Abbreviations 18AA: amino acid; BP: bee pollen; DBP: dried bee pollen; MUFA: monounsaturated fatty acids; 19 PA: polyamine; SFA: saturated fatty acids; TL: total lipid; UFA: unsaturated fatty acids 20 2 ABSTRACT 21 22This work evaluated the nutritional, phytochemical composition and botanical origin of 23 commercial bee pollen from three different countries. Fructose (17-23%) was the most 24 abundant sugar in all samples, followed by glucose (14-16 %) and sucrose (5-6%). The 25 protein content in Colombian (24%) and Italian (22%) pollen was higher compared to Spanish 26 sample (14%). The total lipid contents were higher for the Spanish (6%) and Colombian 27 pollens (6%) than the Italian sample (2.5%). Twenty-one fatty acids were identified, and the 28 most abundant were palmitic, α-linolenic, linoleic and oleic acid. Colombian pollen was rich 29 in n-3 fatty acids, while Italian and Spanish samples contained high amounts of n-6 fatty 30 acids. Polyphenols and carotenoids were identified by UHPLC-DAD-Orbitrap mass 31 spectrometry detection. Thirty-nine polyphenols were identified, and the dominant 32 compounds were tri-caffeoyl-and caffeoyl-di-p-coumaroyl spermidine derivatives. Di-lauryl-33 zeaxanthin was the main carotenoid detected in all the samples analysed. Colombian pollen 34 contained traces of lutein, zeaxanthin, β-carotene and phytoene, while only β-carotene was 35 present in the Spanish and Italian samples. After saponification, the average total amount of 36 carotenoids was 57, 25 and 221 µg g -1 in pollen from Spain, Italy and Colombia, respectively. 37The free proline to total free amino acid ratio was 53, 59 and 78 for pollen from Spain, Italy 38 and Colombia, respectively. 39 40

Bee‐pollen is a product collected by bees, gathered for human consumption given its nutritional and bioactive characteristics. However, its external structure is extremely recalcitrant and prevents nutrients and bioactive compounds to be completely digested into the gastrointestinal tract. The aim of this study was to assess enzymatic hydrolysis as a strategy to modify the structure of bee‐pollen and promote the release of compounds. Six different commercial enzymes were used and treatments were evaluated by Differential Scanning Calorimetry and Scanning Electron Microscopy, as well as protein, amino acids, phenolics, flavonoids, and antioxidant activity. The calorimetric analysis showed an increase in the heat flow of hydrolyzed products compared to bee‐pollen. It was also found that proteases improved the protein content of about 13%–18%, phenolics 83%–106%, flavonoids 85%–96%, antioxidant activity up to 68%, and increased all essential amino acids. Finally, a total ranking method established as the best treatment hydrolysis with Protamex. Practical applications Bee‐pollen is an attractive food of plant origin from a nutritional and functional point of view. The modification of its structure through enzymatic hydrolysis increases the availability of compounds that theoretically could be assimilated more easily in the gastrointestinal tract, improving the quality of bee‐pollen as a food resource. The treatment is safe, relatively inexpensive and easy to apply, compared to other bee‐pollen modification strategies such as fermentation.

Bee-pollen is a product of the hive which has had a growth in consumption in recent years due to the recognition of its nutritional and bioactive potential. However, several reports have shown that the external structure of the grain limits the absorption of nutrients in the human gastrointestinal tract. A structural modification could be achieved through fermentative processes, favoring the release of compounds found inside this food, in addition to obtaining a product with potential probiotic characteristics. The objective of this work was to evaluate how fermentation through the inclusion of yeasts of the species Saccharomyces cerevisiae, bacteria of species Lactobacillus plantarum or a commercial culture Choozit® affeccted such parameters as Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), phenolic compounds, flavonoids and antioxidant activity. The results found that the use of consortia between yeast and lactic acid bacteria significantly increased in such characteristics as total phenolics and antioxidant activity by 31% and 39% respectively. The analysis by DSC showed an increase in the heat flow of the fermented products compared to fresh bee-pollen, which could indicate structural modification caused by the activity of microorganisms, a fact made visible through micrographs obtained by Scanning Electron Microscopy.

No abstract

Bee pollen is characterized by its high nutritional value that could be used in human diet, specifically for its value in protein and antioxidant capacity. Different studies emphasize that pollen shows a restriction in nutrient absorption caused by its complex external cell wall, being not easily digestible by monogastric species as bees and humans. The objective of this study was to apply different pretreatments: enzymatic, alkaline, dry thermal and wet thermal. In order to evaluate the effect of each pretreatment, protein by Bradford method, in vitro digestibility, antioxidant capacity and total phenols were quantified. Protein estimated by Bradford method decreased in pretreated pollen, due to the breakage of peptide bonds, and the digestibility raise from 62% in untreated pollen to 85-98% in pretreated pollen. In relation to antioxidant capacity, it showed a nonrepresentative decrease regarding other vegetable matrices, with the exception of a raise in phenols for some pretreatments. Such results coincide with microstructural changes observed in pretreated pollen micrographs. Finally, the variables assessed by principal component analysis showed differences for every pretreatment. Keywords: Cell wall, chemical, enzymatic, hydrolysis, thermal. ResumenEl polen apícola se caracteriza por su alto contenido nutricional que podría ser empleado en la alimentación de los seres humanos, específicamente por su valor en proteína y capacidad antioxidante. Diferentes estudios resaltan que el polen presenta restricción en su absorción de nutrientes por su compleja pared celular externa, siendo poco digerible para especies monogástricas como abejas y seres humanos. El objetivo de este estudio fue aplicar diferentes pretratamientos: enzimático, alcalino, térmico seco y térmico húmedo. Para evaluar el efecto de los pretratamientos, se cuantificó proteína por el método de Bradford, digestibilidad in vitro, capacidad antioxidante y fenoles totales. Se encontró una disminución de proteína para el polen pretratado por el método de Bradford, debido al rompimiento de los enlaces peptídicos, así como el incremento en la digestibilidad del polen sin tratar del 62% al 85-98% del polen pretratado. En cuanto a la capacidad antioxidante presentó una disminución no representativa respecto a otras matrices vegetales, excepto para los fenoles al revelar un incremento para algunos pretratamientos, resultados que concuerdan con los cambios microestructurales de las micrografías del polen pretratado. Finalmente todos los pretratamientos presentaron diferencias al correlacionar las variables evaluadas mediante un análisis de componentes principales.