Characterization and Differentiation of Greek Commercial Thyme Honeys According to Geographical Origin Based on Quality and Some Bioactivity Parameters Using Chemometrics

Analytical insights for ensuring authenticity of Greek agriculture products: Unveiling chemical marker applications

Food authentication, including the differentiation of geographical or botanical origin, the method of production i.e. organic vs. conventional farming as well as the detection of food fraud/adulteration, has been a rapidly growing field over the past two decades due to increasing public awareness regarding food quality and safety, nutrition, and health. Concerned parties include consumers, producers, and legislators. Thus, the development of rapid, accurate, sensitive, and reproducible analytical methods to guarantee the authenticity of foods is of primary interest to scientists and technologists. The aim of the present article is to summarize research work carried out on the authentication of Greek agricultural products using spectroscopic (NIR, FTIR, UV-Vis, Raman and fluorescence spectroscopy, NMR, IRMS, ICP-OES, ICP-MS) and chromatographic (GC, GC/MS, HPLC, HPLC/MS, etc.) methods of analysis in combination with chemometrics highlighting the chemical markers that enable product authentication. The review identified a large number of chemical markers including volatiles, phenolic substances, natural pigments, elements, isotopes, etc. which can be used for (i) the differentiation of botanical/geographical origin; conventional from organic farming; production procedure and vintage year, etc. and (ii) detection of adulteration of high quality plant and animal origin foods with lower value substitutes. Finally, the constant development of reliable analytical techniques in combination with law enforcement authorities will ensure authentic foods in terms of quality and safety for consumers.

Use of polyphenolic fingerprints established by comprehensive two-dimensional liquid chromatography for the classification of honeys according to their floral origin

In this work, the polyphenolic composition of honeys from three different floral origins (chestnut, heather, and thyme), coming from different geographical areas of Spain was investigated. First, samples were characterized in terms of total phenolic content (TPC) and antioxidant capacity, which was established by three different assays. The results revealed that the studied honeys presented similar TPCs and antioxidant capacities, with a wide variability within each floral origin. Next, a comprehensive two-dimensional liquid chromatography method was developed for the first time to establish polyphenol fingerprints of the three types of honeys, after optimizing the separation in terms of column combination and mobile phase gradient programs. After that, the detected common peaks were used for the construction of a linear discriminant analysis (LDA) model able to discriminate honeys according to their floral origin. The LDA model obtained was adequate for the classification of the floral origin of the honeys based on polyphenolic fingerprint data.

Physicochemical quality indicators of honey: An evaluation in a Ukrainian socioecological gradient

Physical and chemical quality indicators of 65 polyfloral honey samples from three administrative districts of Chernivtsi region in South Western Ukraine were studied. The chosen administrative districts were Putyla (representing the ‘Traditional villages’ stratum), Storozhynets (the ‘Intermediate’ stratum) and Khotyn (the ‘Intensive agriculture’ stratum), which reflect a steep gradient of social and ecological conditions such as land cover and land use, level of economic development, culture and demography. The quality of honey was determined in accordance with the requirements of the Ukrainian national standard and the EU Directive relating to honey (or Codex Alimentarius Honey Standard) by using the following indicators: reducing sugars and moisture content, diastase activity, free acidity, pH, electrical conductivity, hydroxymethylfurfural (HMF) and proline content. The profile of carbohydrates was analyzed, in particular glucose, fructose, sucrose, maltose, trehalose, melezitose, raffinose. The ratio of fructose to glucose (F/G) was determined. All tested samples complied with the international standards for the mass fraction of reducing sugars, diastase activity and hydroxymethylfurfural content. For physical and chemical parameters, the studied honey samples were of high quality. The content of the reducing sugars in the honey samples varied within the range of 66.0–97.6%. The fructose content ranged from 342 to 549 mg/g, and the glucose content variation ranged within 283–517 mg/g. The average fructose/glucose ratio was 1.2 for honey samples from the three studied districts. Besides fructose and glucose, some oligosaccharides, such as maltose, trehalose and melezitose, were found in the examined honey. Melezitose was detected in the honey samples from ‘Traditional village’ (21 samples) and ‘Intermediate’ (5 samples) districts. The total variability of HMF content in the studied 65 honey samples from apiaries in the three districts of Chernivtsi region ranged from 0.19 to 30.8 mg/kg. The minimum moisture content was found to be 16.2% (in the ‘Traditional village’ and ‘Intermediate’ strata), and 22.2% was the maximum (in the ‘Intermediate’ stratum). Our studies have shown that free acidity of the samples varied within the range 13.5 to 58.0 meq/kg. Proline content variability for the three studied geographical areas ranged from 82.3 to 1201.2 mg/kg. The studied samples of honey had a low pH level (~ 3.7), high content of proline (~ 513 mg/kg) and reducing sugars (~ 80%), which indicates its nutritional value and naturalness. Deviations from the honey standards in moisture content, acidity and electrical conductivity was revealed in 8% to 10% of all samples.

Bioactive compounds in Apis mellifera monofloral honeys

Honey is a natural product with a sweet flavor. Honey is made by the honeybee (Apis mellifera L.) from the nectar of flowers or other plant secretions that are collected near the hive. These products are mixed with bee saliva and stored. Several studies have demonstrated that honey exhibits antioxidant, antimicrobial, nematicidal, antifungal, anticancer, and anti-inflammatory activities. These properties are influenced by the plants from which the secretions are harvested, from the naturally occurring compounds present in the nectar. Studies of the properties and applications of honey have distinguished honey from other natural products due to the presence of certain compounds and due its bioactive properties. The focus of this review is to discuss the identified and isolated compounds from monofloral honey produced by A. mellifera, with specific emphasis on antioxidant and antimicrobial properties of honey and its therapeutic health benefits.