Effect of grape pectic enzyme treatment on foaming properties of white musts and wines

White grapes of three different varieties (Macabeo, Xarel.lo and Parellada), which are used in Spanish sparkling wines production (O.A.C. Cava), were treated with a pectic-enzyme preparation on an industrial scale. Foam capacity (foamability (HM), Bickerman coefficient (Σ), foam stability time (TS) and surface tension (ST)) of nine musts from pectic enzyme treated grapes and their corresponding wines were compared to their respective control samples. The HM, Σ, and TS values decreased and ST increased in most of the treated samples. This could be the case, because samples from enzyme-treated grapes had lower protein and polysaccharide contents and higher values of polyphenols than untreated samples: HM and Σ were positively correlated with proteins and polysaccharides and negatively with ST; polyphenol contents had a negative relationship with TS values.