Pollen Proteins Research Articles

Effects of Extraction Temperature of Protein from Date Palm Pollen on the Astringency Taste of Tea

The astringency of tea, predominantly attributed to epigallocatechin gallate (EGCG), plays a crucial role in shaping its overall quality, and plant-based proteins are gaining popularity as a preferred alternative to milk-based proteins for enhancing the flavor profile of tea. This study investigated the impact of extraction temperature on date palm pollen (DPP) protein quality and tea astringency, comparing temperatures of 30 °C and 80 °C. Results indicated that higher extraction temperatures yield more protein and improve the thermal and surface properties of DPP. The molecular interaction between DPP and EGCG was investigated in an aqueous solution, and spectroscopic analyses (FTIR, UV, and CD) revealed that EGCG interactions at a 1:1 molar ratio induced structural changes in α-helix and β-sheet content in secondary structures in DPP, particularly at 80 °C, which strengthened and enhanced the hydrophobic interactions and hydrogen bonds between DPP molecules as EGCG concentration increased. A sensory evaluation using quantitative descriptive analysis (QDA) confirmed a significant reduction in astringency in DPP–tea polyphenol solutions extracted at 80 °C. This research highlights the potential of DPP as a functional ingredient in the food industry, creating a protein-polyphenol complex that reduces tea’s astringency while maintaining its unique flavor profile, thus offering a novel approach to enhance tea beverages.

Immunoproteomic analysis and identification of possible allergenic proteins in Artemisia annua pollen.

Artemisia annua (A. annua) is a wind-pollinated weed and a major allergen responsible for allergic respiratory diseases in Northern China. This study involved the separation of pollen proteins from A. annua utilizing SDS-PAGE and Coomassie Blue staining techniques. The effectiveness of extracting allergens from Artemisia annua pollen (AAP) were confirmed both in vivo and in vitro. A mouse model was established using A. annua pollen (AAP) extracts. In vitro, the interaction between allergenic proteins in the AAP extract and specific IgE antibodies present in patients' sera was analyzed, using IgE-immunoblotting and ELISA methods. Protein bands were subsequently analyzed by mass spectrometry. The recombinant Art an 3 (rArt an 3) protein was obtained via recombination, expression, and purification. Finally, the binding activity of rArt an 3 specific IgE was subsequently examined using Western blot and inhibition ELISA (iELISA). The electrophoretic profiles of AAP showed band patterns ranging from 10 to 70kDa, with the most prominet IgE-binding pollen proteins detected at approximately 12kDa. After stimulation of AAP, the sensitized group of mice exhibited significant allergic symptoms compared to the control group. Mass spectrometry analysis identified 7 proteins, including putative aldehyde oxidase Art an 7, Art v 1-like protein, Art an 3.0101 allergen precursor, Art an 3.0102 allergen precursor, Art an 3.0201 allergen precursor, lipid transfer protein 3, and non-specific lipid-transfer protein. The results of immunoblotting and iELISA showed that rArt an 3 could bind to IgE antibodies in the patient sera, and co-incubation of rArt an 3 with serum, the binding serum significantly inhibited IgE binding to the crude AAP. The Art an 3 is a key allergenic protein in AAP with a high IgE sensitization rate in the studied population sample. These findings enhance our understanding of the sensitization components of AAP and its sensitization characteristics within the Chinese population, thereby promoting the development of precise molecular diagnostics and therapeutic interventions.

Bee pollen peptides as potent tyrosinase inhibitors with anti-melanogenesis effects in murine b16f10 melanoma cells and zebrafish embryos

One important functional food ingredient today, valued for its health properties and ability to prevent disease, is bee pollen, which comprises a combination of nectar, pollen from plants, and the secretions of bees. In this research, the tyrosinase (TYR) inhibiting abilities of the peptides derived from bee pollen protein hydrolysates are investigated. Various proteases were utilized to generate these peptides, followed by testing at different concentrations. Tyrosinase inhibition activity was detected in all cases, while the hydrolysate drawn from 5.0% w/v neutrase exhibited the best IC50 value and was thus investigated further via ultrafiltration to separate the active fractions. The highest potential for tyrosinase inhibition was recorded for the fractions below 0.65 kDa. Subsequent purification steps via SEC and RP-HPLC led to the identification of the VDGYPAAGY (named VY-9) peptide via LC-Q-TOF-MS/MS in fraction F1–2, known for its non-toxic and hydrophobic characteristics albeit poor water solubility. The synthesized VY-9 peptide demonstrated competitive inhibition, with IC50 values of 0.55 ± 0.03 µM for mono-phenolase and 2.54 ± 0.06 µM for di-phenolase activities, as confirmed by molecular docking analysis revealing dominant hydrogen bond interactions with TYR. Effective concentrations of 0.2–1.6 µM of VY-9 showed negligible cytotoxicity in B16F10 cells. Melanin synthesis suppression was examined via qRT-PCR, and western blot in MITF, TYR, TRP-1, and TRP-2. Cell death in zebrafish embryos was evaluated in vivo using a toxicity assay which revealed no significant influence from VY-9, while anti-melanogenic effects were observed when the concentration was 4 µM, suggesting bee pollen-derived peptides’ potential in cosmetic and pharmaceutical depigmentation applications.

Spray-drying encapsulation of sunflower pollen peptides using carbohydrate polymers: Physicochemical, antioxidant, structural and morphological analysis

Flower pollen collected by honey bees is a rich source of bioactive peptides (BPs). Different carriers such as maltodextrin (MD), gum Arabic (GA), and β-cyclodextrin (βCD) and their combinations were used for encapsulation of BPs from sunflower pollen protein (SPP). Different physicochemical, antioxidant, functional, structural and morphological properties of the obtained microparticles were evaluated. The amino acid composition of SPP and the derived peptides revealed a high proportion of hydrophobic (∼40%), antioxidant (∼18%), and essential (∼31%) amino acids, indicating their biological potential. Among the microencapsulated samples, the MD-βCD composition exhibited the highest production efficiency (∼65%) and improved physicochemical properties, such as microbial stability, density, flowability, wettability, and solubility, compared to the spray-dried free peptides (free SD-BPs) without a carrier. The encapsulation process helped to maintain the structural integrity of the microparticles and reduced moisture absorption. The SPP-derived peptides encapsulated in MD-βCD also demonstrated potent antioxidant activity, inhibiting ABTS+ (∼75%) and DPPH- (∼69%) free radicals. The results suggest that the BPs obtained from sunflower pollen can be a valuable ingredient for enriching various food products due to their favorable nutritional, functional, and antioxidant properties.

Differential effects of pollen nutritional quality on male and female reproductive success within a diverse co‐flowering community

Abstract Pollen protein content has been demonstrated to be an essential nutritional component for bees and thus important in mediating plant–pollinator interactions. However, little is known on the drivers and consequences of among‐species variation in pollen protein content and how this can impact male and female reproductive success across plant species. Among‐species variation in resources allocated to pollen nutrition could further be constrained by life‐history strategies (e.g. survival‐reproduction trade‐offs) or evolutionary history. Here, we surveyed pollen protein content for 29 species within a diverse co‐flowering community and evaluated the effect of pollen protein on male and female reproductive success. We also tested the role of life history (annuals vs. perennials) and phylogeny in mediating differences in resource allocation to pollen nutrition. We found that pollen protein content influences components of male (bee visitor abundance and pollen dispersal) but not female (conspecific pollen deposition and pollen tube growth) reproductive success, suggesting this trait affects plants only via male function. This sex‐specific effect further suggests the potential for sexual conflicts driven by differential investment on this trait. We found no phylogenetic signal on pollen protein content. However, pollen protein content was higher in annual compared to perennial species suggesting survival versus reproduction trade‐offs also contribute to variation in pollen protein at the community level. Our study underscores the importance of understanding the ecological and evolutionary drivers of pollen protein content across plant species. Our results further suggest the existence of sexual conflicts and ecological trade‐offs mediated by differential investment in pollen nutritional quality, with important implications for community assembly and the structure of plant–pollinator interactions. Read the free Plain Language Summary for this article on the Journal blog.

Nectar and pollen in Acer trees can contribute to improvement of food resources for pollinators

In the present study, we quantified floral resources (nectar and pollen production) and their quality (nectar sugar composition, pollen protein content, pollen amino acid composition) in five Acer species (f. Sapindaceae) growing in forests and commonly planted in urban areas in the temperate zone. Acer trees provide high amounts of sugars and/or pollen. No nectar was produced by A. negundo flowers. The other species produced nectar in functionally female flowers. The floral nectar was composed of sucrose, glucose, and fructose and was classified as hexose-rich or sucrose-rich. The pollen of all the Acer species contained essential amino acids. Acer trees should be planted for improvement of cost-effective food resources in various landscape types (agroforestry, urban areas), with the exception of A. negundo (an invasive species with no nectar available). However, maple trees alone are not sufficient to support pollinators, and other plant species flowering before and after Acer spp. should be planted to ensure a continued supply of food for pollinators.

Wildflower plantings and honeybee competition impact nutritional quality of wild bee diets

Abstract Wildflower habitats planted along field borders are a widely promoted strategy for supporting bees in agricultural landscapes. However, honeybees (Apis mellifera), which are often stocked at high densities in crop lands can compete with wild bees for pollen and nectar, potentially limiting the successfulness of wildflower plantings in supporting diverse bee communities. Using weekly samples of five study sites in Northern California we assessed how plants in pollinator‐friendly seed mixes varied in their ability to provide bees with abundant and nutritious pollen under intense honeybee competition. We quantified pollen production, protein and lipid content, and end‐of‐day pollen availability for different plant species. We also sampled bee visits to flowers and assessed the composition of pollen on bee bodies. Using these data, we investigate how the nutritional quality of pollen in wildflower plantings and honeybee abundance impacted native bee pollen nutrition. Bees collected more nutritious pollen (i.e. pollen with more protein) from plantings with more nutritious plant species (i.e. sites with more high‐protein plants). However, as honeybee abundance increased, the nutritional quality of native bee diets declined. We also detected important interactions between honeybee abundance and the nutritional quality of flowers in plantings, such that, for some bee taxa, there was no impact of competition on pollen diet quality in high‐nutrition plantings. Synthesis and applications: Our study reveals that honeybee competition can reduce the nutritional quality of native bee diets. From an applied conservation perspective, we therefore recommend that honeybee introductions in natural areas be approached with extreme caution. However, our results also suggest that high‐protein flower plantings could mitigate negative effects of honeybee competition in managed landscapes. Where simultaneous support of managed and wild bees is a key management objective, we recommend including high‐protein plant species in plant mixes to support diverse bee populations.

Bees that love tears: A review of Lisotrigona congregating at human and animal eyes (Hymenoptera: Apidae, Meliponini)

Stingless bees (Apinae: Meliponini) exhibit astonishing and unusual behaviours, including tear-drinking or lachryphagy. In this review, we summarize lachryphagy in stingless bees, providing updated insights into their taxonomy, foraging patterns, ecology, hosts, evolutionary origins, and potential for pathogen transmission. In Northern Thailand, marked workers of the minute stingless bees Lisotrigona cacciae (Nurse) and L. furva Engel repeatedly return to human eyes, harvesting tears in short bouts that can last for hours or even over multiple days. Behavioural evidence suggests the presence of specialized tear collectors within these species. Single, experienced individuals can harvest tears gently, going unnoticed by the host, though large congregations can become bothersome. Lachryphagy occurs year-round and appears to be driven by high protein content in tears, in addition to salt and water. While Lisotrigona also visit flowers for nectar and pollen, tear collection may supplement or even replace pollen protein when floral resources are scarce or absent in their restricted habitats. Confirmed hosts include humans, zebu, dogs, cats, rabbits, chickens, and yellow tortoises. Lachryphagy has also been reported in other species of Lisotrigona in India. Interestingly, the similarly minute and widespread Tetragonula fuscobalteata (Cameron) is not lachryphagous but sucks sweat, as do other stingless bees, including Lisotrigona, though all visit flowers. This review also examines the potential for pathogen transmission via tear-drinking, particularly concerning viruses entering through the ocular surface, and discusses the evolutionary origins of lachryphagy in stingless bees.

Identification of cross-reactive IgE-binding proteins from Philippine allergenic grass pollen extracts.

Respiratory allergies are one of the most common allergic diseases that affect Filipinos. Grass pollen accounts for the majority of the outdoor allergens triggering these respiratory allergies. Cross-reactivity among the Philippine grass pollen grains has not been extensively studied. This study aims to investigate the cross-reactivity of our local grasses and identify the cross-reactive allergens. Grass pollen grains were collected and processed into crude allergenic extracts. The IgE-reactivity of these crude allergenic pollen extracts was studied using sera from patients who tested positive for the mentioned extracts. The proteins from the immunoblots of cross-reactive pollen allergen extracts were sequenced and identified. Allergenic pollen proteins were identified as cross-reactive among the grass pollen extracts. Four of these have not been listed yet as grass allergens in the World Health Organization/International Union of Immunological Societies allergen nomenclature database. Local grass pollen allergens are cross-reactive with probable new allergens identified.

Functional characterization of complete and immunodominant epitopes of a novel pollen allergen from Parthenium hysterophorus.

Background. Parthenium hysterophorus pollen induces chronic clinical conditions such as allergic rhinitis and bronchial asthma. Among the plethora of proteins in the pollens, only few were reported to induce allergy. Currently sensitization to P. hysterophorus pollen allergen is diagnosed by skin prick test (SPT) using the entire pollen extract instead of using the specific allergen. Methods. In P. hysterophorus sensitized patients, SPT was done using the crude pollen extract, 40 kDa allergenic pollen protein and two commercially synthesized allergen epitopes (17 and 24) of P. hysterophorus. Dot-blot of allergen epitopes was done using P. hysterophorus sensitized sera. Crude pollen extract (1, 1.25, 2.5, 5 and 10 µg/mL), 40 kDa allergenic protein (3 µg/mL), and allergen epitopes (3µg/mL) were used to perform Basophil Activation Test (BAT). Results. Crude pollen extract at 2.5, 5, 10 μg/mL and 40 kDa allergenic protein at 3μg/mL concentrations induced wheal and flare reaction by around 15 minutes, whereas commercially synthesized allergen epitopes at 3μg/mL induced wheal and flare reactions in less than 10 minutes. Allergen epitopes (3 µg/mL) revealed strong reactivity with sensitized patient's IgE in dot-blot analysis. Basophil activation Test using crude pollen extract (2.5, 5, 10 µg/mL), 40 kDa allergenic protein (3 µg/mL), and allergenic epitopes (3µg/mL) indicated significant basophil activation (as measured by CD63 expression) in sensitized patients. Conclusions. The 40 kDa allergenic protein and its allergenic epitopes (17 and 24) induced phenotypic and cellular immune responses in P. hysterophorus sensitized individuals. The tested allergenic epitopes (17 and 24) induced faster wheal and flare reactions in comparison with the crude extract and the 40 kDa allergenic protein. The novel 40kDa allergenic protein and its allergen epitopes identified here may be useful for the development of component-resolved diagnosis (CRD) while also serving as a potential therapeutic lead for desensitization treatment for P. hysterophorus pollen induced allergy.

Experience of allergen-specific immunotherapy in the patient with oral and systemic manifestations of birch pollen allergy

Introduction. Allergy to birch pollen is a common allergic disease. The main allergen of birch pollen is Bet v 1. The Bet v 1 protein structure is the similar to proteins of hazel, alder and elm pollen, as well as fruits proteins (apples, apricots, peaches, cherries) and vegetables ones (carrots, celery). Therefore, children with an allergy to the Bet v 1 protein may experience oral allergy syndrome (OAS) and even anaphylaxis when eating these foods. Allergen-specific immunotherapy (ASIT) is the indication for the pollen allergy treatment.Presentation of the clinical case. A 11 years old child was observed with a diagnosis of bronchial asthma, allergic form, moderate persistent clinical course. Pollinosis. Allergic rhinitis. Allergic conjunctivitis. Allergy to birch pollen (Bet v 1). Cross food hypersensitivity: oral syndrome (PR-10 proteins) and anaphylaxis (hazelnuts, peanuts). Systemic manifestations of pollen allergy limit immunotherapy due to the possible development of adverse reactions.The child was prescribed sublingual immunotherapy (SLIT) with the medication “Staloral birch pollen allergen”. Baseline therapy was chosen for the child to achieve control of asthma and rhinitis, a hypoallergenic diet with the exclusion of significant food allergens was prescribed. Asthma and rhinitis exacerbation and OAS was observed during the 1st and 2nd treatment courses. Against the background of baseline therapy, SLIT was continued. The full maintenance dose was achieved during the 3rd SLIT course. Immunotherapy contributed to the reduction of symptoms of rhinitis and asthma, reduction of disease clinical course severity, reduction of baseline medications doses and OAS relief.

Non-Specific Lipid Transfer Protein Amb a 6 Is a Source-Specific Important Allergenic Molecule in Ragweed Pollen.

Pollen from common ragweed is an important allergen source worldwide and especially in western and southern Romania. More than 100 million patients suffer from symptoms of respiratory allergy (e.g., rhinitis, asthma) to ragweed pollen. Among the eleven characterized allergens, Amb a 6 is a non-specific lipid transfer protein (nsLTP). nsLTPs are structurally stable proteins in pollen and food from different unrelated plants capable of inducing severe reactions. The goal of this study was to produce Amb a 6 as a recombinant and structurally folded protein (rAmb a 6) and to characterize its physicochemical and immunological features. rAmb a 6 was expressed in Spodoptera frugiperda Sf9 cells as a secreted protein and characterized by mass spectrometry and circular dichroism (CD) spectroscopy regarding molecular mass and fold, respectively. The IgE-binding frequency towards the purified protein was evaluated using sera from 150 clinically well-characterized ragweed-allergic patients. The allergenic activities of rAmb a 6 and the nsLTP from the weed Parietaria judaica (Par j 2) were evaluated in basophil activation assays. rAmb a 6-specific IgE reactivity was associated with clinical features. Pure rAmb a 6 was obtained by insect cell expression. Its deduced molecular weight corresponded to that determined by mass spectrometry (i.e., 10,963 Da). rAmb a 6 formed oligomers as determined by SDS-PAGE under non-reducing conditions. According to multiple sequence comparisons, Amb a 6 was a distinct nsLTP with less than 40% sequence identity to currently known plant nsLTP allergens, except for nsLTP from Helianthus (i.e., 52%). rAmb a 6 is an important ragweed allergen recognized by 30% of ragweed pollen allergic patients. For certain patients, rAmb a 6-specific IgE levels were higher than those specific for the major ragweed allergen Amb a 1 and analysis also showed a higher allergenic activity in the basophil activation test. rAmb a 6-positive patients suffered mainly from respiratory symptoms. The assumption that Amb a 6 is a source-specific ragweed allergen is supported by the finding that none of the patients showing rAmb a 6-induced basophil activation reacted with Par j 2 and only one rAmb a 6-sensitized patient had a history of plant food allergy. Immunization of rabbits with rAmb a 6 induced IgG antibodies which strongly inhibited IgE binding to rAmb a 6. Our results demonstrate that Amb a 6 is an important source-specific ragweed pollen allergen that should be considered for diagnosis and allergen-specific immunotherapy of ragweed pollen allergy.

Comparison of nectar and pollen resources in various Tilia species. A case study from southern Poland

Management of food resources is considered fundamental for supporting insect pollinators, whose abundance shows a downward trend on the global scale. Here, the nectar and pollen production (per flower, per 1 m2 of tree crown), the composition of nectar carbohydrates and the levels of pollen proteins was evaluated in eight Tilia species (Malvaceae) growing in SE Poland. In the warm-summer continental climate, Tilia species can improve nectar and pollen resources mainly in June/July. Although the flowering period of each species is short (8.0–14.7 days), appropriate selection of species can extend the availability of food for more than a month. However, the considerable variations in the flowering onset (11.2–20.1 days) may cause significant inter-seasonal shifts in food accessibility.The nectar with its highly changeable sugar concentration (29.5–77.4%) was composed of sucrose, glucose, and fructose; protein content in pollen was 7.2–16.8%. The mean sugar yield was in the range of 0.95–19.1 g per 1 m2 (T. amuriensis – T. platyphyllos, respectively), whereas the mean pollen yield was 1.37–4.1 g per 1 m2 of tree crown (T. amuriensis – T. × euchlora, respectively). Significant year-to-year fluctuations of sugar and pollen yield in linden trees have to be taken into account in conservation schemes, and the introduction of other flowering plants with more stable sugar and pollen production should be considered in an area with a high density of linden trees. Linden flowers mainly support honey bees; nevertheless, wild pollinators (bumble bees, solitary bees, and dipterans) can also benefit from linden floral resources.

Characterization of Microbials in the Lung Induced by Allergenic Platanus Pollen Protein (Pla a3) and Ambient Fine Particulate Matter

Characterization of Microbials in the Lung Induced by Allergenic Platanus Pollen Protein (Pla a3) and Ambient Fine Particulate Matter

Pollen transcriptomic analysis provided insights into understanding the molecular mechanisms underlying grafting-induced improvement in potato fertility.

Heterologous grafting has been proven to be a valid approach to improving potato fertility, especially when grafting potatoes with other Solanaceae family plants. However, the mechanisms underlying grafting-induced improvement in potato fertility are still unknown. In this study, a poor-fertility potato cultivar "Qingshu No. 9" (Q9) was grafted with a tomato cultivar "Zhongyan988" (ZY988) to study the effects of heterologous grafting in the former. The tuber yield was controlled by different grafting and cultivation approaches, and the correlation between tuber yield and pollen vigor was studied. Comparative transcriptomic analysis of the potential mechanisms of pollen in potato scion fertility changes. Grafting with the tomato rootstock effectively promoted the flower and fruit formation in the scion potato and improved its pollen viability by 15%-20%. In addition, a significant negative correlation was observed between the potato tuber yield and pollen viability, suggesting a potential impact on the metabolic regulatory network related to tuber formation. From the comparative transcriptomic analysis between the pollens from Q9 self-grafted plants and Q9-tomato grafting scion, 513 differentially expressed genes (DEGs) were identified. These DEGs were found to be related to gametophyte and pollen development, carbohydrate metabolism, and protein processing. Thus, these DEGs might be involved in improved fertility after reduced tuberization in plants subjected to heterologous grafting. Potato/tomato heterologous grafting significantly improved the pollen viability of scion potatoes and was associated with the absence of potato tubers. Heterologous grafting promotes the transcription of genes related to protein processing, carbohydrate metabolism, and pollen development in pollen cells, resulting in the production of fertile pollen. Our results provided initial clues to understanding the improvement of potato fertility using the heterologous grafting method, which might be a useful tool in assisted potato breeding.

Effect of protein and lipids in pollen on the developmental success of the native solitary bee Osmia lignaria Say

The health of solitary bees is dependent on the pollen they consume, driving their development from larvae to pupae. Nutrients such as proteins and lipids play an important role in bee development and could be an important key in conservation efforts to support declining populations. We examined the concentration of protein, total lipids, and 13 individual lipid classes in pollen provisions collected from the native solitary nesting bee, Osmia lignaria Say, at 22 sites in urban and rural landscapes in western Washington over three years and during two distinct foraging periods. The results indicate that protein concentrations in pollen did not significantly affect larval development. We detected higher lipid concentrations in the second foraging period, which was also associated with increased larval developmental success. Using Next-Generation sequencing on collected pollen, we also ascertained the plant genera in pollen and observed that plant richness did not differ significantly between the two foraging periods even though levels of lipid concentrations did. Individual lipid classes may play a role in the successful development of O. lignaria, as hexosylceramide and cholesterol ester were positively associated with O. lignaria larval developmental success, which emphasizes the need for additional studies on the role of individual lipid classes on bee development.

Amino acid composition of pollen <i>Pinus sylvestris</i> L. and <i>Pinus sibirica</i> Du Tour growing in the Baikal region

The purpose of the study was to determine the qualitative and quantitative amino acid composition of pollen Pinus sylvestris L. and Pinus sibirica Du Tour. Pine pollen was collected in June 2021 at natural sites on the southeastern coast of Lake Baikal. The mass fraction of crude protein was determined by the Kjeldahl method; the protein composition and individual amino acid content were determined by high-performance liquid chromatography with post-column modification of ninhydrin on an LA8080 automatic analyser (Hitachi, Japan). The crude protein content of the pollen was 14.38–15.94%. Pine pollen protein is shown to contain 17 amino acids, including 9 essential amino acids: valine, isoleucine, leucine, threonine, methionine, phenylalanine, lysine, histidine, and arginine. The content of the sum of amino acids was 141.4–156.5 mg/g, including essential amino acids 45.9-48.4%. The following amino acids are dominant in Pinus sylvestris and Pinus sibirica pollens (mg/g): monoaminodicarboxylic acids – glutamic (21.3–24.2) and aspartic (13.0–14.2), diaminocarboxylic acid arginine (17.0–17.4) and heterocyclic amino acid proline (14.7–16.2). The obtained results can be useful in the development of drugs and biologically active additives based on pollen Pinus sylvestris and Pinus sibirica, which, due to the presence of the above amino acids, have a nootropic, immunomodulatory, cardiac stimulating, and detoxifying effect.

Assessing the analytical reliability of traditional and novel sampling methods for the study of flower rewards quality

AbstractPollinator insects are declining worldwide also due to the alteration of their diet which plays a pivotal role in influencing their health status. Despite interspecific and intraspecific diversity in the diet, pollinators completely or partly rely on pollen and nectar as food sources. A precise characterization of the chemical composition of these flower resources represents a key step in the definition of pollinators' nutritional ecology. However, pollen and nectar represent challenging sources to collect and analyze, especially due to their small amounts per flower, and the application of suitable sampling and analysis tools is a pivotal step to perform dedicated studies and comparisons. Here, we compared a recently proposed tool based on a portable vacuum cleaner for floral pollen collection (E‐PoSa, i.e., Electronic Pollen Sampler) with traditional pollen sampling methods (i.e., anther collection and anther sieving) together with the evaluation of different nectar sampling techniques (i.e., centrifugation, microcapillaries, washing, and microrinsing) by looking at the differences in their quantitative recovery as well as their chemical profiling. Pollen and nectar were collected from three model flower species each. Our results demonstrated that different collection methods introduce biases in the nutritional profiling of floral rewards and specifically: (1) underestimation of the pollen protein and lipid content in the anther collection method; (2) reduction in the volume of recovered nectar by centrifugation; (3) overestimation of the glucose content in the nectar collected by flower washing and underestimation of the glucose content by microrinsing; and (4) relevant biases in the phytochemical profiles of pollen and nectar by analyzing the whole anthers and the nectar collected by washing the entire flower. Differences in methods were not directly related to the different productivity of pollen and nectar across species. The final goal of the study is to propose standardized, comparable, and easily accessible strategies for the study of flower resources that ultimately impact on pollinators' nutritional ecology. Acknowledging the potential influences of the sampling techniques and moving toward shared field protocols will advance the comprehension of species interactions, foraging patterns, and pollinators' nutritional needs.

Production and characterization of nanovesicles carrying hydrolyzed bee pollen proteins for fortification of honey

This study evaluated the practical feasibility of using nanoliposomes and nanoniosomes loaded with hydrolyzed pollen protein (using Pepsin and Alcalase) as a suitable compound for honey fortification.The study also examined the physiochemical properties and bioactivity of these compounds. The size of the vesicles increased from 73-119 nm to 90–187 nm after loading with hydrolyzed proteins and to 179 nm after coating with chitosan. Chitosan-coated nanoliposomes exhibited the highest polydispersity index (0.389) and encapsulation efficiency (93.08 %). In general, the loading of hydrolyzed proteins in nanovesicles preserved 88–98 % of angiotensin converting enzyme inhibition (ACEI) activity, 82–96 % of iron ion reducing power, and 81–91 % of DPPH radical inhibition activity. Scanning electron microscopy (SEM) showed that the vesicles were spherical with a smooth surface. Chitosan-coated nanoliposomes formed compact clusters. Fourier transform infrared (FTIR) spectroscopy demonstrated that the peptides were compatible with the vesicles.Nanoniosomes exhibited a more sustained release behavior in simulated digestive fluid compared to nanoliposomes. Chitosan-coated nanoliposomes and uncoated nanoliposomes had the lowest (61.62 %) and highest (100 %) release rates, respectively. After fortification with nanovesicles, honey showed a 6 % increase in DPPH radical scavenging activity, a 16 % increase in reducing power, and a 14 % increase in ACEI. Honey containing nanoniosomes received the highest acceptance score. These findings are important for the development of hydrolyzed protein-containing functional foods.

Effect of temperature and shear stress on properties of nanovesicles carrying hydrolyzed pollen protein

In this study, the effect of storage (65 °C, 24 h) and shear rates (2-100 s−1, 10 min) on the particle size, poly-dispersity index (PDI), encapsulation efficiency (EE), Angiotensin-converting enzyme (ACE) and DPPH radical inhibition, iron ion reduction ability and flow behavior of nanovesicles containing hydrolyzed bee pollen (produced by alcalase and pepsin) were evaluated. Nanoliposomes were coated by chitosan (0.2 % w/w). After storage at 65 °C, the size of the nanovesicles raised 2–2.5 folds while EE showed 5–8 % decline. ACE and DPPH radical inhibition activity were also decreased. After applying the shear stress, PDI was increased significantly (P<0.05), while EE of the nanoniosomes showed a drastic decline (P<0.05). Nanoliposomes and nanoniosomes exhibited decline in the ACE inhibitory and antioxidant activity. At low shear rates Newtonian-like and weak pseudo-plastic behavior of the chitosan-coated nanoliposomes were observed. The flow index (n), (k) and (R2) indicated the suitability of power law model for describing the flow characteristics.