Characterisation of brewpub beer carbohydrates using high performance anion exchange chromatography coupled with pulsed amperometric detection

Ion Chromatography and Related Techniques in Carbohydrate Analysis: A Review

Ion chromatography and related techniques have been the most popular separation methods used in the determination of organic and inorganic anions and cations, predominantly in water and wastewater samples. Making progress in their development and introducing new stationary phases, methods of detection and preparation of samples for analyses have given rise to the broadening of their analytical range. Nowadays, they are also used for substances that are not ionic by nature but can convert to such forms under certain conditions. These encompass, among others, carbohydrates, whose role and significance in humans' lives and environment is invaluable. Their presence in the air is mostly due to the industrial burning of biomass for energy production purposes. In addition, the content of sugars in plants, fruits and vegetables, constituting the base of human diets, affects our health condition. Given that, there is not only a need for their determination by means of routine methods but also for searching for novel analytical solutions. Based on literature data from the past decade, this paper presents the possibilities and examples of applications regarding ion chromatography and related techniques for the determination of carbohydrates in environmental samples, biomass and plants constituting food or raw materials for food production. Attention has been paid to the virtues and limitations of the discussed separation methods in this respect. Moreover, perspectives on their development have been defined.

Bioactive polysaccharides and oligosaccharides from garlic (Allium sativum L.): Production, physicochemical and biological properties, and structure-function relationships

Garlic is a common food, and many of its biological functions are attributed to its components including functional carbohydrates. Garlic polysaccharides and oligosaccharides as main components are understudied but have future value due to the growing demand for bioactive polysaccharides/oligosaccharides from natural sources. Garlic polysaccharides have molecular weights of 1 × 10³ to 2 × 10⁶  Da, containing small amounts of pectins and fructooligosaccharides and large amounts of inulin-type fructans ((2→1)-linked β-d-Fruf backbones alone or with attached (2→6)-linked β-d-Fruf branched chains). This article provides a detailed review of research progress and identifies knowledge gaps in extraction, production, composition, molecular characteristics, structural features, physicochemical properties, bioactivities, and structure-function relationships of garlic polysaccharides/oligosaccharides. Whether the extraction processes, synthesis approaches, and modification methods established for other non-garlic polysaccharides are also effective for garlic polysaccharides/oligosaccharides (to preserve their desired molecular structures and bioactivities) requires verification. The metabolic processes of ingested garlic polysaccharides/oligosaccharides (as food ingredients/dietary supplements), their modes of action in healthy humans or populations with chronic conditions, and molecular/chain organization-bioactivity relationships remain unclear. Future research directions related to garlic polysaccharides/oligosaccharides are discussed.

Determination of Saccharides in Honey Using Supercritical Fluid Chromatography Coupled with Single Quadrupole Mass Spectrometry

Saccharides are one of the most important biomoleculars in the world, which are responsible for various roles in living organisms. In this work, a combined use of mass spectrometry (MS) together with supercritical fluid chromatography (SFC) was applied for the separation of eight saccharides. A satisfactory separation was achieved within 15 min on a Unitary Diol column using 10 mM ammonium acetate in methanol as mobile phase additive at a temperature of 60°C. Compared to liquid chromatography-MS (LC-MS), the SFC-MS presented faster running time and better selectivity. The SFC-MS was validated and applied to the analysis of three saccharides (fructose, glucose and sucrose) present in different honey samples. The limits of detection (LODs) and limits of quantification (LOQs) of SFC-MS method for fructose, glucose and sucrose were 5.2, 4.5, 7.4 μg/mL and 17.2, 14.9, 24.1 μg/mL, respectively. The relative standard deviations for intrabatch and interbatch precision were <2.5% and the recoveries ranged from 97.6% to 103.1% for three concentration levels. The values of LODs and LOQs using SFC-MS method were lower (1.5-2.4-fold) than using LC-MS method. The results demonstrated the potential of SFC-MS for fast and sensitive determination of saccharides in honey.

Recent advances in the knowledge of wine oligosaccharides

Oligosaccharides are carbohydrates with a low polymerization degree containing between three and fifteen monosaccharide residues covalently linked through glycosidic bonds. Oligosaccharides are related to plant defense responses and possess beneficial attributes for human health. Research has focused in wine oligosaccharides only in the last decade. In this paper, a summary of these works is provided. They include: (i) wine oligosaccharides origins, (ii) techniques for isolating oligosaccharide fraction and determining their content, composition and structure, (iii) their dependence on the grape origin and cultivar and winemaking process, and (iv) the connection between oligosaccharides and wine sensorial attributes. Further research is required regarding the impact of agricultural aspects and winemaking techniques on wine oligosaccharides. The knowledge concerning their influence on sensorial and physicochemical properties of wines and on human health should also be improved. The implementation of laboratory methods will provide better understanding of these compounds and their performance within wine's matrix.

Profiling of carbohydrates in commercial beers and their influence on beer quality

BACKGROUND

The carbohydrates in beer play an important role as they are essential for fermentation. Any change in their composition may influence the sensory characteristics of the beer and so their determination is of great interest. This study compares the carbohydrates in three types of commercial beer - barley malt beer, wheat beer, and barley malt beer with adjuncts - and examines their influence on beer quality, which is important for selecting raw ingredients and production conditions, and for quality control.

RESULTS

Among the oligosaccharides in three types of beer, raffinose was the most, followed by maltotetraose, maltotriose and maltose. Monosaccharides were only present in small amounts. Dextrin, oligosaccharides with 2-6 polymerization degree and non-starch polysaccharides (NSP) make up 15.90-34.83%, 17.59-38.63%, and 2.33-7.47% of the total carbohydrates in beer, respectively. The dextrin content and NSP content were significantly (P < 0.05) different in wheat beer and barley malt beer, and their content was significantly (P < 0.01) correlated with the content of extracts in beer. Non-starch polysaccharide, dextrin, trisaccharide, and tetrasaccharide content significantly (P < 0.05) correlated with beer viscosity. These beer samples could be categorized clearly into three groups by principal component analysis.

CONCLUSION

The oligosaccharides in beer reflect yeast utilization, depending on the type of beer. Dextrin, oligosaccharides with 2-4 polymerization, and NSP, were major carbohydrates in beer. Their composition and concentration influenced its characteristics and quality, and played an important role in the discrimination of different beer types. © 2020 Society of Chemical Industry.

A review of the analytical methods used for beer ingredient and finished product analysis and quality control

Beer is an incredibly complex beverage containing more than 3000 different compounds, including carbohydrates, proteins, ions, microbes, organic acids, and polyphenols, among others. Beer becomes even more complex during storage, for over time it may undergo chemical changes that negatively affect the flavor, aroma, and appearance. Thus, it can be expected that maintaining the quality of beer throughout its lifetime is a difficult task. Since it is such a popular drink throughout the world, being familiar with proper analytical techniques for beer evaluation is useful for researchers and brewers. These techniques include, but are not limited to, gas chromatography, liquid chromatography, matrix assisted laser desorption/ionization, capillary electrophoresis, mass spectrometry, ultraviolet-visible spectroscopy, and flame ionization detection. This review aims to summarize the various ingredients and components of beer, discuss how they affect the finished product, and present some of the analytical methods used for quality control and understanding the formation of chemicals in beer during the brewing process.

Chemical characterization of PM2.5 collected from a rural coastal island of the Bay of Bengal (Bhola, Bangladesh)

This work focuses on the chemical characterization of fine aerosol particles (PM_2.5) collected from a rural remote island of the Bay of Bengal (Bhola, Bangladesh) from April to August, 2013. PM_2.5 particle-loaded filters were analyzed for organic carbon (OC), elemental carbon (EC), water-soluble ions, and selected saccharides (levoglucosan, mannosan, galactosan, arabitol, and mannitol). The average PM_2.5 mass was 15.0 ± 6.9 μg m^-3. Organic carbon and elemental carbon comprised roughly half of the analyzed components. Organic carbon was the predominant contributor to total carbon (TC) and accounting for about 28% of PM_2.5 mass. Secondary organic carbon (SOC) was inferred to be ~ 26% of OC. The sum of ions comprised ~ 27% of PM_2.5 mass. The contribution of sea salt aerosol was smaller than expected for a sea-near site (17%), and very high chloride depletion was observed (78%). NssSO₄^2- was a dominant ionic component with an average concentration of 2.0 μg m^-3 followed by Na⁺, NH₄⁺, and nssCa²⁺. The average concentration of arabitol and mannitol was 0.11 and 0.14 μg m^-3, respectively, while levoglucosan and its stereoisomers (mannosan and galactosan) were bellow detection limit. NH₄⁺/SO₄^2- equivalent ratio was 0.30 ± 0.13 indicating that secondary inorganic aerosol is not the main source of SO₄^2-. Enrichment factor (EF) analysis showed that SO₄^2- and NO₃^- were enriched in atmospheric particles compared to sea aerosol and soil indicating their anthropogenic origin. Higher OC/EC ratio (3.70 ± 0.88) was a good indicator of the secondary organic compounds formation. Other ratios (OC/EC, K⁺/EC, nssSO₄^2-/EC) and correlation analysis suggested mixed sources for carbonaceous components. Arabitol and mannitol both showed strong correlation with EC having R ² value 0.89 and 0.95, respectively. Air mass trajectories analysis showed that concentrations of soil and anthropogenic species were lower for air masses originating from the sea (May-August) and were higher when air came from land (April).

Glucose sensing on graphite screen-printed electrode modified by sparking of copper nickel alloys

Electric spark discharge was employed as a green, fast and extremely facile method to modify disposable graphite screen-printed electrodes (SPEs) with copper, nickel and mixed copper/nickel nanoparticles (NPs) in order to be used as nonenzymatic glucose sensors. Direct SPEs-to-metal (copper, nickel or copper/nickel alloys with 25/75, 50/50 and 75/25wt% compositions) sparking at 1.2kV was conducted in the absence of any solutions under ambient conditions. Morphological characterization of the sparked surfaces was performed by scanning electron microscopy, while the chemical composition of the sparked NPs was evaluated with energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The performance of the various sparked SPEs towards the electro oxidation of glucose in alkaline media and the critical role of hydroxyl ions were evaluated with cyclic voltammetry and kinetic studies. Results indicated a mixed charge transfer- and hyroxyl ion transport-limited process. Best performing sensors fabricated by Cu/Ni 50/50wt% alloy showed linear response over the concentration range 2-400μM glucose and they were successfully applied to the amperometric determination of glucose in blood. The detection limit (S/N 3) and the relative standard deviation of the method were 0.6µM and <6% (n=5, 2µM glucose), respectively. Newly devised sparked Cu/Ni graphite SPEs enable glucose sensing with distinct advantages over existing glucose chemical sensors in terms of cost, fabrication simplicity, disposability, and adaptation of green methods in sensor's development.