Effect of different starter cultures on chemical and microbial parameters of buckwheat honey fermentation

Honey microbiota, methods for determining the microbiological composition and the antimicrobial effect of honey - A review

Honey is a natural product used since ancient times due to its taste, aroma, and therapeutic properties (antibacterial, antiviral, anti-inflammatory, and antioxidant activity). The purpose of this review is to present the species of microorganisms that can survive in honey and the effect they can have on bees and consumers. The techniques for identifying the microorganisms present in honey are also described in this study. Honey contains bacteria, yeasts, molds, and viruses, and some of them may present beneficial properties for humans. The antimicrobial effect of honey is due to its acidity and high viscosity, high sugar concentration, low water content, the presence of hydrogen peroxide and non-peroxidase components, particularly methylglyoxal (MGO), phenolic acids, flavonoids, proteins, peptides, and non-peroxidase glycopeptides. Honey has antibacterial action (it has effectiveness against bacteria, e.g. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter, etc.), antifungal (effectiveness against Candida spp., Aspergillus spp., Fusarium spp., Rhizopus spp., and Penicillium spp.), antiviral (effectiveness against SARS-CoV-2, Herpes simplex virus type 1, Influenza virus A and B, Varicella zoster virus), and antiparasitic action (effectiveness against Plasmodium berghei, Giardia and Trichomonas, Toxoplasma gondii) demonstrated by numerous studies that are comprised and discussed in this review.

The Emerging Pathogen Candida metapsilosis: Biological Aspects, Virulence Factors, Diagnosis, and Treatment

Fungal infections represent a constant and growing menace to public health. This concern is due to the emergence of new fungal species and the increase in antifungal drug resistance. Mycoses caused by Candida species are among the most common nosocomial infections and are associated with high mortality rates when the infection affects deep-seated organs. Candida metapsilosis is part of the Candida parapsilosis complex and has been described as part of the oral microbiota of healthy individuals. Within the complex, this species is considered the least virulent; however, the prevalence has been increasing in recent years, as well as an increment in the resistance to some antifungal drugs. One of the main concerns of candidiasis caused by this species is the wide range of clinical manifestations, ranging from tissue colonization to superficial infections, and in more severe cases it can spread, which makes diagnosis and treatment difficult. The study of virulence factors of this species is limited, however, proteomic comparisons between species indicate that virulence factors in this species could be similar to those already described for C. albicans. However, differences may exist, taking into account changes in the lifestyle of the species. Here, we provide a detailed review of the current literature about this organism, the caused disease, and some sharing aspects with other members of the complex, focusing on its biology, virulence factors, the host-fungus interaction, the identification, diagnosis, and treatment of infection.

Digestion dynamics of acetamiprid during royal jelly formation and exposure risk assessment to honeybee larva based on processing factor

Previous studies to the exposure effects of acetamiprid on honeybees were based on the analysis of bee pollen and honey sacs from field trials or of beebread and honey in the hive, which overestimate or underestimate the risk of exposure to pesticide residues. It was believed that the processing factor (PF) is an important variable to determine the final pesticide residue during royal jelly formation and the actual risk to honeybee larva. Hence, a QuEChERS method to determine acetamiprid contents in honeybee samples was established in this study. Then, the PFs for acetamiprid in beebread fermentation, honey brewing, and royal jelly formation were determined to be 0.85, 0.76, and 0.16, respectively. The PF for royal jelly formation was 0.04 when acetamiprid was detected in beebread alone, and it was 0.12 when acetamiprid was only detected in honey. Finally, the predicted exposure concentration of acetamiprid in royal jelly was calculated to be 2.05 µg/kg using the PF without significant difference with the 90th percentile value (3.64 µg/kg) in the actual sample. However, the value was 16.62 µg/kg without considering the PF. This study establishes a methodology for the correct evaluation of the risk to bee larva of acetamiprid residues in bee pollen and honey sac contents and the residual levels in royal jelly.

Polyphenolic and Chemical Profiles of Honey From the Tara Mountain in Serbia

This study presents a detailed characterization of 27 honey samples from the Tara Mountain region in Serbia using different comprehensive techniques and methods. The types of the honey samples were defined as monofloral (4 samples), honeydew (5 samples) and polyfloral (18 samples) honey based on determined polyphenol content, antioxidant activity, electrical conductivity and melissopalynological analyses. Physicochemical parameters such as pH (4.13–4.94), diastase activity (24.20–41.70 DN), acidity (14.60–29.70 meq/kg), content of 5-(hydroxymethyl)furfural (in range below 5, up to 16.90 mg/kg), sucrose (0.20–3.90 g/100 g), and moisture content (15.01–19.23%) confirmed the required quality of the honey samples. Sensory analysis revealed honey characteristics favorable to consumers. Analyses of 19 phenolic compounds using ultra-high-performance liquid chromatography with a diode-array detection and triple quadrupole mass spectrometry (UHPLC-DAD-MS/MS) revealed six phenolic acids and 13 other compounds from the group of flavonoids and their glycosides. In all the samples the highest content was determined for p-coumaric acid, followed by caffeic acid and pinocembrin. Besides total phenolic content and radical scavenging activity, antimicrobial activity was also examined. Most honey samples showed bactericidal activity against Staphylococcus aureus and bacteriostatic activity against Escherichia coli, while none of the honey samples inhibited the growth of Candida albicans. Chemometric analyses were applied for an in-depth study of the results to further evaluate the characteristics of the honey samples studied. Principal component analysis (PCA) was used for assessing the differences in physicochemical parameters, polyphenols content and antioxidant capacity between honey samples. The unrooted cluster tree was used to group the samples based on the melissopalynological analyses.

Analysis of honey bee exposure to multiple pesticide residues in the hive environment

Since the loss of honeybees in hives could have a greater impact on colony health than those of their foraging bees, it is imperative to know beehives' pesticide exposure via oral ingestion of contaminated in-hive matrices. Here, a 4-year monitoring survey of 64 pesticide residues in pollen, nectar and related beehive matrices (beebread and honey) from China's main honey producing areas was carried out using a modified version of the QuEChERS multi-residue method. The results showed that 93.6% of pollen, 81.5% of nectar, 96.6% of beebread, and 49.3% of honey containing at least one target pesticide were detected either at or above the method detection limits (MDLs), respectively, with up to 19 pesticides found per sample. Carbendazim was the most frequently detected pesticide (present in >85% of the samples), and pyrethroids were also abundant (median concentration = 134.3-279.0 μg/kg). The transfer of pesticides from the environment into the beehive was shown, but the pesticide transference ratio may be affected by complex factors. Although the overall risk to colony health from pesticides appears to be at an acceptable level, the hazard quotient/hazard index (HQ/HI) value revealed that pyrethroids were clearly the most influential contributor, accounting for up to 45% of HI. Collectively, these empirical findings provide further insights into the extent of contamination caused by agricultural pesticide use on honeybee colonies.

Genome and Pangenome Analysis of Lactobacillus hilgardii FLUB-A New Strain Isolated from Mead

The production of mead holds great value for the Polish liquor industry, which is why the bacterium that spoils mead has become an object of concern and scientific interest. This article describes, for the first time, Lactobacillus hilgardii FLUB newly isolated from mead, as a mead spoilage bacteria. Whole genome sequencing of L. hilgardii FLUB revealed a 3 Mbp chromosome and five plasmids, which is the largest reported genome of this species. An extensive phylogenetic analysis and digital DNA-DNA hybridization confirmed the membership of the strain in the L. hilgardii species. The genome of L. hilgardii FLUB encodes 3043 genes, 2871 of which are protein coding sequences, 79 code for RNA, and 93 are pseudogenes. L. hilgardii FLUB possesses three clustered regularly interspaced short palindromic repeats (CRISPR), eight genomic islands (44,155 bp to 6345 bp), and three (two intact and one incomplete) prophage regions. For the first time, the characteristics of the genome of this species were described and a pangenomic analysis was performed. The concept of the pangenome was used not only to establish the genetic repertoire of this species, but primarily to highlight the unique characteristics of L. hilgardii FLUB. The core of the genome of L. hilgardii is centered around genes related to the storage and processing of genetic information, as well as to carbohydrate and amino acid metabolism. Strains with such a genetic constitution can effectively adapt to environmental changes. L. hilgardii FLUB is distinguished by an extensive cluster of metabolic genes, arsenic detoxification genes, and unique surface layer proteins. Variants of MRS broth with ethanol (10-20%), glucose (2-25%), and fructose (2-24%) were prepared to test the strain's growth preferences using Bioscreen C and the PYTHON script. L. hilgardii FLUB was found to be more resistant than a reference strain to high concentrations of alcohol (18%) and sugars (25%). It exhibited greater preference for fructose than glucose, which suggests it has a fructophilic nature. Comparative genomic analysis supported by experimental research imitating the conditions of alcoholic beverages confirmed the niche specialization of L. hilgardii FLUB to the mead environment.

Can pseudocereals modulate microbiota by functioning as probiotics or prebiotics?

Amaranth, quinoa, and buckwheat, known as pseudocereals, have been consumed since ancient times and are considered sacred in most cultures. Their grains can be used as cereals for breakfast or mixed with other grains in meals and their health-enhancing effects have been investigated more in recent years. They have an antioxidant effect and their nutrient profiles are enriched with processing techniques such as sprouting and fermentation. Their suitability to different processing techniques and the rapid increase in microbiota researches highlighted the probiotic/prebiotic effects of pseudocereals. Using cultures or naturally fermented amaranth, quinoa and buckwheat exhibited good substrate properties for probiotic bacteria, especially for Lactobacillus strains. Studies have found that they reduce the number of pathogen microorganisms, increase the synthesis of short-chain fatty acids due to their prebiotic effects. Also the number of bacterial colonies do not change during the storage period and their organoleptic properties are revealed. It has been determined that pseudocereals decrease Ruminococcacea, Lachnospiraceae, Helicobacteracea, Clostridium, Escherichia and increase Peptoclostridium, Prevotellaceae, Lactobacillus, Bifidobacterium, Enterococcus, and Eubacteriaceae. Due to these effects, they are considered as good sources for synbiotic formulations to be developed for the treatment of dysbiosis, obesity, Celiac Disease, lactose intolerance, inflammatory bowel diseases and inflammation-mediated chronic disorders.

Flavor Formation in Chinese Rice Wine (Huangjiu): Impacts of the Flavor-Active Microorganisms, Raw Materials, and Fermentation Technology

Huangjiu (Chinese rice wine) has been consumed for centuries in Asian countries and is known for its unique flavor and subtle taste. The flavor compounds of Huangjiu are derived from a wide range of sources, such as raw materials, microbial metabolic activities during fermentation, and chemical reactions that occur during aging. Of these sources, microorganisms have the greatest effect on the flavor quality of Huangjiu. To enrich the microbial diversity, Huangjiu is generally fermented under an open environment, as this increases the complexity of its microbial community and flavor compounds. Thus, understanding the formation of flavor compounds in Huangjiu will be beneficial for producing a superior flavored product. In this paper, a critical review of aspects that may affect the formation of Huangjiu flavor compounds is presented. The selection of appropriate raw materials and the improvement of fermentation technologies to promote the flavor quality of Huangjiu are discussed. In addition, the effects of microbial community composition, metabolic function of predominant microorganisms, and dynamics of microbial community on the flavor quality of Huangjiu are examined. This review thus provides a theoretical basis for manipulating the fermentation process by using selected microorganisms to improve the overall flavor quality of Huangjiu.

Impact of Fermentation Processes on the Bioactive Profile and Health-Promoting Properties of Bee Bread, Mead and Honey Vinegar

Recently, an increasing interest is paid to bee products obtained as a result of the fermentation process. Some of them can be consumed directly (bee-collected pollen, honey, bee bread etc.), while others are the result of lactic and/or acid fermentation (honey vinegar and honey wine). Bee bread is the result of pollens’ lactic fermentation, whereas mead is obtained by honeys’ lactic fermentation. Moreover, as a result of honey acetic acid fermentation, honey vinegar is obtained. Sensory characteristics and aroma composition have been scarcely studied, which may depend on the starter culture and fermentation process. Along with the medicinal properties they are a vital resource for future researches as they are of particular importance in the food market. In this review, we discuss the aroma-active compounds, taste, and sensorial characteristics of fermented bee products along with the approaches that can be developed for the flavor improvement based on existing technologies. Furthermore, the beneficial effects on human health are also described, with special attention that should be attributed to finding the use of probiotics in these fermented products as health-promoting effects.