Bee pollen is a beekeeping product made by honeybees (Apis mellifera L.) from pollen collected from flowering plants, mixed with their own secretions and some nectar or honey. Pollen, a vital nutrient source for bees, plays a significant role, especially in the development of larvae, the growth of tissues and organs in young bees, and meeting the protein, vitamin, and mineral needs of adult and older bees. It is also consumed by humans as a food supplement and functional food ingredient.

Production 

When bees visit flowers, flower pollen adheres to their bodies. They then moisten and bind these pollen grains with their oral secretions and approximately 10% nectar, forming pellets. These pollen pellets are collected in the pollen baskets (corbiculae) on the bees' hind legs. Beekeepers collect these pollen pellets using grid-shaped pollen traps placed at the hive entrances. Freshly collected pollen, due to its high moisture content (21-30%), is prone to spoilage and is therefore dried until its moisture content is reduced to the 2-9% range. The drying process is crucial for preserving the nutritional value of the pollen and is recommended to be done in temperature-controlled drying cabinets (36−45°C). Storing dried pollen under appropriate conditions (1-2 months at room temperature, 1 year at 5°C, or for extended periods at −15°C) helps maintain its nutritional value.

Physical Properties 

The physical properties of bee pollen vary depending on its botanical origin and are important for processes such as handling and storage.

• Shape and Size: Fresh bee pollen can be cylindrical, round, triangular, or bell-shaped, while dried pollen is generally spherical or needle-shaped. Their average lengths range from 2.98-3.70 mm, widths from 2.50-3.27 mm, and thicknesses from 1.26-1.74 mm. According to the Turkish Standards Institute (TS 10255), pollen diameter should be between 10−100μm.

• Weight: The average weight of a pollen pellet is around 7.50-8.00 mg. This value can vary between 8.40-15.32 mg depending on different plant sources. The weight of 1,000 pollen grains has been found to be between 4.47-8.14 g.

• Texture: The textural properties of bee pollen, such as hardness, adhesiveness, and springiness, vary depending on its structural integrity.

• Color: Pollen color is an important parameter indicating its quality and varies according to its botanical source and maturity level. It is generally yellow but can also be red, white, light or dark purple, pink, or black. The colors originate from carotenoids, flavonoids, and other aromatic compounds in the pollen.

Functional Properties 

Bee pollen possesses significant functional properties from a food technology perspective.

• Solubility: Pollen has a solubility ranging from 84.91-87.56%, depending on the protein and carbohydrate content in its structure and their interactions. Protein solubility is between 2.80-25.90%, and carbohydrate solubility is between 31.20-75.00%.

• Water and Oil Holding Capacity: Water holding capacity depends on the hydrophilic groups of proteins and carbohydrates in the pollen and ranges between 0.47−2.25g/g. Oil holding capacity is affected by sporopollenin in the exine layer of the pollen and the hydrophobic parts of proteins, ranging from 1.00−3.53g/g.

• Emulsification: The emulsifying activity of bee pollen has been found to be in the range of %44.83-46.76, and emulsion stability in the range of %21.62-26.32. These properties vary depending on the structure and concentration of proteins and solvent conditions.

• Foaming Properties: Bee pollen has low foam stability (%17.50-20.00) and capacity (%6.21-8.69); this is attributed to the presence of surface-active lipids.

Chemical Composition

 The chemical composition of bee pollen varies greatly depending on many factors such as botanical and geographical origin, climate, collection time, and bee species. It has been reported to contain approximately 200 different components.

• Water: Fresh pollen has a water content of 21-30%, which is reduced to 2-9% to increase its stability. According to TS 10255, the moisture content should be below 10%.

• Carbohydrates: Constitute 40-85% of its dry weight. The main carbohydrates are fructose, glucose, and sucrose. Carbohydrates such as cellobiose, isomaltose, maltose, raffinose, stachyose, melezitose, trehalose, and erlose can also be found. Crude fiber content is approximately 3.72%.

• Proteins and Amino Acids: Protein content ranges from 10-40%. According to TS 10255, crude protein content should be above 7%. Main protein fractions are albumins, globulins, glutelins, and prolamins. Bee pollen contains a total of 20 different essential and non-essential amino acids. Common amino acids include proline, glutamic acid, aspartic acid, leucine, alanine, lysine, glycine, valine, serine, and isoleucine. Proline is often the predominant amino acid.

• Lipids and Fatty Acids: Lipids constitute 1-20% of its dry weight. According to TS 10255, crude lipid content should be above 1.2%. The lipid fraction consists of fatty acids, carotenoids, and sterols. The ratio of unsaturated fatty acids to saturated fatty acids is 2.67 on average. It contains essential fatty acids such as linolenic (ω-3), linoleic (ω-6), and oleic (ω-9) acids. Phospholipids (phosphatidylcholine, phosphatidylethanolamine) and phytosterols (β-sitosterol, campesterol) are also present.

• Vitamins: It contains fat-soluble vitamins A, E, D (0.10%) and water-soluble B-group vitamins (B1, B2, B3, B5, B6, B7, B9) and vitamin C (approximately 0.60%). Vitamin K may also be present.

• Minerals: Contains many minerals such as potassium, magnesium, calcium, phosphorus, iron, zinc, copper, and selenium.

• Phenolic Compounds: Contains an average of 1.60% phenolic acids, flavonoids (quercetin, kaempferol, myricetin, rutin, naringenin, luteolin), leukotrienes, catechins, flavonols, and their glycosides. These compounds are responsible for the bioactive effects and color of the pollen.

• Carotenoids: Carotenoids such as zeaxanthin, lutein, β-carotene, cryptoxanthin, antheraxanthin, violaxanthin, neoxanthin, flavoxanthin, and luteoxanthin are found. These compounds contribute to pollen color, antioxidant activity, and provitamin A activity.

Biological Effects 

Bee pollen has various biological effects due to its rich bioactive component content.

• Antimicrobial Effect: Exhibits antibacterial, antifungal, and antiviral properties. This effect is attributed to flavonoids (rutin, quercetin, kaempferol, luteolin), phenolic compounds, and other secondary plant metabolites. It has been reported to be effective against microorganisms such as Staphylococcus aureus, Streptococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Candida albicans.

• Antioxidant Effect: It is a natural source of antioxidants. The main antioxidant components are carotenoids and phenolic compounds. Vitamins A, C, and E also contribute to antioxidant activity.

• Anti-inflammatory Effect: Shows anti-inflammatory activity due to components like phenolic acids, fatty acids, and phytosterols. The flavonoid kaempferol has been reported to suppress the inflammatory response.

• Immunomodulatory Effect: It is reported to strengthen the immune system. Flavonoids (kaempferol, myricetin, luteolin, quercetin) can prevent allergic reactions by inhibiting mast cell activation. Polysaccharides have also been found to have liver-protective and pro-inflammatory cytokine secretion-stimulating effects.

• Effect on the Nervous System: Hydroxycinnamic acid amides have been reported to exhibit antidepressant and anti-Parkinson's activity. A bee pollen-probiotic mixture has been reported to reduce neurotoxic effects, and bee pollen has been shown to ameliorate neuronal death in methylmercury exposure. It has been reported to provide protection against neuroinflammation in an autism model.

• Anticancer Effect: Aldehydes, alcohols, fatty acids, phenolic compounds, terpenes, and esters are stated to contribute to anticancer activity. Cytotoxic effects on various cancer cell lines (breast, cervical, colorectal, stomach, lung) have been reported.

Use in Foods and Consumption 

Bee pollen can be consumed directly or added to various food products to enhance nutritional value and functional properties.

• Direct Consumption: It is recommended to be consumed in the morning before breakfast. Daily consumption amounts are stated as 15-20 g for adults, 5-10 g for children aged 3-5, and 10-15 g for children aged 6-12.

• Food Enrichment: It has been used in products like cookies, cakes, pasta, sausages, fermented milk drinks, yogurt, bread, pudding, honey powder, ice cream, citrus juice, and malt beverages. The addition of bee pollen has increased the ash, fat, protein, and polyphenol content and antioxidant activities of products, and in some cases, did not negatively affect sensory acceptability.

Bee Bread (Perga) 

Another product closely related to bee pollen is bee bread. It is formed when pollen stored by bees in honeycomb cells is mixed with honey and bee secretions and undergoes lactic acid fermentation. Bee bread contains higher levels of vitamin K, reduced sugars, and digestive enzymes compared to bee pollen. Its proteins are more easily digestible, and it has better taste properties than bee pollen. Bee bread also possesses rich nutritional content and biological activities.