Table 3.
Concentration of phenolic compounds in Istarska bjelica (IB) and Rosinjola (RO) monovarietal virgin olive oils obtained from fresh fruits immediately after harvest (control) and oils obtained from fruits stored seven days at three different storage temperature (RT—room temperature, +4 °C and −20 °C) prior to production.
| Phenolic Compounds (mg/kg) | IB-Control | IB-RT | IB+4 | IB-20 | RO-Control | RO-RT | RO+4 | RO-20 |
|---|---|---|---|---|---|---|---|---|
| Simple phenols | ||||||||
| hydroxytyrosol | 9.30 ± 0.96 b | 27.50 ± 6.48 a | 20.15 ± 0.90 a | 7.31 ± 2.83 b | 10.76 ± 1.51 b | 31.47 ± 2.62 a | 22.25 ± 5.72 a | 20.93 ± 5.40 ab |
| tyrosol | 7.67 ± 0.73 c | 40.16 ± 8.53 a | 20.22 ± 1.62 b | 11.42 ± 2.36 bc | 2.13 ± 0.26 b | 9.12 ± 3.53 a | 8.16 ± 2.07 ab | 3.62 ± 3.09 ab |
| hydroxytyrosol acetate | 1.14 ± 0.39 b | 2.86 ± 0.60 a | 2.01 ± 0.18 ab | 1.11 ± 0.27 b | 0.87 ± 0.24 | 1.31 ± 0.22 | 1.20 ± 0.09 | 0.85 ± 0.14 |
| vanillin | 0.20 ± 0.02 | 0.19 ± 0.02 | 0.21 ± 0.01 | 0.20 ± 0.03 | 0.31 ± 0.04 | 0.25 ± 0.07 | 0.17 ± 0.06 | 0.20 ± 0.09 |
| Total simple phenols | 18.30 ± 0.88 c | 70.72 ± 15.19 a | 42.58 ± 0.53 b | 20.05 ± 5.36 c | 14.08 ± 2.03 b | 42.15 ± 5.87 a | 31.78 ± 7.82 a | 25.60 ± 8.27 ab |
| Secoiridoids | ||||||||
| secologanoside | 0.34 ± 0.09 | 0.21 ± 0.21 | 0.15 ± 0.18 | 0.24 ± 0.13 | 0.13 ± 0.14 | 0.18 ± 0.19 | 0.17 ± 0.08 | 0.26 ± 0.24 |
| elenolic acid glucoside (isomer) | 1.99 ± 0.46 a | 0.74 ± 1.13 ab | 0.44 ± 0.62 ab | 0.16 ± 0.10 b | 0.43 ± 0.67 | 0.73 ± 1.17 | 1.28 ± 1.07 | 0.47 ± 0.70 |
| 3,4-DHPEA-EDA | 120.02 ± 36.92 a | 29.58 ± 9.90 c | 84.78 ± 3.87 ab | 50.36 ± 4.75 bc | 73.30 ± 5.57 a | 48.63 ± 10.97 a | 58.65 ± 14.35 a | 35.30 ± 5.75 b |
| oleuropein aglycone (isomer I) | 62.34 ± 17.93 | 46.23 ± 3.49 | 52.90 ± 1.78 | 44.50 ± 9.08 | 152.05 ± 6.27 a | 98.64 ± 16.17 bc | 111.01 ± 7.86 bc | 73.26 ± 11.66 c |
| p-HPEA-EDA | 49.03 ± 8.82 a | 31.47 ± 5.70 b | 47.18 ± 2.80 a | 35.86 ± 1.82 ab | 11.24 ± 0.66 a | 10.13 ± 1.65 ab | 9.85 ± 2.20 ab | 6.79 ± 0.54 b |
| oleuropein + ligstroside aglycones I and II |
51.52 ± 4.84 a | 28.75 ± 5.73 b | 35.64 ± 2.18 b | 33.31 ± 3.16 b | 14.55 ± 0.60 a | 10.27 ± 0.99 bc | 12.05 ± 1.81 ab | 8.02 ± 1.61 c |
| oleuropein aglycone (isomer II) | 91.19 ± 15.37 a | 60.43 ± 2.27 b | 83.55 ± 4.17 ab | 69.99 ± 8.19 ab | 68.50 ± 2.39 | 72.68 ± 8.09 | 59.62 ± 5.95 | 62.16 ± 0.99 |
| ligstroside aglycon (isomer III) | 1.61 ± 0.21 b | 2.72 ± 0.78 ab | 3.59 ± 0.98 a | 4.11 ± 0.05 a | 1.41 ± 0.14 a | 1.52 ± 0.04 a | 1.53 ± 0.37 a | 0.80 ± 0.09 b |
| oleuropein aglycone (isomer III) | 9.93 ± 2.77 | 11.37 ± 1.23 | 14.87 ± 2.44 | 15.87 ± 3.04 | 6.33 ± 0.36 | 7.82 ± 1.00 | 7.20 ± 1.59 | 5.32 ± 0.49 |
| Total secoiridoids | 387.98 ± 71.14 a | 211.49 ± 22.77 c | 323.09 ± 13.86 ab | 254.41 ± 21.81 bc | 327.94 ± 8.77 a | 250.60 ± 33.36 b | 261.35 ± 35.28 ab | 192.38 ± 19.30 b |
| Lignans | ||||||||
| pinoresinol | 12.46 ± 2.11 b | 17.35 ± 0.37 a | 17.94 ± 0.06 a | 10.96 ± 0.40 b | 3.11 ± 0.11 a | 2.96 ± 0.04 a | 3.03 ± 0.02 a | 2.72 ± 0.08 b |
| acetoxypinoresinol | 24.85 ± 1.60 a | 24.84 ± 0.51 a | 25.80 ± 1.01 a | 20.99 ± 1.08 b | 30.25 ± 0.55 a | 30.66 ± 0.78 a | 30.59 ± 0.95 a | 25.53 ± 1.64 b |
| Total lignans | 37.31 ± 3.56 b | 42.20 ± 0.89 ab | 43.75 ± 1.08 a | 31.96 ± 0.72 c | 33.36 ± 0.66 a | 33.62 ± 0.75 a | 33.62 ± 0.93 a | 28.25 ± 1.60 b |
| Phenolic acids | ||||||||
| vanillic acid | 0.96 ± 0.09 b | 0.86 ± 0.08 b | 0.94 ± 0.01 b | 1.20 ± 0.04 a | 1.03 ± 0.03 | 1.05 ± 0.06 | 1.06 ± 0.10 | 1.03 ± 0.73 |
| p-coumaric acid | 1.74 ± 0.21 b | 5.16 ± 1.17 a | 2.12 ± 0.11 b | 1.28 ± 0.05 b | 0.46 ± 0.01 c | 4.74 ± 0.26 a | 1.26 ± 0.06 b | 0.43 ± 0.10 c |
| Total phenolic acids | 2.70 ± 0.27 b | 6.02 ± 1.11 a | 3.06 ± 0.10 b | 2.48 ± 0.05 b | 1.49 ± 0.04 b | 5.79 ± 0.32 a | 2.33 ± 0.16 b | 1.46 ± 0.71 b |
| Flavonoids | ||||||||
| luteolin | 1.96 ± 0.25 a | 1.14 ± 0.05 b | 1.43 ± 0.10 b | 0.70 ± 0.05 c | 0.96 ± 0.11 a | 0.77 ± 0.04 a | 0.90 ± 0.08 a | 0.49 ± 0.09 b |
| apigenin | 1.01 ± 0.09 a | 0.60 ± 0.01 bc | 0.72 ± 0.05 b | 0.48 ± 0.02 c | 0.35 ± 0.04 a | 0.29 ± 0.02 b | 0.34 ± 0.01 a | 0.24 ± 0.04 b |
| Total flavonoids | 2.97 ± 0.33 a | 1.74 ± 0.07 b | 2.15 ± 0.16 b | 1.18 ± 0.05 c | 1.32 ± 0.15 a | 1.06 ± 0.05 a | 1.24 ± 0.09 a | 0.73 ± 0.11 b |
| TOTAL PHENOLS | 449.26 ± 74.39 a | 332.17 ± 9.24 b | 414.63 ± 14.35 ab | 310.06 ± 24.78 b | 378.19 ± 9.16 a | 333.22 ± 28.63 a | 330.32 ± 28.64 a | 248.42 ± 18.35 b |
Results are expressed as mean values ± standard deviation of three technical repetitions. Mean values labeled with a different superscript letter, within the same row and same cultivar are statistically different (Tukey’s test, p ˂ 0.05). In case there were no statistically significant differences the letters were omitted.