Characterisation of sparkling cider by the yeast type used in taking foam on the basis of polypeptide content and foam characteristics

This paper describes the characterisation of sparkling ciders from Asturias, northern Spain, by means of the analysis of their protein content and their foam characteristics. A capillary sieving electrophoretic method was used in the protein analysis to determine molecular mass and the Bradford method to determine total protein content. The foam parameters were measured using the Bikerman method. Chemometric techniques, such as principal component analysis (PCA) and soft independent modelling of class analogy analysis (SIMCA), allowed the sparkling cider to be differentiated on the basis of the yeast strain used in their manufacture. As a result, feasible models for classifying sparkling ciders were computed (classification hits higher than 96%). Furthermore, the relationship between polypeptides and foam was demonstrated with a prediction equation of foam stability time, which was computed using the partial least square (PLS) regression technique. This mathematical equation confirmed that the polypeptides of high molecular mass are especially related to this foaming parameter