Proteome comparison for discrimination between honeydew and floral honeys from botanical species Mimosa scabrella Bentham by principal component analysis

SDS-PAGE Protein and HPTLC Polyphenols Profiling as a Promising Tool for Authentication of Goldenrod Honey

The aim of the study was to use protein and polyphenolic profiles as fingerprints of goldenrod honey and to apply them for verification of the labeled variety. The markers for 10 honey samples were correlated with the standard physicochemical parameters and biological activity measured in vitro as antioxidant, antifungal and antibacterial activities. Honey proteins were examined regarding soluble protein, diastase and SDS-PAGE protein profile. The polyphenolic profile was obtained with the use of the HPTLC and the antioxidant activity was detected with standard colorimetric methods. The antimicrobial effect of representative honey samples of different chemical profiles was verified against E. coli and budding yeast. It was found that the SDS-PAGE technique allows for creating the protein fingerprint of the goldenrod honey variety which was consistent for 70% of tested samples. At the same time, the similarity of their polyphenolic profile was observed. Moreover, specific chemical composition resulted in higher bioactivity of honey against tested bacteria and yeast. The study confirmed the usefulness of both SDS-PAGE and HPTLC techniques in honey authentication, as an initial step for selection of samples which required pollen analysis.

The Use of HPTLC and SDS-PAGE Methods for Coniferous Honeydew Honey Fingerprinting Compiled with Mineral Content and Antioxidant Activity

Fir honeydew honey is a uniquely beneficial product which is often subjected to adulteration; however, pollen analysis is not useful to verify this honey type. Fourteen samples of EU protected designation of origin fir honeydew honey gathered directly from apiaries were studied. Standards of legal requirements and additional parameters, i.e., specific optical rotation, mineral content, and antioxidant activity, were tested. Five nectar honeys of different varieties were used as a comparative material. HPTLC and SDS-PAGE methods were used to fingerprint the honey types. All honeys tested fulfilled the quality requirements in terms of water content, pH, total acidity, conductivity, HMF, and diastase number. They were defined as dark amber on the Pfund scale and exhibited positive specific rotation (+2.5 to 25). Honeydew honey surpassed the tested nectar honeys in terms of mineral content and antioxidant activity as well as total polyphenolic content, except for buckwheat honey. The sugar and polyphenolic profile obtained by HPTLC allowed to distinguish honeydew from nectar honeys. The same was achieved by SDS-PAGE protein profiling. Both techniques seem to be cheap and quick tools for precisely distinguishing honeydew honey.

The Comparison of Physicochemical Parameters, Antioxidant Activity and Proteins for the Raw Local Polish Honeys and Imported Honey Blends

Many imported honeys distributed on the Polish market compete with local products mainly by lower price, which can correspond to lower quality and widespread adulteration. The aim of the study was to compare honey samples (11 imported honey blends and 5 local honeys) based on their antioxidant activity (measured by DPPH, FRAP, and total phenolic content), protein profile obtained by native PAGE, soluble protein content, diastase, and acid phosphatase activities identified by zymography. These indicators were correlated with standard quality parameters (water, HMF, pH, free acidity, and electrical conductivity). It was found that raw local Polish honeys show higher antioxidant and enzymatic activity, as well as being more abundant in soluble protein. With the use of principal component analysis (PCA) and stepwise linear discriminant analysis (LDA) protein content and diastase number were found to be significant (p < 0.05) among all tested parameters to differentiate imported honey from raw local honeys.

A single honey proteome dataset for identifying adulteration by foreign amylases and mining various protein markers natural to honey

Honey adulteration is a common practice that deceives consumers and devalues the unique curative and food properties of honey. For marketing, each honey must satisfy an internationally valid Codex standard. One of the quality parameters is diastase/amylase activity, which, if lowered, may be compensated for by the addition of foreign amylases. However, the estimation of enzyme activity does not enable identification of artificially added amylases. 45 honey samples were analyzed using label-free nanoLC-MS/MS proteomics. Four honeys were found to contain the foreign amylases from Aspergillus niger, Bacillus amyloliquefaciens and/or Bacillus licheniformis. This result was confirmed via proof of specificity at multiple levels. Furthermore, we identified a series of plant-related protein groups. Despite plant-related proteins constituting a significant portion of honey proteins, they were minor components compared to the major honey bee-derived proteins. Bioinformatic analysis also provided evidence for aphid and catalase proteins in honey, but the limited specificity of the MS/MS identified peptides must be considered. Overall, we demonstrate a proteomics approach employing LC-MS/MS that is useful for proving adulteration and assessing honey quality. As an resource useful for reference, we provide curated sequence databases. In addition, we provide many markers that are naturally found in honey for future studies. SIGNIFICANCE: Honey is unique natural product used since ancient times as a food and natural medicine. Humans strive to understand honey components because they can characterize different types of honey and be used for authentication and origin assessment. One of the important honey components are proteins. The proteins present in honey can naturally occur in honey, but some of them can be used to mask deficiencies in some honey quality properties. Diastases/amylases are such proteins, and their activity, a measure of honey freshness, can decrease in time or due to processing. To our knowledge, we for the first time specifically identify foreign amylases in honey. However, this study provided new information on other non-honey bee proteins in honey. Thus, this study is also of importance due to its identification of plant and aphid proteins and catalase-related proteins. This study provides a clue explaining the controversial presence of catalase in honey, since catalases can be identified and their origin determined via proteomics.

The Unique Protein Composition of Honey Revealed by Comprehensive Proteomic Analysis: Allergens, Venom-like Proteins, Antibacterial Properties, Royal Jelly Proteins, Serine Proteases, and Their Inhibitors

Honey is a unique natural product produced by European honeybees. Due to its high economic value, honey is considered to be well characterized chemically, and it is often discovered to be an adulterated commodity. However, this study shows that our knowledge of honey protein composition, which is of high medical and pharmaceutical importance, is incomplete. In this in-depth proteomic study of 13 honeys, we identified a number of proteins that are important for an understanding of honey properties and merit additional pharmaceutical research. Our major result is an expanded understanding of the proteins underlying honey's antimicrobial properties, such as hymenoptaecin and defensin-1, glucose dehydrogenase isoforms, venom allergens and other venom-like proteins, serine proteases and serine protease inhibitors, and a series of royal jelly proteins. In addition, we performed quantitative comparisons of all of the proteins previously known or newly identified. The honey proteins, determined using label-free nLC-MS/MS in which the same protein quantity was analyzed in one series, were found in relatively similar proportions, although eucalyptus honey differed most widely from the remaining honeys. Overall, the proteome analysis indicated that honeybees supply proteins to honey in a relatively stable ratio within each proteome, but total protein quantity can differ by approximately an order of magnitude in different honeys.

Antibacterial Activity of Different Blossom Honeys: New Findings

Antibacterial activity is the most investigated biological property of honey. The goal of this study was to evaluate the antibacterial activity of 57 Slovak blossom honeys against Staphylococcus aureus and Pseudomonas aeruginosa and investigate the role of several bioactive substances in antibacterial action of honeys. Inhibitory and bactericidal activities of honeys were studied to determine the minimum inhibitory and bactericidal concentrations. The contents of glucose oxidase (GOX) enzyme, hydrogen peroxide (H2O2), and total polyphenols (TP) were determined in honeys. We found that honey samples showed different antibacterial efficacy against the tested bacteria as follows: wildflower honeys > acacia honeys > rapeseed honeys. Overall antibacterial activity of the honeys was statistically-significantly correlated with the contents of H2O2 and TP in honeys. A strong correlation was found between the H2O2 and TP content. On the other hand, no correlation was found between the content of GOX and level of H2O2. Antibacterial activity of 12 selected honeys was markedly reduced by treatment with catalase, but it remained relatively stable after inactivation of GOX with proteinase-K digestion. Obtained results suggest that the antibacterial activity of blossom honeys is mainly mediated by H2O2 levels present in honeys which are affected mainly by polyphenolic substances and not directly by GOX content.

An overview of physicochemical characteristics and health-promoting properties of honeydew honey

Honeydew honey has differentiated chemical and physicochemical characteristics besides potential functional properties such as antimicrobial, anti-inflammatory and antioxidant. In this sense, the interest and consumption of this honey as a functional product by the food industry and consumers have increased. Honeydew honeys usually present dark color, a lower content of monosaccharides and higher values of pH, acidity, electric conductivity, proteins, minerals, phenolic compounds, and oligosaccharides compared to blossom honeys, which contribute to its outstanding biological activities. Consequently, contaminations and adulterations of this honey can occur and compromise the quality, safety and authenticity of honeydew honey. Thus, detailed knowledge of the composition and properties of honeydew honeys is of great importance, especially considering that honeydew honeys are still few studied and therefore underestimated. Therefore, in this review, the physicochemical characteristics, chemical and bioactive composition, functional and health-promoting properties of honeydew honey as well as contamination, adulteration and authenticity of this honey are summarized.

Physicochemical characteristics of bracatinga honeydew honey and blossom honey produced in the state of Santa Catarina: An approach to honey differentiation

Due to the increasing demand and interest of the consumers of bracatinga honeydew honey, it becomes important to know its characteristics in order to guarantee the quality of this dark honey. It is also necessary to investigate possible parameters that easily determine their differentiation from other honeys, thus guaranteeing their authenticity. Therefore, in the present study, the physicochemical characteristics and the reducing/scavenging proprieties of 16 bracatinga (Mimosa scabrella Bentham) honeydew honey samples and 25 blossom honey (different botanical origin) samples from Santa Catarina, Brazil, were investigated. Bracatinga honeydew honeys were defined by its high free acidity, electrical conductivity and reducing/scavenging capacity, and low glucose content.Still, these specific parameters allowed the differentiation between bracatinga honeydew honeys and blossom honeys, from the of principal component analysis, contributing to the differentiation of these honeys.