. 2020 Mar 20;9(3):58. doi: 10.3390/biology9030058

Table 6.

Total tannins (mg/g) in grape seeds of the Touriga Nacional and the Touriga Franca grape variety during different time of sampling until maturation.

Variety/Sampling Time	Control	Kaolin 5%	Potassium Silicate (0.1%)	Potassium Silicate (0.05%)
Touriga National
26/07	128.15 ± 4.29 ^b	109.37 ± 7.38 ^a	128.39 ± 1.23 ^a	130.79 ± 4.46 ^a
02/08	116.67 ± 7.95 ^b	118.96 ± 10.24 ^a	119.43 ± 8.17 ^a	114.92 ± 0.54 ^a
09/08	114.14 ± 9.08 ^a	103.58 ± 6.77 ^a	116.67 ± 18.68 ^b	113.42 ± 10.66 ^b
17/08	105.97 ± 2.29 ^a	100.51 ± 10.45 ^a	107.17 ± 3.02 ^ab	104.47 ± 5.58 ^ab
23/08	102.51 ± 0.82 ^a	93.94 ± 6.14 ^a	103.29 ± 4.82 ^ab	107.62 ± 8.45 ^ab
07/09	93.26 ± 7.22 ^a	72.11 ± 8.11 ^a	82.81 ± 6.16 ^a	73.70 ± 3.99 ^a
20/09	84.56 ± 3.62 ^abA	78.72 ± 4.68^A	78.15 ± 9.60 ^abA	87.94 ± 2.66 ^abA
Touriga Franca
26/07	156.04 ± 10.58 ^a	159.44 ± 10.19 ^a	162.03 ± 2.63 ^a	148.40 ± 6.49 ^b
02/08	157.32 ± 3.52 ^a	166.19 ± 11.83 ^a	151.73 ± 32.69 ^a	167.52 ± 3.47 ^b
09/08	150.52 ± 22.83 ^a	152.43 ± 2.00 ^a	150.99 ± 5.36 ^a	157.39 ± 14.89 ^a
17/08	145.25 ± 5.13 ^a	147.23 ± 3.97 ^a	146.66 ± 11.66 ^a	145.09 ± 4.69 ^ab
23/08	129.51 ± 12.27 ^a	134.64 ± 19.38 ^a	126.27 ± 12.69 ^a	129.60 ± 1.91 ^a
07/09	105.58 ± 5.53 ^a	128.68 ± 4.68 ^a	114.30 ± 3.03 ^a	121.96 ± 18.79 ^a
20/09	104.84 ± 15.67 ^aA	109.14 ± 4.48 ^aA	108.37 ± 8.39 ^aA	127.68 ± 7.28 ^abA

Means (average ± standard deviation) within a column followed by different lower case letters are significantly different (p < 0.05). Values with the same capital letter on the same line for each grape variety at final maturation data are not significantly different from each other at p < 0.05.