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 (μg/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 μg/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

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 (µg/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 µg/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) oilsXUNTA 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)S

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

Comprehensive study of honey with protected denomination of origin and contribution to the enhancement of legal specifications

In this study the characterization of a total of 60 honey samples with Protected Denomination of Origin (PDO) collected over three harvests (2009–2011, inclusive), from the Northeast of Portugal was carried out based on the presence of pollen, physicochemical and microbiological characteristics. All samples were found to meet the European Legislation, but some didn’t meet the requirements of the PDO specifications. Concerning the floral origin of honey, our results showed the prevalence of rosemary (Lavandula pedunculata) pollen. The microbiological quality of all the analyzed samples was satisfactory, since fecal coliforms, sulfite-reducing clostridia and Salmonella were absent, and molds and yeasts were detected in low counts. Significant differences between the results were studied using one-way analysis of variance (ANOVA), followed by Tukey’s HSD test. The samples were submitted to discriminant function analysis, in order to determine which variables differentiate between two or more naturally occurring groups (Forward Stepwise Analysis). The variables selected were in this order: diastase activity, pH, reducing sugars, free acidity and HMF. The pollen spectrum has perfect discriminatory power. This is the first study in which a honey with PDO was tested, in order to assess its compliance with the PDO book of specificationsX.F. would also like to thank the Xunta de Galicia (Isidro Parga Pondal Program for young researchers, Grant No. IPP-020)S

Strange Behaviour of Transport Properties in Novel Metal Thiocyanate Based Ionic Liquids

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUGThe following are the Supplementary data to this article: https://ars.els-cdn.com/content/image/1-s2.0-S0167732221018882-mmc1.docx[Abstract] In a previous paper some of us presented the structure and some properties of a new family of ionic liquids, ILs, with a common cation, 1-butyl-3-methyl imidazolium (the popular [C4C1Im]⁺ or [BMIM]⁺) and a variety of anions based in thiocyanate (SCN)¯: one reference sample and ten with anionic metal complexes of different valences: Al¹¹¹, Mn¹¹, Fe¹¹, Cr¹¹¹, Ni¹¹, Hg¹¹, Zn¹¹, Co¹¹ and Cu¹, resulting, respectively, [BMIM](SCN), [BMIM]₃ Al(SCN)₆, [BMIM]₄ Mn(SCN)₆, [BMIM]₃ Fe(SCN)₆, [BMIM]₃ Cr(SCN)₆, [BMIM]₄ Ni(SCN)₆, [BMIM]₂ Hg(SCN)₄, [BMIM]₂ Zn(SCN)₄, [BMIM]₂ Co(SCN)₄ and [BMIM]₃ Cu(SCN)₄. In this paper we show experimental measurements of electrical conductivity of these ILs in a broad temperature range (about 90 K). Viscosity has been measured for six compounds in a wide temperature range. In addition, the diffusion coefficient for both ions forming the IL has been measured for some of the samples using NMR-Dosy technique. In spite of being very similar compounds from a chemical point of view, they present very different transport property values. Thus, viscosity varies more than two orders of magnitude among those metal thiocyanate ILs, being the highest for the compound with Al and the lowest for that with Hg. Moreover, differences between ionic conductivity and diffusion coefficient values extend more than one order of magnitude among the thiocyanate ILs. These three properties will be related in pairs, thus through Walden’s rule we compare molar conductivity and fluidity, while using Kohlrausch’s law and Nerst-Einstein equation molar conductivity and diffusion coefficient are related. Also, diffusion coefficient and fluidity (the inverse of viscosity) are compared by means of Stokes-Einstein relationship. In addition, we calculate the Laity interionic friction coefficients for both anions of the IL with Hg. Finally, a theoretical model is suggested to explain all the experimental evidences reported.We acknowledge the financial support of Ministerio de Economía y Competitividad MINECO) (MAT2017-86109-P and MAT2017-89239-C2-(1.2)-P); and Xunta de Galicia (AGRU 015/11. GRC ED431C 2016/001 and ED431D 2017/06). All these research projects were partially supported by FEDER. Also, D.A. acknowledges Gil Dávila Foundation for his postgraduate grant. Funding for open access charge: Universidade da Coruña/CISUG.Xunta de Galicia; ED431C 2016/001Xunta de Galicia; ED431D 2017/06https://ars.els-cdn.com/content/image/1-s2.0-S0167732221018882-mmc1.doc