Saccharide Levels Research Articles

The Effect of Illumination Patterns during Mung Bean Seed Germination on the Metabolite Composition of the Sprouts

Mung bean (Vigna radiata (L.) Wilczek) sprouts are popular over the world because of their taste, nutritional value, well-balanced biochemical composition, and other properties beneficial for human health. Germination conditions affect the composition of metabolites in mung bean sprouts, so a detailed study into its variability is required. This article presents the results of a comparison of the metabolite composition in the leaves of mung bean sprouts germinated first in the dark (DS) and then in the light (LS). Gas chromatography with mass spectrometry (GC–MS) made it possible to identify more than 100 compounds representing various groups of phytochemicals. Alcohols, amino acids, and saccharides predominated in the total amount of compounds. The analysis of metabolomic profiles exposed a fairly high intra- and intervarietal variability in the metabolite content. DS and LS differed in the qualitative and quantitative content of the identified compounds. The intravarietal variability was more pronounced in DS than in LS. DS demonstrated higher levels of saccharides, fatty acids, acylglycerols, and phenolic compounds, while amino acids were higher in LS. Changes were recorded in the quantitative content of metabolites participating in the response of plants to stressors—ornithine, proline, GABA, inositol derivatives, etc. The changes were probably induced by the stress experienced by the sprouts when they were transferred from shade to light. The analysis of variance and principal factor analysis showed the statistically significant effect of germination conditions on the content of individual compounds in leaves. The identified features of metabolite variability in mung bean genotypes grown under different conditions will contribute to more accurate selection of an illumination pattern to obtain sprouts with desirable biochemical compositions for use in various diets and products with high nutritional value.

α-Galactosidase interacts with persistent organic pollutants to induce oxidative stresses in rice (Oryza sativa L.)

Persistent organic pollutants (POPs) in agricultural soil often triggered metabolic alterations and phytotoxicity in plants, ultimately threatening crop quality. Unraveling the phytotoxic mechanisms of POPs in crops is critical for evaluating their environmental risks. Herein, the molecular mechanism of POP-induced phytotoxicity in rice (Oryza sativa L.) was analyzed using metabolic profile, enzyme activity, and gene expression as linkages, including polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, polychlorinated biphenyls, and phthalate esters. Despite no observable changes in phenotypic traits (e.g., biomass and length of aboveground), the levels of reactive oxygen species (ROS) were promoted under stresses of the tested POPs, particularly 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), dibutyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP). Metabolomics analysis revealed that ROS contents positively correlated with metabolic perturbation levels (r = 0.83), among which the galactose metabolism was significantly inhibited when exposed to DBP, DEHP, or BDE-47. The α-Galactosidase (α-Gal) involved in galactose metabolism was targeted as the key enzyme for the phytotoxicity of DBP, DEHP, and BDE-47, which was revealed by the inhibition of saccharide levels (45.5−82.1%), the catalytic activity of α-Gal (18.5−24.3%), and the gene expression (28.5−34.5%). Molecular docking simulation suggested that the three POPs occupied the active sites of α-Gal and formed a stable protein-ligand complex, thus inhibiting the catalytic activity of α-Gal. Partial least-squares regression analysis indicated that α-Gal activity was negatively associated with hydrogen bond acceptor, rotatable bond, and topological polar surface area of POPs. The results offered novel insights into the molecular mechanisms of phytotoxicity of POPs and provided important information for evaluating the environmental risk of POPs.

Enzymatic liquification pattern of superior sweet potato starch of CIP-type

The liquification pattern of each type of starch at the best temperature and enzyme concentration varies, and the physical and chemical properties influence it. The whiter the starch, the smaller and more uniform the size of the granule and the higher amylose level and more amorphous regions, thus it results in a better liquification pattern and feasibility of starch for industrial raw materials. This research aimed to study the best changes in saccharide pattern during the liquification process of superior Centro International de La Papa (CIP)-type sweet potato starch at a temperature of 85oC and the concentration of alpha-amylase enzyme (0.07%) obtained from preliminary research. Hence, the advantages of the resulting hydrolyzate products were compared. The sweet potato starches tested were CIP-1, CIP-2, and CIP-5, tested using the Completely Randomized Design method with two repetitions. The variables observed were DE, dextrin, changes in amylase and amylopectin levels, high saccharide levels, maltotriose, maltose, glucose, and viscosity. The results showed that liquification of CIP-1 sweet potato starch for 225 mins produced better hydrolysate (30.52% DE, 16.28% maltose, 18.70% maltotriose, 1.06% glucose). Meanwhile, 20 mins of liquification resulted in higher dextrin (84.86%). However, the viscosity of CIP-1 was slightly thicker (22 cPs) than CIP-2 (15 cPs) and CIP -5 (15 cPs). The results showed that three types of starch were qualified for raw materials in the advanced hydrolysis industry (DE value was in the range of 20 - 45%), such as saccharification, with the order that CIP-1 was better than CIP-2 and CP-2 was better than CIP-5.

ApGA20ox1, a key gibberellin biosynthesis gene, regulates somatic embryogenesis and plant height in Agapanthus praecox

Agapanthus praecox is cultivated worldwide as an ornamental plant, and a dwarf ideotype has become more popular due to its superior lodging resistance and its suitability for use in cut flowers. The main bioactive gibberellin (GA) controlling scape height in A. praecox is GA4. A GA biosynthesis gene, ApGA20ox1, controls GA4 biosynthesis in this species. Here, we report the development of an A. praecox dwarf phenotype, which was generated by targeted suppression of the biosynthetic pathway for GAs. We utilized Agrobacterium-mediated genetic transformation using embryogenic callus with RNA interference (RNAi) to selectively reduce the expression of the ApGA20ox1 gene. Interestingly, suppression of ApGA20ox1 resulted in poor somatic embryogenesis potential in A. praecox, which was accompanied by a higher accumulation of hydrogen peroxide and poorer catalase activity. Subsequently, the RNAi plantlets showed lower GA levels, leading to inhibition of cell longitudinal size in leaves, which reduced plant height. Furthermore, the dwarf (RNAi) plantlets accumulated higher levels of saccharides and plant hormones such as indole acetic acid (IAA) and abscisic acid (ABA) than the wild type accumulated. However, the levels of endogenous hormones such as GAs, brassinosteroids (BRs), cytokinins (CTKs), which respond to cell proliferation and cell expansion, were significantly decreased. Isobaric tags for relative and absolute quantification (iTRAQ) proteomics revealed that differentially accumulated proteins (DAPs) were enriched differently between control and RNAi plantlets in the categories of cell wall, hormone metabolism, carbohydrate metabolism and stress response. This study provides new insights into the role of GAs in the process of somatic embryogenesis and plant height control in A. praecox.

Transcriptomic and metabolomic investigation of metabolic disruption in Vigna unguiculata L. triggered by acetamiprid and cyromazine

A variety of pesticides are often used in agricultural management to control target pests but may trigger disruptions in the metabolism of nontarget organisms, ultimately affecting crop quality. Acetamiprid (ACE) and cyromazine (CYR) are two frequently used insecticides on cowpea, so it is critical to understand whether these two insecticides cause metabolic disorders in cowpea quality changes and the mechanism by which they do so. Here, we used metabolomic and transcriptomic methods to explore the mechanisms of the effects of ACE, CYR, and their mixture (MIX) on cowpea. In this study, ACE, CYR and MIX had no significant effects on plant biomass or growth status but decreased the contents of starch, soluble protein, and total flavonoids. All treatments reduced the total flavonoid content, but MIX showed the largest reduction of 10.02%. Metabolomic and transcriptomic analyses revealed that ACE markedly affected amino acid metabolism, and CYR and MIX affected sugar metabolism and flavonoid synthesis pathways. ACE and CYR reduced the levels of alanine, glutamic acid, isoleucine and phenylalanine and the expression of amino acid-related genes in cowpea, while MIX significantly increased the levels of most amino acids. All pesticide treatments reduced saccharide levels and related genes, with the most pronounced reduction in the MIX treatment. Exposure to ACE decreased the content of naringenin chalcone and quercetin and increased the content of anthocyanins in cowpeas, while MIX caused a significant decrease in the contents of quercetin and anthocyanins. According to the current study, single and mixed pesticides had different effects on the active ingredients of cowpea, with MIX causing the most significant decrease in the metabolite content of cowpea. These results provide important insights from a molecular perspective on how neonicotinoids and triazine insecticides affect cowpea metabolism.

Confectionery gels: Gelling behavior and gel properties of gelatin in concentrated sugar solutions

Gummies are gelatin-based confectionery gel products where the sweeteners play vital roles in the product texture. This study focused on the impacts of sweeteners, which make up ~70–80% of the total solids, on the sol properties, gelling, and melting behaviors of gelatin (4–6%) gels. Gelling and melting properties of gelatin solutions with and without sweeteners (sucrose and glucose syrup) were characterized with rheology and differential scanning calorimetry, while the final gel texture and surface properties were analyzed with texture analyzer and tensiometer. In contrast to the plain systems without sweeteners, which gelled at around 22 °C and melted at 35 °C, the high-sweetener systems exhibited coil-to-helix transition at a higher temperature level, and the subsequent sol-gel transition depended greatly on the bulk viscosity. Below the sucrose-syrup level of 75.9%, the transition was observed at 34–43 °C; higher levels of saccharides postponed or inhibited the transition. The internal interactions of high-sugar gels were considerably weaker than the plain gels, suggesting smaller and more dispersed junction zones. The quantities of melting enthalpy and internal interactions increased with gelatin concentration but decreased with sucrose-syrup level, due to the high viscosity. Gel surfaces were generally hydrophobic (non-polar) except for the 4% gelatin gels, whose surface polarity increased with sugar level. Gel hardness and tackiness increased with gelatin concentration but did not change significantly with moisture/sugar content at 5–6% gelatin.

Multi-Component Antioxidative System and Robust Carbohydrate Status, the Essence of Plant Arsenic Tolerance.

Arsenic (As) contaminates the food chain and decreases agricultural production through impairing plants, particularly due to oxidative stress. To better understand the As tolerance mechanisms, two contrasting tobacco genotypes: As-sensitive Nicotiana sylvestris and As-tolerant N.tabacum, cv. ‘Wisconsin’ were analyzed. The most meaningful differences were found in the carbohydrate status, neglected so far in the As context. In the tolerant genotype, contrary to the sensitive one, net photosynthesis rates and saccharide levels were unaffected by As exposure. Importantly, the total antioxidant capacity was far stronger in the As-tolerant genotype, based on higher antioxidants levels (e.g., phenolics, ascorbate, glutathione) and activities and/or appropriate localizations of antioxidative enzymes, manifested as reverse root/shoot activities in the selected genotypes. Accordingly, malondialdehyde levels, a lipid peroxidation marker, increased only in sensitive tobacco, indicating efficient membrane protection in As-tolerant species. We bring new evidence of the orchestrated action of a broad spectrum of both antioxidant enzymes and molecules essential for As stress coping. For the first time, we propose robust carbohydrate metabolism based on undisturbed photosynthesis to be crucial not only for subsidizing C and energy for defense but also for participating in direct reactive oxygen species (ROS) quenching. The collected data and suggestions can serve as a basis for the selection of plant As phytoremediators or for targeted breeding of tolerant crops.

Development of a dedicated repertoire and food frequency questionnaire for estimating dietary fiber intake taking into account prebiotic (oligo)saccharides

AbstractRationaleThe scientific rationale for the recommendation in dietary fiber (DF) intake comes from the recognition of their health benefits. European Food Safety Authority (EFSA) recommend 25 g/d, based on the amount needed for intestinal laxation. Gut microbiota related health benefits are not yet included in the current dietary recommendations. Appropriate (and consensual) quantitative and qualitative analysis of DF are missing in food composition tables. One of the aim of the FiberTAG(1) project was to develop a dedicated database and a food frequency questionnaire (FFQ) allowing DF intake estimation including prebiotic (oligo)saccharides.MethodsA repertoire of DF detailing total, soluble and insoluble DF in food products consumed in Europe has been established based on the Souci-Fachmann-Kraut database, completed for soluble versus insoluble DF () and for prebiotic (oligo)saccharide levels using published data. The FiberTAG FFQ was submitted to healthy volunteers (7 men, 8 women; mean age: 21 yrs; mean BMI: 22kg/m2) and DF intakes were calculated using the new FiberTAG repertoire.ResultsThe FiberTAG repertoire detailed DF in 400 food items allocated into 4 categories (fruits, vegetables, cereal products and others) and 15 subcategories. The fiberTAG FFQ consists in 280 items regrouped in 4 high DF-containing food groups (vegetables including legumes, fruits including nuts and seed, cereal products and others) using frequency scale (6 categories), photographs for portion size and taking into account the seasonal occurrence for some vegetables or fruits. Data obtained from FiberTAG FFQ indicate a total DF intake of 36.44 g/d. This reveals a higher DF intake compared to previously reported intake for adults in Europe ranging from 16 to 24 g/d based on 24 h-recall or 3–7 days records(2). This difference might be explained by a more adequate inclusion of fruits and vegetables intake in FFQ than with other methods, as previously reported(3). Our data also showed that fructan, inulin and fructo-oligosaccharides intakes were 4.18, 2.95 and 1.00 g/day, respectively whereas galacto-oligosaccharides intake was 0.28 g/d.ConclusionThe new FiberTAG DF repertoire and FFQ are tools to evaluate the total amount of DF including prebiotic (oligo)saccharides ingested by healthy volunteers. The FiberTAG project generates scientific knowledge that helps to take into account microbiota-nutrient interactions to establish DF intake recommendations as part of healthy lifestyles.

가수량에 따른 누룩의 발효기간별 품질 특성

To investigate the effects of water contents on the characteristics of Nuruk, three sets of Nuruks were prepared with water contents of 20%, 26%, and 30%. Morphological shapes, internal temperature, physicochemical properties, enzyme activity, metabolites, and volatile chemical patterns were monitored for 30 days. Regardless of the water content, the morphological shapes showed that the mold mycelia were extended to the inside and the weight and size were decreased in the three Nuruks. The internal temperature was the highest (39.7℃) for a water content of 26%. Higher water contents were accompanied by lower pH. α-Amylase activity was increased 1.5-fold in Nuruk containing 30% water. Acidic protease activity was also the highest (1,800 U/g) after 20 days for Nuruk with 30% water content. In addition, the levels of saccharides (glucose, galactose, and fructose) were increased 2.4-, 1.97-, 1.5-fold, respectively, with higher water contents. Organic acid (lactic acid) content was the highest (2.2 mM) in Nuruk containing 30% water. Free amino acid (glutamate and proline) contents in Nuruk with 26% and 30% water contents were higher than those in the 20%. The volatile patterns were different in the three Nuruks with 20%, 26% and 30% water contents. This study suggests that the range of water content of 26-30% might be appropriate for the production of Nuruk with high saccharification and proteolytic activities.

Environmental controls on extracellular polysaccharide accumulation in a California grassland soil

Areas with Mediterranean climate regimes, such as California, have cool wet winter growing seasons and hot dry summers. Summer is a time of stress for plants, yet soil microbes survive and biochemical processes continue. One mechanism soil microorganisms might use to survive drought is to produce extracellular polysaccharides (EPSac). We hypothesized that in dry soils, pools of microbial EPSac would therefore increase, but that this increase would depend on having carbon available from fresh plant inputs. We manipulated plant cover and dry season length and measured soil saccharides in a seasonally dry California grassland soil; we evaluated total sugars as well as the mix of sugars present in the soil. Soil cores were collected monthly from July 2014 to February 2015. Sugar residues were analyzed using Gas Chromatography—Mass Spectroscopy (GC-MS). Drier soils showed larger pools of sugar residues; these residues decreased as moisture increased across sample dates and treatments. Plant removal only slightly reduced soil saccharide levels. However, the pools of individual saccharides varied only modestly across all treatments and dates, and correlated with total microbial biomass, suggesting that extracellular polysaccharides may be a constitutive response to survival in soil, rather than an inducible response to dry conditions.

The assessment of changes to the nontuberculous mycobacterial metabolome in response to anti-TB drugs.

Mycobacterium species can cause a range of nontuberculous infections of healthy and immunocompromised people as well as infected people during and after surgical procedures. The similarity of nontuberculous mycobacteria (NTM) to the tuberculosis bacilli (TB) could ultimately enable the use of anti-TB drugs for the genus. Hence, three NTM (Mycobacterium smegmatis, Mycobacterium phlei and Mycobacterium avium) were cultured under different lab conditions, causing two mycobacterial phenotypes (active and dormant), and treated with isoniazid (INH) and ethambutol (EMB) independently or in combination. Metabolite profiling was applied to facilitate the investigation and characterisation of intracellular targets affected by the antibiotics. Aliquots of the cell culture were taken over the treatment period and the metabolite profile of the cells analysed by gas chromatography mass spectrometry. Comparative analysis of the metabolite levels to untreated mycobacteria confirmed the successful action of the antibiotics on the metabolism of all three species. Furthermore, single metabolites and metabolite pathways affected by the antibiotics could be identified and included, besides the known target sites for INH and EMB on mycobacterial cells, changes in e.g. nucleotide and saccharide levels. The combined treatment highlighted the property of EMB to enhance the effects of INH even under hypoxic culture conditions.

Candida species Rewired Hyphae Developmental Programs for Chlamydospore Formation.

Chlamydospore formation is a characteristic of many fungal species, among them the closely related human-pathogenic dimorphic yeasts Candida albicans and C. dubliniensis. Whereas function and regulation of filamentation are well-studied in these species, the basis of chlamydospore formation is mostly unknown. Here, we investigate the contribution of environmental and genetic factors and identified central proteins involved in species-specific regulation of chlamydosporulation. We show that specific nutrient levels strongly impact chlamydospore initiation, with starvation favoring sporulation and elevated levels of saccharides or peptone inhibiting it. Thresholds for these nutritional effects differ between C. albicans and C. dubliniensis, which explain species-specific chlamydospore formation on certain diagnostic media. A C. albicans nrg1Δ mutant phenocopied C. dubliniensis, putting Nrg1 regulation at the basis of species-specific chlamydospore formation under various conditions. By screening a series of potential chlamydospore regulators, we identified the TOR and cAMP pathways as crucial for sporulation. As rapamycin treatment blocked chlamydosporulation, a low basal Tor1 activity seems to be essential. In addition, TOR effector pathways play an important role, and loss of the NCR (nitrogen catabolite repression) gene regulators Gat1 and Gln3 reduced chlamydospore formation. A severe reduction was seen for a C. albicans gcn4Δ deletion strain, implicating a link between regulation of amino acid biosynthesis and chlamydospore development. On the other hand, deletion of the GTPase gene RAS1 and the adenylyl cyclase gene CYR1 caused a defect in chlamydospore formation that was mostly rescued by cAMP supplementation. Thus, cAMP-signaling is a second major pathway to control chlamydospore production. Finally, we confirmed light exposure to have a repressive effect on chlamydosporulation. However, permanent illumination only reduced, but not abolished chlamydospore production of C. albicans whereas C. dubliniensis sporulation was unaffected. In summary, we describe novel environmental factors which determine chlamydosporulation and propose a first model for the regulatory network of chlamydospore formation by different Candida species.

Optimization of Protein Removal from Soybean Whey Wastewater Using Chitosan Ultrafiltration

AbstractProteins were removed from soybean whey wastewater using the chitosan flocculation technique, and this method was compared with lime flocculation, and transglutaminase polymerization. Compared with other flocculation methods, chitosan flocculation exhibited higher saccharide levels (p < 0.05), lower protein movement (p < 0.05) through the membrane and lower ultrafiltration membrane pollution levels and could be[0] useful for the development of industrial flocculation processes. The chitosan flocculation procedure was optimized by an L18(37) orthogonal array experimental design (OAD) with four factors at three levels. Optimum variables were a chitosan dosage of 0.8 g/L and a standing pH, time and temperature of 5.5, 60 min and 30C, respectively. Under these conditions, the experimental rate of protein removal was 61.21%, which was consistent with the predicted value (58.85%). These results showed that chitosan flocculation alleviated membrane fouling to a large extent.Practical ApplicationsThis study demonstrated the differences in the protein removal properties due to the different processes, i.e., lime flocculation, transglutaminase polymerization and chitosan flocculation technique, in the purification soybean whey wastewater. The information on chitosan combined with ultrafiltration would help in understanding their influences on soybean whey wastewater. Chitosan‐ultrafiltration process will facilitate the subsequent recovery of soybean polysaccharides and can be used as an environmentally friendly means for soy whey wastewater purification.

Seasonal variations and source estimation of saccharides in atmospheric particulate matter in Beijing, China

Saccharides are important constituents of atmospheric particulate matter (PM). In order to better understand the sources and seasonal variations of saccharides in aerosols in Beijing, China, saccharide composition was measured in ambient PM samples collected at an urban site in Beijing. The highest concentrations of total saccharides in Beijing were observed in autumn, while an episode with abnormal high total saccharide levels was observed from 15 to 23 June, 2011, due to extensive agricultural residue burning in northern China during the wheat harvest season. Compared to the other two categories of saccharides, sugars and sugar alcohols, anhydrosugars were the predominant saccharide group, indicating that biomass burning contributions to Beijing urban aerosol were significant. Ambient sugar and sugar alcohol levels in summer and autumn were higher than those in spring and winter, while they were more abundant in PM2.5 during winter time. Levoglucosan was the most abundant saccharide compound in both PM2.5 and PM10, the annual contributions of which to total measured saccharides in PM2.5 and PM10 were 61.5% and 54.1%, respectively. To further investigate the sources of the saccharides in ambient aerosols in Beijing, the PM10 datasets were subjected to positive matrix factorization (PMF) analysis. Based on the objective function to be minimized and the interpretable factors identified by PMF, six factors appeared to be optimal as to the probable origin of saccharides in the atmosphere in Beijing, including biomass burning, soil or dust, isoprene SOA and the direct release of airborne fungal spores and pollen.

Organic tracers of primary biological aerosol particles at subtropical Okinawa Island in the western North Pacific Rim

AbstractPrimary biological aerosol particles (PBAPs) play an important role in affecting atmospheric physical and chemical properties. Aerosol samples were collected at Cape Hedo, Okinawa Island, Japan, from October 2009 to February 2012 and analyzed for five primary saccharides and four sugar alcohols as PBAP tracers. We detected high levels of sucrose in spring when blossoming of plants happens and prolifically emits pollen to the air. Concentrations of glucose, fructose, and trehalose showed levels higher than the other saccharides in spring in 2010. In comparison, primary saccharide levels were mutually comparable in spring, summer, and autumn in 2011, indicating the interannual variability of their local production in subtropical forests, which is driven by local temperature and radiation. High trehalose events were found to be associated with Asian dust outflows, indicating that Asian dust also contributes to PBAPs at Okinawa. Sugar alcohols peaked in summer and correlated with local precipitation and temperature, indicating high microbial activities. Positive matrix factorization analysis confirmed that the PBAPs are mainly derived from local vegetation, pollen, and fungal spores. A higher contribution of PBAP tracers to water‐soluble organic carbon (WSOC) was found in summer (14.9%). The annual mean ambient loadings of fungal spores and PBAPs were estimated as 0.49 µg m−3 and 4.12 µg m−3, respectively, using the tracer method. We report, for the first time, year‐round biomarkers of PBAP and soil dust and their contributions to WSOC in the subtropical outflow region of the Asian continent.

Development and characterization of Haemophilus influenzae type b conjugate vaccine prepared using different polysaccharide chain lengths

Capsular polysaccharide conjugates of Haemophilus influenzae type b (Hib) are important components of several mono- or multi-valent childhood vaccines. However, their access to the most needy people is limited due to their high cost. As a step towards developing a cost effective and more immunogenic Hib conjugate vaccine, we present a method for the preparation of Hib capsular polysaccharide (PRP)–tetanus toxoid (TT) conjugates using optimized PRP chain length and conjugation conditions. Reactive aldehyde groups were introduced into the polysaccharides by controlled periodate oxidation of the native polysaccharide, which were subsequently covalently linked to hydrazide derivatized tetanus toxoid by means of reductive amination. Native polysaccharides were reduced to average 100 or 50kDa polysaccharide and 10kDa oligosaccharides in a controlled manner. Various conjugates were prepared using Hib polysaccharide and oligosaccharide yielding conjugates with polysaccharide to protein ratios in the range of 0.25–0.5 (w/w) and free saccharide levels of less than 10%. Immunization of Sprague Dawley rats with the conjugates elicited specific antibodies to PRP. The low molecular weight PRP–TT conjugates were found to be more immunogenic as compared to their high molecular weight counterparts and the PRP–TT reference vaccine.

Alterations in milk and blood metabolomes during the first months of lactation in dairy cows

The molecular composition of milk is influenced by various genetic and environmental factors. Time is one important factor, and the fact that certain milk components change over the course of lactation is widely accepted. Untargeted global metabolomics is an approach to study hundreds of low molecular weight compounds simultaneously. In this study, mass spectrometry-based global metabolomics was used to follow the course of changes in milk (n=133) and blood plasma (n=133) during the early stage of lactation. Little correlation was found between the molecular composition of blood plasma and milk. Blood showed a higher dependence on animal individuality than did milk, in which common evolutions in time resolved. Citrate and lactose had the greatest effect on these changes; however, the most significant changes in milk during the first months of lactation were associated with phosphorylated saccharide levels, whereas the most significant changes in blood plasma were associated with levels of polyunsaturated fatty acids containing phosphatidylcholine. In conclusion, a new systemic approach was used to search for minor metabolites whose concentrations were significantly altered in milk and blood during the first months of lactation.

Gas chromatography‐mass spectrometric method for metabolic profiling of tobacco leaves

A gas chromatography-mass spectrometric method was developed for profiling of tobacco leaves. The differentiation among tobacco leaves planted in two different regions was investigated. Prior to analysis, the extraction solvent formulation was optimized and a combination of water, methanol and acetonitrile with a volume ratio of 3:1:1 was found to be optimal. The reproducibility of the method was satisfactory. Kendall tau-b rank correlation coefficients were equal to 1 (p<0.05) for 82% of the resolved peaks (up to 95% of the overall peak areas), indicating the good response correlation. Forty-four compounds including 9 saccharides, 9 alcohols, 9 amino acids, 16 organic acids and phosphoric acid were identified based on standard compounds. The method was successfully applied for profiling of tobacco leaves from Zimbabwe and Yunnan of China. Our result revealed that levels of saccharides and their derivatives including xylose, ribose, fructose, glucose, turanose, xylitol and glyceric acid were more abundant while sucrose, glucitol and D-gluconic acid were less abundant in tobacco leaves from Yunnan as compared to those from Zimbabwe. Amino acids such as L-alanine, L-tyrosine and L-threonine were found to be richer in Zimbabwe tobacco than in Yunnan tobacco.

Response to “Response to the Letter Regarding ‘Sugar Content of Popular Sweetened Beverages'”

TO THE EDITOR: In the response of Goran et al. ((1)) we appreciate acknowledgement that there is no longer a dispute regarding the sugar composition of high-fructose corn syrup (HFCS) and that there were errors caused by the limitations of the method used in the study. It is important to note that the levels of saccharides in HFCS are not misrepresented and conform to the Food Chemical Codex specifications for High Fructose Syrups. We believe that there is a simple mathematical error at the root of this issue. Both Association of Official Analytical Chemists (AOAC) 977.20 and AOAC 979.23 correctly measure the individual sugars in percentage by volume of the sample. They do not necessarily measure the percentage of individual sugars as a percentage of total sugars in the sample. Exclusion of the undetected 5% of maltose and degree of polymerization (DP3+) sugars typically present in HFCS 55 results in an overestimation of the fructose content of the ingredient syrup when calculated on a percent of total sugar basis. Thus, in our studies of 55% HFCS, the average fructose content was 55.9% on a percent of total sugars basis. However, it increased to 58% or greater when maltose and DP3+ sugars were excluded. We would point out that the 65:35 fructose to glucose ratio referred to in the response implies that no other sugars are present. In their response, Goran et al. already acknowledged this not to be the case for beverage samples using HFCS. For a beverage sweetened with 55 HFCS, the proper ratio of sugars would be 55.6 fructose: 40.1 glucose: 4.3 maltose and higher sugars based on the average of our 55 HFCS analysis using a method which accounts for the higher sugars that are present. We would agree that further study using appropriate methods is warranted. The flaws created in this study by the exclusion of maltose and higher sugars make it difficult to draw conclusions in the current form and we believe that the application of rigorous methodology that includes all the saccharides present will resolve the current uncertainties. The authors declared no conflict of interest.

Effects of xylooligosaccharides and sugars on the functionality of porcine myofibrillar proteins during heating and frozen storage

The gel properties of mixed gels of salt-soluble proteins (SSP) and xylooligosaccharides (XOS) or other sugars were investigated. Furthermore, the water-holding capacity, synaeresis, and protein surface hydrophobicity of heated SSP/sugar mixed gels under frozen storage were evaluated. Addition of XOS and sugars lowered expressible moisture and thus elevated the water-holding capacity of mixed gels. The protein surface hydrophobicity (RSo) of heated (71.1 °C) XOS-added gels was lower than that of other treatments, indicating possible lower exposure of protein hydrophobic groups. Results from freeze/thaw stability and protein solubility showed a descending pattern of SSP/sugar mixed gels during frozen storage, with XOS-added gels being better in both test items than other treatments. Increasing saccharide levels improved freeze/thaw stability and protein solubility of frozen mixed gels. Addition of xylooligosaccharides resulted in the lowest RSo among treatments and appears to impact better cryoprotective function to meat proteins than other sugars.