11 research outputs found
Detection of ambiguous patterns in a SOM based recognition system: application to handwritten numeral classification
This work presents a system for pattern recognition that combines a self-organising unsupervised technique (via a Kohonen-type SOM) with a bayesian strategy in order to classify input patterns from a given probability distribution and, at the same time, detect ambiguous cases and explain answers. We apply the system to the recognition of handwritten digits. This proposal is intended as an improvement of a model previously introduced by our group, consisting basically of a hybrid unsupervised, self-organising model, followed by a supervised stage. Experiments were carried out on the handwritten digit database of the Concordia University, which is generally accepted as one of the standards in most of the literature in the field
Detection of ambiguous patterns in a SOM based recognition system: application to handwritten numeral classification
This work presents a system for pattern recognition that combines a self-organising unsupervised technique (via a Kohonen-type SOM) with a bayesian strategy in order to classify input patterns from a given probability distribution and, at the same time, detect ambiguous cases and explain answers. We apply the system to the recognition of handwritten digits. This proposal is intended as an improvement of a model previously introduced by our group, consisting basically of a hybrid unsupervised, self-organising model, followed by a supervised stage. Experiments were carried out on the handwritten digit database of the Concordia University, which is generally accepted as one of the standards in most of the literature in the field
Detection of ambiguous patterns in a SOM based recognition system: application to handwritten numeral classification
This work presents a system for pattern recognition that combines a self-organising unsupervised technique (via a Kohonen-type SOM) with a bayesian strategy in order to classify input patterns from a given probability distribution and, at the same time, detect ambiguous cases and explain answers. We apply the system to the recognition of handwritten digits. This proposal is intended as an improvement of a model previously introduced by our group, consisting basically of a hybrid unsupervised, self-organising model, followed by a supervised stage. Experiments were carried out on the handwritten digit database of the Concordia University, which is generally accepted as one of the standards in most of the literature in the field
Palynological, physicochemical, and microbiological attributes of organic lavender (Lava ndula stoechas) honey from Portugal
At the present time, the quality, integrity, sanitation, and nutritional value of honeys receive attention on an
international level due to the increasing content of chemicals in the aforementioned matrix. The present study aims
to characterize organic honey (n=73) from Northeast Portugal, with respect to floral nectar origin, physicochemical
parameters, microbial safety, and commercial quality. All organic honey samples can be classified as monofloral
lavender (Lavandula stoechas L.), exceed in quality the international physicochemical standards, and show low
microbiological counts (yeast, moulds, and aerobic mesophiles), with negative results in respect to faecal coliforms,
Salmonella, and sulphite-reducing clostridia. Correlating the palynological, physicochemical, and microbiological
results is necessary in order to check the authenticity, quality, and sanitation of honey
Organic honey from Trás-os-Montes region (Portugal): chemical, palynological, microbiological and bioactive compounds characterization
At the present time, the quality, integrity, sanitation and nutritional value of honeys receive attention on
an international level due to the increasing content of chemicals in the aforementioned matrix. This work
was conducted to evaluate the quality of 75 organic honey samples from the Trás-Os-Montes region (Portugal).
Mean values obtained for physico-chemical parameters were: pH 3.7; 15.6% moisture; 0.26 mS/cm
electrical conductivity; 0.25% ash; 1.1 mg/kg HMF; 15.3 Gothe diastase activity; 40.3 meq/kg free acidity;
67.8% invert sugars and 2.7% apparent sucrose. All honey samples can be classified as monofloral Erica sp.,
as showed by pollen features. The amounts of phenols and flavonoids in the samples were also determined.
In respect to sanitary quality (fecal coliforms) and safety (sulfite-reducing clostridia and Salmonella),
all organic honey samples were negative. Furthermore, yeast and molds were detected in low
counts, with mean values obtained of 5.5 cfu/g and the value of total aerobic mesophiles obtained from
honeys was established in 1.3 102 cfu/g ± 7.5 101 cfu/g. The levels of flavonoids had a stronger impact
on both mesophiles (p = 0.0004) and molds (p = 0.0138) than the sucrose concentration (p = 0.001 and
0.0278; respectively). The results reported in this study should be introduced in the organic honey label,
and may help beekeepers, the industry, researchers and consumers better understand honey properties
Physicochemical and pollen analysis of Local honeys from the Lima Valley (Portugal)
An evaluation was done on the physicochemical quality of nineteen (n=19) Apis mellifera
honeys produced in the Lima Valley, Portugal. The rural landscape of the Lima Valley is
valuable in social, environmental and economic terms and its conservation and preservation
are essential. The evaluated physicochemical characteristics were: moisture, ash, electrical
conductivity, pH, hydroxymethylfurfural (HMF), free acidity, apparent sucrose, reducing
sugars and diastase activity. All honey samples met the International physicochemical
quality standards. A short study of pollen source was done by acetolisis method. The
families Fabaceae and Rosaceae were found with 6 and 2 pollen types each respectively.
The most important pollen source is Erica, moreover two samples are listed as Erica
monofloral honey
Evaluation of the effect of hidrogen peroxide (H2O2) in the antimicrobial activity of honey
Bee hive products such as honey, propolis and royal jelly have been extensively used in the
past. Their use in Medicine dates back at least 4000 years, to Ancient Egypt where it was used for
the treatment of wounds among other conditions. With the discovery of modern antibiotics in the
early 20th century, the use of many effective products of traditional medicine was discontinued.
Although modern antibiotics use has meant a decrease in mortality, its widespread use has led
to the emergence of antibiotic-resistant bacteria and fungi decreasing the treatment options.
This led to an increase research of antimicrobial activity of honey as possible alternatives at least
for dermatological or wound applications.
Honey is a complex substance made up of hundreds of different compounds. Honey’s
antimicrobial activity was initially attributed to the high sugar content and low pH and later to
the activity of glucose oxidase which transforms glucose and water into hydrogen peroxide and
gluconic acid upon honey dilution, which is responsible for the antimicrobial activity in most
honeys.
Monofloral heather (Erica sp.) honey samples harvested in Portugal according to European
organic apiculture standards, were analyzed to test antibacterial activity against Bacillus cereus,
Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. A catalase solution was
added to honey samples to inactive the hydrogen peroxide and then the honeys were tested
to see if there was still any antibacterial activity. It was found out that the presence of catalase
induced a significant increase of the Minimum Inhibitory Concentration, suggesting that the
antimicrobial activity of honey was mainly due to the presence of peroxide. The non-peroxide
antimicrobial activity may be related with the concentration of phenolic compounds. In
addition it was verified a significant interaction between the catalase effect and the different
microorganisms.
Since antimicrobial properties of honey depend strongly on plant source and geographic
origin, together with other factors such as climatic conditions, soil type, and beekeeper activities,
the characterization of antimicrobial properties of honeys of diverse origins still appears to be
a sound research priority to obtain a reliable data on this valuable beehive product for medical
purposes
Organic bee pollen: botanical origin, nutritional value, bioactive compounds, antioxidant activity and microbiological quality
Organic bee pollen (BP, n = 22) harvested from the Douro International Natural
Park (DINP, Portugal) was studied. Nine botanical families were found in the mixture of
the samples. The water activity and pH ranged 0.21–0.37 and 4.3–5.2, respectively. The BP
analyses averaged 67.7% carbohydrates, 21.8% crude protein, 5.2% crude fat and 2.9% ash.
The energy ranged from 396.4 to 411.1 kcal/100 g. The principal fatty acid found was
linolenic, followed by linoleic acid, palmitic acid and oleic acid. The phenolic and flavonoid
contents varied from 12.9 to 19.8 mg of gallic acid equivalents/g of extract and from 4.5 to
7.1 mg of catechin equivalents/g of extract, respectively. The scavenger activity and β-carotene
bleaching assays values (EC50) were 3.0 ± 0.7 mg/mL and 4.6 mg/mL ± 0.9 mg/mL,
respectively. E. coli, sulphite-reducing Clostridia, Salmonella and S. aureus were not
found. Since there are studies indicating appreciable differences among BPs from different
regions, the full characterization of BP from diverse origins still appears to be a sound
research priority in order to obtain reliable data about this beehive product
Triacylglyceride, antioxidant and antimicrobial features of virgin camellia oleifera, C. reticulata and C. sasanqua oils
Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata
(CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition,
antioxidant and antimicrobial activities. Levels of fatty acids determined by 1H-nuclear
magnetic resonance analysis were similar to those reported for olive oils (82.30%–84.47%;
5.69%–7.78%; 0.26%–0.41% and 8.04%–11.2%, for oleic, linoleic, linolenic and saturated
acids, respectively). The CR oil showed the best antioxidant potential in the three in vitro
models tested. With regard to EC50 values (ÎĽg/mL), the order in DPPH radical-scavenging
was CR (33.48) < CO (35.20) < CS (54.87). Effectiveness in reducing power was CR
(2.81) < CO (3.09) < CS (5.32). IC50 for LPO inhibition were 0.37, 0.52 and 0.75 ÎĽg/mL
for CR, CO and CS, respectively. All the oils showed antimicrobial activity, and exhibited
different selectivity and MICs for each microorganism tested (E. coli, B. cereus and
C. albicans). B. cereus was the less sensitive species (MIC: 52.083 ± 18.042 for CO;
41.667 ± 18.042 for CR; 104.167 ± 36.084 for CS mg/mL) and the E. coli was the most
sensitive to camellia oil’s effect. The standard gentamicin presented higher MIC for E. coli
(4.2) than the CR (MIC= 2.6) and CO (MIC = 3.9) oils
Antimicrobial properties of Camellia oleifera oil
Camellias have been used in oriental ethnomedicine and appear very promising for
pharmaceutical exploitation since modern science has made it possible to specify their potential
medical significance with antimicrobial, antioxidant, antiallergic, antiviral and skin healing
properties. In the present study oil obtained from seeds of Camellia oleifera was studied for its
antimicrobial activity using clinically isolated bacterial and yeast strains. The oil evidenced
antimicrobial activity, and showed different selectivity and MICs for each microorganism tested.
Obtained results indicate that the tested oil acted best in relation to Gram (-) bacteria than Gram
(+). The data obtained in the in vitro models clearly establish its antimicrobial potency.XUNTA DE GALICIA for financial support: Grants INCITE09 262346PR and
PGIDIT06RAG26103PR. X.F. would also like to thank the Xunta de Galicia (Isidro Parga Pondal
Program for young researchers, Grant No. IPP-020