Physico-chemical characteristics of some oenological gelatins and their action on selected red wine components

Five oenological gelatins were characterised by analytical methods and used on red wine for clarification tests. Both the degree of hydrolysis (expressed as the distribution of molecular weights) and the net charge density of the gelatins provided useful information for their characterisation. These parameters were also the most indicative for the evaluation of efficiency. The monitoring of the timecourse of sedimentation allowed the 'minimum active gelatin dosage' in relation to their net charge density to be established. Statistical analysis showed that the clarification treatments significantly modified turbidity, total polyphenols, colour intensity and brown polymers and that the amount of these variations was related to the specific gelatin used. However, these results were not confirmed by the results of the sensorial analysis of two selected gelatins.