FODMAP Content Like-by-like Comparison in Spanish Gluten-free and Gluten-containing Cereal-based Products.

Gluten-free foods (GF) availability on supermarket shelves is growing and it is expected to continue expanding in the years ahead. These foods have been linked to a lower content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), molecules that trigger gastrointestinal symptoms in sensitive persons. In this study, the FODMAP content of 25 cereal-based GF foods in Spain (breakfast cereals, pasta, bread, biscuits, bakery products, and dough and puff pastry) and 25 gluten-containing equivalents (GC) available in the same supermarket were analysed and compared. Lactose, fructose, glucose, sorbitol, mannitol, raffinose, stachyose and fructans were quantified. In a like-by-like analysis, GF foods were found to generally contain fewer FODMAPs than their GC counterparts. The ingredients used in the manufacture of GF cereal-based foods may contribute to this fact. When the individually wrapped size was considered, the proportion of samples classified as high-FODMAPs in GC and GF foods showed a trend towards fewer samples in the GF. However, not all the GF samples were low-FODMAP. Altogether, our findings provide essential information for FODMAP content databases of GF products in Spain.

Evaluating the metabolic perturbations in Mangifera indica (mango) ripened with various ripening agents/practices through gas chromatography - mass spectrometry based metabolomics.

Mangifera indica L. (mango) is said to be the king of fruits due to its rich nutritional properties and mainly originates from the Indian sub-continent. The consumption pattern of the mangoes has increased drastically, due to which, many ripening practices/agents were used to make it ready-to-eat fruit or juice for the consumers. The fruit quality and metabolic composition are said to be altered due to different ripening agents/practices. The present communication mainly deals to understand the metabolic perturbations in mango fruits due to different ripening practices/agents (room temperature ripening, ethylene, and calcium carbide) using gas chromatography - mass spectrometry based metabolomics. The partial least square-discriminant analysis has found 16 differential metabolites for different ripening agents/practices which are belong to the classes of amino acids, fatty acids, sugars, and polyols. Four metabolic pathways were found to alter in the fruit metabolome due to different ripening agents/practices. Fructose, glucose, and galactose were found to be significantly up-regulated due to calcium carbide ripening in comparison to other ripening agents/practices. Overall findings from the present study advocates that mass spectrometry based metabolomics can be valuable tool to understand the fruit quality and safety with respect to consumer health.

Characterisation and prediction of carbohydrate content in zucchini fruit using near infrared spectroscopy.

BACKGROUND: Zucchini fruit plays an important part in healthy nutrition due to its high content of carbohydrates. Recent studies have demonstrated the feasibility of visible-NIRS to predict quality profile. However, this procedure has not been applied to determine carbohydrates. RESULTS: Visible-NIR and wet chemical methods were used to determine individual sugars and starch in zucchini fruits. By applying a principal component analysis (PCA) with NIR spectral data a differentiation between the less sweet versus the sweetest zucchini accessions could be found. For the determination of carbohydrate content effective prediction models for individual sugars such as glucose, fructose, sucrose and starch by using partial least squares (PLS) regression have been developed. CONCLUSION: The coefficients of determination in the external validation (R2 VAL) ranged from 0.66 to 0.85. The standard deviation (SD) to standard error of prediction ratio (RPD) and SD to range (RER) were variable for different quality compounds and showed values that were characteristic of equations suitable for screening purposes. From the study of the MPLS loadings of the first three terms of the different equations for sugars and starch, it can be concluded that some major cell components such as pigments, cellulose, organic acids highly participated in modelling the equations for carbohydrates. © 2017 Society of Chemical Industry.

Understanding selective molecular recognition in integrated carbon nanotube-polymer sensors by simulating physical analyte binding on carbon nanotube-polymer scaffolds.

Macromolecular scaffolds made of polymer-wrapped single-walled carbon nanotubes (SWCNTs) have been explored recently (Zhang et al., Nature Nanotechnology, 2013) as a new class of molecular-recognition motifs. However, selective analyte recognition is still challenging and lacks the underlying fundamental understanding needed for its practical implementation in biological sensors. In this report, we combine coarse-grained molecular dynamics (CGMD) simulations, physical adsorption/binding theories, and photoluminescence (PL) experiments to provide molecular insight into the selectivity of such sensors towards a large set of biologically important analytes. We find that the physical binding affinities of the analytes on a bare SWCNT partially correlate with their distribution coefficients in a bulk water/octanol system, suggesting that the analyte hydrophobicity plays a key role in determining the binding affinities of the analytes considered, along with the various specific interactions between the analytes and the polymer anchor groups. Two distinct categories of analytes are identified to demonstrate a complex picture for the correlation between optical sensor signals and the simulated binding affinities. Specifically, a good correlation was found between the sensor signals and the physical binding affinities of the three hormones (estradiol, melatonin, and thyroxine), the neurotransmitter (dopamine), and the vitamin (riboflavin) to the SWCNT-polymer scaffold. The four amino acids (aspartate, glycine, histidine, and tryptophan) and the two monosaccharides (fructose and glucose) considered were identified as blank analytes which are unable to induce sensor signals. The results indicate great success of our physical adsorption-based model in explaining the ranking in sensor selectivities. The combined framework presented here can be used to screen and select polymers that can potentially be used for creating synthetic molecular recognition motifs.

Predictive models of biohydrogen and biomethane production based on the compositional and structural features of lignocellulosic materials.

In an integrated biorefinery concept, biological hydrogen and methane production from lignocellulosic substrates appears to be one of the most promising alternatives to produce energy from renewable sources. However, lignocellulosic substrates present compositional and structural features that can limit their conversion into biohydrogen and methane. In this study, biohydrogen and methane potentials of 20 lignocellulosic residues were evaluated. Compositional (lignin, cellulose, hemicelluloses, total uronic acids, proteins, and soluble sugars) as well as structural features (crystallinity) were determined for each substrate. Two predictive partial least square (PLS) models were built to determine which compositional and structural parameters affected biohydrogen or methane production from lignocellulosic substrates, among proteins, total uronic acids, soluble sugars, crystalline cellulose, amorphous holocelluloses, and lignin. Only soluble sugars had a significant positive effect on biohydrogen production. Besides, methane potentials correlated negatively to the lignin contents and, to a lower extent, crystalline cellulose showed also a negative impact, whereas soluble sugars, proteins, and amorphous hemicelluloses showed a positive impact. These findings will help to develop further pretreatment strategies for enhancing both biohydrogen and methane production.

Fructose and methylglyoxal-induced glycation alters structural and functional properties of salivary proteins, albumin and lysozyme.

Glycation process refers to reactions between reduction sugars and amino acids that can lead to formation of advanced glycation end products (AGEs) which are related to changes in chemical and functional properties of biological structures that accumulate during aging and diseases. The aim of this study was to perform and analyze in vitro glycation by fructose and methylglyoxal (MGO) using salivary fluid, albumin, lysozyme, and salivary α-amylase (sAA). Glycation effect was analyzed by biochemical and spectroscopic methods. The results were obtained by fluorescence analysis, infrared spectroscopy (total attenuated reflection-Fourier transform, ATR-FTIR) followed by multivariate analysis of principal components (PCA), protein profile, immunodetection, enzymatic activity and oxidative damage to proteins. Fluorescence increased in all glycated samples, except in saliva with fructose. The ATR-FTIR spectra and PCA analysis showed structural changes related to the vibrational mode of glycation of albumin, lysozyme, and salivary proteins. Glycation increased the relative molecular mass (Mr) in protein profile of albumin and lysozyme. Saliva showed a decrease in band intensity when glycated. The analysis of sAA immunoblotting indicated a relative reduction in intensity of its correspondent Mr after sAA glycation; and a decrease in its enzymatic activity was observed. Carbonylation levels increased in all glycated samples, except for saliva with fructose. Thiol content decreased only for glycated lysozyme and saliva with MGO. Therefore, glycation of salivary fluid and sAA may have the potential to identify products derived by glycation process. This opens perspectives for further studies on the use of saliva, an easy and non-invasive collection fluid, to monitor glycated proteins in the aging process and evolution of diseases.

Fructose determination in fruit juices using an electrosynthesized molecularly imprinted polymer on reduced graphene oxide modified electrode.

The present work reports the development of a novel electrochemical sensor for the selective detection of fructose. The sensor was developed through electropolymerization of a molecularly imprinted polymer film on a reduced graphene oxide modified electrode. The modified electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, atomic force microscopy and RAMAN spectroscopy. Through the application of the modified electrode, the recognition of fructose molecules occurred in a concentration range of 1.0 × 10-14 to 1.0 × 10-11 mol L-1, under a Langmuir adsorption isothermal model. The sensitivity and limits of detection and quantification obtained for the sensor were 9.9 × 107 A L mol-1, 3.2 × 10-15 mol L-1 and 1.1 × 10-14 mol L-1, respectively. The analytical method used for the detection of fructose presented good reproducibility, stability and accuracy, and was successfully applied for the quantification of this sugar in orange, apple and grape juices.

Dietary fiber components, microstructure, and texture of date fruits (Phoenix dactylifera, L.).

Date fruits vary widely in the hardness of their edible parts and they are classified accordingly into soft, semi-dry, and dry varieties. Fruit texture, a significant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profile of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fiber contents varied 5.2-7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profile analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the different fiber constituents correlated variably with the different parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate significantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness.

The effect of raisin-containing cereals on the pH of dental plaque in young children.

PURPOSE: The purpose of this study was to investigate the effect of raisins and raisin-containing cereals on plaque acidogenicity in young children. METHODS: Twenty 7- to 11-year-olds participated in this randomized controlled study. The test food groups were raisins, bran flakes, commercial raisin bran cereal (cRB) and experimental raisin bran cereal (eRB). Ten percent sucrose and sorbitol were used as positive and negative controls. The in vivo plaque pH was measured with a touch microelectrode (Beetrode) prior to (baseline) and 2, 5, 10, 15, 20, and 30 minutes after consuming a test food or rinsing with a control solution. RESULTS: All test foods reduced plaque pH over the 30-minute period, with the largest reduction noted between 10 to 15 minutes. Consumption of cRB produced the largest pH drop compared to the other food groups at 10 minutes (P < .001). Addition of raisins to bran flakes (eRB) promoted a less pronounced pH drop beyond 10 minutes when compared to bran flakes alone (P < .001). Consumption of raisins or eRB did not reduce plaque pH below 6 over the 30-minute testing period. CONCLUSION: The ranking in order of study test foods in promoting plaque acidogenicity is: (1) commercial raisin bran cereal; (2) bran flakes; (3) raisins; and (4) experimental raisin bran cereal.

[Extraction and purification of Atractylodes macrocephala monosaccharide composition].

OBJECTIVE: To study the method of Atractylodes macrocephala monosaccharide composition (AMMC)'s extraction, purification and analysis. METHODS: To extract AMMC with water extraction method and purify it with neutro-alumina and resin adsorption method, to observe removal impurity effect of several methods and determine the technology parameters. To detect monosaccharide's content in AMMC with hydrochloric acid-ultraviolet spectrophotometric determination and Evaporative light scattering detector (ELSD). RESULTS: After purificated with neutro-alumina, the yield and purity of AMMC were 23% - 25.5% and 56% - 60%, respectively. According to the static decoloring curve of D900, D201 and AB-8 resins, their decolorization effect's rank was D900 > AB-8 > D201. The yield of AMMC purificated with D900 ion exchange resin was above 17%, and the purity of monosaccharide was above 76%. CONCLUSION: The effect of AMMC purificated with D900 ion exchange resin after water extration is much better, the ideal method for the quantitative analysis of monosaccharide is hydrochloric acid-ultraviolet spectrophotometric determination.

Cariogenic and erosive potential of the medication used by HIV-infected children: pH and sugar concentration.

OBJECTIVE: The aim of this work was to analyze pH and sugar concentration in seven antiretroviral and three antibacterial medications frequently prescribed to HIV infected paediatric patients. METHOD: Sugars (sucrose, glucose, lactose and fructose) and pH were measured from every one of ten medications with different serial numbers in two samples. The pH was determined by a previously calibrated digital pHmeter (Beckman). Analysis of free sugars was performed using thin-layer chromatography (TLC). The pH results and the amount of sugar originated from the two samples in each lot were added. The arithmetic mean of these results were computed. RESULTS: Two antiretrovirals (Zidovudin and Abacavir Sulphate) had pH below critical level (3.55 and 3.93, respectively). All three antibacterials analyzed had pH above 5.5, and one of them (Azithromycin) had the highest pH level of the ten medications examined (9.28). Sugar was present in seven out of 10 of the medications analyzed. The antibacterials contained the highest concentration of sucrose, ranging from 40% to 54%. Glucose was found in one of the ten, sucrose was present in seven of them and none showed lactose. Fructose was not observed with the technique used. CONCLUSIONS: A number of medications frequently used by HIV-infected children may cause a significant risk of both caries and dental erosion.

Fructan and free fructose content of common Australian vegetables and fruit.

Fructans are not digested in the small intestines of humans. While many health benefits have been attributed to these carbohydrates, they can cause gastrointestinal symptoms in some individuals. We measured the total fructans in 60 vegetables and 43 fruits using the Megazyme fructan assay. Vegetables with the highest quantity of fructans included garlic, artichoke, shallots, leek bulb, and onions (range, 1.2-17.4 g/100 g fw). Fruits with low, but detectable, fructans included longon, white peach, persimmon, and melon (range, 0.21-0.46 g/100 g fw). The fructan assay was modified to provide an estimate of the average chain length (degree of polymerization) for high fructan vegetables. d-Fructose can also be malabsorbed in the small intestine of humans, so the d-fructose content in some foods was measured to supplement the current food tables. Research in this area will be facilitated through the availability of more comprehensive food composition data.

The potential for sodium hexametaphosphate (SHMP) found in common children drinks to limit acid production in the oral biofilm.

OBJECTIVE: Sodium hexametaphosphate (SHMP) is a widely used industrial preservative commonly found in children's drinks. In this paper we examined the effect of SHMP incorporated into children's drinks on acid production by the oral biofilm by monitoring salivary concentrations of lactic acid. MATERIALS AND METHOD: Twelve healthy adult subjects with an average age 36 years (range 26-54 years) consumed 10 ml from four children's beverages (Coca Cola and three types of Sunny Delight supplemented with SHMP) and a standard solution of sucrose. Saliva was collected at intervals following exposure of the oral biofilm to the drinks and the clearance of carbohydrates and the appearance of lactate was measured using standard enzymatic techniques. RESULTS: All the carbohydrates derived from the drinks were cleared from saliva within 15 min of consumption. Comparison of two drinks [Sunny D Normal and Sunny C] with the same carbohydrate, but different SHMP concentrations suggested that SHMP in these beverages had no significant effect on acid production. CONCLUSIONS: In this clinical study the role of SHMP, incorporated in common beverages, did not inhibit acid production from carbohydrates.

Selective adsorption of carbohydrates and glycoproteins via molecularly imprinted hydrogels: application to visible detection by a boronic acid monomer.

Selective adsorption of carbohydrates and glycoproteins was effectively achieved by molecularly imprinted hydrogels (MIHs) with a poly(ethylene glycol) (PEG)-based crosslinker and 4-vinylphenylboronic acid. In addition, an MIH with a novel boronic acid monomer provided selective adsorption and enabled visible detection of fructose.

The role of dietary fiber in satiety, glucose, and insulin: studies with fruit and fruit juice.

Healthy volunteers ingested sugar-equivalent meals of oranges and orange juice and of grapes and grape juice. Satiety, assessed by two subjective scoring systems, was greater after whole fruit than after juice and the return of appetite was delayed. With oranges, as previously reported with apples, there was a significantly smaller insulin response to fruit than to juice and less postabsorptive fall in plasma glucose. With grapes, the insulin response to the whole fruit was, paradoxically, more than that to the juice, while postabsorptive glucose values were similar. The glucose in grapes appeared to be more insulinogenic than that in oranges and apples. Conversely, grape juice evoked less insulin than expected, possibly because its high osmolality delayed gastric emptying. However, diluting it did not increase its insulinogenicity. The plasma insulin and glucose responses to fruit appear to depend on the fiber as well as the glucose content of the fruit.

Building fluorescent sensors by template polymerization: the preparation of a fluorescent sensor for D-fructose.

[formula: see text] The application of molecular imprinting in making fluorescent sensors has been hampered by the lack of suitable fluorescent tags, which would respond to the binding event with significant fluorescence intensity changes. We have designed and synthesized a fluorescent monomer which allows for the preparation of fluorescent sensors of cis diols using molecular imprinting methods. This monomer was used for the preparation of sensitive fluorescent sensors for D-fructose.

Fructose-3-phosphate production and polyol pathway metabolism in diabetic rat hearts.

Previous studies have suggested that polyol-pathway and nonenzymatic glycation may be involved in the development of cardiac myopathy, a well-known manifestation of diabetes. Although the exact etiology of this complication is not fully understood, it is likely to be multifactorial. In this study, we investigated the metabolic consequences of diabetes and the effect of aldose reductase inhibitor (ARI) treatment on cardiac tissues of Sprague-Dawley rats. Perchloric acid (PCA) extracts of hearts from the animals were examined using 31P-nuclear magnetic resonance (NMR), gas chromatography/mass spectrometry (GC/MS), and high-performance liquid chromatography (HPLC). In 31P-NMR spectra of diabetic animals, a peak resonating at the chemical shift of 5.8 ppm with a coupling constant of 10 Hz was identified as fructose-3-phosphate (F3P). Undetectable in controls (< approximately 20 nmol/g), this metabolite was present at a concentration of 81.3 +/- 16.3 nmol/g wet weight (n = 4) in diabetic rat hearts. GC/MS analysis of these extracts from diabetics also identified a decomposition product of F3P, 3-deoxyglucosone (3DG), at a concentration of 9.4 +/- 3.5 nmol/g (n = 3), compared with 0.98 +/- 0.43 nmol/g (n = 3) in controls. No evidence was found for the expected detoxification products of 3-DG, 3-deoxyfructose and 2-keto 3-deoxygluconate. Concomitant with the elevation of F3P and 3DG, fructose and sorbitol levels were also elevated in diabetic animals. Surprisingly, ARI treatment was found to have no effect on the levels of these metabolites. These data suggest that either the heart may be unique in its production of fructose or it may not readily transport the ARI sorbinil. Production of the potent glycating agents F3P and 3DG in diabetics suggests that these compounds may be contributing factors in the glycation of cardiac proteins in the diabetic rat heart.

Accumulation of fermentable sugars and metabolic acids in food particles that become entrapped on the dentition.

Earlier studies (Kashket et al., 1991) showed that particles of high-starch snack foods remained longer on the teeth than those of high-sucrose, low-starch foods. The question arose whether the prolonged presence of food particles enhances cariogenicity. A study was undertaken to measure sugars, starches, and metabolic acids in retained food particles. Subjects consumed portions of different foods, and particles were removed from all bicuspids and first molars at defined times after swallowing. Dry weights, sugars, and short-chain carboxylic acids were determined. High-sucrose foods were cleared rapidly from the teeth, while high-starch foods were retained for up to 20 min. Sucrose, glucose, and fructose persisted in the retained particles. Particles of high-starch foods accumulated maltose and maltotriose, presumably from the breakdown of starch by salivary amylase. At maximum, maltose plus maltotriose constituted 94% of total sugars in particles of potato chips; corresponding values in doughnuts, peanut butter cookies, and salted crackers were 43, 51, and 61%, respectively. Total fermentable sugars in the particles of high-starch foods were similar to those for the high-sucrose confectionery products. Carboxylic acids accumulated within the particles, presumably due to the fermentation of the sugars by entrapped salivary micro-organisms. At maximum (5 to 7 min), acetic, formic, lactic, and propionic acids rose 17-, 30-, 15-, and 1.3-fold, respectively, in doughnuts, and to smaller degrees in potato chips, salted crackers, and chocolate-caramel-peanut bars. In summary, the study demonstrated the persistence of sugars, the progressive accumulation of starch breakdown products, and the fermentation of the accumulated sugars in retained food particles. The findings support the view that high-starch foods contribute to the development of caries lesions.

A short-term evaluation of semen and accessory sex gland function in phase III trial subjects receiving intravasal contraceptive RISUG.

Following the intravasal injection of a new male contraceptive RISUG (reversible inhibition of sperm under guidance) in volunteers, routine semen analysis, semen biochemistry and germ cell morphology were evaluated in comparison with the corresponding preinjection samples for a maximum period of 6 months. Sperm counts in all 25 subjects before injection varied from 45 to 120 x 10(6)/ml. Out of 25 subjects, 6 became azoospermic after 1 month, 15 after 2 months, 3 after 3 months and 1 after 4 months of contraceptive injection. The mean volume of the ejaculates was found to be less as compared to preinjection samples. Occasional sperm or sperm heads and immature germ cells were identified in only a few postinjected subjects. However, no pregnancy was reported in these subjects during the study period. Abnormal morphology found in most of the sperm, but not in the accompanying immature germ cells, may be due to a charge-related effect on the former but not on the latter cells. Neutral alpha-glucosidase, the biochemical marker for epididymis, was estimated to be significantly lower in the seminal plasma of all the postinjected subjects. On the other hand, acid phosphatase activity and fructose levels in the seminal plasma were found to be in the normal range. Based on the above findings, it is concluded that at least for the present study period, RISUG, a new male contraceptive, is effective as a partially occluding agent in the vas deferens.

An integrated bienzyme glucose oxidase-fructose dehydrogenase-tetrathiafulvalene-3-mercaptopropionic acid-gold electrode for the simultaneous determination of glucose and fructose.

A bienzyme biosensor for the simultaneous determination of glucose and fructose was developed by coimmobilising glucose oxidase (GOD), fructose dehydrogenase (FDH), and the mediator, tetrathiafulvalene (TTF), by cross-linking with glutaraldehyde atop a 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM) on a gold disk electrode (AuE). The performance of this bienzyme electrode under batch and flow injection (FI) conditions, as well as an amperometric detection in high-performance liquid chromatography (HPLC), are reported. The order of enzyme immobilisation atop the MPA-SAM affected the biosensor amperometric response in terms of sensitivity, with the immobilisation order GOD, FDH, TTF being selected. Similar analytical characteristics to those obtained with single GOD or FDH SAM-based biosensors for glucose and fructose were achieved with the bienzyme electrode, indicating that no noticeable changes in the biosensor responses to the analytes occurred as a consequence of the coimmobilisation of both enzymes on the same MPA-AuE. The suitability of the bienzyme biosensor for the analysis of real samples under flow injection conditions was tested by determining glucose in two certified serum samples. The simultaneous determination of glucose and fructose in the same sample cannot be performed without a separation step because at the detection potential used (+0.10 V), both sugars show amperometric response. Consequently, HPLC with amperometric detection at the TTF-FDH-GOD-MPA-AuE was accomplished. Glucose and fructose were simultaneously determined in honey, cola softdrink, and commercial apple juice, and the results were compared with those obtained by using other reference methods.