Optimising conditions for enzymatic extraction of edible gelatin from the cattle bones using response surface methodology

This work was initiated to optimise the factors affecting the enzymatic extraction of edible gelatin from the cattle bones using response surface methodology. A central composite rotatable design was used to evaluate the effects of the enzyme concentration, time of enzymatic treatment and extraction temperature on the yield of extraction, gel strength, apparent viscosity and absorption at 420 nm. The R-2 values of regression models for all the response variables were higher than 0.9. Data analysis showed that all the process variables significantly (P < 0.01) affected the gel strength and apparent viscosity of extracted gelatin, whereas the effect of extraction temperature on both yield of extraction and absorption at 420 nm was not significant (P > 0.05). Graphical optimum conditions for the extraction yield, gel strength, apparent viscosity and absorption at 420 nm were determined as 6.1 ppm, 15.6 h, 70 degrees C; 9.1 ppm, 11.9 h, 70.3 degrees C; 7.86 ppm, 14.9 h, 77.5 degrees C and 2.8 ppm, 10 h, 60 degrees C, respectively. For all the response variables, the experimental values were very close to the predicted values and were not statistically different (P < 0.05).