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Papers by sandra osés

Resumenes de Ponencias presentadas en el I Congreso de Apicultura y Meliponicultura en Ecuador, r... more Resumenes de Ponencias presentadas en el I Congreso de Apicultura y Meliponicultura en Ecuador, realizado del 21-22 Febrero 2015. Lugar: Machala (UTMACH; CCE-EO; GADPEO), Provincia El Oro

ACS Applied Materials & Interfaces

We have developed an in situ methodology for determining nitrite concentration in processed meats... more We have developed an in situ methodology for determining nitrite concentration in processed meats that can also be used by unskilled personnel. It is based on a colorimetric filmshaped sensory polymer that changes its color upon contacting the meat and a mobile app that automatically calculates the manufacturing and residual nitrite concentration by only taking digital photographs of sensory films and analyzing digital color parameters. The film-shaped polymer sensor detects nitrite anions by an azo-coupling reaction, since they activate this reaction between two of the four monomers that the copolymer is based on. The sensory polymer is complemented with an app, which analyzes the color in two different digital color spaces (RGB and HSV) and performs a set of 32 data fittings representing the concentration of nitrite versus eight different variables, finally providing the nitrite concentration of the test samples using the best fitting curve. The calculated concentration of nitrite correlates with a validated method (ISO 2918: 1975) usually used to determine nitrite, and no statistically significant difference between these methods and our proposed one has been found in our study (26 meat samples, 8 prepared, and 18 commercial). Our method represents a great advance in terms of analysis time, simplicity, and orientation to use by average citizens.

Journal of Apicultural Science, 2020

This study was aimed to assess quality, authentication parameters and trolox equivalent antioxida... more This study was aimed to assess quality, authentication parameters and trolox equivalent antioxidant capacity (TEAC) of Algerian and imported honeys sold in Algerian markets. Results indicated that 80% Algerian samples fulfilled international standards, whereas only 21.4% imported honeys were in agreement with the current regulations. 13.3% Algerian samples and 7.1% imported honeys showed values of proline lower than 180 mg/kg, which is the recommended limit for authentic honeys. Comparing Algerian and imported honeys, electrical conductivity, degrees Brix, diastase activities and proline contents were higher in Algerian honeys, in contrast to moisture percentages, hydroxymethylfurfural contents and acid phospatase activities that were higher in imported honeys. Methanolic extracts of Algerian samples were richer both in total phenolics and flavonoids determined in alkaline medium. There were not significant differences between Algerian and imported samples concerning pH, free acid, ...

Foods, 2021

The effect of chemical extraction and in vitro digestion of different kinds of honey on bioactive... more The effect of chemical extraction and in vitro digestion of different kinds of honey on bioactive compounds (total phenolic compounds and flavonoids) and biological activities (antioxidant, antimicrobial and anti-inflammatory) was investigated. The antioxidant activity was evaluated against three radicals (ABTS•+, ROO•, •OH), and the antimicrobial activity was studied against five bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Streptococcus mutans and Pseudomona aeruginosa) and one yeast (Candida albicans). The results show that in comparison with raw honeys, the methanolic extracts exhibited lower values for phenols, flavonoids and antioxidant activity and higher anti-inflammatory and antimicrobial activities against L. monocytogenes. The higher anti-inflammatory activity indicates a possible use of dried honey extracts in the pharmaceutical and cosmetic industries. The digested honeys showed higher total phenolics and higher antioxidant activity than th...

Propolis has demonstrated a strong antioxidant activity 1 . This property, together with other co... more Propolis has demonstrated a strong antioxidant activity 1 . This property, together with other compositional parameters 2 could contribute to the difficult standardization of propolis. Antioxidant activity should be determined by methods based on different mechanisms, and against several free radicals 3 . The purpose of this research was to help characterize propolis from Aragon (Spain) by determining the oxygen radical absorbance capacity (ORAC) 4 , trolox equivalent antioxidant capacity (TEAC) 5 , 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay 6 , as well as the radical-scavenging effect on hydroxyl radicals (AOA) 5 on hydroalcoholic extracts of eight Aragonese propolis samples. Propolis extracts were obtained with 70% (V/V) ethanol. All extracts showed high antioxidant activities. The following averages were obtained: For ORAC 11070 µmol trolox/g, for TEAC 1040.7 µmol trolox/g, for IC 50 DPPH 0.0698 mg/ml and for AOA 0.8783 mmol uric acid/g. At the 95.0% confidence level, significant...

World Academy of Science, Engineering and Technology, International Journal of Nutrition and Food Engineering, 2017

LWT, 2021

Abstract In order to obtain the best physicochemical and the most appealing honey powder as possi... more Abstract In order to obtain the best physicochemical and the most appealing honey powder as possible, this research assessed three procedures (spray drying, vacuum drying and freeze drying) as well as three carrier agents (Arabic gum, whey protein isolate and maltodextrin) for dehydrating ling-heather honeys (Calluna vulgaris (L.) Hull). Using each carrier agent, both vacuum and freeze drying were the procedures that provided higher recoveries (76%–98%) and higher honey final concentrations in the powders (56%–73%). The most suitable carrier agent was maltodextrin, because with it, lower moisture (1.90%–4.20%), higher solubility (21 s–123 s) and lower hygroscopicity (6.32%–13.68%) was achieved. Honey powders obtained with maltodextrin by vacuum and freeze drying exhibited higher recoveries (88%–98%) and the best sensory characteristics, with stronger floral odours and flavours, stronger sweetness, lower viscosity and lower waxy perceptions.

Food Chemistry, 2021

A new original application for a polyacrylic film based on the monomers 2-(dimethylamino)ethyl me... more A new original application for a polyacrylic film based on the monomers 2-(dimethylamino)ethyl methacrylate (NNDA), 2-hydroxyethyl acrylate (2HEA) and methylmethacrylate (MMA) as a starch azure container has been set up for a simple determination of honey diastase activity. The proposed method is based on the correlation of reducing sugars generated during the enzymatic process with the Schade reference assay. The polyacrylic film is charged with starch azure acting as a container for this substance; thus, the starch does not interfere in the measurement of reducing sugars, so that the diastase activity is easily calculated. The method has been contrasted with Schade method, showing good correlation and differences under 0.4% between methods in some honey samples. The polyacrylic film has great potential for the routine honey diastase activity assessment in small laboratories, dramatically reducing analysis time and cost.

Food Bioscience, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Food Chemistry, 2020

We have developed a new method for the rapid (2 h) and inexpensive (materials cost < 0.02 €/sampl... more We have developed a new method for the rapid (2 h) and inexpensive (materials cost < 0.02 €/sample) "2-in-1" determination of the total phenolic content (TPC) and the antioxidant activity (AOX) in honey samples. The method is based on hydrophilic colorimetric films with diazonium groups, which react with phenols rendering highly colored azo groups. The TPC of the sample is correlated to its trolox equivalent antioxidant capacity (TEAC). The intensity of the color allows us to determine both TPC and TEAC of the sample by the analysis of a picture taken with a smartphone that is analysed by the use of the color-definition-parameters (RGB). The controlled light conditions and the systematic use of the same camera avoid the periodical calibration of the system improving the efficiency of the method. Thus, it is a simple method carried out by non-specialized personnel and it involves much lower money and time investment compared to traditional methods.

Antioxidants, 2020

Propolis is a resinous vegetal exudate modified by bees, and is interesting as a preservative and... more Propolis is a resinous vegetal exudate modified by bees, and is interesting as a preservative and potentially functional product. This work dealt with studying the common phenolic profiles and antioxidant capacities of 13 bee propolis from different geographical areas. Both hyaluronidase and angiotensin converting enzyme (ACE) inhibitory activities were also assessed and related when possible with particular phenolic compounds. High performance liquid chromatography-ultraviolet detection (HPLC-UV) analysis showed that every propolis contained p-coumaric acid (1.2–12.2 mg/g) and ferulic acid (0.3–11.0 mg/g). Pinocembrin, catechin, and caffeic acid phenethyl ester (CAPE) plus galangin were the main flavonoids. Antioxidant activities were higher than 280 µmol trolox/g for trolox equivalent antioxidant capacity (TEAC), 0.099 mmol uric acid/g for radical-scavenging effect on hydroxyl radicals, and 0.19 mg/mL for half maximal inhibitory concentration (IC50) of antioxidant activity against...

LWT, 2019

The aim of this study was to investigate the phytochemical composition and biological proporties ... more The aim of this study was to investigate the phytochemical composition and biological proporties of Tunisian propolis from four different regions: Kasserine, Béja, Kèf and Monastir. Ethanolic extracts of propolis were prepared using two extraction methods; solvent and ultrasonic extraction. Total phenolics, flavonoids, ABTS free radical and hydroxyl radicals scavenging abilities, anti-inflammatory, anti-hypertensive, as well as antimicrobial activities of propolis extracts were determined. Identification and quantification of phenolic and flavonoid compounds were performed by using both HPLC-UV and HPLC-ESI-MS. The results revealed high contents of total phenolics and flavonoids and polyphenols extraction was more efficient by sonication. Caffeic acid phenethyl ester (CAPE), galangin, and genistein were the major identified compounds. Antihypertensive activity, evaluated in propolis extracts for first time by HPLC-UV, was higher than 90% for all extracts. Tunisian propolis is an important natural source of polyphenols and flavonoids. The best extraction method was ultrasonic for antioxidants and most of biological activities; conventional method seems to be more suitable for anti-inflammatory activity. Propolis from Béja contains the highest amount of antioxidants and have a stronger potential biological activities. Tunisian propolis could be, therefore, a promising raw material for food and pharmaceutical industry.

Journal of Food Composition and Analysis, 2018

This research was aimed to study the sugar composition of fifty-four representative artisanal hon... more This research was aimed to study the sugar composition of fifty-four representative artisanal honeys from the northern Iberian plateau. Moisture, specific rotation, and crystallization indexes were also determined. Sugars were analyzed by gas chromatography-flame ionization detector (GC-FID) after Pourtallier´s derivatization procedure. Fourteen carbohydrates were reliably quantified: two monosaccharides, five disaccharides, six trisaccharides and one tetrasaccharide. Honeydew honeys showed the highest disaccharides (6.71%) and trisaccharides (1.81%) averages and the lowest monosaccharides (63.10%) average, in contrast to heather honeys that had the lowest disaccharides (4.93%) and trisaccharides (0.69%) averages and the highest monosaccharides (70.96%). Chestnut honeys possessed low concentrations of monosaccharides, sucrose, trehalose, and trisaccharides. Clover and lavender honeys possessed high monosaccharide and disaccharide percentages. As expected, lavender samples showed the highest sucrose concentrations (0.05-5.18%). Isomaltose contents were particularly high in honeydew (1.17-2.49%) and chestnut (1.34-1.74%) samples, and low in lavender (0.6-1.16%) honeys, the latter also being low in raffinose (0.01-0.05%). Moisture percentages (14.4-18.6%) indicated optimum honey ripeness. Averages for all groups of samples were levorotatory. In contrast to honeydew and chestnut honeys, lavender samples showed the fastest granulation tendency. In the analyzed honeys, the higher the percentage of isomaltose was, the lower the crystallization tendency the honeys exhibited.

Journal of Apicultural Research, 2018

A thorough updated review of both standardized and the most used and novel analytical methods for... more A thorough updated review of both standardized and the most used and novel analytical methods for the analysis of honey is presented. The methodologies applied to honey in the analysis of the physical parameters (electrical conductivity, rheological properties, specific rotation, color and water activity), the analysis of the properties and the most important components of honey (moisture, sugars, enzymes, HMF, types of acidity and pH, formol index, insoluble solids, organic acids, proteins, amino acids, vitamins, minerals, volatile and semi-volatile compounds and polyphenols), and the antioxidant and antimicrobial activities are described. Finally, the most applied methods for multicomponent analysis and/or for honey authenticity verification (both the botanical and/or geographical origin honey classification and the detection of honey adulteration) are provided.

Separation & Purification Reviews, 2017

Polyphenols are secondary plant metabolites playing a major role as potentially functional compon... more Polyphenols are secondary plant metabolites playing a major role as potentially functional components. They can also be used for honey authentication. This review gathers the recent literature references about honey extraction procedures, as well as instrumental analysis of honey phenolic compounds. Liquid-Liquid extraction is widely used for both extraction and purification purposes with adequate recovery percentages. However, the use of high solvent volumes is a mojor disadvantage. More environmentally friendly methods include accelerated solvent extraction (ASE), dispersive, and inverse dispersive liquid-liquid microextraction (DLLME and IDLLME, respectively). Solid phase extraction (SPE) is the most common method for honey polyphenols' isolation. Polyphenol isolation by a combination of liquid-liquid and solid phase extraction allows good recoveries for a variety of different compounds. High performance liquid chromatography (HPLC) with ultraviolet or mass spectrometry detectors is by far, the most employed instrumental procedure to separate and quantify polyphenols in honey although capillary electrophoresis has been also successfully used for these purposes. The use of new sorbents, the optimization of current procedures and the development of other simple and rapid analytical techniques are challenges for future investigations of polyphenols analysis in honey.

Food and Bioprocess Technology, 2017

This paper assesses the actual reliability of four rheological parameters to help describe honeys... more This paper assesses the actual reliability of four rheological parameters to help describe honeys that exhibit non-Newtonian behavior, being the most representative of which, ling heather (Calluna vulgaris (L.) Hull) honeys. Sampling included a representative number of unifloral ling heather honeys, non-unifloral honeys close to ling heather uniflorality, and other non-unifloral honeys containing ling heather. All experiments were performed at 25°C and consisted on researching viscosity curves at different shear rates, as well as the time dependency of honey samples at a constant shear rate. Viscosity curves were correctly fitted by the Ostwald-de Waele model. Consistency coefficients (k) and flow behavior indexes (n) were calculated, and the Weltmann model was used to determine the stress decay behavior. The influence of honey moisture on k value was also researched. Hysteresis area and time-dependent thixotropic index B proved to be the most suitable parameters for a reliable ling heather honey authentication.

Journal of Apicultural Research, 2015

Propolis is a natural bee hive product with potential functional activities. Nowadays, many propo... more Propolis is a natural bee hive product with potential functional activities. Nowadays, many propolis products are available on the market, including cosmetics and food commodities. However, it is still unknown if edible products with propolis are fully accepted by consumers and are thus commercially viable, due to the bitter and resinous flavor and taste of propolis. This work is focused on the design of a “honey with propolis” foodstuff that can be welcomed by consumers, and, if possible, provide added benefits compared to the honey itself. Propolis tinctures containing three different concentrations of ethanol and times of maceration were prepared, giving the best results with 90% ethanol and two days of maceration. Then, in order to study the maximum amount of propolis in honey that could be accepted by a representative group of consumers, a forced choice paired comparison preference test with 69 people was carried out, giving the best results with a honey product containing 0.3-0.5% propolis extract. Phenolic and flavonoid contents, as well as TEAC antioxidant and antimicrobial activities of propolis, honey, and the product “honey with propolis” were then analyzed. As expected, propolis showed the highest phenolics and flavonoids contents, as well as the highest antioxidant and antimicrobial activities. The product “honey with propolis” showed a significantly higher antimicrobial activity, however, when compared to honey alone. In conclusion, the commercialization of a food product of “honey and up to 0.5% propolis” is promising, interesting and viable, as such a product is greatly appreciated by consumers, as well as being potentially healthy.