Use of patatin, a protein extracted from potato, as alternative to animal proteins in fining of red wine

The use of plant-derived proteins as wine fining agent has gained increased interest owing to the potential allergenicity of animal proteins in susceptible subjects. Patatin P is the name of a family of glycoproteins that can be recovered from potato aqueous by-product. In this study, a comparative fining trial simulating industrial procedures with 10, 20 and 30 g/hL of commercial preparations of patatin, potassium caseinate, gelatin and egg albumin on an Aglianico (Vitis vinifera L.) red wine was performed. Color indexes and phenolics were analyzed by spectrophotometric methods and HPLC. The potential astringency has been evaluated by an index based on the ability of wine to precipitate salivary proteins (SPI, Saliva Precipitation Index). Patatin is a suitable alternative to animal proteins used as fining agent because: (i) a decrease in total phenolics and tannins after the treatments with 10, 20 and 30 g/hL of commercial preparation containing P was detected; (ii) Patatin, as well as all the fining agents used in this experiment, is able to diminish astringency and the content of red wine phenolics able to react with salivary proteins. Considering all concentrations tested, the effectiveness in reducing proteins reactive towards wine polyphenols was patatin = gelatine > egg albumin > casein (p < 0. 05); (iii) at each concentration considered, the treatment with patatin causes no depletion of chromatic characteristics of red wine although a significant slight loss of individual anthocyanins was observed