Melissopalynology an..

Melissopalynological and chemical analyses of
Robinia pseudo-acacia L. (balck locust) honeys
from Hungary
Zsófia Medzihradszky (Hungarian Natural History Museum),
Zoltán Herpai (Wessling Hungary Ltd.)
and Ágnes Korbonski (Golden Nectar Ltd.)
Apimondia 2009. Montpellier
Robinia pseudo-acacia in Hungary
Since the 18. century
Very invasive species,
with very low biodiversity
About 23-30% of the „forests”
During our investigation about 8-10000 black locust honey samples
– according to the definition of the beekeepers –
were analysed by palynological method
From this big amount of samples we selected some types to chemical analyses
Types: depended on
1. percentage of Robinia pollen
2. main secondary pollen type
3. weather condition
4. geographical origin
In average of the analysed samples the water content was between 17,5–23,5%,
the sacharose between 7–15%.
The diastase activity was relatively low, 6–12 DN.
The fructose/glucose ratio was about 1,53.
The collecting of the samples from all over the country was organised
by the help of the Hungarian Association of Beekeepers.
Secondary pollen types – of planted species
Temperature in Hungary 2006-2009
30
25
20
15
10
5
0
May
April
average of 50 years
2006
2007
2008
2009
Daily average temperature in 2006
Warm April, moderate May
25
Precipitation: 60-100mm
20
15
10
5
0
2006
average of 50 years
Quality of the Robinia honey:
High pollen percentage
1,5-1,6 F/G ratio
Main secondary pollen: Brassica napus
Daily average temperature in 2007
Warm April, warm May
30
25
20
15
10
5
0
average of 50 years
2007
Quality of the Robinia honey:
moderate pollen percentage: about 26%
1,52-1,6 F/G ratio
Main secondary pollen: Brassica napus, Ailanthus altissima
Daily average temperature in 2008
Moderate April and May
25
20
15
10
5
0
average of 50 years
2008
Quality of the Robinia honey:
high pollen percentages: above 26%
1,7-1,79 F/G ratio
Main secondary pollen: Brassica, Rosaceae
Daily average temperature in 2009
Warm April, extrem variable May
25
20
15
10
5
0
average of 50 years
2009
Quality of the Robinia honey:
high pollen percentages: above 30%
1,7-1,79 F/G ratio
Main secondary pollen: Brassica, Rosaceae
60
50
40
30
20
10
0
1
2
3
4
5
6
7
8
9
F/G ratio exaggeration 10x
10
11
12
13
14
15
16
17
Robinia pollen%
The percentage of the Robinia pollen moved between 20% and 56%,
but the F/G ratio was the same.
Conclusions
1.The quality of the Robinia honey depends mainly on the weather
If we have warm April, the Robinia flowers together with the rape.
The flowering time of the Robinia has more common period with the rape.
The F/G ratio will be lower
2. The best years for Robinia are the years with moderate April and May
around or a little bit higher temperature compared with the
50 years average
3. The climate of the world is changing
The flowering periods, pollen and nectar production of the plants
follow the changes. The beekeepers must follow the changes too.