Straightforward purification method for the determination of the activity of glucose oxidase and catalase in honey by extracting polyphenols with a film-shaped polymer.

Glucose oxidase (GOX) and catalase (CAT) regulate the amount of H2O2 in honey, by generating or consuming it, so they are related to the antibacterial and antioxidant activity of honey. However, their activities are hardly analysed, since the process requires a previous dialysis that is non-selective, very time-consuming (>24 h), eco-unfriendly (>6L of buffer) and expensive. This research shows the design and performance of a material that selectively removes the actual interferents. The film-shaped-polymer is immersed for 90́ within a honey solution (12.5 mL of buffer), where it interacts exclusively with 1,2-dihydroxybenzenes, which we proved to be the real interferents (the material contains motifs derived from phenylboronic acid to interact with 1,2-diols). Polymeric chains favour condensation to occur exclusively with 1,2-dihydroxybenzenes, excluding monosaccharides. The interferents' removal using our designed polymer is selective, low cost (1.42€ per test), rapid and eco-friendly (saves 6L of buffer and 20.5 h of experimental workout per sample).

A simple one-pot determination of both total phenolic content and antioxidant activity of honey by polymer chemosensors.

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.

Presencia de ácido láctico y otros compuestos semivolátiles en mieles de meliponini / Presence of lactic acid and other semivolatil compound in meliponini honeys

Durante el estudio de compuestos semivolátiles, se encontró ácido láctico en mieles producidas por cuatro especies de abejas sin aguijón. Además, se identificaron otros compuestos: ácido 2-etil-2-hidroxi-propanoico en mieles de Melipona favosa, 5-(hidroximetil)-2-furancarboxaldehído y a-(fenilmetil)-benceno etanol, en mieles de Scaptotrigona mexicana, 2-butanol, eneicosano y heptacosano en mieles deTrigona carbonaria.

During the study of semivolatile compounds, lactic acid was found in the honey produced by four species of stingless bees. Moreover, other compounds were identified: 2-ethylhydroxy- propanoic acid in Melipona favosa honeys, 5-(hydroxymethyl)-2-furancarboxaldehyde and a-phenylmethyl benzene ethanol in Scaptotrigona mexicana honey, 2-butanol, heneicosane and heptacosane in Trigona carbonaria honey.