Percorrer por autor "Mekki, Imen"
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- Bee pollen nutritional value and microbiological stability: influence of preservation techniquesPublication . Mekki, Imen; Lema, Filipe; Tomás, Andreia; Falcão, Soraia; Martins, Vitor Manuel Ramalheira; Rodrigues, Paula; Vilas-Boas, MiguelBee pollen is an important beehive product, with a rich chemical composition and biological properties, which vary according to the region of production, plant age and agroecological conditions. Its moisture content may vary from 18 - 25%, depending on the technique and the time of collection [1]. Bee pollen is subject to proliferation of microbiological contamination that can make its consumption and commercialization unfeasible when not properly preserved, its nutritional value can be rapidly reduced due to Maillard reactions [2].
- Bee pollen nutritional value and microbiological stability: influence of preservation techniquesPublication . Mekki, Imen; Lema, Filipe; Tomás, Andreia; Falcão, Soraia; Martins, Vitor Manuel Ramalheira; Rodrigues, Paula; Vilas-Boas, MiguelBee pollen is an important beehive product, with a rich chemical composition and biological properties, which vary according to the region of production, plant age and agroecological conditions. Its moisture content may vary from 18 - 25%, depending on the technique and the time of collection [1]. Bee pollen is subject to proliferation of microbiological contamination that can make its consumption and commercialization unfeasible when not properly preserved, its nutritional value can be rapidly reduced due to Maillard reactions [2].
- Microbial contamination of bee pollen and impact of preservation methodsPublication . Mekki, Imen; Rodrigues, Paula; Martins, Vitor Manuel Ramalheira; Hezbri, KarimaSince ancient times, bee pollen has gained reputation as an important source of energy and beneficial substances from the nutritional and health points of view. However, in recent years this natural product has gained much more interest, largely consumed and used in increasing quantities as a food. Due to the nutrient content of bee pollen, a variety of spoilage microorganisms can grow, especially when handling practices are not appropriate. Taking into account human safety, the production of high quality products is of paramount importance. This work intended to: i) characterise Portuguese bee pollen in terms of microbial loads and potential hazards based on established analytical methods; ii) evaluate the impact of different preservation methods (oven drying at 35 ºC, 40 ºC, and 45 ºC, freezing, and freeze-drying) on the microbial stability of bee pollen. For bee pollen characterisation, the studied microorganisms were aerobic mesophiles (AM), lactic acid bacteria (LAB), yeasts and moulds (Y&M), coliforms, Escherichia coli, Salmonella and sulphite-reducing Clostridium. For the impact of the different preservation methods, AM, LAB, and Y&M were enumerated after one month, three months and six months of storage. Our results showed that bee pollen has a poor microbial quality, and the loads differ between regions. E. coli and Salmonella were absent in all the samples. Our results showed that freezing and freeze drying techniques present the highest microbial levels, while the oven drying technique presents the lowest microbial loads throughout time, without a significant difference between the different temperatures tested. There is the need to adopt appropriate preservation practices of Portuguese bee pollen to prevent possible contamination by equipment or handling.
- Preservation techniques and their impact on bee pollen chemical and microbiological compositionPublication . Lema, Filipe; Mekki, Imen; Falcão, Soraia; Tomás, Andreia; Rodrigues, Paula; Martins, Vitor Manuel Ramalheira; Vilas-Boas, MiguelBee pollen has been used as a food supplement for many years because of its antioxidant, antibacterial and antifungal properties, and is currently undervalued in the Portuguese market compared to honey. This may be partly explained by the lack of information on the benefits of pollen and on the influence of preservation methods on composition and chemical quality. Therefore, this work will evaluate the possible impact of various preservation techniques, namely freezing, oven drying at 35ºC, 40ºC and 45ºC and freeze-drying, on the chemical composition and microbiological load of the pollen.
- Preservation techniques and their impact on bee pollen chemical and microbiological compositionPublication . Lema, Filipe; Mekki, Imen; Falcão, Soraia; Tomás, Andreia; Rodrigues, Paula; Martins, Vitor Manuel Ramalheira; Vilas-Boas, MiguelBee pollen has been used as a food supplement for many years because of its antioxidant, antibacterial and antifungal properties, and is currently undervalued in the Portuguese market compared to honey. This may be partly explained by the lack of information on the benefits of pollen and on the influence of preservation methods on composition and chemical quality. Therefore, this work will evaluate the possible impact of various preservation techniques, namely freezing, oven drying at 35ºC, 40ºC and 45ºC and freeze-drying, on the chemical composition and microbiological load of the pollen.
- The impact of preservation techniques on bee pollen nutritional value, microbiological stability, and antioxidant propertiesPublication . Lema, Filipe; Mekki, Imen; Tomás, Andreia; Falcão, Soraia; Rodrigues, Paula; Martins, Vitor Manuel Ramalheira; Vilas-Boas, MiguelAfter its collection the bee pollen can present moisture contents that can range from 18% to 25%. These moisture contents, combined with the high nutritional value of bee pollen, provide conditions highly favourable to microorganism growth, undesirable pollen fermentation, and reduction of the nutritional value, caused by Maillard reactions. Thus, after collection it is necessary to reduce the bee pollen moisture content in order to maintain its overall nutritional quality and microbiological safety. Moreover, several studies have recently highlighted the beneficial biological properties of bee pollen, which may also be influenced by the preservation techniques applied to reduce the bee pollen moisture content. Therefor, the main objective of this work is to provide an insight regarding the potential influence of the applied preservation techniques on the nutritional value, microbiological quality, and antioxidant properties of bee pollen. The bee pollen, which was collected in beehives located in the northeastern Portuguese region of Bragança, presented a moisture content of 13.8%. Subsequently, the fresh pollen was submitted to various preservation techniques, namely oven drying at three distinct temperatures (35ºC, 40ºC, and 45ºC) and freeze-drying. The pollen samples dried at 35ºC, 40ºC, and 45ºC presented moisture contents of 9.6%, 9.8%, and 10.1%, while the freeze-dried sample had a moisture content of 5.8%. The nutritional value, microbiological quality, and antioxidant properties of the preserved bee pollen was assessed throughout time during a period of 6 months. In general, the different treatments showed no significant immediate impact on the nutritional value and microbiological loads of bee pollen, but some changes were observed on the antioxidant properties, particularly for the oven-dried bee pollen. Also, during the storage period, mostly in microbiological parameters, such as total viable counts and lactic acid bacteria, and antioxidant properties. Also, impact on the microbiological loads of bee pollen, but changes were observed after one months of storage, mostly in total viable counts and lactic acid bacteria.
- The impact of preservation techniques on bee pollen nutritional value, microbiological stability, and antioxidant propertiesPublication . Lema, Filipe; Mekki, Imen; Tomás, Andreia; Falcão, Soraia; Rodrigues, Paula; Martins, Vitor Manuel Ramalheira; Vilas-Boas, MiguelAfter its collection the bee pollen can present moisture contents that can range from 18% to 25%. Thus, it is necessary to reduce the moisture content in order to maintain bee pollen overall nutritional quality and microbiological safety. Moreover, several studies have recently highlighted the beneficial biological properties of bee pollen, which may also be influenced by the preservation techniques applied to reduce the moisture content. Therefore, the main objective of this work is to provide an insight regarding the potential influence of preservation techniques on the nutritional value, microbiological quality, and antioxidant properties of bee pollen. The bee pollen, presented an initial moisture content of 13.8%, which was subsequently reduced to 9.6%, 9.8%, 10.1%, and 5.8% by oven-drying at 35ºC, 40ºC, and 45ºC, and freeze-drying, respectively. The nutritional value, microbiological quality, and antioxidant properties of the preserved bee pollen were assessed throughout time during a period of 6 months. In general, the different treatments showed no significant immediate impact on the nutritional value and microbiological loads of bee pollen, but some changes were observed on the antioxidant properties. Also, changes were observed after one month of storage, mostly in total viable counts and lactic acid bacteria.