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- Comparison of the quality of bee pollen stored frozen and driedPublication . Anjos, Ofélia; Paula, Vanessa B.; Dias, Teresa; Estevinho, Leticia M.Bee pollen is a healthy food product that is usually consumed as dried crunchy pellets. Even so, i tis possible consume this product as frozen fresh pellets. In this study we present the effect of the storage conditions on the chemical composition of different monofloral bee pollen samples and the changes on the lipid profile of bee pollen samples submited to freezing and drying conservations methods. Nine bee pollen samples with different botanical origins were harvested in the Northeast of Portugal and divided into two different groups: the first one was frozen at -20ºC and the second was dried at 42ºC until the moisture ranged 6 to 8%. The following parameters were analysed and compared amongst the two storage methods: pH, water activity, total acidity and the content of fibre, ash, reducing sugars, protein, lipid and lipid profile, total phenols, total flavonoids, content of vitamin C, B-carotene and lycopene. Microbiological analyses were also made in order to certify if the product was in accordance with the standards for consumer`s safety. A two way analysis of variance was performed with two factors: species storage method. The differences in the botanical origin for furtemost of the analysed parameters are a significant factor explaining the variation between samples. Even though the differences on the botanical origin play a key role, the storage method was also found to be a highly significant factor influencing several analysed parameters namely: reducing sugars, lipid, total phenols, total flavonoids, content of vitamin C, B-carotene and lycopene. Frozen bee pollen presented a significant higher concentration of some dietary. From nutritional point of view, our results suggest that is better consume bee pollen frozen at -20ºC in comparision to that dried in an electric oven. However, it is important to define very well the conditions during the frozen process to ensure a lower microbiological contamination that is easier obtain when the bee pollen is dried.
- Variation of lipids indexes in pollen with its botanical originPublication . Anjos, Ofélia; Maria, G. Campos; Dias, Teresa; Estevinho, Leticia M.Bee pollen is one of nature's healthful food products with promising nutritional and therapeutic properties due to its chemical composition, particularly its protein content, which includes almost all the essential amino acids. Nevertheless the composition in lipids it is not completely known and supposedly will be highly variable depending on the floral origin. As such, this parameter must be ascertained in line with the research for bioactivity [1]. The aim of this work was to evaluate some health-related lipid indexes of bee pollen, namely omega-6/omega-3 fatty acid ratio (n-6/n-3); polyunsaturated fatty acid/saturated fatty acid ratio (PUFA/SAT), atherogenic index (AI) and thrombogenic index (TI) in samples harvested in Portugal. The selected parameters were calculated from the Fatty-Acid Profile, which was determined as previously reported by Bárbara et al. [3]. Bee pollen samples, after harvest, were cleaned and frozen at -20 oC and were codified according the predominant pollen. Figure 1 associates the lipid indexes of the different samples with their botanical origins. n-6/n-3 and PUFA/SAT ratios were in within the limits recommended by World Health Organization (below 4.0 and above 0.45, respectively), suggesting that bee pollen is a good product with the nutritional point of view, with potential beneficial effects for the consumer's health. Also, both AI and TI indexes of this natural product were low, even though this effect depended on bee pollen's botanical origin (Figure 1). [1] Campos MG, Olena L. and Anjos O. 2016. Chapter 3, Chemical Composition of Bee Pollen. In Cardoso SM & Silva AMS, Chemistry, biology and potential applications of honeybee plant-derived products, Bentham Science Publishers, United Arab. Pp. 67 – 88 (22)
- Application of FTIR-ATR spectroscopy on the bee pollen characterizationPublication . Anjos, Ofélia; Santos, António J.A.; Dias, Teresa; Estevinho, Leticia M.Bee pollen contains almost all nutrients required by the human organism as well as diverse health-promoting substances. However, its composition and nutritional value greatly depend on the botanical origin. As such, it is important to develop a rapid and non-expensive methodology that allows studying its characteristics, making labelling more objective and easier. The FTIR-ATR technique was used to predict some nutritional parameters in 126 bee pollen samples. FTIR-ATR spectrum obtained in the region between 4000 and 400 cm -1 with PLS Regression models were used to correlate spectral information with the data obtained using reference methods. In this first approach with pollen samples, good correlation models with appropriate accuracy were obtained for the evaluated parameters with r 2 varying from 74.8 to 97% and residual prediction deviation between 2.0 and 5.8. These results suggest that FTIR-ATR may be a useful technique for assessing bee pollen’s composition.
- Influence of the storage conditions (Frozen vs. Dried) in health-related lipid indexes and antioxidants of bee pollenPublication . Estevinho, Leticia M.; Dias, Teresa; Anjos, OféliaFollowing harvest, bee pollen must be submitted to processing in order to maintain properties for consumers’ health insurance. In this study, the changes on the lipid profile, contents of vitamin C, β-carotene and lycopene of bee pollen samples submitted to two conservation methods (freezing and drying) are evaluated. Eleven fatty acids, eight saturated, one monounsaturated, and two polyunsaturated are quantified. The PUFA/SFA ratio ranges from 1.18 to 3.95 g 100−1 g−1 and is significantly higher in the frozen extracts. On the other hand, the ratio n6:n3 (ranging between 0.36 and 0.86 g 100−1 g−1) did not differ among processing methodologies, for most of the cases. The atherogenicity (AI) and thrombogenecity (TI) indexes are similar among preservation processes and coherent with the found on other health-promoting foods. The contents of vitamin C, β-carotene and lycopene are, for all samples, significantly superior in the frozen bee pollen. Practical Applications: In the recent years the interest in natural products has mushroomed. Indeed, in addition to the good nutritional composition bee pollen possesses important bioactive compounds and promising health promoting activities that remain unstudied. In this study, it is evaluated the influence of the geographical origin and two storage methods (drying and freezing) in the fatty-acid profile, lycopene, vitamin C and β-carotene contents and on two lipid indexes of bee pollen. Results suggest that bee pollen may act as a complement for the prevention of atherosclerosis and thrombogenesis. Regarding storage it wi inferred that freezing allows preserving the bioactive compounds in a greater extent and, therefore, must be the preferred method. Further studies may be performed in order to take advantage of this natural products’ potential. From the nutritional point of view, it is better to consume bee pollen frozen in comparison to that of dried.