To investigate the changes in sulfur dioxide (SO₂) residues in 4 kinds of pickled vegetables under different packaging materials, evaluate their sensory quality, and analyze the correlation between them.

The 4 kinds of pickled vegetables—chopped peppers, pickled mustard, chili oil cowpeal and crystal Allium Chinense—packaged with different materials, stored under room temperature and natural light conditions. On 0, 7, 14, 21, 28, 35, 60, 90 and 150 d, detected the SO₂ residues by the acid-base titration method, the first method of National food safety standard-Determination of sulfur dioxide in food, analyzed alongside the sensory quality scores on 35 d and 150 d.

The SO₂ residues decreased significantly in the first 7 d in chopped peppers, pickled mustard and crystal Allium Chinense. The SO₂ residues in chopped peppers packaged with polyethylene terephthalate (PET) plastic bottles decrersed faster, with more pronounced quality degradation. The SO₂ residues in pickled mustard packaged with biaxially oriented polyethylene/vacuum metallized polyethylene terephthalate (BOPP/vmPET) and biaxially oriented nylon/aluminum oxide-biaxially oriented polyester terephthalate/polyethylene (BOPA/Al₂O₃-BOPET/PE) decreased relatively slowly, remaining 32.7% and 14.1% after 150 d, respectively. On 35 d, significant differences were observed in color and texture scores. The SO₂ residues in crystal Allium Chinense packaged with BOPA/Al₂O₃-BOPET/PE decreased slowly, remaining 25% on 150 days, with better sensory quality. The SO₂ residues in chili oil cowpeal packaged with poly⁃ethylene terephthalate/aluminum foil/polyethylene (PET/Al/PE) and BOPP/vmPET decreased slowly, with stable sensory quality. On 150 d, the SO₂ residues decreased by 14.2% and 41.7%, respectively, and only the texture score of BOPP/vmPET samples was lower than 7 points.

The SO₂ residues in all 4 kinds of pickled vegetables decrease over time, with noticeable declines in color, texture and aroma as SO₂ levels drop. However, differences are observed in the rate of SO₂ residues and sensory quality scores among different packaging materials.Additionally, variations in SO₂ residue decline are noted between different kinds of pickled vegetables packaged in the same material. By analyzing the changes in SO₂ residues and sensory quality of 4 kinds of pickled vegetables packaged with different materials over time, this study summarizes the variation patterns of SO₂ residues under various packaging conditions, examined the correlation between the sensory quality of pickles and SO₂ residue changes, and provides references and recommendations for product packaging materials, sensory quality improvement and market risk supervision.