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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, invertase, total carotenoid, total phenolics of raw honeys and TEAC, as well as regarding total flavonoids determined in neutral medium and o-diphenols of honeys' methanolic extracts. Principal components analysis showed a good separation between Algerian and imported samples, only one multifloral Algerian honey being misclassified. Our research showed that a legal frame for Algerian honeys is of utmost importance. Spurge-labeled honeys were grouped, showing interesting common features that should be taken into account in a future regulation, in which a protected designation of origin for spurge honeys could be considered. [ABSTRACT FROM AUTHOR]

In this study, several antioxidant-related parameters were researched on 56 Spanish honeys, setting up and optimising some assays. Melissopalynology and colour (L*, a*, b*) were determined. Solid-phase extraction (SPE) was used to obtain honeys' phenolic extracts. Total phenolics, total flavonoids and trolox equivalent antioxidant capacity (TEAC) were determined in both honeys and extracts. It was verified that total flavonoids determination in neutral media must be carried out on extracts instead of on honeys, because of sugars' interferences; likewise, extracts' colours must be corrected in this assay. The endpoint for honeys' trolox equivalent antioxidant capacity (TEAC) was researched. Significant linear relationships were found between TEAC values of honeys and honeys' phenolic extracts, as well as between the results of TEAC measured at different times. Therefore, it would be possible to reliably calculate TEAC at 60 min (endpoint), measuring the absorbance at 6 min, thus saving analysis time and reducing costs. [ABSTRACT FROM AUTHOR]

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 superoxide anion radical. Working with solutions of 10 mg/mL propolis, hyaluronidase inhibitory activity ranged between 0% and 68.20%, being correlated to ferulic acid content. ACE inhibitory effect determined by HPLC was higher than 78%, being correlated with catechin and p-coumaric acid. Therefore, propolis could be useful for food, pharmaceutical, and cosmetic companies, also helping to reduce risk factors for diseases related to oxidative damage, inflammatory processes, and hypertension. This research also highlights the necessity for harmonized analysis methods and the expression of results for propolis. [ABSTRACT FROM AUTHOR]

• Sensors (film-shaped polymers) change their colour in presence of phenols. • The sensory materials are polymers with chemically anchored sensory motifs. • Sensors allow onepod determination of total phenolic content & antioxidant activity. • Proof of concept: 8 honeys were measured with the proposed sensors and a smartphone. 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. [ABSTRACT FROM AUTHOR]