Development of state diagram of bovine gelatin by measuring thermal characteristics using differential scanning calorimetry (DSC) and cooling curve method

A state diagram of bovine gelatin was developed by measuring the freezing curve, glass transition, unfolding, solids-melting lines, and ultimate maximum-freeze-concentration conditions. The freezing point decreased with the increase of solids; whereas glass transition, unfolding, and solids-melting decreased with the decrease of solids up to solids content 0.84 g/g gelatin and then remained constant. The freezing point, glass transition and solids-melting were modeled by Chenʹs model based on the Clausius-Clapeyron equation, modified Gordon-Taylor model, and Floryʹs equation, respectively. The ultimate maximum-freeze-concentration conditions were found as image equal to −11.9 °C and image equal to −14.9 °C, and the characteristic solids content, image as 0.80 g/g sample (i.e. un-freezable water, image = 0.20), respectively. Similarly the value of image (i.e. intersection of vertical line passing through image and glass transition line) was estimated as 34 °C.