Table 5.
Effect of, and interaction between, year, production system (ORG vs. CON), and table grape type (black vs. red vs. white) on the DMcontent, SC of pulp/juice, TPC, total antioxidant activity (TAA; DPPH and ABTS assays) and TAC in grape samples produced in the Mediterranean (3-factor ANOVA, the values presented are means ± SE).
| Factors | Dry Matter Content % |
Sugar Content (SC) | Total Phenolic Content | Antioxidant Activity (TAA) | Total Anthocyanin Content (TAC) |
|||
|---|---|---|---|---|---|---|---|---|
| (Pulp) Brix° |
(Juice) Brix° |
(TPC) mg GAE kg−1 |
DPPH µmol TE g−1 |
TEAC µmol TE g−1 |
mg cyan kg−1 | mg mal kg−1 | ||
| Year (Yr) | ||||||||
| 2015 (n = 152) | 19.1 ± 0.2 | 17.1 ± 0.2 | 17.6 ± 0.2 | 1858 ± 63 | 93 ± 3 | 11.3 ± 0.6 | 116 ± 17 | 123 ± 18 |
| 2016 (n = 93) | 19.2 ± 0.3 | 17.4 ± 0.3 | 17.7 ± 0.3 | 1735 ± 60 | 98 ± 4 | 4.3 ± 0.2 | 234 ± 33 | 247 ± 35 |
| Production system (PS) | ||||||||
| ORG (n = 124) | 19.4 ± 0.3 | 17.4 ± 0.2 | 17.9 ± 0.2 | 1891 ± 67 | 96 ± 4 | 9.5 ± 0.7 | 158 ± 25 | 167 ± 27 |
| CON (n = 121) | 18.8 ± 0.2 | 17.0 ± 0.2 | 17.3 ± 0.2 | 1730 ± 62 | 94 ± 4 | 7.8 ± 0.5 | 164 ± 22 | 173 ± 23 |
| Grape Type (GT) | ||||||||
| black (n = 55) |
18.5 ± 0.3 b | 16.8 ± 0.3 b | 17.3 ± 0.3 b | 2262 ± 90 a | 130 ± 3 a | 11.9 ± 1.2 a | 557 ± 41 a | 588 ± 43 a |
| red (n = 78) |
20.2 ± 0.2 a | 17.9 ± 0.2 a | 18.2 ± 0.2 a | 2070 ± 72 a | 117 ± 4 b | 8.6 ± 0.6 b | 95 ± 10 b | 100 ± 11 b |
| white (n = 112) | 18.7 ± 0.3 b | 17.0 ± 0.2 b | 17.3 ± 0.2 b | 1410 ± 52 b | 62 ± 2 c | 7.1 ± 0.6 b | 13 ± 1 c | 13 ± 1 c |
| ANOVA | ||||||||
| p-values | ||||||||
| Main effects | ||||||||
| Yr | NS | NS | NS | NS | NS | <0.0001 | <0.0001 | <0.0001 |
| PS | 0.0875 | 0.0837 | 0.0253 | 0.0294 | NS | 0.007 | NS | NS |
| GT | 0.0001 | 0.0014 | 0.0047 | <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
| Interactions * | ||||||||
| Yr:PS | NS | NS | NS | 0.0005 | NS | 0.0109 | NS | NS |
| Yr:GT | 0.0456 1 | NS | NS | NS | 0.0003 1 | <0.0001 1 | 0.0013 1 | 0.0013 1 |
| PS:GT | NS | NS | NS | NS | NS | 0.0247 2 | NS | NS |
GAE, Gallic acid equivalent; TE, Trolox equivalent; cyan, cyanidin 3-glucoside equivalent; mal, malvidin 3-glucoside equivalent; means labeled with the same lower case letter within the same column are not significantly different (General Linear Hypothesis test p < 0.05); p-values in italic are for trends (0.1 < p < 0.05); p-values in bold are significant (p < 0.05). * only interactions for which significant results were detected are shown; 1 see Table 6 for interaction means ± SE; 2 see Table 11 for interaction means ± SE.