Screening of factors influencing the extraction of gelatin from the skin of cuttlefish using supersaturated design

•Supersaturated design was used to optimize the extraction of gelatin.•Five factors influenced gelatin extraction yield.•Cuttlefish skin gelatin (CSG) had excellent functional properties.•CSG was able to clarify apple juice. Supersaturated design (SSD) was used for screening the key parameters influencing gelatin extraction yield from cuttlefish (Sepia officinalis) skin. Results indicated that among a list of 17 factors only five parameters, namely, alkali (NaOH) concentration, acid reagent (acetic acid), enzyme, thermal treatment temperature and centrifugation time, were factors influencing gelatin yield. The optimal conditions for gelatin extraction were found to be: pretreatment with NaOH 0.03M for 1h; treatment with pepsin for 24h at 4°C in acetic acid 100mM; extraction for 14h at 40°C. The yield of gelatin extraction was 54.6%. Cuttlefish skin gelatin (CSG) contained protein as the major compound (90.95%) and low fat (0.3%) and ash (0.05%) contents. The physico-chemical properties of the CSG were characterized and compared with those of bovine gelatin (BG). The result of textural properties showed that hardness, elasticity and cohesiveness of CSG were lower than those of BG. Further, the gel strength of CSG (192.01g) was lower than that of BG (259.65g), possibly due to lower imino-acid content. The functional properties, including emulsion activity index and foam stability were similar to those of BG. The CSG showed stronger ability of apple juice clarification, than BG without affecting its nutritional values.