Abstract:

Objective: To compare the influence of two emulsifiers, monoglyceride and sucrose ester, on the quality of leek
stuffing in quickly-frozen leek. Methods: Using a mixture of anhydrous ethanol and acetone (mole ratio = 1:1) as leaching
solution, the contents of chlorophyll and carotenoid were determined and HS-SPME-GC-MS was used to determine the
volume fraction of the volatile gas with unpleasant odor from the quick-frozen leek. An improved pathological slicing
method was utilized to observe the influence of the emulsifiers on the cellular structure of leek after frozen storage for
3 months. Results: Chlorophyll and carotenoid were better retained with an increase in sucrose ester content, but the volume
fraction of unpleasant gas was decreased. The amount of retaining chlorophyll in 1% sucrose ester addition group was
0.44 mg/g, and the amount of retaining carotenoid was 0.052 mg/g, which were 83.3% and 96.1% higher than those in
control group after frozen storage for 3 months, respectively. In addition, the volume fraction of the unpleasant gas was
42.08%, which was 13.2% lower than that of control group. The leek cell with the addition of emusifiers was superior
to the ordinary leek cell in terms of dehydration degree and structural integrity. Conclusions: Sucrose ester is superior to
monoglyceride in retaining the chlorophyll and carotenoid and reducing the unpleasant gas. Addition of emulsifier is a better
way to preserve leek cell structure than direct quick-frozen leek.

Key words: leek, monoglyceride, sucrose ester, emulsifier, quality