Influence of Wine-Grape Skin Hardness on the Kinetics of Anthocyanin Extraction

Figures & data

Table 1 Total anthocyanin content (TA) and profile of Nebbiolo CVT 71 berries containing 242 ± 8 g L⁻¹ of sugars (2007 vintage)

TA (mg kg^−1 grapes)	Free glucosides (%)	Acetyl-glucosides (%)	Cinnamoyl-glucosides (%)	∑ of delphinidin derivatives (%)	∑ of cyanidin derivatives (%)	∑ of petunidin derivatives (%)	∑ of peonidin derivatives (%)	∑ of malvidin derivatives (%)
516 ± 7	82.10 ± 0.52	5.17 ± 0.11	12.73 ± 0.45	5.88 ± 0.31	7.37 ± 0.30	6.61 ± 0.30	42.20 ± 0.65	37.94 ± 0.72
Means of three replicates (average value ± standard deviation). Cinnamoyl-glucosides included both p-coumaroyl and caffeoyl anthocyanin forms.

Table 2 Kinetic of extraction of anthocyanins, content (mgL⁻¹) and percentage of extraction (%), during maceration in a model solution, from the skins of the two groups of Nebbiolo CVT 71 berries

	10 min	20 min	30 min	1 h	2 h	3 h	4 h	5 h	24 h	48 h	Non-extracted skins
						mg L^−1
S	26 ± 2	31 ± 1	51 ± 4	57 ± 2	107 ± 3	134 ± 9	150 ± 7	159 ± 4	174 ± 8	178 ± 8	78 ± 4
H	29 ± 1	39 ± 1	58 ± 3	67 ± 3	116 ± 3	147 ± 7	167 ± 7	184 ± 4	199 ± 2	203 ± 3	53 ± 6
Sign	ns	*	ns	ns	ns	ns	ns	*	*	*	*
						%
S	9.7 ± 0.7	11.9 ± 0.5	19.1 ± 1.3	21.6 ± 0.9	40.2 ± 1.2	50.7 ± 3.6	56.6 ± 2.7	60.0 ± 1.6	65.7 ± 2.9	67.2 ± 3.2	29.3 ± 1.7
H	11.1 ± 0.3	14.7 ± 0.5	21.9 ± 1.1	25.4 ± 1.1	43.9 ± 1.2	55.6 ± 2.6	62.9 ± 2.5	69.2 ± 1.3	75.2 ± 0.9	76.6 ± 1.1	19.9 ± 0.9
Sign	ns	*	ns	ns	ns	ns	ns	*	*	*	*
S = soft skin 0.26 ± 0.04 N; H = hard skin 0.47 ± 0.05 N. Sign = Significance; ns = not significant; *Significant at p ≤ 0.05.

Table 3 Nebbiolo clone CVT 71: Anthocyanin profile (expressed in %) of the extracts (solutions B_time) as influenced by different extraction times and skin hardness

		10 min	20 min	30 min	1 h	2 h	3 h	4 h	5 h	24 h	48 h
Free glucosides	S	97.21 ± 2.16	97.90 ± 0.60	97.54 ± 0.26	96.98 ± 0.36	91.87 ± 0.28	89.93 ± 1.96	88.13 ± 0.34	88.21 ± 0.45	88.77 ± 2.73	89.39 ± 2.04
	H	97.51 ± 0.50	96.76 ± 0.43	96.84 ± 0.14	96.51 ± 0.47	91.98 ± 1.12	89.81 ± 0.35	89.62 ± 0.53	88.48 ± 0.27	88.63 ± 4.77	87.97 ± 0.31
Sign		ns	ns	*	ns	ns	ns	ns	ns	ns	ns
Acetyl-glucosides	S	2.79 ± 2.16	1.55 ± 0.21	1.73 ± 0.33	2.32 ± 0.41	3.93 ± 0.26	4.65 ± 0.50	4.87 ± 0.10	4.77 ± 0.07	4.88 ± 0.03	4.48 ± 0.14
	H	1.77 ± 0.22	2.78 ± 0.45	2.26 ± 0.15	2.86 ± 0.28	4.26 ± 0.21	4.82 ± 0.11	4.49 ± 0.18	4.66 ± 0.22	4.77 ± 1.00	4.62 ± 0.22
Sign		ns	*	ns	ns	ns	ns	ns	ns	ns	ns
Cinnamoyl-glucosides	S	nd	0.55 ± 0.50	0.73 ± 0.24	0.70 ± 0.12	4.20 ± 0.06	5.42 ± 1.45	7.00 ± 0.24	7.02 ± 0.40	6.35 ± 2.74	6.13 ± 2.02
	H	0.72 ± 0.34	0.46 ± 0.02	0.91 ± 0.07	0.63 ± 0.31	4.80 ± 0.53	5.37 ± 0.24	5.89 ± 0.71	6.86 ± 0.16	6.60 ± 0.78	7.20 ± 0.46
Sign		-	ns	ns	ns	ns	ns	ns	ns	ns	ns
∑ of delphinidin derivatives	S	5.78 ± 0.67	5.49 ± 0.62	6.47 ± 0.51	7.04 ± 0.62	7.18 ± 0.20	7.43 ± 0.50	6.78 ± 0.36	6.96 ± 0.17	6.97 ± 0.54	6.95 ± 0.19
	H	4.96 ± 0.19	5.29 ± 0.02	5.99 ± 0.29	6.98 ± 0.76	7.07 ± 0.10	7.06 ± 0.01	6.83 ± 0.25	6.68 ± 0.18	7.41 ± 0.48	6.70 ± 0.15
Sign		ns	ns	ns	ns	ns	ns	ns	ns	ns	ns
∑ of cyanidin derivatives	S	7.10 ± 0.77	8.46 ± 2.86	9.14 ± 0.42	8.21 ± 0.64	8.00 ± 0.21	7.84 ± 0.38	7.53 ± 0.25	7.73 ± 0.41	7.61 ± 0.16	7.52 ± 0.43
	H	10.77 ± 0.91	8.17 ± 0.52	9.37 ± 0.56	8.83 ± 0.67	8.75 ± 0.46	8.35 ± 0.69	8.46 ± 0.60	8.36 ± 0.45	8.30 ± 0.59	8.05 ± 0.47
Sign		**	ns	ns	ns	ns	ns	ns	ns	ns	ns
∑ of petunidin derivatives	S	3.60 ± 0.20	4.31 ± 1.21	5.17 ± 0.11	5.28 ± 0.79	6.17 ± 0.23	6.50 ± 0.17	6.47 ± 0.17	6.55 ± 0.04	6.52 ± 0.27	6.41 ± 0.16
	H	4.43 ± 0.29	3.70 ± 1.12	4.81 ± 0.43	5.24 ± 0.38	6.26 ± 0.14	6.38 ± 0.08	6.35 ± 0.29	6.20 ± 0.14	5.92 ± 0.49	6.23 ± 0.13
Sign		*	ns	ns	ns	ns	ns	ns	ns	ns	ns
∑ of peonidin derivatives	S	46.67 ± 0.48	47.18 ± 0.49	46.28 ± 1.71	42.09 ± 1.69	40.86 ± 1.50	39.05 ± 0.62	40.44 ± 1.65	40.31 ± 1.18	39.55 ± 2.66	39.68 ± 1.63
	H	52.67 ± 0.55	49.29 ± 1.42	48.59 ± 1.14	44.52 ± 1.16	43.65 ± 0.60	42.32 ± 1.03	42.04 ± 0.40	42.28 ± 0.89	40.86 ± 1.14	41.41 ± 0.84
Sign		***	ns	ns	ns	*	ns	ns	ns	ns	ns
∑ of malvidin derivatives	S	36.84 ± 0.68	34.56 ± 5.17	32.94 ± 0.74	37.38 ± 1.06	37.79 ± 1.25	39.19 ± 0.09	38.78 ± 1.25	38.45 ± 1.70	39.35 ± 2.01	39.43 ± 1.72
	H	27.17 ± 1.39	33.54 ± 3.07	31.24 ± 1.74	34.43 ± 1.83	35.33 ± 2.09	35.88 ± 1.82	36.32 ± 0.93	36.47 ± 1.59	37.51 ± 1.66	37.41 ± 1.12
Sign		***	ns	ns	ns	ns	ns	ns	ns	ns	ns
S = soft skin 0.26 ± 0.04 N; H = hard skin 0.47 ± 0.05 N. Average value ± standard deviation (n = 3). Sign = Significance; ns = not significant; *p ≤ 0.05, **p ≤ 0.01, ***p≤ 0.001; nd = not detected. Cinnamoyl-glucosides included both p-coumaroyl and caffeoyl anthocyanin forms.

Table 4 Nebbiolo clone CVT 71: anthocyanin profile, expressed in %, of the non-extracted skins (solutions C)

	Free glucosides	Acetyl-glucosides	Cinnamoyl-glucosides	∑ of delphinidin derivatives	∑ of cyanidin derivatives	∑ of petunidin derivatives	∑ of peonidin derivatives	∑ of malvidin derivatives
S	84.90 ± 0.54	4.26 ± 0.14	10.84 ± 0.43	5.91 ± 0.60	7.17 ± 0.24	6.09 ± 0.27	41.69 ± 2.49	39.14 ± 1.72
H	84.42 ± 1.24	4.58 ± 0.70	11.00 ± 0.63	5.74 ± 0.27	7.73 ± 0.59	6.02 ± 0.16	42.95 ± 0.62	37.56 ± 1.45
Sign	ns	ns	ns	ns	ns	ns	ns	ns
S = soft skin 0.26 ± 0.04 N; H = hard skin 0.47 ± 0.05 N. Average value ± standard deviation (n = 3); Sign = Significance; ns = not significant. Cinnamoyl-glucosides included both p-coumaroyl and caffeoyl anthocyanin forms.

Figure 1 Trends in the berry skin mechanical properties of Nebbiolo clone CVT 71 grapes during ripening (vintage 2007). (a) F_sk = Berry skin break force; (b) W_sk = Berry skin break energy; (c) E_sk = Skin Young's modulus; (d) Sp_sk = Berry skin thickness. Average values ± standard error (n = 30). Mean values followed by the same letter are not significantly different for p ≤ 0.05.

Table 5 Berry skin mechanical characteristics from different Nebbiolo clone grapes grown in the same vineyard, at harvest in 2007

	Fsk (N)	Wsk (mJ)	Esk (N/mm)	Spsk (μm)
CVT 71	0.36 ± 0.06 ^a	0.20 ± 0.07 ^ab	0.30 ± 0.05 ^ab	197 ± 26 ^ab
CVT 141	0.37 ± 0.09 ^a	0.22 ± 0.09 ^a	0.29 ± 0.04 ^b	203 ± 36 ^a
CVT 180	0.36 ± 0.08 ^ab	0.19 ± 0.08 ^ab	0.31 ± 0.06 ^a	179 ± 32 ^c
CVT 185	0.32 ± 0.08 ^b	0.17 ± 0.07 ^b	0.29 ± 0.04 ^b	186 ± 36 ^bc
CVT 308	0.35 ± 0.07 ^ab	0.18 ± 0.07 ^ab	0.31 ± 0.04 ^ab	199 ± 32 ^ab
Fsk = Berry skin break force; Wsk = Berry skin break energy; Esk = Skin Young's modulus; Spsk = Berry skin thickness. Average value ± standard deviation (n = 30). Mean values followed by the same letter are not significantly different for p ≤ 0.05).