregnation on the quality changes of turnip during the pickling process. A texture analyzer and a colorimeter were used to analyze the texture and color of pickled turnip, respectively. The physicochemical properties including sodium chloride, moisture, total acid, amino acid nitrogen and nitrite contents were measured by titration, oven-drying method and spectrophotometry. The volatile components were determined by gas chromatography (GC). The results showed that contents of sodium chloride, moisture, total acid and amino nitrogen gradually rose while the hardness increased at first and then decreased. In addition, the quality characteristics of vacuum impregnated turnip during the pickling process changed faster than turnip subjected to atmospheric impregnation. Vacuum impregnated turnip with a salt content of 20% changed fastest. The quality characteristics of pickled turnip reached steady state on the ninetieth day. The volatile components of pickled turnip produced by vacuum impregnation with 20% salt content and the traditional process were different; 27 and 31 volatile components were detected in the two samples, respectively. In conclusion, vacuum impregnation could improve the pickling speed and shorten the pickling time, but its use in conjunction with microbial fermentation is needed to maintain the flavor of pickled vegetables.

Key words: turnip, vacuum impregnation, pickling, brittleness, color