From:  From grape pomace to functional muffins: development, characterization, bioaccessibility of phenolic compounds and apparent glycemic index

 Phenolic profiles of samples, control muffin (CM), and muffin enriched with grape pomace flour (M15).

CompoundCM (mg/g FW)M15 (mg/g FW)
Hydroxybenzoic acids and derivatives
        Benzoic acida2.94 ± 0.03N.D.
        Gallic acid< L.O.Q.< L.O.Q.
        3-O-Methylgallic acida< L.O.Q.67.39 ± 1.01
        4-O-Methylgallic acida< L.O.Q.< L.O.Q.
        Pyrogallola< L.O.Q.< L.O.Q.
        Protocatechuic acid5.36 ± 0.106.64 ± 0.49*
        Protocatechuic aldehydeb15.86 ± 0.3115.26 ± 0.34
        Pyrocatechuic acidbN.D.< L.O.Q.
        Syringic acidN.D.4.47 ± 0.16
        VanillinaN.D.2.88 ± 0.02
Hydroxycinnamic acids and derivatives
        Caffeic acid< L.O.Q.< L.O.Q.
        Ferulic acidc1.16 ± 0.022,031.59 ± 70.57*
        Isoferulic acidc< L.O.Q.1.01 ± 0.04
        m-Coumaric acid< L.O.Q.< L.O.Q.
        p-Coumaric acidd< L.O.Q.< L.O.Q.
Flavonoids
        CatechinN.D.< L.O.Q.
        EriodictyoleN.D.< L.O.Q.
        EsculetinIDID
        Hesperetin88.79 ± 0.11*82.83 ± 0.05
        MyricetinN.D.< L.O.Q.
        Naringenin< L.O.Q.217.89 ± 7.11
        NorathyriolN.D.ID
        TaxifolineN.D.11.19 ± 0.01
Organic acids
        Citric acidIDID
        Succinic acidIDID

The results are expressed as the mean of three independent samples ± standard deviation. * Significant differences between samples (P < 0.05). FW: fresh weight. L.O.Q: under the limit of quantification. N.D.: not detected. ID: compound identified by MS/MS spectral information. The letters indicate the compounds that were quantified by a structurally related compound [a gallic acid, b protocatechuic acid, c caffeic acid, d m-coumaric acid, e naringenin].