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

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

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

Implementation and effectiveness of the HACCP and pre-requisites in food establishments

[EN] The aim of this paper was to identify the most important weaknesses in the implementation and effectiveness of the pre-requisites and HACCP found in food establishments. To cover these objectives, official control audits of the manuals and their implementation in 1350 small and 66 medium size organizations: restaurants, hotels and cafeterias in one area of the Valencian region (Spain) were carried out from 2007 to 2010. The microbiological quality of 1054 ready-to-consume dishes was also evaluated as an indicator of the effectiveness of the control at Critical Control Points. The results showed that the main deficiencies in the implementation of the pre-requisites and HACCP were found in conditions and structural design followed by hygiene & cleaning. Moreover, the analysis of Listeria monocytogenes in dishes at the time of consumption shows that 99.6% were of good microbiological quality. This indicates that in relation to this hazard, the implementation of safety management systems in the majority of the food establishments was effective. These results demonstrate the crucial role played by official control to ensure the welfare of consumers and how it facilitates continuous improvement in the safety management of these businesses. © 2011 Elsevier Ltd.Doménech Antich, EM.; Amorós, J.; Pérez Gonzalvo, M.; Escriche Roberto, MI. (2011). Implementation and effectiveness of the HACCP and pre-requisites in food establishments. Food Control. 22(8):1419-1423. doi:10.1016/j.foodcont.2011.03.001S1419142322