*3.1.2 1DLC analysis*

 Maltol, ethyl maltol, vanillin, ethyl vanillin, benzoic acid, sorbic acid, and saccharin sodium were separated on a 2010 AT chromatographic instrument from Shimadzu Corporation (Kyoto, Japan). A C18 analytical column (4.6 × 150 mm, 5 μm) was used. The mobile phases were ammonium acetate buffer (25 mM, pH 6.6) (solvent A) and ACN/water = 90/10 (v/v) (solvent B); the following gradient program was used: 0–2.8 min, 0% ACN; 2.8–5 min, progressing linearly to 45% ACN; and 5–15 min, maintaining at 45% ACN. The flow rate was 1.0 mL/min, and the column temperature was maintained at 40°C. The injection volume was 5 μL, and the detection wavelength was 214 nm. The peak area was calculated for quantification, and each sample or standard was injected in triplicate.
