A reliable and rapid method for soluble sugars and RFO analysis in chickpea using HPAEC-PAD and its comparison with HPLC-RI

Exploring bioactive compounds in chickpea and bean aquafaba: Insights from glycomics and peptidomics analyses

The objective of this study was to identify bioactive oligosaccharides and peptides in the cooking water of chickpeas and common beans, known as aquafaba. The oligosaccharides stachyose, raffinose and verbascose were quantified by high-performance anion-exchange chromatography; 78 and 67 additional oligosaccharides were identified in chickpea and common bean aquafaba, respectively, by LC-MS/MS. Chickpea aquafaba uniquely harbored ciceritol and other methyl-inositol-containing oligosaccharides. In prebiotic growth assays, chickpea aquafaba oligosaccharides were differentially utilized, promoting growth of Limosilactobacillus reuteri DSM 20016 and Bifidobacterium longum subsp. infantis ATCC 15697, but not Lacticaseibacillus rhamnosus GG. Dimethyl labeling, along with LC-MS/MS, effectively differentiated α- and γ-glutamyl peptides, revealing the presence of several γ-glutamyl peptides known to possess kokumi and anti-inflammatory activities, including γ-Glu-Phe and γ-Glu-Tyr in chickpeas aquafaba and γ-Glu-S-methyl-Cys and γ-Glu-Leu in beans aquafaba. This work uncovered unique bioactive peptides and oligosaccharides in aquafaba, helping promote its valorization, food system sustainability, and future health-promoting claims.

Investigation of γ-polyglutamic acid production via asynchronous saccharification and fermentation of raw corn starch

Starch, a crucial raw material, has been extensively investigated for biotechnological applications. However, its application in γ-polyglutamic acid (γ-PGA) production remains unexplored. Based on γ-PGA output of Bacillus subtilis SCP010-1, a novel asynchronous saccharification and fermentation process for γ-PGA synthesis was implemented. The results revealed that a starch concentration of 20%, α-amylase dosage of 75 U/g, liquefaction temperature of 72℃, and γ-PGA yield of 36.31 g/L was achieved. At a glucoamylase dosage of 100 U/g, saccharification 38 h at 60℃, the yield of γ-PGA increased to 48.88 g/L. The contents of total sugar, glucose, maltose and oligosaccharide in saccharified liquid were determined. Through batch fermentation of saccharified liquid in fermentor, the γ-PGA output was elevated to 116.08 g/L. This study can offer a potential cost reduction of 40%, which can be a promising advancement in industrial γ-PGA production. Moreover, our approach can be applied in other starch-based fermentation industries.

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.

Effect of cooking methods on metabolites of deep purple-fleshed sweetpotato

The effects of different cooking methods on purple-fleshed sweetpotato (PFSP) metabolites were systematically explored, containing the changes of starch, soluble sugar, volatile organic compounds and non-target metabolites after steaming, boiling and baking. Compared to raw samples, the steamed samples showed the greatest changes in starch (degraded from 53.01% to 39.5%) and soluble sugar content (increased from 11.82% to 29.08%), while the baked samples showed insignificant changes in starch (51.06%). In total, 64 volatile organic compounds were identified in PFSP, with aldehydes decreasing and terpenes increasing after cooking. However, most of them were low in content and contributed weak aroma for PFSP. More importantly, 871 non-volatile metabolites were detected in PFSP, and 83.5% of which were well-preserved after cooking, while most of the changes were concentrated in phenylpropanoids, amino acids and carbohydrates. This study enriches the understanding of quality changes after PFSP cooking and helps consumers choose the right cooking method.

Characterization of free oligosaccharides from garden cress seed aqueous exudate using PGC LC-MS/MS and NMR spectroscopy

Garden cress seeds produces mucilage that has found various food applications, however, there is little information on the free oligosaccharides (FOS) contents in these seeds. Herein, we explored the presence of FOS in cress seed aqueous exudate. PGC-LC MS/MS analysis indicated the presence of mainly hexose containing oligosaccharides such as raffinose, stachyose and verbascose belonging to raffinose family of oligosaccharides (RFOs). In addition, minor fraction of planteose, isomeric tri- and tetrasaccharides were also observed. Further, the structural confirmation of the abundant tri- and tetrasaccharide were obtained through 1D and 2D NMR analysis. Thus, the RFOs presence in cress seeds would enhance its bio-functionalities.

Discrimination of raffinose and planteose based on porous graphitic carbon chromatography in combination with mass spectrometry

Raffinose and planteose are non-reducing, isomeric trisaccharides present in many higher plants. Structurally, they differ in the linkage of α-D-galactopyranosyl to either glucose C(6) or to C (6') of fructose, respectively and thus differentiating each other is very challenging. The negative ion mode mass spectrometric analysis is shown to distinguish planteose and raffinose. However, to facilitate the robust identification of planteose in complex mixtures, herein, we have demonstrated the use of porous graphitic carbon (PGC) chromatography combined with QTOF-MS² analysis. The separation of planteose and raffinose was achieved on PGC, wherein both have recorded different retention time. Detection through MS² analysis revealed the specific fragmentation patterns for planteose and raffinose that are distinctive to each other. The applicability of this method on oligosaccharides pool extracted from different seeds showed clear separation of planteose that allowed unambiguous identification from complex mixtures. Therefore, we propose PGC-LC-MS/MS can be employed for sensitive, throughput screening of planteose from wider plant sources.

Synthesis of naphthalimide-type chemsensor and its application in quality evaluation for polygonatum sibiricum Red

The premise and key of ensuring the safety and effectiveness of traditional Chinese medicine (TCM) is to construct appropriate quality evaluation system of TCM. This study aimed to establish a pre-column derivatization HPLC method for achieving the quality control of Polygonatum sibiricum by reacting synthesized 4-hydrazino-1,8-naphthalimide (HAN) with diverse monosaccharides from the hydrolytic product of P. sibiricum polysaccharides (PSPs), followed by HPLC separation. The HAN was synthesized based on a CuI-catalyzed cross-coupling reaction in water, and then employed as a novel chemosensor that reacts with reducing sugars. Good separation was achieved at a detection wavelength of 448 nm using an ZORBAX SB-C8 column under a gradient elution at a flow rate of 0.5 ml/min within 12 min. The monosaccharide compositions of PSP mainly include two hexoses [glucose (Glc), galactose (Gal)] and two hexuronic acids [glucuronic acid (GlcA) and galacturonic acid (GalA)], and the molar ratio of Glc, Gal, GlcA and GalA is 16.67:52.94:10.58:19.81. The verified HPLC method, possessing excellent precision and good accuracy, successfully achieved rapid qualitative and quantitative determination for PSP. Additionally, the HAN displayed fluorescence enhancement through “push–pull” mode, and fluorescence decreased through “pull–pull” mode after binding to monosaccharides, which is a potential for fluorescence determination of different monosaccharides.

Separation of Monosaccharide Anomers on Photo-Click Cysteine-Based Stationary Phase: The α/β Interconversion Process Studied by Dynamic Hydrophilic Liquid Chromatography

In High-Performance Liquid Chromatography (HPLC), the separation of reducing sugars can typically show three possible typologies of chromatographic profiles (i.e., single peak, two resolved peaks and two peaks interconnected by a plateau) due to the rate at which the relevant α/β anomers interconversion (anomerization) can take place in relation to their elution-time. By analyzing these chromatographic profiles, thermodynamic and kinetic properties of anomerization phenomenon can be extrapolated. In this work we studied the anomerization of some monosaccharides by using a recently developed photo-click cysteine-based stationary phase through dynamic hydrophilic interaction liquid chromatography (D-HILIC) conditions. In the 5–25 °C temperature range, the ΔG#α→β and ΔG#β→α barriers were found to achieve values within the interval 21.1/22.2 kcal/mol for glucose, with differences between α→β and β→α reactions of about 0.4 kcal/mol. For xylose, in the same temperature range, the ΔG#α→β and ΔG#β→α barriers are between 20.7 to 21.5 kcal/mol, with differences between α→β and β→α reactions of about 0.2 kcal/mol. The experimental data are in agreement with those reported in literature, confirming the this new stationary phase using HILIC conditions is a robust platform to measure kinetic and thermodynamic properties of the isomerization reaction.

The role of functional oligosaccharides as prebiotics in ulcerative colitis

The incidence rate of ulcerative colitis (UC) has increased significantly over the past decades and it places an increasing burden on health and social systems. The current studies on UC implicate a strong correlation between host gut microbiota immunity and the pathogenesis of UC. Meanwhile, more and more functional oligosaccharides have been reported as prebiotics to alleviate UC, since many of them can be metabolized by gut microbiota to produce short-chain fatty acids (SCFAs). The present review is focused on the structure, sources and specific applications of various functional oligosaccharides related to the prevention and treatment of UC. The available evidence for the usage of functional oligosaccharides in UC treatment are summarized, including fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), chito-oligosaccharides (COS), alginate-oligosaccharides (AOS), xylooligosaccharides (XOS), stachyose and inulin.

Glucose sensing on screen-printed electrochemical electrodes based on porous graphene aerogel @prussian blue

As one of the three major chronic diseases, diabetes often causes many complications, which can affect various parts of the body and even threaten the life of the patients. At present, the situation of diabetes in the world is quite serious. Accurate detection of blood glucose is very important for the diagnosis, treatment and medication of diabetes as well as the self-management of diabetic patients. In this paper, an electrochemical glucose biosensor was developed based on screen-printed electrode (SPE) modified with composite material of graphene aerogel (GA) and Prussian blue (PB) (denoted as GA@PB), which was fabricated via chemical reduction using L-ascorbic acid as a reducing agent through a freeze-drying process. Glucose was specifically captured by glucose oxidase (GOx) which were immobilized into the GA@PB by chitosan. The structure and performance of the sensor were characterized by scanning electron microscopy (SEM), Raman spectroscopy measurements, Fourier transform infrared spectrometer (FTIR), cyclic voltammetry (CV) and amperometric detection. The sensor exhibited a linear range of 0.5-6.0 mmol·L^-1 with limit of detection (LOD) of 0.15 mmol·L^-1, indicating that the combination of graphene aerogel and Prussian blue possess well conductivity and catalytic performance.

Nutritional Composition and In Vitro Starch Digestibility of Crackers Supplemented with Faba Bean Whole Flour, Starch Concentrate, Protein Concentrate and Protein Isolate

The nutritional quality of common wheat-based foods can be improved by adding flours from whole pulses or their carbohydrate and protein constituents. Faba bean (Vicia faba L.) is a pulse with high protein concentration. In this study, prepared faba bean (FB) flours were added to wheat based baked crackers. Wheat cracker recipes were modified by substituting forty percent wheat flour with flours from whole faba bean, starch enriched flour (starch 60%), protein concentrate (protein 60%) or protein isolate (protein 90%). Baked crackers were ground into meal and analyzed for their macronutrient composition, starch characteristics and in vitro starch hydrolysis. Faba bean supplemented crackers had lower (p ≤ 0.001) total starch concentrations, but proportionally higher protein (16.8-43%), dietary fiber (6.7-12.1%), fat (4.8-7.1%) and resistant starch (3.2-6%) (p ≤ 0.001) than wheat crackers (protein: 16.2%, dietary fiber: 6.3%, fat: 4.2, resistant starch: 1.2%). The increased amylose, amylopectin B1- chain and fat concentration from faba bean flour and starch flour supplementation in cracker recipe contributed to increased resistant starch. Flours from whole faba bean, starch or protein fractions improved the nutritional properties and functional value of the wheat-based crackers. The analytical analysis describing protein, starch composition and structure and in vitro enzymatic hydrolysis advance understanding of factors that account for the in vivo benefits of faba bean flours added to crackers in human physiological functions as also previously shown for pasta. The findings can be used to guide development of improve nutritional quality of similar wheat-based food products.

RID serve as a more appropriate measure than phenol sulfuric acid method for natural water-soluble polysaccharides quantification

With structural diversity of water-soluble polysaccharides, their precise quantitative analysis by phenol‑sulfuric acid method becomes more difficult and challenging. In this study, the quantification analysis of dextran and glucose in phenol sulfuric acid method was compared in this paper. When the concentration is below 90 μg/mL, the quantification of glucose is close to theoretical value, however, glucose derivatives have significantly different absorption. Later, quantitative factors of water-soluble polysaccharide in RID measurement were investigated. The optimum temperature was 40 °C and linear range was 0.3125-10.0 mg/mL in RID for dextrans (1.0-500 kDa) and glucose derivatives. Method validation studies of the RID method were further performed and compared to conventional phenol sulfuric acid method, which demonstrated that RID measurement is more reliable and satisfactory method. The intervention of water-soluble impurity in RID response should be well control below 6% (w/w). By comparison, the RID measurement could well alleviate drawbacks in phenol‑sulfuric acid method.

Comprehensive analysis of natural polysaccharides from TCMs: a generic approach based on UPLC-MS/MS

Here, we report a new application using liquid chromatography-electrospray mass spectrometry (UHPLC-ESI-MS) using aldononitrile acetate derivatives for simultaneous baseline separation and detection of eight neutral saccharides, two uronic acids, one ketose, and eight alditols within 14 min. The separation was performed on a Cortecs C₁₈ column using acetonitrile (A) and water (B) as the mobile phase with gradient elution. The target components were detected in selected ion monitoring (SIM) mode by mass spectrometry with an electrospray ionization (ESI) source operating in positive ionization mode. A comparison with traditional methods was used to determine the validity of the results. The UHPLC-ESI-MS method was used for quantitative analysis of free carbohydrates in water extracts of Crataegus pinnatifida as well as determination of Polygonatum cyrtonema and Glossy ganoderma monosaccharides in polysaccharides. The results demonstrate that this protocol is a comprehensive and effective technique for qualitative and quantitative analysis of plant polysaccharides from TCMs.

Sequential expression of raffinose synthase and stachyose synthase corresponds to successive accumulation of raffinose, stachyose and verbascose in developing seeds of Lens culinaris Medik

Raffinose, stachyose and verbascose form the three major members of the raffinose family oligosaccharides (RFO) accumulated during seed development. Raffinose synthase (RS; EC 2.4.1.82) and stachyose synthase (STS; EC 2.4.1.67) have been associated with raffinose and stachyose synthesis, but the precise mechanism for verbascose synthesis is not well understood. In this study, full-length RS (2.7 kb) and STS (2.6 kb) clones were isolated by screening a cDNA library prepared from developing lentil seeds (18, 20, 22 and 24 days after flowering [DAF]) to understand the roles of RS and STS in RFO accumulation in developing lentil seeds. The nucleotide sequences of RS and STS genes were similar to those reported for Pisum sativum. Patterns of transcript accumulation, enzyme activities and RFO concentrations were also comparable to P. sativum. However, during lentil seed development raffinose, stachyose and verbascose accumulation corresponded to transcript accumulation for RS and STS, with peak transcript abundance occurring at about 22-24 DAF, generally followed by a sequential increase in raffinose, stachyose and verbascose concentrations followed by a steady level thereafter. Enzyme activities for RS, STS and verbascose synthase (VS) also indicated a sudden increase at around 24-26 DAF, but with an abrupt decline again coinciding with the subsequent steady state increase in the RFO. Galactan:galactan galactosyl transferase (GGT), the galactinol-independent pathway enzyme, however, exhibited steady increase in activity from 24 DAF onwards before abruptly decreasing at 34 DAF. Although GGT activity was detected, isolation of a GGT sequence from the cDNA library was not successful.

Multiple reaction monitoring for identification and quantification of oligosaccharides in legumes using a triple quadrupole mass spectrometer

Raffinose family oligosaccharides are non-digestible compounds considered as dietary prebiotics with health-related properties. Hence, it is important to develop highly specific methods for their determination. An analytical method is developed in this study for oligosaccharide identification and quantification using liquid chromatography-tandem mass spectrometry equipped with a triple quadrupole analyser operating in Multiple Reaction Monitoring mode. Raffinose, stachyose and verbascose are separated in a 10-minute run and the method is validated over a broad concentration range, showing good linearity, accuracy, precision and high sensitivity. A low-cost, short eco-friendly procedure for oligosaccharide extraction from legumes, with a high recovery rate extraction, good repeatability and reproducibility is also proposed. No plant-matrix effects were demonstrated. The method applied to the screening of 28 different legumes revealed species-related traits for oligosaccharide distribution, highlighting Pisum sativum (9.22 g/100 g) as the richest source of these prebiotics and its suitability as a functional food ingredient.

Effect of pulsed electric field treatment on the kinetics of rehydration, textural properties, and the extraction of intracellular compounds of dried chickpeas

This study investigated the effect of pulsed electric fields (PEF) pretreatment on rehydration kinetics, firmness, and release of intracellular components of dried chickpeas during rehydration at 35 to 65°C. After soaking preconditioning, chickpeas were subjected to PEF treatments (2.5 and 3.3 kV/cm, 0.2 to 12.0 kJ/kg, 15 µs pulse width, 20 Hz frequency). PEF treated and untreated chickpeas were dried in crossflow air dryer and their rehydration at constant seed/water ratio of 1:5 was studied for 24 hr. During rehydration, moisture, firmness, and concentration of released proteins, carbohydrates and raffinose family oligosaccharides (RFO) were determined and described using appropriate mathematical models. PEF treatment led to up to 70% higher rehydration rates of dried chickpeas. This increase corresponds to rehydration time of approximately 1.5 hr, as opposed to 5 hr for untreated samples. Firmness of PEF treated chickpeas (for energy inputs higher than 3 kJ/kg) during rehydration decreased up to 30% compared to untreated samples. The firmness of untreated samples after 300 min of rehydration was achieved at much shorter times (up to 30 min) for PEF treated samples. At the end of 300 min of rehydration, more than 47.7%, 76.1%, and 86.6% of total raffinose, stachyose, and verbascose, respectively has been extracted, but only 0.03% of nutritionally valuable proteins from PEF treated chickpeas. Consequently, this study demonstrates that PEF processing could be implemented in dried chickpeas processing as pretreatment, for the reduction of rehydration time prior to cooking and of intestinal discomfort caused by RFO.

Sunflower oil preservation by using chickpea flour film as bio-packaging material

The aim of this study was to evaluate the protective effect of biodegradable packages made with chickpea flour on the oxidation of sunflower oil. Chickpea flour films were prepared using the casting technique. To study the influence of storage time on films properties, the chickpea flour films were stored during 60 days at 25 °C and 52% relative humidity. In addition, sunflower oil samples were packaged in chickpea flour packages (CPs) and stored for 60 days at 25 °C. Lipid oxidation indicators were evaluated. The results showed that puncture force and redness values (a*) of chickpea films did not change significantly during storage. Tensile strength, Young's modulus (YM), and yellowness (b*) increased and moisture content (MC), elongation (%E), solubility (%S), water vapor permeability (WVP), and luminosity (L*) decreased. Microscopic images showed the presence of a few cracks in the film network at storage day 60. Conjugated dienes and peroxide value increased less for sunflower oil stored in high-barrier plastic pouches and CPs during storage than the control treatment. CPs helped to preserve the chemical quality of sunflower oil samples, proving to be a promising alternative to develop biodegradable packaging to be used in oily food preservation. PRACTICAL APPLICATION: Discarded chickpea grains are those split and different color grains that are separated from marketable grains, and represent an industrial byproduct. These grains are currently used for feed, constituting a nutritive biomass of low commercial value. Chickpea flour is a potential material for making biodegradable films. This strategy allows adding value to the chickpea industry, transforming a byproduct into a raw material with the potential to develop economical food packaging material. The use of chickpea packages to preserve sunflower oil may be an alternative to pack vegetable oil or high lipid content food, allowing the use reduction of nonbiodegradable pouches.

Workflow for the Quantification of Soluble and Insoluble Carbohydrates in Soybean Seed

Soybean seed composition has a profound impact on its market value and commercial use as an important commodity. Increases in oil and protein content have been historically pursued by breeders and genetic engineers; consequently, rapid methods for their quantification are well established. The interest in complete carbohydrate profiles in mature seeds, on the other hand, has recently increased due to numerous attempts to redirect carbohydrates into oil and protein or to offer specialty seed with a specific sugar profile to meet animal nutritional requirements. In this work, a sequential protocol for quantifying reserve and structural carbohydrates in soybean seed was developed and validated. Through this procedure, the concentrations of soluble sugars, sugar alcohols, starch, hemicellulose, and crystalline cellulose can be determined in successive steps from the same starting material using colorimetric assays, LC-MS/MS, and GC-MS. The entire workflow was evaluated using internal standards to estimate the recovery efficiency. Finally, it was successfully applied to eight soybean genotypes harvested from two locations, and the resulting correlations of carbohydrate and oil or protein are presented. This methodology has the potential not only to guide soybean cultivar optimization processes but also to be expanded to other crops with only slight modifications.

A 3D porous graphene aerogel@GOx based microfluidic biosensor for electrochemical glucose detection

As a chronic disease, diabetes may result in serious complications that endanger the health and life of patients. Accurate and real-time detection of blood sugar levels is of great significance for the prevention and treatment of diabetes. In this paper, an enzymatic electrochemical microfluidic biosensor for glucose detection was developed based on a three-dimensional (3D) porous graphene aerogel and glucose oxidase (GOx). A graphene aerogel was prepared by freeze-drying a graphene hydrogel and has a high electrical conductivity, the 3D porous structure provided a good near-biological condition for GOx and the increased specific surface area allowed more GOx to be immobilized on the graphene aerogel. The microfluidic system greatly reduced the consumption of samples during tests. Amperometric measurements were carried out to test glucose concentrations, and the enzyme biosensor showed a linear range from 1 mM to 18 mM (R² = 0.991). The limit of detection (LOD) was 0.87 mM (S/N = 3) and the sensor showed excellent selectivity and stability. Finally, monitoring glucose in serum samples was achieved by the proposed sensor and good recoveries were obtained. Due to its excellent performance, the proposed biosensor has a favorable application prospect in the prevention and clinical diagnosis of diabetes. Furthermore, our method, which is used to prepare a graphene aerogel modified electrode in a microfluidic chip, can be widely used in various electrochemical sensors.

Determination of Soluble Mono, Di, and Oligosaccharide Content in 23 Dry Beans (Phaseolus vulgaris L.)

Beans provide a rich source of plant-based proteins and carbohydrates. It is well documented in the literature that the raffinose family of oligosaccharides (RFOs: raffinose, stachyose, and verbascose) is linked with flatulence issues. In this study, the soluble sugar content of 23 dry beans was investigated using a newly developed and validated analytical method with high-performance anion-exchange chromatography coupled to an amperometric pulse detection. All seven sugars (galactose, glucose, fructose, sucrose, raffinose, stachyose, and verbascose) showed good linearity (r² ≥ 0.99) between 0.156 and 20 μg/mL. The limit of detection and quantification were determined as 0.01-0.11 μg/mL and 0.04-0.32 μg/mL, respectively. Significant variations in the profiles and concentrations of individual and total sugars were observed in 23 dry beans. Sucrose and stachyose were the two prominent soluble sugars combinedly representing an average of 86% of the total soluble sugars. Yellow split beans, large lima, and black eyed peas contained higher amounts of total soluble sugars (79.8-83.6 mg/g), whereas lower amounts were observed in speckled butter peas and lentils (53.6-56.6 mg/g). Garbanzo beans contained maximum levels of mono and disaccharides (MD), and yellow split beans showed the highest levels of RFOs. Based on the hierarchical cluster analysis of the total soluble sugars (TS), MD, RFOs, and MD/RFOs ratio, 23 beans can be classified into five groups. The average TS content and the MD/RFOs ratios of the five groups were determined as group 1 (TS = 55.1 mg/g and MD/RFOs = 0.30), group 2 (TS = 77.6 mg/g and MD/RFOs = 0.31), group 3 (TS = 78.3 mg/g and MD/RFOs = 0.51), group 4 (TS = 59.1 mg/g and MD/RFOs = 1.06), and group 5 (TS = 68.5 mg/g and MD/RFOs = 0.62). This information is useful for researchers, food industries, and consumers that are looking for plant-based protein source as an alternative to animal proteins with reduced flatulence problems.

Rapid Analysis of Monosaccharides in Sub-milligram Plant Samples Using Liquid Chromatography-Mass Spectrometry Assisted by Post-column Derivatization

Monosaccharides play important roles in plant growth and development, and their biofunctions are closely related to their endogenous contents. Therefore, the determination of monosaccharides is beneficial for the further study of monosaccharide biofunction. In this work, we developed a liquid chromatography-mass spectrometry analytical method assisted by a post-column derivatization technique (LC-PCD-MS) for the fast and automatic determination of 16 monosaccharides in samples. Post-column chemical derivatization of monosaccharides was performed by a reaction of monosaccharides with 4-benzylaminobenzeneboronic acid (4-PAMBA) through boronate ester formation in a three-way connector. 4-PAMBA worked as a derivatization reagent to improve the selectivity and sensitivity of monosaccharide detection by MS. The developed LC-PCD-MS method integrates LC separation, chemical derivatization, and MS detection in one run, thus greatly reducing the analysis time for each sample. The limits of detection and limits of quantification for 16 monosaccharides were in the range of 0.002-0.1 and 0.007-0.5 ng/mL, respectively. Good linearity was obtained from the linear regression, with a determination coefficient (R²) ranging from 0.9928 to 1.0000. The relative recoveries were in the range of 80.7-117.8%, with the intra- and interday relative standard deviations less than 19.7 and 16.5%, respectively, indicating good accuracy and acceptable reproducibility of the method. Finally, the method was successfully applied to investigate the spatial and temporal distribution of 16 monosaccharides in the developing flower and germinating seed of Arabidopsis thaliana.

Hydrophilic Interaction Chromatography Coupled with Charged Aerosol Detection for Simultaneous Quantitation of Carbohydrates, Polyols and Ions in Food and Beverages

Here, we report an accurate and versatile method for the simultaneous determination of 17 sugars (arabinose, erythrose, fructose, galactose, glucose, isomaltulose, lactose, lyxose, maltose, maltotriose, mannose, raffinose, rhamnose, ribose, sucrose, sorbose and xylose), seven polyols (erythritol, inositol, lactitol, maltitol, mannitol, sorbitol and xylitol), five ions (K⁺, Br⁻, Cl⁻, NO³⁻ and SO₄²⁻) and the pseudosaccharide acarbose. For compound separation, hydrophilic interaction chromatography (HILIC) coupled to a corona charged aerosol detector (CAD) was used. The method was validated for linearity, precision, reproducibility, retention factor and optimal injection volume. Standards were measured in the range of 1–1000 mg L⁻¹ and showed good intraday and interday repeatability, as well as precision (relative standard deviation (RSD) < 5%). The LODs and LOQs for the 30 analytes were in the range of 0.032–2.675 mg L⁻¹ and 0.107–8.918 mg L⁻¹, respectively. This method exhibited correlation coefficients of at least R² > 0.97 for all analytes. The method was tested in 24 food and beverage samples to validate the separation efficiency and sensitivity in natural food matrices and to show the practicability of its use for routine food analysis.

Compositional Analysis of Non-Polar and Polar Metabolites in 14 Soybeans Using Spectroscopy and Chromatography Tools

There has been significant interest in soybean oil, fatty acid, and sugar composition to develop new value-added soybean products. Thus, compositional analysis is critical for developing value-added soybeans. In the present study, we showed simple screening tools (near infrared spectroscopy (NIR) and high-performance thin layer chromatography (HPTLC)) coupled with multivariate analysis for the sample classification of 14 soybeans as a proof-of-concept. We further determined major non-polar and polar metabolites responsible for differences between different soybeans using gas and ion chromatography. These differences in soybean profiles were attributed to lower levels of total oil content in wild soybeans (~9%) versus cultivated soybeans (16%–22%). In addition, higher levels of linolenic acid (~17%) and stachyose (~53%) were determined in wild type, whereas higher levels of oleic acid (~19%) and sucrose (~59%) were detected in cultivated soybeans. Interestingly, one cultivated soybean had a desirable sugar profile with a high amount of sucrose (86%) and a low abundance of stachyose (9%). The correlation studies showed a positive correlation between oil and soluble sugars (R² = 0.80) and negative correlations between methyl linolenate and soluble sugars (R² = −0.79), oil (R² = −0.94), and methyl oleate (R² = −0.94) content. Both polar and non-polar metabolites showed significant differences in wild and cultivated soybeans.

Electrodeposition⁻Assisted Assembled Multilayer Films of Gold Nanoparticles and Glucose Oxidase onto Polypyrrole-Reduced Graphene Oxide Matrix and Their Electrocatalytic Activity toward Glucose

The study reports a facile and eco-friendly approach for nanomaterial synthesis and enzyme immobilization. A corresponding glucose biosensor was fabricated by immobilizing the gold nanoparticles (AuNPs) and glucose oxidase (GOD) multilayer films onto the polypyrrole (PPy)/reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) via the electrodeposition and self-assembly. PPy and graphene oxide were first coated on the surface of a bare GCE by the electrodeposition. Then, AuNPs and GOD were alternately immobilized onto PPy-RGO/GCE electrode using the electrodeposition of AuNPs and self-assembly of GOD to obtain AuNPs-GOD multilayer films. The resulting PPy-RGO-(AuNPs-GOD)_n/GCE biosensors were used to characterize and assess their electrocatalytic activity toward glucose using cyclic voltammetry and amperometry. The response current increased with the increased number of AuNPs-GOD layers, and the biosensor based on four layers of AuNPs-GOD showed the best performance. The PPy-RGO-(AuNPs-GOD)₄/GCE electrode can detect glucose in a linear range from 0.2 mM to 8 mM with a good sensitivity of 0.89 μA/mM, and a detection limit of 5.6 μM (S/N = 3). This study presents a promising eco-friendly biosensor platform with advantages of electrodeposition and self-assembly, and would be helpful for the future design of more complex electrochemical detection systems.

A One-Step Extraction and Luminescence Assay for Quantifying Glucose and ATP Levels in Cultured HepG2 Cells

A fluorescence-based enzymatic microplate intracellular glucose assay was designed and fully validated. The method was tested in a hepatocellular cancer cell line (HepG2). Our novel one-step extraction reagent gave stable cell lysates for glucose, adenosine triphosphate (ATP), and total protein determination from the same sample. Limit of detection for glucose was 0.13 µM (26 pmol/well), which is superior to commercially available glucose assays. Both intra- and interday assay imprecision in HepG2 cultures were less than 12% coefficient of variance (CV). In cell lysates spiked with glucose, recovery at two levels varied between 83.70% and 91.81%, and both linearity and stability were acceptable. HepG2 cells treated with agents affecting glucose uptake/metabolism (phloretin, quercetin, quercetin-3'-sulfate, NaF, 3-bromopyruvate, NaN₃, oligomycin A, ochratoxin A, cytochalasin B, and anti-GLUT1 antibody) showed dose-dependent changes in glucose and ATP levels without total protein (cell) loss. Finally, we performed flow cytometric glucose uptake measurement in the treated cells using 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose fluorescent glucose analog. Glucose uptake did not always mirror the intracellular glucose levels, which most likely reflects the differences between the two methodologies. However, interpreting data obtained by both methods and taking ATP/protein levels at the same time, one can get information on the mode of action of the compounds.

Molecular enantiorecognition of l-glucose and d-glucose in whole blood samples

In the past years, enantioanalysis became very important for clinical analysis; biomarkers/substances of biomedical importance with chiral structure should be analyzed and their presence correlated with the specific disorder. Therefore, we developed a method for the assay of l- and d-glucose, based on molecular recognition of l- and d-glucose. While for d-glucose there are many methods to assess its quantity, the l-enantiomer is not routinely detected by standard methods. Two stochastic microsensors based on the immobilization of Copper(II)phthalocyanine and Ni(II)phthalocyanine, in natural diamond powder, were proposed for the enantioanalysis of glucose. The proposed methods proved to have high sensitivities and were able to be used for determination of concentrations as low as 2.5 pg mL^-1 for d-glucose and as low as 2.5 fg mL^-1 for l-glucose. The enatioanalysis was performed with good results in whole blood samples collected from diabetic patients.

Stachyose Improves Inflammation through Modulating Gut Microbiota of High-Fat Diet/Streptozotocin-Induced Type 2 Diabetes in Rats

SCOPE

The present study is undertaken to assess the effects of stachyose (STS) on type 2 diabetes in rats and changes in the gut microbiota compared to metformin (MET).

METHODS AND RESULTS

The type 2 diabetic model is successfully established via a high-fat diet /streptozotocin in Wistar rats, and STS or MET is administered for 4 weeks. Blood is collected to analyze biochemical parameters, pancreas for mRNA expression of related gene, and contents of colon for gut microbiota. STS or MET decreases serum LPS, mRNA expression of IL-6, and tumor necrosis factor-α (TNF-α). In addition, STS and MET show a similar shifting of the structure of the gut microbiota and a selective enrichment of key species. At the genus level, STS shows selective enrichment of Phascolarctobacterium, Bilophila, Oscillospira, Turicibacter, and SMB5, but MET demonstrates a selective effect on Sutterella, Prevotella, 02d06, and rc4. The correlation analysis indicates that STS and MET decrease IL-6 and TNF-α and increase Akt/PI3K expression, which are relative to key species of gut microbiota.

CONCLUSION

STS decreases pancreatic mRNA expression of IL-6 and TNF-α via key species of gut microbiota. The mechanism of this effect is similar to that of MET.

Genotype, environment and G × E interaction influence (1,3;1,4)-β-d-glucan fine structure in barley (Hordeum vulgare L.)

BACKGROUND

The structure of β-glucan influences its use in cereal-based foods and feed. The objective of this study was to determine the effect of environment (E) and genotype (G) on β-glucan fine structure and its genetic control in two-row spring barley with normal starch characteristics.

RESULTS

A population of 89 recombinant inbred lines, derived from the cross of two-row spring barley genotypes Merit × H93174006 (H92076F1 × TR238), was characterized for concentration and structure of grain β-glucan in two environments. Results showed that concentrations of β-glucan, DP3, DP4 and DP3 + DP4 were positively correlated with each other, suggesting no preference for DP3 or DP4 subunit production in high- or low-β-glucan lines. The concentrations of β-glucan, DP3, DP4 and DP3:DP4 ratios were significantly influenced by genotype and environment. However, only DP3:DP4 ratio showed a significant effect of G × E interaction. Association mapping of candidate markers in 119 barley genotypes showed that marker CSLF6_4105 was associated with β-glucan concentration, whereas Bmac504 and Bmac211 were associated with DP3:DP4 ratio. Bmac273e was associated with both β-glucan concentration and DP3:DP4 ratio.

CONCLUSION

The grain β-glucan concentration and DP3:DP4 ratio are strongly affected by genotype and environment. Single-marker analyses suggested that the genetic control of β-glucan concentration and DP3:DP4 ratio was linked to separate chromosomal regions on barley genome. © 2016 Society of Chemical Industry.

Intestinal permeability in a patient with liver cirrhosis

Liver cirrhosis is a worldwide public health problem, and patients with this disease are at high risk of developing complications, bacterial translocation from the intestinal lumen to the mesenteric nodes, and systemic circulation, resulting in the development of severe complications related to high mortality rate. The intestinal barrier is a structure with a physical and biochemical activity to maintain balance between the external environment, including bacteria and their products, and the internal environment. Patients with liver cirrhosis develop a series of alterations in different components of the intestinal barrier directly associated with the severity of liver disease that finally increased intestinal permeability. A "leaky gut" is an effect produced by damaged intestinal barrier; alterations in the function of tight junction proteins are related to bacterial translocation and their products. Instead, increasing serum proinflammatory cytokines and hemodynamics modification, which results in the appearance of complications of liver cirrhosis such as hepatic encephalopathy, variceal hemorrhage, bacterial spontaneous peritonitis, and hepatorenal syndrome. The intestinal microbiota plays a fundamental role in maintaining the proper function of the intestinal barrier; bacterial overgrowth and dysbiosis are two phenomena often present in people with liver cirrhosis favoring bacterial translocation. Increased intestinal permeability has an important role in the genesis of these complications, and treating it could be the base for prevention and partial treatment of these complications.

Differential expression of two galactinol synthase isoforms LcGolS1 and LcGolS2 in developing lentil (Lens culinaris Medik. cv CDC Redberry) seeds

Galactinol synthase (GS, EC 2.4.1.123) catalyzes the transfer of a galactosyl residue from UDP-galactose to myo-inositol to synthesize galactinol, a precursor for raffinose family oligosaccharides (RFO) biosynthesis. Screening, a cDNA library constructed with RNA isolated from developing lentil seeds, with partial GS genes resulted in identification of cDNA clones for two isoforms of GS, LcGolS1 (1336 bp, ORF-1002 bp, 334 amino acids) and LcGolS2 (1324bp, ORF-975bp, 325 amino acids) with predicted molecular weights of 38.7 kDa and 37.6 kDa, respectively. During lentil seed development, LcGolS1 transcripts showed higher accumulation during 26-32 days after flowering (DAF) corresponding to seed desiccation, while LcGolS2 showed maximum accumulation at 24 DAF, prior to increase in LcGolS1 transcripts. GS enzyme activity was maximum at 26 and 28 DAF and corresponded to galactinol accumulation, which also increased rapidly at 22 DAF with maximum accumulation at 26 DAF. Substrates for GS activity, myo-inositol and glucose/galactose were present in high concentrations during early stages of seed development but gradually decreased from 20 DAF to 32 DAF when galactinol concentration increased coinciding with increased GS enzyme activity.

Galactinol synthase enzyme activity influences raffinose family oligosaccharides (RFO) accumulation in developing chickpea (Cicer arietinum L.) seeds

To understand raffinose family oligosaccharides (RFO) metabolism in chickpea (Cicer arietinum L.) seeds, RFO accumulation and corresponding biosynthetic enzymes activities were determined during seed development of chickpea genotypes with contrasting RFO concentrations. RFO concentration in mature seeds was found as a facilitator rather than a regulating step of seed germination. In mature seeds, raffinose concentrations ranged from 0.38 to 0.68 and 0.75 to 0.99 g/100 g, whereas stachyose concentrations varied from 0.79 to 1.26 and 1.70 to 1.87 g/100 g indicating significant differences between low and high RFO genotypes, respectively. Chickpea genotypes with high RFO concentration accumulated higher concentrations of myo-inositol and sucrose during early seed developmental stages suggesting that initial substrate concentrations may influence RFO concentration in mature seeds. High RFO genotypes showed about two to three-fold higher activity for all RFO biosynthetic enzymes compared to those with low RFO concentrations. RFO biosynthetic enzymes activities correspond with accumulation of individual RFO during seed development.

Glucose: Detection and analysis

Glucose is an aldosic monosaccharide that is centrally entrenched in the processes of photosynthesis and respiration, serving as an energy reserve and metabolic fuel in most organisms. As both a monomer and as part of more complex structures such as polysaccharides and glucosides, glucose also plays a major role in modern food products, particularly where flavor and or structure are concerned. Over the years, many diverse methods for detecting and quantifying glucose have been developed; this review presents an overview of the most widely employed and historically significant, including copper iodometry, HPLC, GC, CZE, and enzyme based systems such as glucose meters. The relative strengths and limitations of each method are evaluated, and examples of their recent application in the realm of food chemistry are discussed.