Separation of alditols of interest in food products by high-performance anion-exchange chromatography with pulsed amperometric detection

Punica granatum and Citrus spp. Extract Mix Affects Spoilage Microorganisms Growth Rate in Vacuum-Packaged Cooked Sausages Made from Pork Meat, Emmer Wheat (Triticum dicoccum Schübler), Almond (Prunus dulcis Mill.) and Hazelnut (Corylus avellana L.)

Sausage made from pork meat, emmer wheat (Triticum dicoccum Schübler), almond (Prunus dulcis Mill.), and hazelnut (Corylus avellana L.) was integrated with a mix of Punica granatum and Citrus spp. extracts to evaluate the possible effects on the growth and oxidation of spoilage microorganisms. Two concentrations of the mix were added, respectively, during sausage-making, and the final products were compared with a control group, without the extract mix, during storage. The use of the mix, especially at 10 g/1000 g of the whole ingredients, delayed the pH drop and thiobarbituric acid-reactive substances (TBARs) value during storage. Total viable count, lactic acid bacteria and psychrotrophic microbial counts were also affected, as the extract mix lowered the maximum growth rate of the microbial population considered. The sensory analyses revealed an improvement in the shelf-life of 6 and 16 days, respectively, when 5‰ and 10‰ of the mix were used.

Frankfurters made with pork meat, emmer wheat (Triticum dicoccum Schübler) and almonds nut (Prunus dulcis Mill.): evaluation during storage of a novel food from an ancient recipe

The physical, chemical and microbiological characteristics of reformulated meat-based frankfurters, derived from an ancient Roman cookbook and produced from pork meat, emmer wheat, almond, fish sauce and spices, were investigated during storage. Two different formulations were considered, with pork thigh and pork shoulder muscles, respectively. The products contain 13-16% protein, 14-19% fat, 14% carbohydrates, >7% fibre and a polyunsaturated/saturated fatty acids ratio above 0.4. During the 24 days of storage, both products evidenced a decrease in the pH and increases in the total volatile nitrogen content and TBARs value, whereas, the a_w remained stable. From a microbiological perspective, increases in the total viable count and lactic acid bacteria up to 4.8 log cfu/g occurred during storage, but no pathogens were found. Sensory analyses revealed a change in odour and flavour at 18 days, with the detection of a fermented and rancid taste. Survival sensory analysis defined a shelf life of the products of between 18.6 and 22.7 days.

Reversed phase ion-pair chromatographic separation of sugar alcohols by complexation with molybdate ion

In this study, we developed a simple and sensitive reversed phase ion-pair chromatographic method for the analysis of C4-C6 sugar alcohols. The method is based on the on-line complexation of sugar alcohols with molybdate ion. The resulting dinuclear anionic complexes can be separated on a reversed-phase C18 column using tetrabutylammonium chloride as an ion-pairing reagent. The mobile phase (pH 3.1) consisted of 0.1 mM disodium molybdate, 1 mM hydrochloric acid and 0.4 mM tetrabutylammonium chloride - 10% v/v methanol. By complexing with molybdate ion, sugar alcohols can be detected by their UV absorption at 247 nm with high resolution and sensitivity. The quantification limits of the examined sugar alcohols calculated at S/N = 10 were 0.1 mM for erythritol and xylitol and 0.01 mM for arabitol, sorbitol, mannitol and dulcitol. The detector response was linear over three orders of magnitude of sugar alcohol concentration. The proposed method was successfully applied to measure sugar alcohols in health drinks, eyedrops and mouthwashes.

Hypoglycemic health benefits of D-psicose

Diabetes is an emerging health problem worldwide. The incidence of type 2 diabetes has dramatically increased and is expected to increase more rapidly in the future. Most patients with type 2 diabetes suffer from obesity and diabetes-related complications, including cardiovascular disease and hepatic steatosis. It has been proposed that simple sugar consumption is one of the major risk factors in the development of diabetes. Hence, the replacement of sugars with a low glycemic response would be an effective strategy to prevent type 2 diabetes. Accumulating evidence demonstrates that D-psicose, which has 70% the sweetness of sucrose and no calories, is a functional sugar exerting several health benefits preventing the development of diabetes. Although D-psicose presents in small amounts in natural products, a recent new technique using biocatalyst sources enables large-scale D-psicose production. More importantly, several clinical and animal studies demonstrated that D-psicose has hypoglycemic, hypolipidemic, and antioxidant activities, which make it an ideal candidate for preventing diabetes and related health concerns. This review will summarize the protective effects of D-psicose against type 2 diabetes and its complications, suggesting its potential benefits as a sucrose substitute.

Molecular analysis of a UDP-GlcNAc:polypeptide alpha-N-acetylglucosaminyltransferase implicated in the initiation of mucin-type O-glycosylation in Trypanosoma cruzi

Trypanosoma cruzi, the causative agent of Chagas disease, is surrounded by a mucin coat that plays important functions in parasite survival/invasion and is extensively O-glycosylated by Golgi and cell surface glycosyltransferases. The addition of the first sugar, alpha-N-acetylglucosamine (GlcNAc) linked to Threonine (Thr), is catalyzed by a polypeptide alpha-GlcNAc-transferase (pp-alphaGlcNAcT) which is unstable to purification. Here, a comparison of the genomes of T. cruzi and Dictyostelium discoideum, an amoebazoan which also forms this linkage, identified two T. cruzi genes (TcOGNT1 and TcOGNT2) that might encode this activity. Though neither was able to complement the Dictyostelium gene, expression in the trypanosomatid Leishmania tarentolae resulted in elevated levels of UDP-[(3)H]GlcNAc:Thr-peptide GlcNAc-transferase activity and UDP-[(3)H]GlcNAc breakdown activity. The ectodomain of TcOGNT2 was expressed and the secreted protein was found to retain both activities after extensive purification away from other proteins and the endogenous activity. Product analysis showed that (3)H was transferred as GlcNAc to a hydroxyamino acid, and breakdown was due to hydrolysis. Both activities were specific for UDP-GlcNAc relative to UDP-GalNAc and were abolished by active site point mutations that inactivate a related Dictyostelium enzyme and distantly related animal pp-alphaGalNAcTs. The peptide preference and the alkaline pH optimum were indistinguishable from those of the native activity in T. cruzi microsomes. The results suggest that mucin-type O-glycosylation in T. cruzi is initiated by conserved members of CAZy family GT60, which is homologous to the GT27 family of animal pp-alphaGalNAcTs that initiate mucin-type O-glycosylation in animals.

Acidogenic Potential of “Sugar-Free” Cough Drops

A patient presented with extensive marginal ditching around restorations recently placed during whole-mouth rehabilitation. The patient was not xerostomic and was otherwise normal except for the self-reported excessive use of “sugar-free” cough drops sweetened with sorbitol and Isomalt® (an equimolar mix of glucosyl-mannitol and glucosylsorbitol). This prompted anin vitroinvestigation to determine whetherStreptococcus sobrinus6715, a cariogenic streptococcus, could grow and produce acid in growth medium containing an aqueous extract of such “sugar-free” cough drops. The results indicate thatS. sobrinus6715 uses Isomalt® and sorbitol extensively, producing terminal culture pH as low as 4.2 when grown on medium with cough drop extract containing these sugars. This pH is sufficient to demineralize dental enamel. Patients should be cautioned against the chronic overuse of “sugar-free” cough drops and other “sugar-free” confections sweetened with a mixture of Isomalt® and sorbitol.

Determination of mannitol and sorbitol in infusion solutions by capillary zone electrophoresis using on-column complexation with borate and indirect spectrophotometric detection

Capillary zone electrophoresis with indirect UV detection at 215 nm was applied for the separation and determination of mannitol (MA), sorbitol (SO) and xylitol in the form of anionic borate-polyol complexes. The separation was carried out in a fused silica capillary (total length 60 cm, effective length 50 cm, I.D. 50 microm) at 25 kV. The optimized background electrolyte was 200 mM borate buffer (pH 9.3, adjusted with triethylamine) containing 10 mM 3-nitrobenzoate as the chromogenic co-ion. The separation took approximately 13 min. The rectilinear calibration range was 0.2-2 mg mL(-1) for MA and SO when using xylitol (1 mg mL(-1)) as the internal standard. The limit of detection at a S/N of 3 was approximately 30 microg mL(-1) for either analyte. The method was used for the assay of MA or SO in pharmaceutical infusion solutions. The RSD values were 0.15% or 1.07% (n=6) when determining 100 mg mL(-1) of MA or 50 mg mL(-1) of SO in commercial infusion solutions. The results were in good agreement with those of pharmacopoeial iodimetric titration.

Inhibitory analysis of the effect of polycyclic aromatic hydrocarbons on the activity of chitinase by means of liquid chromatography-mass spectrometry of chitin oligosaccharides

The analytical method of determining enzyme activity by liquid chromatography-mass spectrometry (LC/MS) was developed and applied for investigation of the effect of polycyclic aromatic hydrocarbons (PAHs) on the enzyme activity of chitinase. The measurement of chitinase activity by LC/MS is useful in order to use the nonderivatized substrate, which can show in vivo chitinase activity. Substrate consumption and product formation were monitored in order to determine chitinase activity. It was shown that, for the first time, in vitro addition of PAHs inhibited the activity of chitinase in a noncompetitive manner. The IC(50) value of benzo[a]pyrene was 1.4 microM, and PAHs containing four or more aromatic rings showed the same or higher inhibitory effect, whereas PAHs with a lower number of aromatic rings showed lower inhibition of the chitinase activity than benzo[a]pyrene.

Resolution of common dietary sugars from probe sugars for test of intestinal permeability using capillary column gas chromatography

BACKGROUND

The most widely accepted method for the evaluation of intestinal barrier integrity is the measurement of the permeation of sugar probes following an oral test dose of sugars. The most-widely used sugar probes are sucrose, lactulose, mannitol and sucralose. Measuring these sugars using a sensitive gas chromatographic (GC) method, we noticed interference on the area of the lactulose and mannitol peaks.

METHODS

We tested different sugars to detect the possible makeup of these interferences and finally detected that the lactose interferes with lactulose peak and fructose interferes with mannitol peak. On further developing of our method, we were able to reasonably separate these peaks using different columns and condition for our assay. Sample preparation was rapid and simple and included adding internal standard sugars, derivitization and silylation. We used two chromatographic methods. In the first method we used Megabore column and had a run time of 34 min. This resulted in partial separation of the peaks. In the second method we used thin capillary column and was able to reasonably separate the lactose and lactulose peaks and the mannitol and fructose peaks with run time of 22 min.

RESULTS

The sugar probes including mannitol, sucrose, lactulose, sucralose, fructose and lactose were detected precisely, without interference. The assay was linear between lactulose concentrations of 0.5 and 40 g/L (r(2)=1.000, P<0.0001) and mannitol concentrations of 0.01 and 40 g/L (r(2)=1.000). The sensitivity of this method remained high using new column and assay condition. The minimum detectable concentration calculated for both methods was 0.5 mg/L for lactulose and 1 mg/L for mannitol.

CONCLUSION

This is the first report of interference of commonly used sugars with test of intestinal permeability. These sugars are found in most of fruits and dairy products and could easily interfere with the result of permeability tests. Our new GC assay of urine sugar probes permits the simultaneous quantitation of sucralose, sucrose, mannitol and lactulose, without interference with lactose and fructose. This assay is a rapid, simple, sensitive and reproducible method to accurately measure intestinal permeability.

Sugar contents of Brandy de Jerez during its aging

Brandy de Jerez is aged in American oak casks according to the traditional dynamic system (Soleras y Criaderas) and sometimes additionally by the static system (Anadas). The experimental arrangement used here for the analytical monitoring of brandy aging consisted of 15 casks, 12 of which were set up for aging by the dynamic system, which is well established in the denomination of origin area, whereas the other 3 contained the same brandy but aged according to the static system. This paper studies the kinetics of sugar extraction from oak wood to distillate, as well as the possible correlations between the sugar contents in brandy and its age or the commercial type it belongs to (Solera, Solera Reserva, or Solera Gran Reserva). High-performance anion-exchange chromatography with pulsed amperometric detection was used as the analytical tool to measure the concentrations of glucose, fructose, arabinose, galactose, and xylose, the presence of which in brandy has previously been described.

Analysis of saccharides in beer samples by flow injection with electrospray mass spectrometry

Saccharides in foods play important roles, as they are essential substrates for fermentation processes. In brewing, the concentration of maltooligosaccharides influences the characteristics of beers and therefore their determination is of great practical interest. Electrospray ionization mass spectrometry (ESI-MS) was applied to identify and characterise maltooligosaccharides in beer samples. The effects due to different cation concentrations and dilution of samples were studied. Furthermore, quantitative analyses of maltooligosaccharides by means of flow-injection ESI-MS (FI/ESI-MS) of 1-microL beer samples (diluted 1000-fold) are described.

Determination of phytosiderophores by anion-exchange chromatography with pulsed amperometric detection

Phytosiderophores of the mugineic acid family are separated by anion-exchange HPLC using NaOH gradient elution. Separation of mugineic acid (MA), 2'-deoxymugineic acid (DMA), 3-hydroxymugineic acid (HMA) and 3-epi-hydroxymugineic acid (epi-HMA) is obtained within 15 min. Detection of the underivatised phytosiderophores is performed using pulsed amperometric detection (PAD) at pH 13. The sensitivity of the detection increases in the order DMA < MA < HMA < epi-HMA and respective detection limits of 5 microM (DMA), 1 microM (MA) and < 0.5 microM (HMA, epi-HMA) are achieved. PAD is discussed in comparison with the well-established fluorimetric detection method after post-column derivatisation with ortho-phthaldialdehyde. The main advantage of PAD is the simplicity of the method (no derivatisation) and the high sensitivity for hydroxylated mugineic acids. The method is used for the determination of phytosiderophores in root washings of iron-deficient and non-deficient wheat and barley plants.

Separation and determination of alditols and sugars by high-pH anion-exchange chromatography with pulsed amperometric detection

Carbohydrates such as alditols (polyols or sugar alcohols), monosaccharides and disaccharides are separated as anions by anion-exchange chromatography with a sodium hydroxide eluent, MA1 CarboPac column and pulsed amperometric detection. We report a high-pH anion-exchange chromatographic-pulsed amperometric detection (HPAEC-PAD) method that determines all the polyols used as food additives in food products and the most commonly found mono- and disaccharides on a routine basis. The linearity, repeatability, internal reproducibility and accuracy are described. The applicability of the method has been demonstrated by the analysis of 46 relevant samples and by participation twice in the Food Analysis Performance Assessment Scheme (FAPAS) testing programme for food additives.

Determination of sugar alcohols in confectioneries by high-performance liquid chromatography after nitrobenzoylation

A method was developed for the determination of sugar alcohols, meso-erythritol, xylitol, D-glucitol, D-mannitol, maltitol and parachinit by high-performance liquid chromatography (HPLC). The sugar alcohols were converted into strong ultraviolet (UV)-absorbing derivatives with p-nitrobenzoyl chloride. HPLC was performed on a phenyl column, using acetonitrile-water (67:33) as mobile phase and UV detection (260 nm). The calibration curves for all sugar alcohols tested were linear in the 10-250 microg/ml range. The average recoveries of the sugar alcohols from four sugarless confectioneries spiked at 5 and 10% levels of six sugar alcohol standards ranged from 73.2 to 109.0% with relative standard deviations ranging from 0.7 to 9.0%. The detection limit of the developed method was 0.1% for the above sugar alcohols contained in the samples.

Role of chromatography in the analysis of sugars, carboxylic acids and amino acids in food

An overview is presented of chromatographic methods currently in use to determine sugars, carboxylic acids and amino acids in foods: high-performance liquid chromatography, gas chromatography and capillary electrophoresis. As a basis of selection the following approaches can be distinguished: quantitation of constituents of several food matrices, without derivatization and in the form of different derivatives, in the presence of the matrix, or subsequently to various work-up procedures.

Determination of maltitol, isomaltitol, and lactitol by high-pH anion-exchange chromatography with pulsed amperometric detection

Disaccharide alditols (DAs) such as maltitol, isomaltitol, and lactitol are increasingly being employed in food industry by virtue of their low hydroscopicity, high stability, and good bulking properties. Still, these compounds are reduced-calorie sweeteners, so they are successfully employed in many dietetic foods, like candies, chocolates, baked products, ice creams, and beverages. Here we describe the determination of maltitol, isomaltitol, and lactitol, along with other common carbohydrates, in some foodstuffs such as toffees, biscuits, creams, sponge cakes, chocolates, roasted malt, and chicory leaves. Separations were accomplished by high-pH anion-exchange chromatography (HPAEC) with pulsed amperometric detection using 40 mM NaOH + 1 mM Ba(CH(3)COO)(2) as the mobile phase. The optimal detection potential (E(DET) = +0.10 V) was established in voltammetric experiments carried out in batch and flowing stream solutions. Under optimized conditions there was no need for both postcolumn addition of strong bases to the eluent and, even more important, column regeneration between runs. A pellicular column with a relatively low ion-exchange capacity was adopted, which allows a rapid separation of sorbitol, isomaltitol, lactitol, maltitol, glucose, fructose, sucrose, and lactose. The presence in the alkaline mobile phase of barium ions improved selectivity and reproducibility besides shorter analysis times as well. Limits of detection were on the order of 10-20 pmol injected. The contents of DAs and other free sugars in some dietetic foods were evaluated by calibration graphs.