Carotenoid profile determination of bee pollen by advanced digital image analysis
Graphical abstract
Introduction
Bee pollen is a natural product made by worker bees when they collect nectar and pollen. Floral pollen is mixed with salivary secretions and nectar. Afterward, it is recollected by beekeepers through traps in the hive and since that moment it can be named bee pollen (Fuenmayor et al., 2014, Kieliszek et al., 2018). It is composed of two protective layers, intine and exine, which protect the interior of the oxidation grain, radiation damage and chemical degradation (Atkin et al., 2011). Exine is composed of various organic and inorganic substances, among which sporopollenin is a very complex polymer that gives chemical resistance to pollen (Kovacik et al., 2009). The structure of sporopolenin has been extensively studied, finding that it presents a variety of substances, such as some types of carotenoids, tocopherols, provitamin A and vitamin D (Domínguez-Valhondo et al., 2011).
Among carotenoids, β-carotene, cryptoxanthin, zeaxanthin and lutein were identified in bee pollen (Domínguez-Valhondo et al., 2011, Schulte et al., 2009). In a previous study of Colombian bee pollen, traces of lutein, zeaxanthin, β-carotene and phytoene were identified (Gardana et al., 2018). Carotenoids are important because they are related to different positive effects in cancer, cardiovascular diseases, diabetes, cataracts and others (Kong et al., 2010, Saini et al., 2015). These compounds are also responsible for color (Saini et al., 2015, Sant’Anna et al., 2013).
Some studies characterized bee pollen color and carotenoid content, and looked for a relation between both parameters (Domínguez-Valhondo et al., 2011, Machado De-Melo et al., 2016, Schulte et al., 2009, Xu et al., 2013). However, the heterogeneity of the pollen samples makes it difficult to measure color by conventional colorimetric techniques. In these cases, Digital Image Analysis (DIA) allows to evaluate the color of each point within a given area, which makes this technique ideal for the analysis of bee pollen (Salazar-González et al., 2018). This technology also allows to develop Chemical Imaging, where it is possible to indicate the presence or concentration in pseudo-color scales of a chemical compound in an image (Rodríguez-Pulido et al., 2017).
Several studies have been made in the last years correlating data obtained by DIA with bioactive compounds in several foods: grapes or tomatoes (Rodríguez-Pulido et al., 2012, Stinco et al., 2013). In a study on tomato products (fresh and processed), the authors could correlate Digital Image Analysis with lycopene isomers content (LYC). When tridimensional character of color is considered and a multivariate analysis is needed, the correlation coefficient increased up to 0.77 (Stinco et al., 2013).
Previous studies showed that it is possible to predict chemical composition by Digital Image Analysis in food products. Then, the aim of this work was to evaluate the possibility to predict carotenoid content from image analysis parameters in Colombian bee pollen. These correlations would help beekeeping chain to value its products with one simple image.
Section snippets
Samples
Bee pollen was collected monthly through 2016 by random sampling. The experimental unit was an apiary in the geographic region of the Colombian high Andean forest (2.800 and 3.200 m above sea level) in Boyacá. Samples used in this work were classified into two sets:
- •
Twelve groups: heterogeneous samples were manually classified to obtain pellets with uniform color and from this classification 12 groups were selected (A-M, letter “I” was omitted to avoid mistakes in the analysis). The homogeneity
Results and discussion
Groups A-M were selected to create models that correlate colorimetric characteristics and chemical composition, thus it was necessary that they were homogeneous. This was probed by pollen, color and carotenoid profile analysis, but only the relation between the chemistry of the groups and their optical properties were used to generate the models.
Then, heterogeneous samples (the way that there find in nature) were used to probe the feasibility of the models obtained previously. To accomplish
Conclusions
A methodology was developed for the estimation of individual carotenoids from digital images in bee pollen samples. For α-tocopherol, both lutein isomers, anteraxanthin isomer 1, zeaxanthin and β-cryptoxanthin, high correlations were achieved between the estimated values and those measured by reference methods. This methodology is a great advance for the rapid identification of carotenoids in bee pollen samples; however, other optical techniques, such as infrared spectra and harvest regions,
CRediT authorship contribution statement
Claudia Y. Salazar-González: Investigation, Writing - original draft. Francisco J. Rodríguez-Pulido: Software, Investigation. Carla M. Stinco: Investigation, Writing - original draft. Anass Terrab: Writing - review & editing. Consuelo Díaz-Moreno: Conceptualization, Supervision. Carlos Fuenmayor: Investigation. Francisco J. Heredia: Conceptualization, Supervision.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We thank the School of Engineering of Universidad Nacional de Colombia for its support to international mobility. To the Asociación Universitaria Iberoamericana de Posgrado -AUIP- and its program “Becas de Movilidad entre Universidades Andaluzas e Iberoamericanas Convocatoria 2017”. Finally, we are thankful to the staff of Biology Service (SGI, Universidad de Sevilla) for the technical assistance.
This work received funding from El Patrimonio Autónomo Fondo Nacional de Financiamiento para la
References (30)
- et al.
UV and visible light screening by individual sporopollenin exines derived from Lycopodium clavatum (club moss) and Ambrosia trifida (giant ragweed)
J. Photochem. Photobiol. B Biol.
(2011) - et al.
Nutrients, phytochemicals and botanical origin of commercial bee pollen from different geographical areas
J. Food Compos. Anal.
(2018) - et al.
Pollen and bee bread as new health-oriented products: A review
Trends Food Sci. Technol.
(2018) - et al.
Carotenoid profiling from 27 types of paprika (Capsicum annuum L.) with different colors, shapes, and cultivation methods
Food Chem.
(2016) - et al.
Electron tomography of structures in the wall of hazel pollen grains
J. Struct. Biol.
(2009) - et al.
Multiple regression models and Computer Vision Systems to predict antioxidant activity and total phenols in pigmented carrots
J. Food Eng.
(2013) - et al.
Preliminary study to determine the phenolic maturity stage of grape seeds by computer vision
Anal. Chim. Acta
(2012) - et al.
Carotenoids from fruits and vegetables: Chemistry, analysis, occurrence, bioavailability and biological activities
Food Res. Int.
(2015) - et al.
Tracking bioactive compounds with colour changes in foods – A review
Dye. Pigment.
(2013) - et al.
Analysis of α-cryptoxanthin, β-cryptoxanthin, α -carotene, and βcarotene of Pandanus conoideus oil by high-performance liquid chromatography (HPLC)
Procedia Food Sci.
(2015)
Simultaneous determination of dietary isoprenoids (carotenoids, chlorophylls and tocopherols) in human faeces by Rapid Resolution Liquid Chromatography
J. Chromatogr. A
Lycopene isomers in fresh and processed tomato products: Correlations with instrumental color measurements by digital image analysis and spectroradiometry
Food Res. Int.
El Polen Apícola como Producto Forestal no Maderable en la Cordillera Oriental de Colombia
Botanical origin and geographic differentiation of bee-pollen produced in high mountains from the Colombian eastern Andes
Grana
Amazon pollen manual. Part I
Cited by (14)
Green and fast prediction of crude protein contents in bee pollen based on digital images combined with Random Forest algorithm
2024, Food Research InternationalGreen sample preparation methods for the analysis of bioactive compounds in bee products: A review
2023, Advances in Sample PreparationEffects of hot-air drying temperature on drying characteristics and color deterioration of rape bee pollen
2022, Food Chemistry: XCitation Excerpt :The carotenoids in the samples were mainly composed of yellow carotenoids. It has been reported that xanthophylls, such as antheraxanthin, lutein and zeaxanthin are the dominant pigments identified in bee pollen, which have an important effect on the color of rape bee pollen (Salazar-González et al., 2020). It is well known that carotenoids are susceptible to deterioration in the yellow color and the nutritional quality during thermal processing.
Characterization of carotenoid profile and α-tocopherol content in Andean bee pollen influenced by harvest time and particle size
2022, LWTCitation Excerpt :Cartesian coordinates a* and b* were also expressed as polar coordinates: chroma (C*ab) and hue (hab) (Salazar-González et al., 2018). For the qualitative analysis, samples were acetolysed according to Erdtman (1969), as reported by Salazar-González et al. (2020). Pollen pellets were washed with acetic acid, followed by the mixture for acetolysis and centrifuging.
Quality properties and bioactive compounds of reduced-fat cookies with bee pollen
2022, International Journal of Gastronomy and Food ScienceCitation Excerpt :Also, high light intensity and high temperature cause an increase in carotenoids. Therefore, carotenoid profiles and composition vary widely (Salazar-González et al., 2020). Zuluaga et al. (2016), BP mixed with peptone water (1.5 g/mL) and a pineapple juice-based beverage were also not detected in the samples without BP, regarding the total carotenoid content.
Unlocking Quercetin's Neuroprotective Potential: A Focus on Bee-Collected Pollen
2024, Chemistry and Biodiversity