The kinetics of gelation of gelatin + water solutions have been investigated by several experimental methods, in particular optical rotation, 1H nuclear magnetic resonance and rheological measurements. During quenching and isothermal annealing of the solutions, the gelatin chains undergo a conformational coil→helix transition which is responsible for the network growth. The amount of helix (derived from optical rotation measurements) shows a time evolution which could be analysed as the combination of two processes, the first obeying an Avrami equation, the second proceeding logarithmically in time. The water 1H n.m.r. measurements reveal that the spin‐spin relaxation time T2 is affected by these processes, thus implying that a fraction of water contributes to the network structure. Finally, the sol‐gel transition could be followed with a Weissenberg rheogoniometer in oscillatory shear, for a suitable range of temperatures, when the system changes from a purely viscous liquid (the shear modulus G′=0), to an almost purely elastic solid (the loss modulus G″=0).

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