Standardizing the analysis of phenolic profile in propolis

[EN] The analysis of propolis is controversial, hampering the comparison of its biological properties and estimation of its commercial value. This work evaluates the effectiveness of combining maceration and ultrasonication extraction techniques on the yield, total phenol content (Folin-Ciocalteau) and the specific phenolic compounds (HPLC-UV), on propolis from different origins. The extraction method was not significant in any case; therefore ultrasonication is recommended (time-saving) but only when a double extraction is performed. Propolis yield varies significantly between samples, as it includes impurities, consequently the results should be expressed considering the yield (as balsam) instead of raw propolis. Of the 13 quantified phenolic compounds, CAPE and pinocembrin (803 and 701 mg/g balsam) stand out. The phenolic profile of a propolis must be fixed using both total phenol content (with a consensus reference compound) and the specific phenolic compounds, since the latter provides information about compounds that can play a significant antioxidant role.The research was funded by the 2016 ADSIDEO-Cooperation Programa of the Centre for Development Cooperation of the Universitat Politecnica de Valencia (Spain).Escriche Roberto, MI.; Juan Borras, MDS. (2018). Standardizing the analysis of phenolic profile in propolis. Food Research International. 106:834-841. doi:10.1016/j.foodres.2018.01.055S83484110

Liver transcriptome profile in pigs with extreme phenotypes of intramuscular fatty acid composition

Abstract Background New advances in high-throughput technologies have allowed for the massive analysis of genomic data, providing new opportunities for the characterization of the transcriptome architectures. Recent studies in pigs have employed RNA-Seq to explore the transcriptome of different tissues in a reduced number of animals. The main goal of this study was the identification of differentially-expressed genes in the liver of Iberian x Landrace crossbred pigs showing extreme phenotypes for intramuscular fatty acid composition using RNA-Seq. Results The liver transcriptomes of two female groups (H and L) with phenotypically extreme intramuscular fatty acid composition were sequenced using RNA-Seq. A total of 146 and 180 unannotated protein-coding genes were identified in intergenic regions for the L and H groups, respectively. In addition, a range of 5.8 to 7.3% of repetitive elements was found, with SINEs being the most abundant elements. The expression in liver of 186 (L) and 270 (H) lncRNAs was also detected. The higher reproducibility of the RNA-Seq data was validated by RT-qPCR and porcine expression microarrays, therefore showing a strong correlation between RT-qPCR and RNA-Seq data (ranking from 0.79 to 0.96), as well as between microarrays and RNA-Seq (r=0.72). A differential expression analysis between H and L animals identified 55 genes differentially-expressed between groups. Pathways analysis revealed that these genes belong to biological functions, canonical pathways and three gene networks related to lipid and fatty acid metabolism. In concordance with the phenotypic classification, the pathways analysis inferred that linolenic and arachidonic acids metabolism was altered between extreme individuals. In addition, a connection was observed among the top three networks, hence suggesting that these genes are interconnected and play an important role in lipid and fatty acid metabolism. Conclusions In the present study RNA-Seq was used as a tool to explore the liver transcriptome of pigs with extreme phenotypes for intramuscular fatty acid composition. The differential gene expression analysis showed potential gene networks which affect lipid and fatty acid metabolism. These results may help in the design of selection strategies to improve the sensorial and nutritional quality of pork meat.This work was funded by MICINN projects AGL2008-04818-C03/GAN and AGL2011-29821-C02 (Ministerio de Economía y Competitividad), and by the Innovation Consolider-Ingenio 2010 Program (CSD2007-00036, Centre for Research in Agrigenomics). Y. Ramayo-Caldas was funded by a FPU PhD grant from the Spanish Ministerio de Educación (AP2008-01450), J. Corominas was funded by a FPI PhD grant from the Spanish Ministerio de Educación (BES-2009-018223), A. Esteve-Codina is recipient of a FPI PhD fellowship from the Ministerio de Educación (BES-2008-005772), Spain.Peer Reviewe

Thermal properties of honey as affected by the addition of sugar syrup

[EN] Ensuring the authenticity of honey is a priority for producers and regulatory authorities. The aim of this work was to evaluate the thermal properties (using a Differential Scanning Calorimeter DSC ) of ten types of sugar syrup, six types of honey and mixtures of sunflower honey with all these syrups at different proportions simulating the adulteration of honey (ratio honey/syrup: 80/20; 90/10; 95/05). The glass transition temperature (Tg midpoint) ranged from 60.2 C to 67.3 C in honey samples and from 32.8 C to 95.8 C in syrup samples. The differences in sugar composition of the syrups mainly affect their thermal properties. In the adulterated samples, the glass transition temperature was affected by the type of syrup, proportionally to the adulteration level. These results offer compelling evidence that the DSC can be used for the identification of addition of syrup to honey, although to be conclusive a greater number of honey types must be considered.The authors thank the Generalitat Valenciana and the Spanish Government for funding the AICO/2015/104 project.Sobrino-Gregorio, L.; Vargas, M.; Chiralt, A.; Escriche Roberto, MI. (2017). Thermal properties of honey as affected by the addition of sugar syrup. Journal of Food Engineering. 213:69-75. https://doi.org/10.1016/j.jfoodeng.2017.02.014S697521

Differentiation of Acacia, Sunflower and Tilia Honeys from Different Countries Based on Sugar Composition, Physicochemical and Color Parameters

The purpose of this work was to characterize three different types of honey (sunflower, tilia, and acacia) commercialized in Spain, Romania, and Czech Republic from the point of view of their values on physical-chemical (HMF, diastase activity, moisture, electrical conductivity), sugar composition and colour parameters. A multivariate analysis made it possible to differentiate these three types of honey according to the parameters analysed. However, it was found that the country had less influence in its differentiation than the variety of honey

Volatile Fraction Composition of Acacia (Robinia Pseudoacacia) Honey from Romania, Spain and Check Republic

The aim of this work was to evaluate the volatile fraction profile of acacia raw honey from different countries: Romanian, Spain, and Czech Republic. A melissopalynological analysis was conducted on all the batches in order to verify them as belonging to this type of honey. A number of 35 volatile compounds, more specifically: 2 acids, 10 alcohols, 7 aldehydes, 3 ketonas, 2 esters, 5 hydrocarbons, 4 terpenes, 1 furanes and 1 sulfur compound were identified by Purge and Trap-Thermal Desorption-GC/MS. The overall volatile profile of this honey allowed its classification by geographical origin. The promising results proved its usefulness for the differentiation of honey according to their origin. However further research on a higher number of samples is required in order to confirm this expectation

Quality parameters, pollen and volatile profiles of honey from North and Central Mozambique

[EN] Honey from different provinces of North and Central Mozambique was characterised considering their physicochemical quality parameters, colour, sugars, total antioxidants, pollen analysis and volatile profile. Flora that surrounds the hives, and the apicultural practices also influence in their characteristics. According to a similar pollen spectrum, eight types of honey were found. In these, the predominant pollens were: I-Astragalus type; II-Acanthus sp; III-Celastraceae; IV-Brassicaceae; V16 Anacardiaceae and Astragalus type; VI-Astragalus type and Myrtaceae; VII-Asteraceae family and VIII-unknown. Group I (from Nampula), especially distanced itself from the others mainly due to the 18 special abundance of certain compounds (alcohols, aldehydes, esters, acids and terpenes). The presence of furan compounds largely identified in Sofala and Manica honeys could be due to inadequate beekeeping practices or storage conditions. A discriminant analysis correctly classified 96.7% of the groups, being electrical conductivity and moisture followed by the volatile-compound 3- Methylbutan-1-ol and the free acidity, the variables that most contributed.Tanleque-Alberto, F.; Juan-Borras, MDS.; Escriche Roberto, MI. (2019). Quality parameters, pollen and volatile profiles of honey from North and Central Mozambique. Food Chemistry. 277:543-553. https://doi.org/10.1016/j.foodchem.2018.11.007S54355327

Quality stability assessment of a strawberry-gel product during storage

A strawberry-gel product was formulated by using osmotic treatment. The osmotic solution (OS) used to dehydrate the fruit was mixed with carrageenan and employed to formulate the gel. In order to prevent a further dehydration of the fruit during product storage, the OS was previously diluted so that its water activity is the same as the dehydrated fruit. Changes in water, soluble solids, citric acid, ascorbic acid and anthocyanin contents, water activity, surface color, mechanical properties and volatile profile during 15 days of storage (5C) were evaluated. The use of the OS increased the nutritive and functional properties of the product. Changes in volatile profile, mechanical properties and color of the strawberry occur mainly in the first 2 days of storage and are not due to the presence of the gel matrix, as they occur also in the samples not placed in gel. The flux of anthocyanins from the fruit to the gel produces redness, giving a more attractive aspect to the formulated product. © 2009 Wiley Periodicals, Inc.The authors thank the Ministerio de Educacion y Ciencia and the Fondo Europeo de Desarrollo Regional (FEDER) for financial support throughout the projects AGL2002-01793 and AGL 2005-05994.Martín-Esparza, M.; Escriche Roberto, MI.; Penagos, L.; Martínez Navarrete, N. (2011). Quality stability assessment of a strawberry-gel product during storage. Journal of Food Process Engineering. 34(2):204-223. https://doi.org/10.1111/j.1745-4530.2008.00349.xS20422334

Monitoring honey adulteration with sugar syrups using an automatic pulse voltammetric electronic tongue

[EN] The new tendency to detect adulterated honey is the development of affordable analytical equipment that is in-line and manageable, enabling rapid on site screening. Therefore, the aim of this work was to apply an electronic tongue based on potential multistep pulse voltammetry, in combination with multivariate statistical techniques to detect and quantify syrup in honey. Pure monofloral honey (heather, orange blossom and sunflower), syrup (rice, barley and corn), and samples simulating adulterated honey with different percentages of syrup (2.5, 5, 10, 20 and 40) were evaluated. An automatic, electrochemical system for cleaning and polishing the electronic tongue sensors (Ir, Rh, Pt, Au) significantly improved the repeatability and accuracy of the measurements. PCA analysis showed that the proposed methodology is able to distinguish between types of pure honey and syrup, and their different levels of adulterants. A subsequent PLS analysis successfully predicted the level of the adulterants in each honey, achieving good correlations considering the adjusting parameters. The best results being for sunflower honey adulterated with corn syrup and heather honey with barley syrup (r2 ¿ 0.997), and heather with corn (r2 ¿ 0.994) whereas the weakest was found for heather honey adulterated with brown rice syrup (r2 ¿ 0.763) and orange blossom honey with corn syrup (r2 ¿ 0.879). The measurement system here proposed could be a very quick and effective option for the honey packaging sector with the finality of providing information about a characteristic as important as the adulteration of honey.This study forms part of the projects funded by the "Agencia Estatal de Investigacion" (AGL2016-77702-R) and by the "Generalitat Valenciana" (AICO/2015/104) of Spain, for which the authors are grateful.Sobrino-Gregorio, L.; Bataller Prats, R.; Soto Camino, J.; Escriche Roberto, MI. (2018). Monitoring honey adulteration with sugar syrups using an automatic pulse voltammetric electronic tongue. Food Control. 91:254-260. https://doi.org/10.1016/j.foodcont.2018.04.003S2542609

Detection of honey adulteration by conventional and real-time PCR

[EN] This work applies both conventional and real-time PCR DNA amplification techniques for detecting and quantifying rice molasses in honey. Different levels of adulteration were simulated (1, 2, 5, 10, 20, 50%) using commercial rice molasses. Among the different specific genes of rice tested by PCR, the PLD1 primer was the most effective. This allowed the visualization in agarose gel of this type of adulterant up to 5-20%. Moreover, by means of real-time PCR it was possible to distinguish the different levels of rice DNA, and therefore the percentage of adulteration (1-50%). A standard curve built with the DNA serial dilutions of rice genomic DNA concentrations showed that the quantification level was between 2-5%. These results offer compelling evidence that DNA techniques could be useful not only for the detection of adulterations of honey with rice molasses but also for the quantification of levels lower than those of conventional techniques.This study is part of part of the projects funded by the "Agencia Estatal de Investigacion" (AGL2016-77702-R) and by the "Generalitat Valenciana" (AICO/2015/104) of Spain, for which the authors are grateful.Sobrino-Gregorio, L.; Vilanova Navarro, S.; Prohens Tomás, J.; Escriche Roberto, MI. (2019). Detection of honey adulteration by conventional and real-time PCR. Food Control. 95:57-62. https://doi.org/10.1016/j.foodcont.2018.07.037S57629

Antioxidant characteristics of honey from Mozambique based on specific flavonoids and phenolic acid compounds

[EN] The most recent guidelines of IUPAC and AOAC recommend the analysis of specific compounds present in antioxidant fractions. For the first time, honey from different provinces of North (Nampula) and Central Mozambique (Sofala, Manica and Zambezia) was analysed considering specific flavonoids and phenolic acid profiles. Seven phenolic acids (chlorogenic, caffeic, ellagic, ferulic, gallic, p-coumaric and sinapic) and eight flavonoids (catechin, chrysin, kaempferol, luteolin, naringenin, pinocembrin, quercetin and rutin) were screened in the samples. Nampula honey had a higher content of most of these compounds and the total antioxidant activity (even reaching up to 40 mg TE/100 g) compared honey from the other provinces. Unlike in other African honeys, luteolin had the greatest impact in the flavonoid content (in some cases up to 72 mg/100 g), representing alone more than 50% of this family. Resulting from a discriminant analysis, specific flavonoids (pinocembrin, kaempferol, rutin and catechin) followed by the chlorogenic phenolic acid were the most important variables that distinguishes Nampula from the other provinces. This work underlines the importance of Mozambiquean honey as a source of natural antioxidants both of which concern the health benefits and its exploitation as a viable and sustainable income for the local population.The authors thank the Ministerio de Ciencia e Tecnologia Ensino Superior e Tecnico Profissional de Mocambique (Project: HEST "Ensino Superior, Ciencia e Tecnologia") and Universidade Rovuma, Nampula (Mozambique) for the grant awarded to Fernando Tanleque-Alberto.Tanleque-Alberto, F.; Juan-Borras, MDS.; Escriche Roberto, MI. (2020). Antioxidant characteristics of honey from Mozambique based on specific flavonoids and phenolic acid compounds. Journal of Food Composition and Analysis. 86:1-7. https://doi.org/10.1016/j.jfca.2019.103377178