Moldar o futuro
Keen, Peter G. W.
1994
Search results
26 records were found.
O pólen recolhido pelas abelhas
é geralmente usado com o objetivo
de alimentar as suas larvas nos estágios
iniciais de desenvolvimento, sendo uma
fonte importante de nutrientes
e micronutrientes para as abelhas
jovens da colmeia. Uma alimentação
rica em pólen em fases precoces do
ciclo de vida permite o desenvolvimento
em obreiras fortes e consequentemente
uma colmeia muito ativa e com elevado
rendimento de aprodução de mel
e outros produtos. Devido
à sua constituição química, o pólen
é também um alimento nutricionalmente
importante para os seres humanos.
Following 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.
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 importante 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 r2 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.
This study aimed to evaluate the potential of FT-Raman spectroscopy in the prediction of the chemical composition of Lavandula spp. monofloral honey. Partial Least Squares (PLS) regression models were performed for the quantitative estimation and the results were correlated with those obtained using reference methods. Good calibration models were obtained for electrical conductivity, ash, total acidity, pH, reducing sugars, hydroxymethylfurfural (HMF), proline, diastase index, apparent sucrose, total flavonoids content and total phenol content. On the other hand, the model was less accurate for pH determination. The calibration models had high r2 (ranging between 92.8% and 99.9%), high residual prediction deviation - RPD (ranging between 4.2 and 26.8) and low root mean square errors. These results confirm the hypothesis that FT-Raman is a useful technique for the quality control and chemical properties' evaluation of Lavandula spp honey. Its application may allow improving the efficiency, speed and cost of the current laboratory analysis.
Sugar identification of Lavandula spp. Honey.
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Honey spirit is an alcoholic beverage produced by fermentation followed by distillation of the honey must, which has distinct organoleptic characteristics derived mostly from the raw material used. In order to accurately monitor the quality of the product throughout the distillation process (head, heart and tail stages), FT-RAMAN spectroscopy was applied. Dark honey, light honey and honey obtained following waxes' wash was used to produce honey spirit. The pH, alcoholic strength, methanol content, acetaldehyde content, ethyl acetate content and higher alcohols content were evaluated during the distillation process. The FT-RAMAN technique was used to obtain spectral information for all fractions collected during beverage production. The results suggest that the honey spirit had good quality concerning the volatile composition and methanol was not detected in any sample. FT-RAMAN is promising for the online monitoring of the distillation process in order to improve the final quality of this beverage.
Spirits are alcoholic beverages commonly consumed in European countries. Their raw
materials are diverse and include fruits, cereals, honey, sugar cane, or grape pomace. The main aim of
this work is to present and discuss the source, quality control, and legal limits of methanol in spirits
produced using fruit and honey spirits. The impact of the raw material, alcoholic fermentation, and the
distillation process and aging process on the characteristics and quality of the final distilled beverage
are discussed. In addition, a critical view of the legal aspects related to the volatile composition of
these distillates, the origin and presence of methanol, and the techniques used for quantification are
also described. The methanol levels found in the different types of spirits are those expected based on
the specific raw materials of each and, almost in all studies, respect the legal limits.
Vibrational spectroscopy applied to honey spirit characterization.
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Mead, one of the oldest fermented drinks, is derived from the fermentation of diluted honey by yeasts. In the context of wine production, several procedures are applied to stabilize the beverage and to improve its organoleptic properties. This study aims to evaluate the impact of adding fining agents on the production of mead. In general, the best results were obtained for the samples containing just one fining agent instead of two combined. However, the best performance was obtained for the combined fining agents (bentonite + gelatine + egg albumin). Tannins decreased significantly the content of volatile compounds. On the other hand, silica appears to be the best fining agent, resulting in the lowest loss of volatile compounds. Thirty‐six volatile compounds were determined by gas chromatograph–flame ionization detector and gas chromatography–mass spectrometry, including alcohols (42.5%), carbonyl compounds (40.4%), acetates (14.4%) and esters (1.8%). Eleven volatile compounds had odour activity values >1, representing those with a major impact on the aroma of mead. Significant differences (p < 0.05) were found in 10 volatile compounds independently to the type of treatment used and no differences (p > 0.05) were observed for remaining compounds.
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The aim of this work was to develop computational intelligence models based on neural networks (NN), fuzzy models (FM), and support vector machines (SVM) to predict physicochemical composition of bee pollen mixture given their botanical origin. To obtain the predominant plant genus of pollen (was the output variable), based on physicochemical composition (were the input variables of the predictive model), prediction models were learned from data. For the inverse case study, input/output variables were swapped. The probabilistic NN prediction model obtained 98.4% of correct classification of the predominant plant genus of pollen. To obtain the secondary and tertiary plant genus of pollen, the results present a lower accuracy. To predict the physicochemical characteristic of a mixture of bee pollen, given their botanical origin, fuzzy models proven the best results with small prediction errors, and variability lower than 10%.
Some diseases still need better therapeutic approaches, including the prevention of development. Natural resources are investigated with this purpose; among them, we decided to use an
invasive plant as a main strategy. This will help in two ways: screening new compounds in flowers
prevents the plant from causing widespread damage by controlling the dissemination and also obtains crude material for further applications. In the present study, flower extracts from Acacia dealbata
Link harvested in Portugal were studied during three stages of flowering. Phenolic compounds were
evaluated using HPLC/DAD and the total phenolics as the total flavonoids content was determined.
The bioactivities screened were antioxidant potential, inhibitory activities of some enzymes (acetylcholinesterase, lipase and α-glucosidase) and, to complete the screening, the inhibition of microbial
growth was determined against Gram-negative and Gram-positive bacteria, as well as for yeasts. The
data obtained suggested that the hydroethanolic extracts gave good results for all these biological
activities and varied according to the maturation status of the flowers, with the early stage being
the most active, which can be related to the chalcones content. This new approach will lead to the
possible control of the invasive plant and also future perspective research for therapeutic purposes.
The effect of an extreme heat processing on Zantaz honey samples was studied using a panel of physicochemical parameters, antioxidant activities and FTIR-ATR spectroscopy. Honey samples were heated at 121 °C for 30 min and the heat processing effect was confirmed indirectly through the assessment of hydroxymethylfurfural content, for which the values increased significantly (p < 0.01), and diastase activity, which was totally absent after the thermal processing. Besides, the effects of the heat on the antioxidant activities were diverse. Indeed, while the ability to scavenge 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid cation radicals (ABTS·+) and 2,2-diphenyl-1-picrylhydrazyl radicals was enhanced (p < 0.05 only for ABTS·+), after the heat processing, nitric oxide radicals scavenging activity was reduced drastically (p < 0.01). Regarding the chelating power, it was totally abolished following heating. Other activities showed no significant alteration. The initial values of antioxidant activities seem to be determinant in the changes occurring after the heat processing. Amongst the analysed parameters, following the heat processing, the honey colour was the variable where the influence of baseline values was the greatest. The spectral analyses confirmed that FTIR-ATR is a useful technique to discriminate the chemical differences occurring in honey after heat processing.
Honey with Bupleurum spinosum (zandaz) as a main pollen source has not been the subject of previous detailed study. Therefore, twelve Moroccan samples of this honey were subjected to melissopalynological, physicochemical and micro-biological quality characterization, as well as antioxidant activity assessment. From a quality point of view, almost all samples were within the limits established by Codex Alimentarius, and/or the European legislation. All samples presented predominance of B. spinosum pollen (more than 48%). Relatively high levels of trehalose (1.3–4.0 g/100 g) and elezitose (1.5–2.8 g/100 g) were detected. Those sugars, not common in monofloral honeys, could be used as na important factor to discriminate zandaz honey. Flavonoid content correlated positively with the honey color, melanoidin and polyphenol content, and negatively with the IC50 values of scavenging ABTS (2,2´-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals, while proline amount correlated negatively with IC50 values of nitric oxide scavenging activity and chelating power. This correlation supports the use of anti-oxidant activities as important variables for PCA (principal component analysis). Both components explained 70% from the given data, and showed certain homogeneity upon analyzed samples independent of the region, suggesting the importance of B. spinosum nectar in the resulting
honey characteristics.
Monofloral Lavandula spp. honey is very appreciated by consumers due to its characteristic and pleas antaroma and flavor. Given the economic importance of this ype of honey, it is important to develop a rapid and nonexpensive methodology that allows certifying its quality. In this context, this study aimed to compare the applicability and accuracy of FTIR-ATR and FT-Raman techniques for the quality evaluation of Lavandula spp. honey.
Calibration models, with PLS regression models, were
obtained for both methodologies concerning the following
parameters: total acidity, reducing sugars, hidroximetilfurfural (HMF), electrical conductivity, ash, proline content, diastase activity, apparent sucrose, total flavonoids,
and total phenolic contents. The calibration models had
high regression coefficients, r
2 (FTIR-ATR: 0.965–0.996;
FT-Raman: 0.983–0.999), high ratios of performance to
deviation, RPD (FTIR-ATR: 5.4–15.7; FT-Raman: 7.6–53.7),
and low root mean square errors (RMSEs; FTIR-ATR:
0.005–3.0; FT-Raman: 0.004–1.02). These results corroborate the potentiality of FTIR-ATR and FT-Raman for quality
evaluation and evaluation of the chemical properties of
Lavandula spp. honey even though FT-Raman technique
provided more accurate models.
The antioxidant activity of bee pollen (mainly composed by Cistus ladanifer pellets) was explored in the context of black pudding production. For this purpose, three black pudding formulations comprising varying antioxidant compounds (sodium ascorbate, bee pollen and bee pollen extract) were produced.
Bee pollen was characterized according to the botanical origin, antioxidant activity, total phenol and flavonoid contents and phenolic profile. Black pudding was characterized by the microbiological safety, lipid oxidation, pH, water activity and humidity at 1, 10, 21, 30 and 37 days. Sensory acceptance was evaluated on the four first periods of storage. Salmonella spp., Escherichia coli and Listeria monocytogenes were absent in all samples. Small variations on humidity and pH were observed during the black pudding's storage. Regarding lipid oxidation, it increased, on average, from 1.36 mg to 2.11 mg malondialdehyde/kg meat. Differences among the three formulations were only significant on the first days of storage. The sensory assessment did not differ between products. This study suggests that bee pollen may be used as a natural antioxidant in meat products, yet a careful labelling is essential to alert allergic consumers.
This study aimed to characterize the pollen and physicochemical profiles, and to evaluate the anti-oxidant capacity of six samples of Moroccan honey. The pollen grains of Eragrostis spp. Were predominant in all samples (from a minimum of 46.5861.59% to 72.7262.43% as a maximum), exceeding the minimum (generally 45%) required for the monoflorality nomination of a honey sample, and suggestion a case of newly reported honey. The analyzed samples had low diastase activity and hydroxymethylfurfural (HMF) content. Potassium was the dominant element in practi-cally all samples, except the sample with the highest Eragrostis spp. pollen percentage, which showed sodium predominance. The honey color ranged from water white to light amber, and posi-tively correlated the concentrations of phenols, proline and the capacity for scavenging free radicals. However, great variability observed in all the analyzed parameters, and could not be explained by the variability of the Eragrostis spp. pollen percentage, which suggests a hypothesis of low concentrated nectar.
The emergence of multidrug-resistant bacteria has prompted the development of alternative
therapies, including the use of natural products with antibacterial properties. The antibacterial
properties of Zantaz honey produced in the Moroccan Atlas Mountains against Escherichia coli,
Pseudomonas aeruginosa, and Staphylococcus aureus was evaluated and analyzed using chemometric
tools. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC)
against S. aureus were the lowest (112.5 ± 54.5 mg/mL), revealing that this species was most sensitive
to Zantaz honey. P. aeruginosa showed an intermediate sensitivity (MIC= 118.75 ± 51.9 mg/mL), while
E. coli was the most resistant to treatment (MIC = 175 ± 61.2 mg/mL). Content of monosaccharides,
certain minerals, and phenolic compounds correlated with antibacterial activity (p < 0.05). Principal
component analysis of physicochemical characteristics and antibacterial activity indicated that the
parameters most associated with antibacterial activity were color, acidity, and content of melanoidins,
fructose, epicatechin, methyl syringate, 4-coumaric acid, and 3-coumaric acid.
“Bee pollen” is pollen collected from flowers by honey bees. It is used by the bees to nourish themselves, mainly by provid ing royal jelly and brood food, but it is also used for human nutrition. For the latter purpose, it is collected at the hive entrance as pellets that the bees bring to the hive. Bee pollen has diverse bioactivities, and thus has been used as a health food, and even as medication in some countries. In this paper, we provide standard methods for carrying out research on
bee pollen. First, we introduce a method for the production and storage of bee pollen which assures quality of the product.
Routine methods are then provided for the identification of the pollen’s floral sources, and determination of the more
important quality criteria such as water content and content of proteins, carbohydrates, fatty acids, vitamins, alkaloids, phen olic and polyphenolic compounds. Finally, methods are described for the determination of some important bioactivities of bee pollen such as its antioxidant, anti-inflammatory, antimicrobial and antimutagenic properties.
