dc.description.abstract |
This investigation was carried out to determine the phenolic
contents and antioxidant activity of Sudanese honey. Seven samples of
Sudanese honey were tested for phenolic content, antioxidant activity and
other parameters such as moisture, pH, refractive index, ash, total soluble
solids, protein, electrical conductivity and colour intensity.
Results of analysis demonstrated that there is a good amount of
phenolic content and antioxidant activity in Sudanese honey. It ranged
from 4.4 to 201.1 mg/TAE/100 g honey for phenolic content. The highest
amount of total phenolic content was found in the Acacia nilotica honey
(Sunut) 201.1 mg/TAE/100 g honey followed by the Balanites aegyptiaca
honey (Heglig) 146.38 mg/TAE/100 g honey and then came Acacia seyal
honey (Talih) 67.11 mg/TAE/100 g honey. Honey from Two types of
Ziziphus spina-christi (Sidir of mountain and Sidir) showed similar
values 21.98 and 20.15 mg/TAE/100 g honey respectively , while honey
of Azadirachta indica (Neem) was found to contain 17.15 mg/TAE/100 g
honey and honey from Cucurbita maxima Duch. (Pumpkin) was found to
contain 4.44 mg/TAE/100 g honey.
For antioxidant activity, it ranged from 3177 to 6247μg for dry
weight sample cause 50% inhibition, which indicates antioxidant activity.
The maximum antioxidant effect was found in Azadirachta indica honey
(Neem) 3177 μg followed by Balanites aegyptiaca honey (Heglig) 4045
μg, then Ziziphus spina-christi honey (Sidir) 4068 μg, and Acacia seyal
honey (Talih) 4679 μg, while Ziziphus spina-christi honey (Sidir of
mountain) was 5125 μg. The minimum antioxidant effect was observed in
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Acacia nilotica honey (Sunut) 6247 μg, followed by Cucuribia maxima
Duch. honey (Pumpkin) 5323 μg.
Results of this study showed highly significant differences
(P<0.01) in phenolic contents of different honey samples. There was no
correlation (r =0.441) between antioxidant activity and total phenolic
content .
Percent of inhibition increased with increasing the concentration.
There was highly positive Correlation between concentrations (5, 25 and
50μl) of diluted honey samples and the percent of inhibition, which
indicates the antioxidant activity.
Results of parameters such as protein, oBrix and electrical
conductivity are within the standard levels and they ranged from 0.200-
0.286, 75.2-79.0 and 0.20-0.80 for protein, oBrix and electrical
conductivity, respectively. Highly significant differences (P<0.01) were
observed for other parameters such as moisture, pH, refractive index and
ash, with Values ranging from 16.20-21.27%, 3.70-4.80%, 1.4833-
1.4960% and 0.1207-1.205% , respectively.The Brix in honey showed
significantly high negative correlation (P<0.05) (r=-0.869) with moisture
content.
Colour of honey samples was measured by using Aminolta
chromameter and the values of L*, a* and b* were obtained and the values
of chroma, hue angle, and browning index were calculated . The ranges of
24.47-59.44, -1.26-8.41 and 2.40-22.02 for L*, a* and b*, respectively,
while the calculated ranges of 2.70-22.30, 62.68-89.51 and 11.76-82.35
were obtained for chroma, hue angle and browning index, respectively. |
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