Browsing by Author "Vilas-Boas, Miguel"
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- Antimicrobial and wound healing effects associated to cytocompatibility and the relationship with phytochemical profile of selected Portuguese monofloral honeysPublication . Machado, Alexandra M.; Marto, Joana; Gonçalves, Lídia Maria; Ribeiro, Helena Margarida; Duarte, Aida; Tomás, Andreia; Falcão, Soraia I.; Vilas-Boas, Miguel; Miguel, Maria da Graça; Figueiredo, Ana CristinaOwing to its applications in both food and pharmaceutical industries honey is regarded as a functional product. This study evaluated 32 Portuguese monofloral honeys and their activity was compared with manuka honey 850 +. The antimicrobial activity was determined against Gram-positive and negative bacteria, and yeast. Antioxidant activity, wound healing ability, and cell viability were studied in the human keratinocyte cell line (HaCaT). Phytochemical profile analysis was performed by UPLC/DAD/ESI-MSn. Chestnut, bell heather, eucalyptus, manuka, and strawberry tree honeys demonstrated higher antioxidant activity and were effective against S. aureus. Incense and orange honeys showed wound healing rates of 89 % and 86 %, respectively. All the honeys had cell viability above 76 %. Bell heather and strawberry tree honeys showed the highest total phenolic content, while incense and orange honeys, showed the lower ones. Phytochemical profile analysis evidenced two main clusters, one dominated by isoprenoids and norisoprenoids, as well as phenolic acids and derivatives, while the other included flavonoids as main compounds. Blending different Portuguese monofloral honeys may be an alternative to faster wound healing, by combining their diverse bioactive components. The gathered knowledge can be further explored in formulations that consider the biological activity capacity and composition of each honey.
- Honey volatiles as a fingerprint for botanical origin: a review on their occurrence on monofloral honeysPublication . Machado, Alexandra M.; Miguel, Maria; Vilas-Boas, Miguel; Figueiredo, Ana CristinaHoneys have specific organoleptic characteristics, with nutritional and health benefits, being highly appreciated by consumers, not only in food but also in the pharmaceutical and cosmetic industries. Honey composition varies between regions according to the surrounding flora, enabling its characterization by source or type. Monofloral honeys may reach higher market values than multifloral ones. Honey's aroma is very specific, resulting from the combination of volatile compounds present in low concentrations. The authentication of honey's complex matrix, according to its botanical and/or geographical origin, represents a challenge nowadays, due to the different sorts of adulteration that may occur, leading to the search for reliable marker compounds for the different monofloral honeys. The existing information on the volatiles of monofloral honeys is scarce and disperse. In this review, twenty monofloral honeys and honeydews, from acacia, buckwheat, chestnut, clover, cotton, dandelion, eucalyptus, fir tree, heather, lavender, lime tree, orange, pine, rape, raspberry, rhododendron, rosemary, strawberry tree, sunflower and thyme, were selected for volatile comparison purposes. Taking into consideration the country of origin, the technique of isolation and analysis, the five main volatiles from each of the honeys are compared. Whereas some compounds were found in several types of monofloral honey, and thus not considered good volatile markers, some monofloral honeys revealed characteristic volatile compounds independently of their provenance.
- Quality assessment of Portuguese monofloral honeys. Physicochemical parameters as tools in botanical source differentiationPublication . Machado, Alexandra M.; Tomás, Andreia; Russo-Almeida, Paulo; Duarte, Aida; Antunes, Marília; Vilas-Boas, Miguel; Miguel, Maria Graca; Cristina Figueiredo, A.The quality evaluation and physicochemical parameters assessment of Portuguese monofloral honeys were performed. Fifty-one monofloral honeys were collected from several regions from mainland Portugal, and from the Azores islands, producer labelled as carob tree (n = 5), chestnut (n = 2), eucalyptus (n = 5), bell heather (n = 6), incense (n = 4), lavender (n = 8), orange (n = 9), rape (n = 2), raspberry (n = 2), rosemary (n = 1), sunflower (n = 3), and strawberry tree (n = 4). Pollen analysis and microbiological safety were evaluated, and the parameters such as colour index, moisture content, electrical conductivity, hydroxymethylfurfural, pH, free and total acidity, diastase activity, proline, and sugar profile were assessed for physicochemical characterization, in all 51 monofloral honeys. After melissopalynological examination, the honeys were either confirmed as monofloral, or classified as multifloral with predominance of a specific pollen type or multifloral. Microbiological analysis showed that honeys were safe for human consumption. Pairwise comparisons of physicochemical parameters, using only honey types with n >= 3, revealed significant differences between honey types. Despite some homogeneity in sugar profile among honeys, eucalyptus honey was significantly different in glucose, maltose and maltulose content compared to incense, orange and sunflower honeys, and also exhibited a higher isomaltose amount compared to all analyzed honeys. Electrical conductivity, colour index, free and total acidity, and diastase activity showed significant differences between the analyzed honeys, indicating that these parameters may provide an additional tool in monofloral honey identification.
- Volatile profile of Portuguese monofloral honeys: significance in botanical origin determinationPublication . Machado, Alexandra M.; Antunes, Marília; Miguel, Maria Graça; Vilas-Boas, Miguel; Figueiredo, Ana CristinaThe volatile profiles of 51 samples from 12 monofloral-labelled Portuguese honey types were assessed. Honeys of bell heather, carob tree, chestnut, eucalyptus, incense, lavender, orange, rape, raspberry, rosemary, sunflower and strawberry tree were collected from several regions from mainland Portugal and from the Azores Islands. When available, the corresponding flower volatiles were comparatively evaluated. Honey volatiles were isolated using two different extraction methods, solid-phase microextraction (SPME) and hydrodistillation (HD), with HD proving to be more effective in the number of volatiles extracted. Agglomerative cluster analysis of honey HD volatiles evidenced two main clusters, one of which had nine sub-clusters. Components grouped by biosynthetic pathway defined alkanes and fatty acids as dominant, namely n-nonadecane, n-heneicosane, n-tricosane and n-pentacosane and palmitic, linoleic and oleic acids. Oxygen-containing monoterpenes, such as cis- and trans-linalool oxide (furanoid), hotrienol and the apocarotenoid α-isophorone, were also present in lower amounts. Aromatic amino acid derivatives were also identified, namely benzene acetaldehyde and 3,4,5-trimethylphenol. Fully grown classification tree analysis allowed the identification of the most relevant volatiles for discriminating the different honey types. Twelve volatile compounds were enough to fully discriminate eleven honey types (92%) according to the botanical origin.