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Contribution of polyphenols to the total antioxidant capacity of pomegranate and grape juices
Author(s) -
Bolling Bradley Warren,
Blumberg Jeffrey B.,
Chen C.Y. Oliver
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.321.2
Subject(s) - dpph , polyphenol , chemistry , anthocyanin , phenols , food science , proanthocyanidin , sugar , antioxidant , organic chemistry
Pomegranate juice (PJ) and grape juice (GJ) have comparable ORAC assay values, but PJ is more potent than GJ in other in vitro measures of Total Antioxidant Capacity (TAC). We examined the basis for these differences in the ORAC, FRAP, and DPPH assays. Juices were fractionated into their sugar, organic acid, neutral phenol, and anthocyanin components to assess the contribution of each to their TAC. Polyphenol fractions contributed ≥75% of the TAC for both juices. For PJ, neutral phenols contributed the most to ORAC, FRAP, and DPPH values with 50, 49, and 46% of TAC of the whole juice, respectively; GJ anthocyanins contributed the most with 53, 47, and 49%, respectively. The contribution of PJ polyphenols to FRAP values was 56% greater than GJ. The contribution of PJ polyphenols to ORAC values were 42% less than GJ. The ORAC/FRAP ratio of GJ neutral phenols and anthocyanin fractions were ≥1.5‐fold higher than those of PJ fractions, while ORAC/DPPH ratios were 3.5‐fold larger. Fraction recombination revealed interactions were dependent upon the assay. Sugars and organic acids antagonized PJ polyphenols in the DPPH assay by 50% and the GJ ORAC value by 22%. Therefore, the differential TAC of PJ and GJ can be attributed to the larger intrinsic electron transfer capacity but smaller hydrogen transfer capacity of PJ phenols and anthocyanins than GJ. Supported by the USDA and POM Wonderful LLC. BWB was supported by NIGMS K12GM074869.