Figures (6)  Tables (6)

    • Figure 1. 

      E-tongue radar map of the four substitute teas.

    • Figure 2. 

      Heat map of (a) flavonoid metabolite and (b) sugar metabolite contents of the four substitute teas.

    • Figure 3. 

      Venn diagram of the differential metabolites of the (a) four substitute tea flavonoids and (b) sugars.

    • Figure 4. 

      Scavenging capacity of the four substitute teas for (a) ABTS radicals and (b) DPPH radicals.

    • Figure 5. 

      Network diagram of antioxidant correlation of flavonoids. Note: The green circles in the figure indicates the substance and the orange circles indicates the antioxidant properties.

    • Figure 6. 

      Flavonoids with high correlation in four kinds of substitute teas. Note: (a)−(i) correspond respectively to Procyanidin B2, (−)-Gallocatechin.

    • SampleTaste
      KDBitter, sweeter, with a sweet aftertaste
      TCSweet, slightly bitter, calm
      LYSweet and mellow, with a camphoraceous flavor
      LCFresh and mellow
      QQSweet, astringent and medicinal flavors

      Table 1. 

      Results of the sensory review of the taste of the four substitute teas

    • KDLYQQTCLC
      Anthocyanins3.13 ± 0.49c6.46 ± 0.78c2.59 ± 0.27c1036.37 ± 59.53b3238.45 ± 82.64a
      Biflavonoids0.12 ± 0.06a−−−−
      Chalcones0.85 ± 0.05b11.9 ± 0.09b1.4 ± 0.01b97.18 ± 12.72a9.03 ± 0.56b
      Flavanols35.79 ± 1.42c49.83 ± 3.02c55.34 ± 2.22c7402.47 ± 136.25b19411.19 ± 365.66a
      Flavanones54.05 ± 2.81b12.04 ± 0.03d5.13 ± 0.13e68.9 ± 2.16a37.93 ± 3.36c
      Flavanonols3.73 ± 0.12c15.27 ± 0.46b1.78 ± 0.04c16.35 ± 0.71b95.21 ± 4.36a
      Flavone glycosides2.48 ± 0.09b1.18 ± 0.02d1.82 ± 0.04c0.9 ± 0.04d6.03 ± 0.55a
      Flavones394.85 ± 13.13a7.74 ± 0.28d19.74 ± 0.93c82.95 ± 3.44b26.5 ± 1.39c
      Flavonols380.02 ± 9.97d1766.96 ± 79.16b787.8 ± 36.16c2763.33 ±1 33.39a423.6 ± 34.27d
      Isoflavanones0.65 ± 0.09c0.14 ± 0.01e0.3 ± 0.05d1.04 ± 0.09b1.37 ± 0.08a
      Phenolic acids8.66 ± 0.22a2.06 ± 0.16c3.2 ± 0.16b3.32 ± 1.14b−
      Xanthones−0.22 ± 0.02b−0.07 ± 0.01c0.59 ± 0.02a
      Others9.49 ± 1.07b11.57 ± 5.05b8.06 ± 3.14b40.05 ± 9.08b1707.99 ± 202.53a
      Total893.82 ± 0.12c1885.37 ± 0.28a887.16 ± 0.35d11512.93 ± 0.14c24957 ± 0.28a.89
      N indicates biological sample size; data are mean ± standard deviation; peer data followed by different letters indicate significant differences (p < 0.05), and those with the same letter indicate non-significant differences (p > 0.05).

      Table 2. 

      Statistical results of the flavonoid content of the four substitute teas. Unit: nmol/g.

    • ClassCompoundsRTKDLYQQTCLC
      DisaccharideSucrose13.0532.55 ± 0.06c39.24 ± 0.36a0.03 ± 0d30.19 ± 0.27b2.77 ± 0.44c
      Trehalose14.3420.1 ± 0a0.01 ± 0d0.03 ± 0b−0.03 ± 0c
      Maltose14.2640.01 ± 0b0.39 ± 0.02a−0.01 ± 0b−
      Lactose13.662−0.02 ± 0a0.01 ± 0b0.01 ± 0c−
      Total disaccharide2.66 ± 0.07c39.66 ± 0.38a0.08 ± 0d30.21 ± 0.27b2.8 ± 0.45c
      MonosaccharideD-Arabinose3.9650.01 ± 0c0.09 ± 0b0.29 ± 0a0.01 ± 0c0.01 ± 0c
      D-Fructose5.7581.15 ± 0.02d13.18 ± 0.32a11.98 ± 0.05b3.33 ± 0.04c0.1 ± 0.01e
      D-Galactose5.9370.13 ± 0.01b0.1 ± 0c0.97 ± 0.01a0.01 ± 0e0.03 ± 0.01d
      Glucose5.9911.19 ± 0.02d31.34 ± 0.74a21.31 ± 0.15b3.23 ± 0.05c0.34 ± 0.04e
      L-Rhamnose4.4240.05 ± 0a0.03 ± 0c0.04 ± 0b0.03 ± 0c0.02 ± 0d
      D-Sorbitol6.361−−−0.01 ± 0b0.01 ± 0a
      L-Fucose4.6340.07 ± 0b−0.04 ± 0c0.11 ± 0a0.01 ± 0d
      Xylitol4.318−−−−0.01 ± 0a
      Total monosaccharide2.61 ± 0.06d44.74 ± 1.12a34.63 ± 0.29b6.73 ± 0.12c0.54 ± 0.13e
      OtherInositol7.7720.5 ± 0.01e4.82 ± 0.06a4.46 ± 0.09b1.38 ± 0.02c0.62 ± 0.07d
      Total sugar5.27 ± 0.14a114.4 ± 0.09b34.71 ± 0.12c36.94 ± 0.52a3.34 ± 2.12c
      Data are mean ± standard deviation. Peer data followed by different letters indicate significant differences (p < 0.05), and those with the same letter indicate non-significant differences (p > 0.05). Total sugar content does not include inositol.

      Table 3. 

      Statistical results of the sugar content of the four substitute teas. Unit: mg/g.

    • SampleFlavonoidsSugars
      R2XR2YQ2R2XR2YQ2
      LC vs. KD0.949110.92610.999
      LC vs. LY0.94210.9980.93411
      LC vs. QQ0.946110.90610.997
      LC vs. TC0.973110.93711

      Table 4. 

      Parameters for PLS analysis of the four substitute teas flavonoids and sugars.

    • LC vs KDLC vs LYLC vs QQLC vs TC
      UpDownUpDownUpDownUpDown
      Anthocyanins1111
      Biflavonoids11-1
      Chalcones25333672
      Flavanols66634
      Flavanones43325424
      Flavanonols23241513
      Flavone glycosides12334
      Flavones155159148125
      Flavonols71018589156
      Isoflavanones62333322
      Phenonic acids3341
      Xanthones2122
      Total flavonoids4139483738474433
      Disaccharide2311131
      Monosaccharide52426232
      Inositol111
      Total sugar72938373

      Table 5. 

      Statistical results of the different flavonoid and sugar metabolites of the four substitute teas.

    • Pearson correlationTotal flavoneTotal sugarTotal DPPG clearanceTotal ABTS clearance
      Total flavone1−0.4610.1030.626*
      Total sugar1−0.286−0.645**
      Total DPPG clearance10.793**
      Total ABTS clearance1
      * Correlation is significant at the 0.05 level (2-tailed).** Correlation is significant at the 0.01 level (2-tailed).

      Table 6. 

      Correlation analysis between taste substances and antioxidant properties.