Comparison of protein composition and structural characterization of prolamin from Jiuzao extracted with different alkaline-alcohol methods.

This study evaluated the efficiency of extracting prolamin from Baijiu Jiuzao using different alkaline alcohol methods, and established an improved method based on the optimization of precipitation process and dialysis steps. Post-dilution acid precipitation enhanced recovery from 29.00 % to 83.08 %, while integrated dialysis increased protein purity to 85-91 %. And the improved method increased purity by 40-50 % over the traditional method. It also effectively removes heavy metals, particularly when combined with ethanol dialysis, reducing Sn, zearalenone, and aflatoxins. The improved method didn't affect the amino acid profile or secondary structure. Ethanol dialysis preserved the ordered structures better than water dialysis. Notably, proteomic analysis revealed that the proteins extracted using the improved method were primarily identified as 19 and 22 kDa α-kafirin. A small difference was observed in lipid transfer proteins and transferase precipitation. These findings highlight that the improved dialysis method effectively enhances the high-quality utilization of Baijiu by-products.