may differ between fish species with different habitat temperatures, leading to a variation of the optimal manufacturing conditions that are not only critical to obtain a desirable yield, purity and structural integrity of collagen, but also time-saving and cost-efficient in prac- tical application. Therefore, this study was conducted to investigate the effects of NaOH concentration and temperature on the efficiency of removing non-collagenous proteins from grass carp (a typical warm-water fish) skins, the effects of acetic acid concentration and temperature on the efficiency of extracting ASC, and also the effects of combined conditions suggested from the above-men- tioned various alkaline pretreatments and acid extraction processes on the structural integrity of the resulting ASC.