Optimization of Process for Preparation of Arabinoxylan from Vinegar Residue and Its Effect on the Quality of Steamed Bread

The arabinoxylan was extracted from the vinegar residues by alkaline extraction. Single-factor experiments were carried out on the concentration of NaOH (containing 0.88% H₂O₂), extraction temperature, solid-liquid ratio, and extraction time, and the four parameter levels with the highest extraction rate of arabinoxylan were found. On this basis, the response surface method was used to optimize. The monosaccharide composition and molecular weight of the optimized polysaccharides were analyzed and their effects on the quality of steamed bread were studied. The results showed that the optimal experimental conditions for alkaline extraction of arabinoxylan were as follows: NaOH (containing 0.88% H₂O₂) concentration 0.92 mol/L, extraction temperature 75 ℃, solid-liquid ratio 1:35 g/mL, extraction time 1.5 h, the yield of arabinoxylan was 8.75%. The main monosaccharides extracted by this experiment were as follow: Arabinose, galactose, glucose, xylose, galacturonic acid, glucuronic acid with ration of 38.9%, 1.32%, 2.37%, 55.84%, 0.66%, 0.91%. The dispersion coefficient of the arabinoxylan extracted by this method was 2.45, average molecular weight was 245997, indicating arabinoxylan was a homogeneous polysaccharide. Additional, adding an appropriate amount of vinegar AX to the flour could reduce the hardness and viscosity of the steamed bread, improve the texture characteristics of the steamed bread, and improve the quality of the steamed bread. The arabinoxylan obtained in this study had good functional characteristics, which also provided data and theoretical support for the utilization of vinegar residues.