The phenolic compound content in peels ranged from 1.43 to
2.46 mg EAG g−1. In studies by Soares, Welter, Kuskoski, Gonzaga, and
Fett (2008), the amounts of polyphenols in peels were close to
1.93 mg EAG g−1 in Isabel grapes and 1.83 mg EAG g−1 in Niagara
grapes. There are phenolic acids in the fruit, however the high
moisture in the pulp (Table 1) possibly reduced the phenolic
compounds included phenolic acids.