See discussions, stats, and author profiles for this publication at: https://www.researchgate.

net/publication/304011810

Pollen: Collection, Harvest, Compostion, Quality

Article · April 2016

CITATIONS READS

4 2,884

1 author:

Stefan Bogdanov
Bee Product Science
124 PUBLICATIONS   6,395 CITATIONS   

SEE PROFILE

All content following this page was uploaded by Stefan Bogdanov on 16 June 2016.

The user has requested enhancement of the downloaded file.

 The Pollen Book, Chapter 1

The Bee Pollen Book

Wild Thyme and Sav'ry set around their cell

Sweet to the Taste and fragrant to the smell
Set rows of Rosemary with flow'ring Stem,
and let the purple Vi'lets drink the Stream
Virgil, "Georgica", 20 BC

Be aware that this online book is only for private use and should not be copied and reprinted as some of the images
are not copyrighted.
I would appreciate your feedback at info@bee-hexagon.net
Stefan Bogdanov, Muehlethurnen, Switzerland

Bee Product Science, www.bee-hexagon.net April 2016 1

 The Pollen Book, Chapter 1

Pollen: Collection, Harvest, Composition, Quality

Stefan Bogdanov
The old Egyptians describe it as "a life-giving dust." In ancient Greece the pollen pellets, carried on the bee’s legs
were considered to be made of wax. Aristotle in his Historia animalism observes, that they resemble wax in
hardness but are in reality sandarace or bee-bread. Later it was called farina.The name bee bread persisted until
many centuries. Pollen (a Latin word for fine flour or dust) was used for the first time by John Ray in Historia
plantarum (1686). The first works on the mechanism of pollen foraging were carried out by Meehan in 1873.
By determining pollen in soil sediments information on the vegetation history of the earth is gathered. The
importance of pollen for the determination of honey origin was realized at the beginning of the 20th century.

POLLEN AND POLLINATION

The pollen contains the plant's male reproductive organs or gametophytes. They are situated in he anthers of the
higher flowering plants. The pollen is transferred onto the stigma of a flower, a process called pollination. This
transfer is carried either by the wind, by or by insects Each pollen grain carries a variety of nutrients and upon
arrival at the stigma it divides into several cells and grows a tube through the often very long stigma of the flower.
Growth continues to the embryo sac in the ovary of the flower, inside which one egg cell will fuse with a sperm
cell from the pollen and complete the fertilization. There are two types of flowers: naked and covered. The open
flowers are pollinated by wind, the covered ones, mostly by insects. The pollination by insects came into being
some 100 millions years ago. Pollen are well preserved in the earth. The science, by which pollen are studied in
order to gain knowledge about the vegetation on
earth in called paleopalynology.
Bees pollinate around 40 000 plant species. The
importance of bee pollination for ecology and
agriculture is immense. The economic importance
for the USA in 1973 was estimated to be the 143
fold of the honey harvest, that is 18.9 billions $ 30
In the USA in other countries beekeepers are paid
by the peasants for pollination services. The
importance of bees for the pollination and
multiplication of wild plants is also immense, but
cannot be quantified in a money value.

ANATOMY AND POLLINATON

Pollen itself is not the male gamete, but each pollen grain
contains vegetative (non-reproductive) cells (only a single cell
in most flowering plants but several in other seed plants) and a
generative (reproductive) cell containing two nuclei: a tube
nucleus (that produces the pollen tube) and a generative nucleus
(that divides to form the two sperm cells). The group of cells is
surrounded by a cellulose-rich cell wall called the intine, and a
resistant outer wall composed largely of sporopollenin called
the exine.

Bee Product Science, www.bee-hexagon.net April 2016 2

 The Pollen Book, Chapter 1

The transfer of pollen grains to the female reproductive

structure (pistil in angiosperms) is called pollination. This
transfer can be mediated by the wind, in which case the plant is
described as anemophilous (literally wind-loving).
Entomophilous (literally insect-loving) plants produce pollen
that is relatively heavy, sticky and protein-rich, for dispersal by
insect pollinators attracted to their flowers. Bees and many
insects and some mites are specialized to feed on pollen, and
are called palynivores.

HOW AND WHICH POLLEN ARE GATHERED BY THE BEES?

How bees collect pollen

When visiting flower’s blossom bees touch the stamen and its body is covered with pollen dust. The honey bee uses
hind legs this plate to compress the pollen into the pollen basket. The bee moistens the pollen with secretion from
it's mouth which helps the pollen cling together and to the basket hairs. This secretion contains different enzymes,
e.g. amylase and catalase. A pollen load contains up to 10% nectar, which is necessary for packing. To collect a
load of pollen, on the average about 8 mg, a bee has to visit about 200 different flowers. Mostly, a load contains
pollen from the same flower. Approximately 10 trips a day are made for pollen by a worker. In good weather
50,000 to pollen loads were brought into the hive daily. In the hive, pollen is removed from the rear legs by a spike
on the mid legs and is placed in cells. Often the head is used to pack the pollen in cells. Honey is added to maintain
pollen quality, which is called beebread.
While honey is the energy source of the bee colony, pollen, is the bees’ main source of the other important
nutrients: proteins, minerals, fats and other substances. Consequently, an adequate pollen supply will be essential
to ensure the long-term survival of a colony and to maintain its productivity.
Honey bee foragers mix freshly collected pollen with some nectar before packing it into their corbiculae. In the
hive, the workers add more nectar and glandular secretions to the pollen, which then undergoes lactic acid
fermentation.
Pollen is a very important factor for the
development of the colony, in the first place for
producing brood. It supplies the necessary food:
proteins, lipids and minerals. It seems that under
normal conditions bees will gather enough pollen
for a sufficient colony development. Thus there is
no need for a pollen supplement.
See further information at 20, 21

Which pollen types are gathered by the bees?

Basic studies on pollen collection by bees were carried out in the Swiss Bee Research Centre by Wille and
collaborators during the 1980’s. These studies have been recently reviewed by Keller et al. 20, 21 and are
summarised here: Different investigations show that the bulk of the pollen generally came from few plant species..
The five most common pollen sources yielded on average more than 60% of the total collected pollen. Following
conclusions are based on this study, carried out in different locations of Switzerland ,in the most important pollen
sources were plants occurring at high densities either naturally or due to cultivation: white and red clover
(Trifolium repens and pratense), corn (Zea mays), rape (Brassica napus) and sunflower (Helianthus sp.). Other
plants such as plantain (Plantago sp.), dandelion (Taraxacum officinale) and mustard (Sinapis arvensis) are
generally abundant in meadows and pastures 7. A third group of important pollen sources included different tree
species such as maple (Acer sp.), willow (Salix sp.), stone fruit (Prunus sp.) and pome (Pyrus sp.). Of course, this
list is strongly influenced by the overrepresentation of study sites from the Swiss midland, and in other sites many
other plant species may be important. Thus, pollen from heather (Calluna vulgaris), sweet chestnut (Castanea
sativa) and scotch broom (Cytisus scoparius) was quite dominant in samples from Intragna in southern Switzerland
(black bars in fig. 1), but was not found at other localities. In two other sites lying the subalpine region of

Bee Product Science, www.bee-hexagon.net April 2016 3

 The Pollen Book, Chapter 1

Switzerland at an elevation of 1250 and 1560 m above sea level respectively dominant plants were: crocus (Crocus
sp.) and sedges (Carex sp.), besides Rhinanthus sp. and Euphrasia sp., found exclusively in one of the locations In
another study the composition of bee-collected pollen was compared with the composition of the surrounding flora
and was found that the bulk of the pollen indeed came from common plants. However, it is likely that the pollen
composition does not simply reflect the proportions of different flowers in the surroundings but is, at least to some
extent, determined by the preferences of the bees.
At the beginning of the vegetation period, a uniform pattern was observed across most available studies with a very
pronounced dominance of different tree species as the most popular pollen sources. These included maple (Acer
sp.), ash (Fraxinus sp.) different fruit trees (Prunus sp. and Pyrus sp.), poplar (Populus sp.), oak (Quercus sp.),
willow (Salix sp.) and elm (Ulmus sp.). At some Swiss locations, dandelion (Taraxacum officinale) was also an
important pollen source in spring. In May and June, the spectrum of pollen types became much more diverse and
generalisations across all study sites were hardly possible. In Ireland and England, some shrub species such as
hawthorn (Crataegus monogyna) and elder (Sambucus sp.) were important pollen sources whereas rape (Brassica
napus) was frequently collected at several of the Swiss locations. In midsummer and early fall, pollen from red and
white clover (Trifolium pratense and repens), corn (Zea mays) and plantain (Plantago sp.) dominated the samples
from all locations from the Swiss midland. In southern Switzerland, European chestnut (Castanea sativa) and
heather (Calluna vulgaris) were the dominant pollen sources at this time of the year. In Ireland, on the other hand,
large amounts of pollen were collected from blackberry (Rubus sp.) and meadowsweet (Filipendula ulmaria).
Towards the end of September, ivy (Hedera helix) became the dominant pollen source at several locations.
60

50

40
number

30

20

10

0
E u s t e u s p.
/ P t hu el i x

ra c e .

fa .
Ac a p .

H pa e n .

a P us p .

Q a r at i s

ia m u i a
n a n e lg e

u e ve va

ge n u s s ac e e
m re ys

B r nc pa r p.
Pr H e d ve r s e
us a n a h p.

is C us p.
an c x .

R sia a e
as nt i n s

m a li p .

V i bu s s p.
H tro san lva t e
l i u S er s s

C r cu n sis

R h t he a i n e a
sic ag a le

ba
as ul a i u s

an m a
Pa pra x sp

ph ra sp

a p
c .
n p

R s re sp
s s i
Br Pla of fic e n

C llu n o a s p

e l e g ic
S i s t a a v u ea

La o r gu s i c c ea
u

pi a a r

rs s y a

in m u dic
A th s
yr s s

ci s
a os

u o s
un e li e r s

c s
cu m ma

n i n
p

ro s
t
xa liu a

u
r a i f o Ze

u s

C a
a
i fo
Ta Tr

F
C

yt
Tr

pollen types
Pollen types gathered in Switzerland in the 1980s: number of studies in which a given plant taxon ranked
among the five most common pollen sources after 20, 21
How much pollen do bees collect?
There are two types of pollen: hand collected and bee collected. Only in the
cases where one wishes to collect the pollen of a certain plant it can be
collected by hand. There is only bee collected pollen on the market.
Beekeepers collect pollen by means of pollen traps, which also provide
quantitative estimates of the pollen harvest of a colony. The information
here is taken from the review of Keller at al.20, 21: There is a large variety of
different trap designs, but all consist of some type of grid, which removes
the pollen pellets from some of the returning foragers as they enter the hive.
The pollen is collected in a tray and can be easily removed by the
researcher. The grid is installed either in front of the hive entrance or
horizontally underneath the entrance to the brood nest (O.A.C. trap design) The percentage of pollen actually
retained in a trap may be quite variable, but will always be considerably less than 100%. Extensive observations by

Bee Product Science, www.bee-hexagon.net April 2016 4

 The Pollen Book, Chapter 1

Imdorf showed that the efficiency of a trap at one colony could vary between 3 and 25% during the course of the
vegetation period. Still larger variation (15 – 43%) was observed between different colonies, even if the same trap
type was used. Such discrepancies may stem from small differences in the material used for the individual traps.
Alternatively, honey bee colonies may vary in the average size of the workers or may collect a different spectrum of
pollen types. The species composition of the collected pollen appears to be of particular importance. Thus, it was
found that the average efficiency of their traps increased from 33% to 60% when they were moved to a different
location where different flowers were available, and the foragers collected significantly larger pollen pellets.
From the above discussion it becomes clear that accurate estimates of the actual quantity of pollen collected by a
colony are virtually impossible. It is also not well understood to what extent honey bee colonies might be harmed
by the permanent use of pollen traps.
In different studies the amount of pollen, gathered in different locations in Europe and the USA was determined
The available estimates of the amount of pollen collected per colony and year in different European and one
American location range between 5.6 kg and 222 kg. Assuming an average trap efficacy of 20 % the amount
gathered by the pollen trap varies from 1.1 to 40. 4 kg. The maximum of 40.4 kg, found in the pollen traps in
California, was considerably higher than the amounts gathered in Europe, which varied between 1.4 and 9.2 kg.
This difference is probably the result of a longer collection period. In the study by Eckert more than 50 kg of pollen
were actually retained in the traps. Factors for pollen gathering are abundance of pollen, weather conditions and
the nutritional need of the colony may influence the foraging behaviour of the bees.
The amount of pollen available for consumption at any given point in time is determined not only by the intensity of
pollen collection but also by the pollen stores of a colony. In experimental colonies, the intensity of pollen foraging
could be decreased by adding and increased by removing pollen stores. In apiaries specialized on the production
of bee pollen in countries with a longer vegetative period up to 10 to 20 kg per colony can be harvested, the normal
however is lower, about 5-15 kg per hive.
Pollen is collected with a pollen trap, made out of a grid, placed
on the entrance of the hive. These traps vary greatly in size,
appearance, and method of installation on the hive. Each has
some feature that makes it particularly adaptable for a specific
purpose. All traps, however, have two basic elements: 1. a grid
through which pollen-carrying bees must crawl to separate the
pollen pellets from the bees’ legs, and 2. a container to store
these pellets. Upon entering the hive the pollen loads of the bees
are stripped away and fall in a drawer beneath.

HARVESTING BY THE BEEKEEPER

Fresh, bee collected pollen contains about 20-30 g water per 100 g. This high
humidity is an ideal culture medium for micro-organisms like bacteria and
yeast. For prevention of spoilage and for preservation of a maximum quality
the pollen has to be harvested daily and immediately placed in a freezer. After
two days of storage in the freezer, the pest insects will be killed27 After
thawing pollen can be kept only for a few hours and should be further
processed as soon as possible.

Drying
The pollen is best dried in an electric oven, where humidity can continuously escape. Then it is purified by a
special machine, similar to the seed cleaning machine. The maximum temperature is 30°C and the drying time
should be as short as possible in order to avoid vitamin losses.
Fresh, bee collected pollen contains about 20-30 g water per 100 g. This high humidity is an ideal culture medium
for micro-organisms like bacteria and yeast. For prevention of spoilage and for preservation of a maximum quality
the pollen has to be harvested daily and immediately placed in a freezer. After thawing pollen can be kept only for
a few hours and should be further processed as soon as possible. After drying the water content should be 6 g
water per 100 g pollen.
Today pollen is dried generally in electric ovens, where humidity can continuously escape. The prescribed
maximum temperature was 40°C. However this temperature seems to be high. The effect of different methods of
preservation (freezing, drying at about 40ºC and lyophilisation) on selected parameters attributed to the biological

Bee Product Science, www.bee-hexagon.net April 2016 5

 The Pollen Book, Chapter 1

quality of bee pollen were tested in Poland. Freezing caused no substantial changes in the chemical composition of
the pollen loads, so this technique should be recommended when the preservation of the pollen load for nutrition or
therapeutic purposes is important. Lyophilisation markedly decreased vitamin C and provitamin A content, but
drying at 40ºC revealed the most disadvantageous effect 44.
A Brazilian study found that pollen drying for 6 hours at 45 °C led to significant losses of vitamin E and β-
carotene, as well as pro-vitamin A by 15 to 25 % 8
A Spanish study showed that freeze drying is better for the preservation of the chemical and the biological
properties of pollen than oven-dried one10
A Portuguese study revealed that quick drying of bee pollen (3 times for 45 seconds) at 50o C in an infra-red oven
did not lead to losses of anti-oxidant activity
Concluding the above results, pollen should be dried at possible low temperatures, a maximum of 30 °C. The better
alternative is to use freeze drying. A pollen freeze drying machine is described in the literature 12 , but its effect on
pollen quality has not been tested.
Drying changes the aroma profile of bee collected pollen11
Storage
Experience in Switzerland showed that from a microbiological and sensory point of view pollen remains stable
until 1.5 years of storage at room temperature. Under these conditions pollen keeps its sensory and microbiological
quality for a storage period of 2 years, if stored in a cool, dry and dark place 3.
As a functional food one of the main health enhancing properties is the strong antioxidant activity of pollen.
Pollen loses a considerable amount of its antioxidant activity (about 59%) after one year4. This loss might be due to
the decrease of phenolic compounds, observed in another study35
The amounts of four out of nine constituents examined (reducing sugars, total proteins, vitamin C, and provitamin
A) markedly decreased upon storage. Taking into account the methods of production practical recommendations
for the means of preservation and optimum conditions for the storage of pollen loads are suggested. Freezing
followed by storage at -20ºC in pure nitrogen guarantees high biological qualities of bee pollen kept for up to 6
months. Pollen stored for a longer periods should, however, be dried by lyophilisation and stored at -20ºC in pure
nitrogen to preserve its highest biological activities. Storage of pollen at 0 to 10 degrees in vacuum has been
proposed in order to prevent antioxidant spoilage 40.
A Brazilian study found no loss of vitamin C and losses of vitamine E and beta-carotenes by 15 to 20 % upon
storage of dry pollen for one year at room temperature 9
Fresh, frozen purified pollen should be stored under nitrogen until consumption for preservation of optimal
biological and nutritive properties 29.
Harvesting of unifloral pollen and of specific pollen types
Normally beekeepers collect mixed pollen. Harvesting of unifloral pollen is important because only this type of
pollen has constant composition and thus can be successfully used in nutrition and medicine. A machine was
constructed in Austria, by the help of which bee pollen can be sorted into different types, the purity of the sorted
pollen being about 90 %32.
The different pollen types differ in colour. This properties was used for the development of a computer based
differentiation of pollen loads6, however, the hardware has not been developed.

Fresh freeze-dried pollen

Patrice Percie du Sert from France invented and patented a technique in 1994
that allows all the nutrients in fresh bee pollen to be preserved. The pollen is
frozen at collection and packed in a nitrogen filled package; oxygen is
excluded, eliminating decay. This process allows the pollen to be presented as
close to its pure state as possible. Fresh, purified pollen can be frozen and
stored under nitrogen until consumption for preservation of optimal biological
and nutritive properties29

Bee Product Science, www.bee-hexagon.net April 2016 6

 The Pollen Book, Chapter 1

Bee bread

Bees store pollen in the hive as beebread. Pollen is

mixed with honey and bee secretions and stored in the
combs. Bee bread undergoes a lactic acid fermentation
and can be thus preserved. Beebread combs will often
be sold as a whole. For that purpose a bee queen
separator is placed between brood and honey combs
during a period of a maximum pollen gathering activity.
When the combs are full, the pollen is harvested by
means of a scraper and filled into a jar.

Production of “home bee bread” after Dany 1988, as described by Krell23

The term “bee bread” is reserved for the original bee pollen stored in the combs. Thus, the product described
below cannot be called “home bee bread” or fermented pollen.
Normally, the term beebread refers to the pollen stored by the bees in their combs. The beebread has already been
processed by the bees for storage with the addition of various enzymes and honey, which subsequently ferments.
This type of lactic acid fermentation is similar to that in yoghurts (and other fermented milk products) and renders
the end product more digestible and enriched with new nutrients. One advantage is almost unlimited storability of
beebread in comparison with dried or frozen pollen in which nutritional values are rapidly lost. The natural
process carried out by the bees can more or less be repeated artificially with dry or fresh bee-collected pollen. It is
important however, to provide the correct conditions during the fermentation process.
The container
Wide-mouthed bottles or jars with airtight lids are absolutely essential. Airtight stainless steel or glazed clay pots
can also be used. Containers should always be large enough to leave enough airspace (20 to 25 % of the total
volume) above the culture.
The temperature
The temperature for the first two to three days should be between 28 and 320C; the bees maintain a temperature of
approximately 34°C. After the first two or three days the temperature should be lowered to 20°C.
The high initial temperature is important to stop the growth of undesirable bacteria as quickly as possible. At this
ideal temperature all bacteria grow fast so that an excess of gas and acid accumulates. Only lactic acid producing
bacteria (lactobacilli) and some yeasts continue to grow. The former soon dominate the whole culture. This final
growth of lactobacilli should proceed slowly, hence the reduction in temperature after 2-3 days.
The starter culture
It is best to start the culture with an inoculation of the right bacteria such as Lactobacillus xylosus or lactobacilli
contained in whey. Freeze-dried bacteria are best if they can be purchased, but otherwise, the best cultures are
those that can be obtained from dairies. Whey itself can be used. If the whey is derived from unprocessed fresh milk
it should be boiled before use. A culture can also be started with natural beebread.
Preservation
Fermentation produces a pleasant degree of acidity (ideally pH 3.6-3.8). Some pollen species may promote
excessive yeast growth but this does not spoil the beebread. If the flavour is strange or some other mildew-like or
unpleasant odours arise from the beebread, discard it and try again. The final product, can be stored for years,
once unsealed, it can be dried and thus is storable for many more months.
General conditions
For successful fermentation, exact quantities are less important than the correct conditions:
- the pollen to be fermented needs to be maintained under pressure
- the air space above the food needs to be sufficient (20-25 % of total volume)
- the container needs to be airtight
- the temperature should not drop below 18°C
Ingredients (in parts by weight):
10 Pollen; 1.5 Honey; 2.5 Clean water 0.02 Whey or very small quantity of dried lactic acid bacteria
Clean and slightly dry the fresh pollen. If dried pollen is used, an extra 0.5 parts of water is added and the final
mix soaked for a couple of hours before placing it in the fermentation vessels. If the mixture is too dry, a little more
honey-water solution can be added.

Bee Product Science, www.bee-hexagon.net April 2016 7

 The Pollen Book, Chapter 1

Heat the water, stir in the honey and boil for at least 5 minutes. Do not allow the mix to boil over. Let the mix cool.
When the temperature is approximately 30-32 0C, stir in the whey or starter culture and add the pollen. Press into
the fermentation container.
When preparing large quantities in large containers, the pollen mass should be weighted down with a couple of
weights (clean stones) on a very clean board.
Close the container well and place in a warm place (30-32 0C).
After 2-3 days, remove to a cool area (preferably at 200C). 8 to 12 days later the fermentation will have passed its
peak and the beebread should be ready. The lower the temperature, the slower is the progress of fermentation.
Leave the jars sealed for storage.
COMPOSITION
The pollen composition varies greatly according to its botanical origin:
Pollen composition after5
Main Components Content Minimum – Maximum
g/100g dry weight
Proteins 10-40
Lipids 1-13
total Carbohydrates* 13-55
Dietary fibre, Pectin 0,3-20
Ash 2-6
undetermined 2-5
Minerals, trace elements mg/kg
Potassium 4000-20000
Magnesium 200-3000
Calcium 200-3000
Phosphorus 800-6000
Iron 11-170
Zink 30-250
Copper 2-16
Manganese 20-110
Vitamins mg/kg
β-Carotene 10-200
B1; Thiamin 6-13
B2; Riboflavin 6-20
B3; Niacin 40-110
B5; Pantothenic acid 5-20
B6; Pyridoxin 2-7
C; Ascorbic acid 70-560
H; Biotin 0.5-0.7
Folic acid 3-10
E: Tocopherol 40-320

Carbohydrates
They are mainly polysaccharides like starch and cell wall material41
The calculated carbohydrate content is higher than the one, determined by analytical methods. The reason is that a
part of the carbohydrates is composed by crude fibre and cell wall material, which are generally not determined by
chemical methods, while their part can be calculated: 100 less the sum of water, fat, protein and ash content.
The sugars fructose, glucose and sucrose comprise about 90 % of all low molecular sugars37
Crude fibre
The crude fibre is composed of starch and insoluble polysaccharides like callose, pectin, cellusose and
sporopollenin41. There is quite a large variation between the minimum and the maximum values, due probably to
the different methods and to the different plants measured1, 15, 37, 39

Bee Product Science, www.bee-hexagon.net April 2016 8

 The Pollen Book, Chapter 1

Protein and amino acids

The protein concentrations in hand-collected pollen from 377 plant species from 93 families . Pollen from different
40 species may vary considerably in protein content, with values
35 ranging between 2.5% in the cypress Cupressus arizonica and
30
25 61.7% in Dodecatheon clevelandii (Primulaceae). Within plant
families, however, protein concentration appears to be highly
%

20
15
10
conserved, except in the species-rich Cactaceae and Fabaceae.
5 On average, animal-pollinated plants do not appear to be
0
richer in pollen protein than wind-pollinated plants 34.
s
.

s
ta

us

s
sp

ay

pu

riu
a

al
m
ol
us

na

a
m
e

op
a
l

nc
pu

s
Ze

sc
ru

sic
la
Po

Py

s
as
go

nu
Br
ta

m
an

a
th
Pl

Figure: Variation of protein in pollen gathered in Switzerland, after 24

ro
Sa

Only about 1/10 of the total protein comes from free amino acids. Generally, there appear to be few qualitative
differences in the amino acid composition of different pollen types and most of them contain all essential amino
acids34 Wille et al. detected also very similar proportions of the different amino acids in bee-collected pollen
samples from 99 plant species20. Pollen proteins play a key role as an allergens33.
Lipids
There are considerable differences of the fat composition, depending on the botanical origin. There are mainly
polar and neutral fats (mono-, di and triglycerides), as well as small amounts of fatty acids, sterines and
hydrocarbons.
In one study 3 % of the total lipids are free fatty acid are reported. about half of them are the unsaturated acids
oleic, linoleic (omega-6) and linolenic (omega-3) 41, while in a study of pollen of different geographic origin it is
reported that 50 to 60 % of the fatty acids are unsaturated (oleic, linoleic and alpha-linoleic) while the rest being
saturated, mainly palmitic acid 42
Other physiologically important compounds are the sterols.
STANDARD AND QUALITY
From hygienic point of view the microbiological safety is the main quality criterion. It is important to control the
microbiological quality of pollen, especially the absence of pathogenic germs and fungi. Destruction of bacteria by
irradiation, ozone treatments45 or chemical fumigants36 is not necessary and leads to toxic residues..
For specific use the composition of biological active components e.g. flavonoids (Campos et al. 1997, Serra-
Bonvehi et al., 2001) or vitamin content should be evaluated.
Pollen is the bee product, least influenced by contaminants from beekeeping2. However, it can be polluted by air
contaminants, e.g. by heavy metals and pesticides. Thus, for optimum quality pollen should be gathered in areas
which are at least 3 km distant from contamination sources such as heavy traffic and pesticide-treated agricultural
areas.
In the last few years there are genetically manipulated plants and also pollen. No studies on the negative effect of
such pollen on human nutrition have been published. The consumer should be aware of that. In the EU there is a
compulsory indication of the content of genetically manipulated organisms (GMO) in food ( and also of pollen, if
there the GMO content exceeds 1 %.

Analysis Quality criteria

Sensory examination Typical odour and taste, no visible contaminants
Microscopic examination Origin test (botanical, geographical)
Microbiological testing Bacterial load should be within legal hygienic limits
Chemical Examination Water content: maximum 6 g/100 g pollen
Content of main ingredients, carbohydrates, fat and protein, if labelled
accordingly:
Contamination Pesticides, heavy metals

Bee Product Science, www.bee-hexagon.net April 2016 9

 The Pollen Book, Chapter 1

Sensory Analysis
Colour, appearance, odour and taste vary according to the botanical origin.
Colour: mostly yellow or yellow-brown, but many different colours are possible16, 22
Appearance: as so called „pollen loads“
Odour: hay-like
Taste: sweet, sour, bitter, spicy,
Defects: off-odour and taste, “molds”, fermented, rancid, visual impurities

Microscopical examination
The pollen should not contain impurities like bee parts, wax, plant particles or other extraneous matter.
Pollen analysis can be used for the determination of the botanical origin. The same methodology, as used for pollen
analysis of honey can be used 26
There is no international standard. Some countries as Brazil, Bulgaria, Poland and Switzerland have national
standards 5. A proposal has been recently made 5:
Proposal for a chemical standard
Component Requirement Content
Water content not more than 8 g/100 g
Total protein content (N x 6.25) not less than 15 g/100 g
Sugar content (total) not less than 40 g/100 g
Fat not less than 1,5 g/100 g
Water content
The maximum allowed humidity varies from country to country: Brazil, 4 %, Switzerland, 6 %, in Russia: 8-10 %,
Bulgaria: 10 %. More than 10 % makes the pollen susceptible to fermentation. The examination of the sensory
quality in Switzerland concluded that humidity of less than 6 % makes the pollen too dry and less acceptable from
sensory point of view.
The determination of pollen water content is carried out after drying to a constant weight in a cabinet dryer or infra-
red oven drier 14, 28 or by Karl-Fischer method 13, 38.
Carbohydrates
Generally the carbohydrate content in g/ per 100 g will be determined by calculation, as the total carbohydrate
content cannot be determined easily: 100 less the sum of water, fat, protein and ash content.
Proteins and amino acids
Protein content is a standard determination after Kjedahl, using a factor of 6.25 or 5.6 31 (Rabie et al., 1983).
According methods for protein content in pollen loads we recommend to use for calculation (Kjeldahl method) N x
5.6 rather than N x 6.25 This factor is used by other authors too.
Lipids
Lipids are determined by extraction with petrol ether 43
Contaminants
Pollen is the bee product that is most susceptible to pesticide contamination 2. Pesticides should be tested whether
they conform to the requirements. Also pollen should be tested for microbial purity: pollen can be contaminated by
funghi, which can produce mycotoxins19
LABELLING
Composition
The composition of pollen varies greatly depending on the botanical composition of the pollen. There are two
possibilities.
1. Determine the composition of each lot and state the composition:
2. Indicate an average composition, example for Swiss pollen:

Bee Product Science, www.bee-hexagon.net April 2016 10

 The Pollen Book, Chapter 1

100 g pollen contain on the average 20 g protein, 60 g carbohydrates 8 g fat and approx. 300 calories.
Also the fiber content could be indicated,
Serving: 2 tea spoons daily (approx. 10 g); children: half dose.
Warning: It is recommended that people who are susceptible to allergies or asthma should avoid intake of bee
pollen.
Storage: store in the dark in a cool dry place
Best before (valid after packaging of product)
Dried pollen stored at room temperature: 12 months
Dried pollen packed in vacuum: 24 months
Frozen fresh pollen stored in the freezer: 12 months
TRADE
There are no official figures on pollen trading. Mainly bee gathered pollen is traded, with the exception of maize
pollen, which is also gathered by special machines. There are no official figures about the trade of pollen, but
according to Crane the production of pollen is the greatest among the secondary bee products (all besides honey).
According to the same sources 1986 60-130 tons were produced in in West Australia7
In Europe production is greatest in Spain, Portugal, France, Germany and Italy, as well as Eastern Europe17, 18
Spain is the biggest producer in Europe, in 1986 about 1200 tons were produced, 943 tons of which being
exported37.
Other countries like like Canada, USA as well as the Latin American countries and China are also good pollen
producers and export some pollen. Especially China is becoming a leading producer and exporter in the world, it
produces at present about 2500 tons per year25

Pollen packed in vacuum packed

Storage in glass for one or more
air-tight plastic bags prevents
years results in decrease of Harvesting of unifloral pollen ensures constant and
oxidation and decrease of
antioxidant activity. Packing in reproducible concentration of biologically active
antioxidant activity due to contact
vacuum or under N2 is better. ingredients.
with oxygen.

References

1. BELL, R R; THORNBER, E J; SEET, J L L; GROVES, M T; HO, N P; BELL, D T (1983) Composition and protein
quality of honey-bee-collected pollen of Eucalyptus marginata and Eucalyptus calophylla. JOURNAL OF
NUTRITION 113 (12): 2479-2484.

2. BOGDANOV, S (2006) Contaminants of bee products. Apidologie 38 (1): 1-18.

3. BOGDANOV, S; BIERI, K; GREMAUD, G; IFF, D; KÄNZIG, A; SEILER, K; STÖCKLI, H; ZÜRCHER, K (2003)

Bienenprodukte; 23 B Pollen. Swiss Food Manual (Schweiz.Lebensmittelbuch): 1-6.

4. CAMPOS, M G; WEBBY, R F; MARKHAM, K R; MITCHELL, K A; DA CUNHA, A P (2003) Age-Induced

Diminution of free radical scavening capacity in bee pollens and the contribution of Consistent flavonoids.
Journal of agricultural and food chemistry 51 (3): 742-745.

5. CAMPOS, M G R; BOGDANOV, S; ALMEIDA-MURADIAN, L B; SZCZESNA, T; MANCEBO, Y; FRIGERIO,

C; FERREIRA, F (2008) Pollen composition and standardisation of analytical methods. Journal of
Apicultural Research 47 (2): 154-161.

Bee Product Science, www.bee-hexagon.net April 2016 11

 The Pollen Book, Chapter 1

6. CHICA, M; CAMPOY, P (2014) Discernment of bee pollen loads using computer vision and one-class classification
techniques (vol 112, pg 50, 2012). Journal of Food Engineering 138: 53.

7. CRANE, E (1990) Bees and beekeeping: Science, practice and world resources. Cornell University Press Ithaca, New
York

8. DE MELO PEREIRA, I (2008) Stability of antioxidant vitamins in bee pollen samples (original in Portuguese). PhD
Pharmaceutical Science School Sao Paolo University, Sao Paolo, Brazil; pp 90pp.

9. DE MELO PEREIRA, I; ALMEIDA-MURADIAN, L (2010) Stability of antioxidant vitamins in bee pollen samples.
Quimica Nova 33: 514-518.

10. DOMINGUEZ-VALHONDO, D; GIL, D B; HERNANDEZ, M T; GONZALEZ-GOMEZ, D (2011) Influence of the

commercial processing and floral origin on bioactive and nutritional properties of honeybee-collected pollen.
International Journal of Food Science and Technology 46 (10): 2204-2211.

11. DOMINGUEZ-VALHONDO, D; GONZALEZ-GOMEZ, D; HERNANDEZ-MENDEZ, T; BOHOYO-GIL, D

(2013) Influence of the industrial processing and the floral origin into the volatile constituents of honeybee-
collected pollen. Food Science and Technology International 19 (2): 167-176.

12. FIVEASH, J; MCCONNEL, J (1989) A Storage Method for Pollen Using Freeze Drying. TreePlanters' Notes: 18-19.

13. GERGEN, I; RADU, F; BORDEAN, D; ISENGARD, H D (2006) Determination of water content in bee's pollen
samples by Karl Fischer titration. Food Control 17 (3): 176-179.

14. GERGEN, I; RADU, F; POIANA, M (2005) Bee's pollen moisture determination by halogen lamp infrared drying
method. Revista de Chimie 56 (1): 54-56.

15. HERBERT, E W; SHIMANUKI, H (1978) Chemical composition and nutritive value of bee-collected and bee-stored
pollen. Apidologie 9 (1): 33-40.

16. HODGES, D (1952) The pollen loads of the honeybee. Bee Research Association Limited London

17. JÉANNE, F (1985) L'apiculture de A à Z. Le pollen. Abeilles et Fleurs: 8-11.

18. JÉANNE, F (1988) Récolte et conservation du pollen. Bulletin Téchnique Apicole 15 (2): 89-96.

19. KACANIOVA, M; JURACEK, M; CHLEBO, R; KNAZOVICKA, V; KADASI-HORAKOVA, M; KUNOVA, S;

LEJKOVA, J; HASCIK, P; MARECEK, J; SIMKO, M (2011) Mycobiota and mycotoxins in bee pollen
collected from different areas of Slovakia. Journal of Environmental Science and Health Part B-Pesticides
Food Contaminants and Agricultural Wastes 46 (7): 623-629.

20. KELLER, I; FLURI, P; IMDORF, A (2005) Pollen nutrition and colony development in honey bees - part I. Bee
World 86 (1): 3-10.

21. KELLER, I; FLURI, P; IMDORF, A (2005) Pollen nutrition and colony development in honey bees - Part II. Bee
World 86 (2): 27-34.

22. KIRK, W (1994) A colour guide to pollen loads of honey bee. International Bee Research Association Cardiff

23. KRELL, R (1996) Value-added products from beekeeping. FAO Food and Agriculture Organization of the United
Nations Roma; 409 pp

24. LEHNHERR, B; LAVANCHY, P; WILLE, M (1979) Pollensammeln 1978; 5. Eiweiss- und Aminosäuregehalt
einiger häufiger Pollenarten. Schweizerische Bienen-Zeitung 102: 482-488.

25. LIHONG, C (2009) Advances in propolis research and propolis industry in China. J.Royal Inst Thailand 1: 136-151.

26. LOUVEAUX, J; MAURIZIO, A; VORWOHL, G (1978) Methods of melissopalynology. Bee World 59 (4): 139-162.

27. MOOSBECKHOFER, R; ULZ, J (1996) Der erfolgreiche Imker. Graz-Stuttgart

Bee Product Science, www.bee-hexagon.net April 2016 12

 The Pollen Book, Chapter 1

28. OLIVEIRA, K (2006) Caracterização do pólen apícola e utilização de vitaminas antioxidantes como indicadoras do
processo de desidratação. University of Sao Paolo Sao Paolo, Brazil

29. PERCIE DU SERT, P (2002) Ces pollens qui nous soignent. Paris; 211 pp (Guy Trédaniel. edition)

30. PICKHARDT, A; FLURI, P (2000) Die Bestäubung der Blütenpflanzen durch Bienen. Biologie, Oekologie,
Oekonomie. Mitteilung des Schweizerischen Zentrums Bienenforschung (38): 1-75.

31. RABIE, A L; WELLS, J D; DENT, L K (1983) The nitrogen content of pollen protein. Journal of Apicultural
Research 22 (2): 119-123.

32. REISNER, W; GARTLEHNER, K (2006) Entwicklung einer maschinentauglichen Identifikationsmethode für

Blütenpollen. Berichte aus Energie und Umweltforschung 24: 1-36.

33. RIMPLER, M (2003) Von Bienen gesammelte Blütenpollen: Eigenschaften und Verwendung. Ärztezeitschrift für
Naturheilverfahren 44 (3): 158-165.

34. ROULSTON, T H; CANE, J H (2000) Pollen nutritional content and digestibility for animals. Plant Systematics and
Evolution 222 (1-4): 187-209.

35. RZEPECKA-STOJKO, A; STEC, M; KURZEJA, E; GAWRONSKA, E; PAWLOWSKA-GORAL, K (2012) The

Effect of Storage of Bee Pollen Extracts on Polyphenol Content. Polish Journal of Environmental Studies 21
(4): 1007-1011.

36. SERRA BONVEHI, J; GOMEZ PAJUELO, A (1987) Etude de la conservation du pollen des abeilles, emploi de
fumigants. Def.Vegetaux 243: 90-94.

37. SERRA BONVEHI, J; GONELL GALINDO, J; GOMEZ PAJUELO, A (1986) Estudio de la composicion y
caracteristicas fisico-quimicas del polen de abejas. Alimentaria: 63-67.

38. SERRA BONVEHI, J; MARTI CASANOVA, T (1987) Estudio analitico para determinar la humedad del polen.
Analytical study of quantification of moisture in pollen. Anales de Bromatologia 39: 339-349.

39. SOLBERG, Y; REMEDIOS, G (1980) Chemical composition of pure and bee-collected pollen. Scientific reports
Agric.Univ.Norway 59 (18): 2-12.

40. SOLOMKA, V (2001) On bees pollen storage technologies. Pasika (3): 22-23.

41. STANLEY, R G; LINSKENS, H F (1974) Pollen. Biology - Biochemistry - Management. Springer-Verlag Berlin,
Heidelberg

42. SZCZESNA, T (2006) Long chain fatty acids composition of of honeybee-collected pollen. Journal of Apicultural
Science 50 (2): 65-79.

43. SZCZESNA, T (2006) Long-chain fatty acids composition of honeybee-collected pollen. Journal of Apicultural
Science 50 (2): 65-79.

44. SZCZESNA, T; RYBAK, H; SKOWRONEK, W (1995) Alterations in the chemical composition of the pollen loads
stored under various conditions: I, III, IV. Pszczelnicze Zeszyty Naukowe 40: 145, 171, 191-156, 189, 207.

45. YOOK, H-S; LIM, S-I; BYUN, M-W (1998) Changes in microbiological and physiochemical properties of bee pollen
by application of gamma irradiation and ozone treatment. Journal of Food Protection 61 (2): 217-220.

Bee Product Science, www.bee-hexagon.net April 2016 13

View publication stats