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Among the structural isomers of sucrose, turanose has been considered as one of good candidates as novel sweetener due to its mild taste, low calorie, and anti-cariogenicity. Here, various physicochemical properties of turanose, such as solubility, temperature and pH stabilities, viscosity, non-enzymatic browning reaction, and dynamic vapor sorption, were investigated by comparing them to those of other commercial sugars. Turanose did not significantly hydrolyze through the simulated digestion tract overall but in the artificial small intestinal environment specifically, turanose degraded by only 18% when sucrose was hydrolyzed by 36% after 4 h. In addition, physicochemical properties of turanose confirmed that it had a potential to replace sucrose due to similar or better product qualities as a food ingredient than other types of sugars with similar chemical structure. Thus, our study suggests that turanose can be applied as a functional sweetener or bulking agent in food processing.

We have previously discovered that heated honey but not unheated honey could induce the secretion of granulocyte-colony stimulating factor (G-CSF) in the MCE301 intestinal epithelial cells. The objective of this study was to identify compounds in honey that could contribute to this activity. We bought several kinds of commercial honey samples derived from different flowers, as well as corn syrup samples, in the markets of China and Japan, and heated them at 180 °C for 30 min. MCE301 cells were treated with the medium containing the samples, and G-CSF levels in the medium were measured by ELISA. By comparing their activities and sugar contents, we discovered that isomaltose was primarily implicated. The optimum heating conditions for isomaltose were at 180 °C for 60 min or at 200 °C for 15–30 min, and these time- and temperature-dependencies were similar to those of honey in our previous study. When heated isomaltose was partitioned by dialysis, the active ingredients were transferred into a high-molecular-weight fraction. By size-exclusion HPLC analysis, the average molecular weight of heated isomaltose was 790 kDa. When heated isomaltose was hydrolyzed by acids, glucose was subsequently produced. Maltose, sucrose, turanose, and trehalose did not exhibited any activity when heated at 180 °C for 60 min, indicating that the glucose groups with α(1 → 6)-binding in the isomaltose molecule play important roles in its activity when oxidatively polymerized by heat. The stimulating activity of heated isomaltose was inhibited by toll-like receptor 4 (TLR4) inhibitor, suggesting that heated isomaltose activates TLR4 to induce G-CSF. Since G-CSF is clinically used for cancer patients to accelerate their recovery from neutropenia following chemotherapy or accompanied with aplastic anemia, these findings indicate that honey which contains high level of isomaltose could improve immunosuppressive conditions when honey is heated, and that heated isomaltose might be of potential therapeutic use in patients with compromised immunity caused by chemotherapeutic agents.

In order to reveal the role of sucrose (Suc) in early drought response in plants, transgenic rice (Oryza sativa L.) plants overexpressing the maize (Zea mays L.) C4-phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) gene (C4-pepc) (PC) and their untransformed wild type (WT) were used under 12 % (m/v) polyethylene glycol 6000 to simulate drought conditions. The results showed that PC has higher relative water content, the increased Suc content, and anthocyanin accumulation than WT during PEG treatment. By spraying 1 % Suc and 1 % Suc non-metabolic analog, turanose, on these plants, Suc in PC leaves increased anthocyanin content and Ca2+ content. Further experiments using the Ca2+ chelator (EGTA), Ca2+ channel antagonist (ruthenium red), and abscisic acid inhibitor (nordihydroguaiaretic acid), showed that, in PC plants, Suc content is closely related to the expression of sucrose nonfermenting-1-related protein kinases 2 (SnRK2s) such as SAPK8, SAPK9, and SAPK10 via abscisic acid, and the SnRK3 such as SnRK3.1, SnRK 3.4, and SnRK3.21 via Ca2+ and calcineurin B-like as well. Furthermore, the target genes associated with anthocyanin synthesis phenylalanine ammonia lyase, chalcone isomerase, chalcone synthase, flavonoid-3-hydrogenase, flavonoid-3'-hydrogenase, dihydroflavonone reductase, and anthocyanin synthase, their regulated genes basic helix-loop-helix (bHLH) proteins OsB1 and OsB2, R2R3-MYB transcription factor OsC1, and some transcription factors (constitutively photomorphogenic 1, elongated hypocotyl 5, and purple acid phosphatase gene 2) in PC plants also increased via Suc and Ca2+ during the PEG treatment. Some Suc tranporter genes OsSUT1 and OsSUT5 in PC lines during PEG treatment further showed an enhancement for the function of the signal of Suc. Thereby, increasing anthocyanin biosynthesis via Suc and Ca2+ signaling cascade is one of the important mechanisms on drought tolerance in the PC lines.

Amylosucrase (AS; EC 2.4.1.4) is an enzyme that has great potential in the biotechnology and food industries, due to its multifunctional enzyme activities. It can synthesize α-1,4-glucans, like amylose, from sucrose as a sole substrate, but importantly, it can also utilize various other molecules as acceptors. In addition, AS produces sucrose isomers such as turanose and trehalulose. It also efficiently synthesizes modified starch with increased ratios of slow digestive starch and resistant starch, and glucosylated functional compounds with increased water solubility and stability. Furthermore, AS produces turnaose more efficiently than other carbohydrate-active enzymes. Amylose synthesized by AS forms microparticles and these can be utilized as biocompatible materials with various bio-applications, including drug delivery, chromatography, and bioanalytical sciences. This review not only compares the gene and enzyme characteristics of microbial AS, studied to date, but also focuses on the applications of AS in the biotechnology and food industries.

The aim of this study was to assess the influence of different adulteration agents (agave, maple, corn, rice and inverted sugar) on honey rheology. There was studied the influence of different percentages of adulteration agent on steady state and dynamic state rheology but also on rheology in the negative temperature domain. The authentic honey and adulterated ones behaved as a Newtonian fluid with a liquid-like behavior (Gʺ>>Gʹ). Regarding the physicochemical parameters analyzed (moisture and sugar content), significant changes depending on the adulteration agent/degree used were observed. The viscoelastical parameters (η*—complex viscosity, Gʹ —elastic modulus and Gʺ—viscous modulus) and glass transition temperature (Tg) were predicted in function of the chemical composition (moisture content, glucose, fructose, sucrose, maltose, raffinose, trehalose, turanose, melesitose, and F/G ratio) using the PLS-R (partial least square regression). All parameters analyzed had a high regression coefficient for calibration (> 0.810) and validation (> 0.790), except for the elastic modulus.

Twelve thermophilic Anoxybacillus strains were isolated from sediment and water samples from a Karvachar hot spring located in the northern part of Nagorno-Karabakh. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, one of the isolates, designated strain K1T, was studied in detail. The cells are straight, motile rods that are 0.2–0.4×2.3–7.2 µm in size. The strain is a Gram-stain-positive, moderately thermophilic facultative anaerobe with an optimum growth temperature of 60–65 °C and a growth temperature range of 45–70 °C. Growth of strain K1T was observed at pH 6–11 (optimum, pH 8–9) and was inhibited in the presence of NaCl concentrations above 2.5 % (optimum, 1–1.5 %). The isolate could utilize a wide variety of carbon sources, including d-arabinose, d-ribose, d-galactose, d-fructose, d-mannitol, maltose, aesculin, melibiose, sucrose, trehalose, raffinose, amidone, glycogen, turanose, d-lyxose, d-tagatose, potassium gluconate and 2-keto-gluconate. The strain was able to hydrolyse starch, casein and gelatin, was positive for oxidase and catalase, and reduced nitrate to nitrite, but was negative for H2S production. Production of urease and indole was not observed. The major cellular fatty acids were C15 : 0 iso, C16 : 0 and C17 : 0 iso (52.5, 13.6 and 19.6 % of total fatty acids, respectively). Strain K1T shares >99 % 16S rRNA sequence similarity and a genomic average nucleotide identity value of 94.5 % with its closest relative, Anoxybacillus flavithermus DSM 2641T, suggesting that it represents a separate and novel species, for which the name Anoxybacillus karvacharensis sp. nov. is proposed. The type strain of Anoxybacillus karvacharensis is K1T (=DSM 106524T=KCTC 15807T).

To develop an economically feasible fermentation process, this study designed a novel bioprocess based on the co-culture of engineered Bacillus subtilis and Escherichia coli for the co-production of extracellular D-psicose and intracellular lipase. After optimizing the co-culture bioprocess, 11.70 g/L of D-psicose along with 16.03 U/mg of lipase was obtained; the glucose and fructose were completely utilized. Hence, the conversion rate of D-psicose reached 69.54%. Compared with mono-culture, lipase activity increased by 58.24%, and D-psicose production increased by 7.08%. In addition, the co-culture bioprocess was explored through metabolomics analysis, which included 168 carboxylic acids and derivatives, 70 organooxygen compounds, 34 diazines, 32 pyridines and derivatives, 30 benzene and substituted derivatives, and other compounds. It also could be found that the relative abundance of differential metabolites in the co-culture system was significantly higher than that in the mono-culture system. Pathway analysis revealed that, tryptophan metabolism and β-alanine metabolism had the highest correlation and played an important role in the co-culture system; among them, tryptophan metabolism regulates protein synthesis and β-alanine metabolism, which is related to the formation of metabolic by-products. These results confirm that the co-cultivation of B. subtilis and E. coli can provide a novel idea for D-psicose and lipase biorefinery, and are beneficial for the discovery of valuable secondary metabolites such as turanose and morusin. Co-cultivation was firstly carried out for the co-production of D-psicose and lipase. The carbon source glucose and fructose were fully utilized during co-culture. The yield of D- psicose was 11.70 g/L, and the conversion rate reached 69.54%. Self-induced expression of lipase was realized with enzyme activity of 16.03 U/mg. Metabolomics analyses were used to explore the co-culture effects of mixed strains.

Effects of turanose on the functional properties of instant fried noodles were assessed mainly in terms of rheology‐ and oil uptake‐related characteristics. The Mixolab results showed that the water absorption of dough decreased as the turanose level increased, whereas the gel stability and starch retrogradation increased. Also, the use of turanose lowered the storage and loss moduli of the dough, showing a more viscous nature. These viscoelastic characteristics were correlated with the decreased resistance to extension and increased extensibility. NMR spin–spin relaxation analysis showed three distinct water populations in the turanose noodle doughs whose relaxation times were varied depending on the level of turanose. After frying, the noodles with turanose exhibited a continuous and smooth surface as well as a less porous structure. These microstructural characteristics were correlated with the reduced oil uptake by 20.8%, the enhanced oxidative stability and furthermore the improved breaking stress.

In the daily diet, sweeteners play an indispensable role. Among them, sucrose, a widely occurring disaccharide in nature, is a commonly used sweetener. However, the intake of sucrose can cause a rapid increase in blood glucose, which leads to a number of health problems. Therefore, there is an urgent need for possible alternatives to sucrose. Currently, four naturally occurring sucrose isomers, trehalulose, turanose, leucrose, and isomaltulose are considered to be possible alternatives to sucrose due to their suitable sweetness, potential physiological benefits, and feasible production processes. This review covers the properties of these alternative sweeteners, including their structure, sweetness, hydrolysis rate, toxicology, and cariogenicity, and exhibits their potential applications in chronic diseases management, anti-inflammatory supplement, prebiotic dietary supplement, and stabilizing agent. The biosynthesis of these sucrose isomers using carbohydrate-active enzymes and their industrial production processes are also systematically summarized.

A facultatively anaerobic and Gram-stain-negative bacterium, strain GY_GT, was isolated from a river (Daedeock-cheon) in Daejeon, Republic of Korea. The isolate was catalase-positive, oxidase-positive and formed yellow colonies. Strain GY_GT was phylogenetically classified as belonging in the genus Sphingorhabdus. Its closely related strains were Sphingorhabdus wooponensis 03SU3-PT (97.1 % similarity), Sphingorhabdus buctiana T5T (96.9 %), Sphingorhabdus contaminans JC216T (96.5 %), Sphingorhabdus rigui 01SU5-PT (96.5 %) and Sphingorhabdus planktonica G1A_585T (96.3 %) based on 16S rRNA gene sequences. The growth conditions for GY_GT were at 10–45 °C (optimum, 25 °C), pH 6–10 (pH 7) and 0–4% NaCl (0.5–1.5 %). Strain GY_GT could utilize turanose, d-fructose-6-phosphate, glucuronamide, α-keto-glutaric acid and acetoacetic acid. The major fatty acids of strain GY_GT were summed features 8 (C18 : 1 ω7c/C18 : 1 ω6c; 40.6 %) and 3 (C16 : 1 ω6c/C16 : 1 ω7c; 24.7 %). The major quinone required for respiration was Q-10. The polar lipids of strain GY_GT were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and sphingolipid. The G+C content of the genome was 57.7 mol%. The average nucleotide identity and average amino acid identity values between strains GY_GT and S. wooponensis were 71.0 and 72.7 %, respectively. Based on phylogenetic and phenotypic attributes, we suggest that strain GY_GT is a novel species in the genus Sphingorhabdus and propose the name Sphingorhabdus pulchriflava. The type strain is GY_GT (=KCTC 62791T=JCM 32855T).

The effects of turanose on the physicochemical properties of rice flour systems (aqueous suspension, dough, and noodles) were investigated in terms of rheology, microstructure, and water mobility. Inclusion of turanose increased the pasting viscosities of rice flour by maintaining a closely-packed structure at high temperatures that was confirmed by the real-time microscopic measurements during heating. The elevated probability of intergranular interactions by turanose apparently raised both storage (G') and loss (G″) moduli of the rice flour pastes as well as their respective viscosities. NMR spin-spin relaxation times showed two distinct water populations in the turanose-rice flour samples. The Mixolab experiments demonstrated that the rice doughs with higher levels of turanose exhibited greater dough stability as well as higher degrees of starch gelatinization and retrogradation. Furthermore, the extruded rice noodles containing turanose exhibited a higher expansion ratio and a firmer texture that contributed to lowering the cooking loss by 24.5%.

A unique thermostable amylosucrase from Bifidobacterium thermophilum was produced as a recombinant protein with the half-life of 577 h at 50 °C. By adding 1.0 M fructose, turanose yield was improved from 22.7% to 43.3% with 1.0 M sucrose, and from 23.7% to 39.4% with 1.5 M sucrose. Sucrose consumption rate was greatest at 55 °C, but the lowest amount of turanose was produced. Thus, turanose yield from sucrose biomass was inversely proportional to reaction temperature and was highly dependent on [fructose]. Meanwhile, insoluble α-glucan yield was clearly reduced as [fructose] increased. With 1.0 M fructose + 1.0 M sucrose, glucan byproduct yield significantly decreased from 29.4% to 1.1%. Molecular weights of linear glucans were almost identical among various [sucrose]s and were homogenous with very low polydispersity. This unique dual reaction patterns of amylosucrase enzyme would be very useful for massive productions of two different biomaterials simply by changing sucrose biomass concentration.

Rapeseed meal is a by-product of oil producing industry which contains a high amount of protein (37–42%). To prepare protein isolates, suitable for human nutrition, the industrial rapeseed meal is often subjected to a pre-treatment with aqueous ethanol solution. The aim of the study was to investigate the phytochemical profile and bioactivity of the ethanol-wash solutes (EWS) obtained as a waste product of the main process of the protein isolate preparation from industrial rapeseed meal. Proximate composition analysis revealed that total carbohydrates were more than half of the product (60.63%). The content of hydrolysable reducing sugars was 44.13%, while glucose was 7.22%. The total phenols amounted 13.38%. EWS contained 1.63% total flavonoids and 242.05 μmol/g dry weight glucosinolates. The major components, as determined by GC–MS analysis, were sucrose, turanose and melibiose with 22.68%, 4.08% and 3.97% of total ion current (TIC) of polar compounds, respectively; cetyl alcohol (2.45% of TIC) and methyl oleate (2.08% of TIC) representing nonpolar compounds, and sinapic acid (73.71% of TIC) which was the prevailing substance of the phenolic acids identified in the EWS. The 0.2% EWS, prepared in aqueous 70% ethanol solution, exhibited 70.68% scavenging capability of DPPH radicals and 585.11 μmol Fe2+/ g EWS (dry weight) reducing capacity. The product demonstrated limited antibacterial but broad antifungal activity which was expressed against Aspergillus niger (ATCC 1015), Aspergillus flavus, Penicillium sp., Rhizopus sp. and Fusarium moniliforme (ATCC 38932) as determined by the agar-well diffusion assay. Overall, EWS exhibited bioactive capacity, which revealed its potential application as a value-added product in the food and nutraceutical industries or agriculture. The broad-spectrum antifungal activity makes the product a prospective agent for food biopreservation or plant bioprotection.

This study focuses on the detectable metabolome of high-quality raw hazelnuts (Corylus avellana L.) and on its changes after dry-roasting. Informative fingerprinting was obtained by comprehensive two-dimensional gas chromatography with fast-scanning quadrupole mass spectrometry (GC&times, GC-qMS) combined with dedicated data processing. In particular, combined untargeted and targeted (UT) fingerprinting, based on pattern recognition by template matching, is applied to chromatograms from raw and roasted samples of Tonda Gentile Trilobata and Anakliuri hazelnuts harvested in Italy and Georgia. Lab-scale roasting was designed to develop a desirable organoleptic profile matching industrial standards. Results, based on 430 peak features, reveal that phenotype expression is markedly correlated to cultivar and pedoclimatic conditions. Discriminant components between cultivars are amino acids (valine, alanine, glycine, and proline), organic acids (citric, aspartic, malic, gluconic, threonic, and 4-aminobutanoic acids), and sugars and polyols (maltose, xylulose, xylitol, turanose, mannitol, scyllo-inositol, and pinitol). Of these, alanine, glycine, and proline have a high informational role as precursors of 2-acetyl- and 2-propionylpyrroline, two key-aroma compounds of roasted hazelnuts. Roasting has a decisive impact on metabolite patterns&mdash, it caused a marked decrease (&minus, 90%) of alanine, proline, leucine and valine, and aspartic and pyroglutamic acid and a &minus, 50% reduction of saccharose and galactose.

Amylosucrase (ASase) is α-glucan-producing enzyme. Four putative ASase genes (bdas, blas, bpas, and btas) were cloned from Bifidobacterium sp. and expressed in Escherichia coli. All ASases from Bifidobacterium sp. (BAS) displayed typical ASase properties with slightly different characteristics. Among the BASs studied, BdAS and BpAS showed maximal enzyme activities at 35 and 30 °C, respectively, whereas BlAS and BtAS were maximally active at higher temperatures, i.e., 45 and 50 °C, respectively. BpAS exhibited optimum pH under slightly basic conditions (pH 8.0), while BdAS, BlAS, and BtAS preferred weakly acidic conditions (pH 5.0–6.0). All BASs showed higher isomerization activities. Particularly, BlAS produced more trehalulose than turanose. Although polymerization was the highest for BtAS, BtAS synthesized α-1, 4-glucans with a lower degree of polymerization than that of the other BASs. The versatile properties of the BASs described could contribute to the efficient production of highly valuable biomaterials for the agriculture, food, and pharmaceutical industries.

The aim of the study was to quantify sugar profile and rheological behaviour of four Indian honey varieties (Cotton, Coriander, Dalbergia, and Murraya). The effect of temperature (5, 10, 20 and 30 °C) on rheological behaviour of these honey varieties was also studied. Fourteen sugars (three monosaccharides, six disaccharides, four trisaccharides, and one oligosaccharide) were quantified. The concentration of glucose and fructose varied from 33.40–34.06% to 36.86–41.15%, respectively. Result indicated that monosaccharides were the dominant sugars among all the honey samples. Low amounts of turanose, trehalose, melibiose, and raffinose were present in the range of 0.02–0.03%, 0.11–0.26%, 0.09–0.18% and 0.06–0.12%, respectively in the analyzed honey varieties. The rheological behaviour of all four honey varieties was analysed at different temperatures i.e. 5, 10, 20 and 30 °C followed an Arrhenius model. In analysed honey varieties storage modulus (G′) was less than loss modulus (G″) which confirmed the Newtonian behaviour of all honey samples. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13197-020-04331-7) contains supplementary material, which is available to authorized users.

Genome of an early-diverged yeast Blastobotrys (Arxula) adeninivorans (Ba) encodes 88 glycoside hydrolases (GHs) including two &alpha, glucosidases of GH13 family. One of those, the rna_ARAD1D20130g-encoded protein (BaAG2, 581 aa) was overexpressed in Escherichia coli, purified and characterized. We showed that maltose, other maltose-like substrates (maltulose, turanose, maltotriose, melezitose, malto-oligosaccharides of DP 4‒7) and sucrose were hydrolyzed by BaAG2, whereas isomaltose and isomaltose-like substrates (palatinose, &alpha, methylglucoside) were not, confirming that BaAG2 is a maltase. BaAG2 was competitively inhibited by a diabetes drug acarbose (Ki = 0.8 &micro, M) and Tris (Ki = 70.5 &micro, M). BaAG2 was competitively inhibited also by isomaltose-like sugars and a hydrolysis product&mdash, glucose. At high maltose concentrations, BaAG2 exhibited transglycosylating ability producing potentially prebiotic di- and trisaccharides. Atypically for yeast maltases, a low but clearly recordable exo-hydrolytic activity on amylose, amylopectin and glycogen was detected. Saccharomyces cerevisiae maltase MAL62, studied for comparison, had only minimal ability to hydrolyze these polymers, and its transglycosylating activity was about three times lower compared to BaAG2. Sequence identity of BaAG2 with other maltases was only moderate being the highest (51%) with the maltase MalT of Aspergillus oryzae.

The prevalence of inflammatory bowel disease (IBD) is increasing worldwide, and the key risk factor is high sugar diet. The objective of this study was to investigate anti-inflammatory effects of turanose on IBD in a dextran sulfate sodium (DSS)-induced colitis mouse model. An amylosucrase from Neisseria sicca (NsiAS) was newly identified and successfully expressed. This enzyme exhibited optimal activity at 45 °C and pH 8.5. By utilizing this recombinant enzyme expressed in the E. coli host, turanose yield maximally reached 47% from 2.0 M sucrose. Colitis was induced with two 5-d cycles of 2.5% DSS in drinking water with a 10-d inter-cycle interval. Mice were fed AIN93G diet with 25% and 50% turanose replacement. Improved disease activity index scores, colon length, histopathological features, and myeloperoxidase activity were observed in the turanose supplemented group. Meanwhile, decreases in micro RNA (miR)-21 expression, histone acetylation, expression of pro-inflammatory cytokines, and phosphorylated ERK and STAT3 were observed in colon tissues. Notably, miR-21 and histone acetylation levels were found to positively correlated with expression of tumor necrosis factor α. In conclusion, turanose can attenuate colitis via regulatory effects on miRNA-21 expression and histone acetylation-related proinflammatory mediators. These findings also support further exploration of turanose as a potential therapeutic sugar substitute for patients with IBD.

Rhizobia-legume interaction recruits cytokinin-signaling that causes local auxin accumulation for the induction of nodule primordia in the cortex. Since sugar signaling can trigger auxin responses and regulate developmental processes, we explored whether sugar treatments could rescue cre1. Here we demonstrate that turanose, a non-metabolizable sucrose analogue can recover functional symbiosis in cytokinin perception mutant cre1. Additionally, turanose significantly upregulated the expression of WUSCHEL-related homeobox 5 (MtWOX5) which prompted us to check if ectopic expression of WOX5 could rescue cre1. Overexpression of WOX5 from Arachis hypogaea (AhWOX5), but not the intrinsic MtWOX5 could completely restore functional symbiosis in cre1 though both WOX5 (Mt and Ah) were functionally equivalent in inducing the expression of cytokinin inducible transcription factor Nodule Inception (NIN). Among the tested markers for cytokinin and auxin responses, significant differences were noted in the expression of IAA-Ala Resistant3 (MtIAR33), an auxin conjugate hydrolase. Turanose and AhWOX5 overexpression resulted in upregulation of MtIAR33 that further increased significantly in presence of rhizobia. On the other hand, MtIAR33 expression was unaffected in MtWOX5 overexpressed roots suggesting deconjugation driven auxin pool to be critical for rescuing symbiosis in cre1. We hypothesize a working model for sugar and WOX5 mediated rescue of symbiosis in cre1.One sentence summaryActivation of sugar-WOX5 signaling axis restores root nodule symbiosis in cytokinin perception mutant cre1

Amylosucrase (ASase) is a glucosyltransferase, which catalyzes the de novo synthesis of amylose-like polymers from sucrose. In the present study, ASase from Neisseria subflava (NsAS) was cloned, sequenced, and expressed in Escherichia coli. The production of NsAS was achieved by inducting gene expression with 0.2 mM isopropyl-β-d-thiogalactopyranoside. The molecular mass of the Ni-NTA column purified NsAS analyzed by SDS-PAGE was determined to be 72 kDa. NsAS exhibited maximal activity at 45 °C and pH 8.0, and showed strong thermal stability at 40 °C with a half-life of 385 h. The reaction pattern of NsAS at [sucrose] range of 0.1-1.0 M showed that at 0.7 M of [sucrose], the production yield of insoluble linear α-(1,4)-glucans reached 24% maximum, and any further increase in [sucrose] resulted in a slight decrease in yield. Meanwhile, the production yield of turanose significantly increased from 16 to 29% by increasing [sucrose] from 0.1 to 1.0 M. The synthesized glucan had degrees of polymerization (DP); for 0.1, 0.4, 0.7, and 1.0 M sucrose, the DP values were 77, 49, 39, and 31 respectively. These results suggested that NsAS would be a promising candidate for food industrial production of linear α-(1,4)-glucans and turanose as a next generation sweetener.

Increased sugar consumption has been proposed to be a risk factor for obesity-related metabolic disorders. The objective of this study was to investigate the anti-inflammatory effect of turanose in Raw 264.7 macrophages. Turanose (3-O-α-D-glucosyl-D-fructose), an isomer of sucrose, naturally exists in honey. For these studies, macrophages were treated with total glucose (Glu), 50% Glu/50% turanose (T50), 25% Glu/75% turanose (T75), and 100% turanose (T100), each with a total concentration of 25 mM in cell media. Expressions of inflammatory enzymes and cytokines were analyzed. Cell viability was not affected in the turanose treated groups compared to the Glu group. Lipopolysaccharide and glucose-induced nitric oxide production, protein expression of inducible nitric oxide synthase, COX-2, and superoxide dismutase 2, and mRNA expression levels of interleukin (IL)-1β and IL-18 were significantly suppressed by turanose treatment. These results demonstrate that turanose exerts anti-inflammatory effects in vitro, and possesses potential to serve therapeutic functional sweetener for testing in vivo and in clinical trials.

In the present study, we report a metabolomics analysis on peanut buds to delineate metabolic changes at LT using gas chromatography time-of-flight mass spectrometry (GC-TOF/MS). Principle component analysis (PCA) determined overall metabolite alterations. It was found that more metabolites were up-regulated (78.1%) than down-regulated (21.9%). Enrichment of the KEGG pathway indicated that 18 metabolic pathways were significantly changed in peanut buds in response to LT. Compared with the metabolites of peanut buds before LT, there were 73 differentially expressed metabolites detected in peanut buds grown at 25 °C for 12 h, and those metabolites that were up-regulated (50.7%) were similar to those that were down-regulated (49.3%). There were 90 differentially expressed metabolites detected in peanut buds grown at 25 °C for 24 h, the types of up-regulated metabolite (60%) exceeded those that were decreased (40%). The result indicated that with peanut buds to restore growth, most of metabolites which accumulated in response to LT decreased quickly. However, some metabolites (e.g., phytosphingosine, proline, putrescine, and turanose) remained elevated as compared to those before LT, which may contribute to cold tolerance of plants. Observations provide a basis for further elucidation of the molecular physiological mechanism in peanut buds in response to LT.

Among most propagated and worldwide cacti used for commercial (food) production is Opuntia ficus-indica. The present study aimed at investigating aroma compound and metabolites distribution in cactus fruits from 3 cultivars (cvs): red ‘Rose’, yellow-orange ‘Gialla’ and greenish-white ‘Bianca’ represented by both its pulp and skin samples. Two methods were applied including UV-vis fingerprinting versus gas chromatography coupled to mass spectrometry (GC-MS). Betalains predominated in red fruits, whereas carotenoids and chlorophyll were more abundant in orange and green fruits, respectively, as revealed from their crude extracts UV absorption spectra. Volatiles were profiled using headspace solid-phase micro-extraction (SPME) coupled to GC-MS. 40 Volatiles were identified with short chain aldehydes (25–32%) and acids (25–29%) as the major volatile classes. Cultivars exhibited comparable aroma profiles suggesting that volatiles cannot serve as a chemical fingerprint to distinguish between cvs. Primary metabolites mediating for fruit taste and nutritional value viz. sugars and amino acid were profiled using GC-MS post silylation with 82 identified metabolites. Glucose (62%) and fructose (16%) were found to predominate sugar composition, whereas proline was the major amino acid (3–8%). Multivariate data analyses revealed for betalain and disaccharides enrichment i.e., turanose and sucrose in fruit skin versus proline, talopyranose and lyxopyranose abundance in pulp tissue.

Mammalian cells in culture rely on sources of carbohydrates to supply the energy requirements for proliferation. In addition, carbohydrates provide a large source of the carbon supply for supporting various other metabolic activities, including the intermediates involved in the protein glycosylation pathway. Glucose and galactose, in particular, are commonly used sugars in culture media for these purposes. However, there exists a very large repertoire of other sugars in nature, and many that have been chemically synthesized. These sugars are particularly interesting because they can be utilized by cells in culture in distinct ways. In the present work it has been found that many infrequently used sugars, and the corresponding cellular response towards them as substrates, led to differences in the protein N-glycosylation profile of a recombinant glycoprotein. The selective media supplementation of raffinose, trehalose, turanose, palatinose, melezitose, psicose, lactose, lactulose, and mannose were found to be capable of redirecting N-glycan oligosaccharide profiles. Despite this shifting of protein glycosylation, there were no other adverse changes in culture performance, including both cell growth and cellular productivity over a wide range of supplemented sugar concentrations. The approach presented highlights a potential means towards both the targeted shifting of protein glycosylation profiles and ensuring recombinant protein comparability, which up to this point in time has remained under-appreciated for these under-utilized compounds. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:511-522, 2017.

A Gram-positive-staining, endospore-forming, facultatively anaerobic, lactic-acid-producing bacterium, strain GD201205T, was isolated from spoiled jelly in China. Strain GD201205T fermented glucose, fructose, mannose, sucrose, raffinose and turanose, but negative for nitrate reduction, catalase and oxidase. The predominant fatty acids of the strain were anteiso-C17 : 0 and anteiso-C15 : 0. Whole-cell hydrolysates contained glycine and alanine with meso-iaminopimelic acid as the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, glycolipid 1 and glycolipid 2. The DNA G+C content of strain GD201205T was 48.7 mol%. 16S rRNA gene sequence analysis indicated that the strain belonged to the genus Sporolactobacillus and was most closely related to Sporolactobacillus vineaeKCTC 5376T and Sporolactobacillus putidusJCM 15325T with 16S rRNA gene sequence similarities of 97.5 and 96.9 %, respectively. Levels of DNA-DNA relatedness between strain GD201205T and Sporolactobacillus vineaeKCTC 5376Tand Sporolactobacillus putidusJCM 15325T were 29.2 and 47.6 %, respectively. Phylogenetic analysis based on the 16S rRNA gene and gyrB gene revealed that strain GD201205T was clearly distinct from all related species of the genus Sporolactobacillus. On the basis of the phylogenetic, chemotaxonomic and phenotypic evidence given in this study, strain GD201205T should be classified as a representative of a novel species of the genus Sporolactobacillus for which the name Sporolactobacillus pectinivorans is proposed. The type strain is GD201205T (=CICC 23867T=KCTC 15488T).

Turanose, a potential novel sweetener in food industry, can be synthesized by Neisseria polysaccharea amylosucrase (NpAS). However, the malt-oligosaccharide byproduct affects the yield. In this study, the NpAS mutant G396S, which was expected to interfer with the extension of glucan by increasing steric hindrance, was obtained. The NpAS and G396S were heterologously expressed in Bacillus subtilis and enzyme properties were analyzed. Results showed that the polymerization activity of G396S was decreased. In addition, the mutant was used in the preparation of turanose. When using 2 M sucrose as substrate, the turanose yield reached 410.4 g·L−1, an increase of 61 g·L−1 compared with that of NpAS. When fructose was added, the optimal fructose concentration for G396S decreased from 0.75 M to 0.5 M. The turanose production reached 523 g·L−1 with the conversion rate of 76.5%. This study contributes the use of turanose in food industry.

Turanose is a natural isomer of sucrose. It is an emerging functional sweetener of the next generation. Turanose is catalytically synthesized from the sucrose biomass by employing amylosucrase enzyme. In this study, a novel gene encoding amylosucrase (Asmet) has been identified from the metagenome of a thermal aquatic habitat. Asmet exhibits 37–55% identity at the protein level with the known amylosucrases characterized till date. Asmet was cloned and expressed in Escherichia coli, followed by protein purification, and characterization. Asmet protein exhibited the maximum total activity at 9.0 pH and 60 °C temperature, whereas, 8.0 pH and 50 °C temperature were found optimum for transglycosylation activity. Asmet showed fairly high thermal tolerance at 50 °C. The conjugation of Asmet protein with functionalized iron nanoparticles significantly improved its thermal tolerance, showing hardly any loss in the enzyme’s activity even after 72 h of heat (50 °C) exposure. The turanose yield of about 47% was achieved from 1.5 M sucrose, containing 0.5 M fructose in the reaction. Turanose was purified (˜95%) via a bio-physical process, and characterized by TLC, HPLC, and NMR. The novel amylosucrase gene was demonstrated to be a potential candidate for turanose production, utilizing various sucrose containing feedstocks.

Trehalose and its precursor, trehalose 6-phosphate (T6P), are essential regulators of plant response to abiotic and biotic stress. Here we used the specific host-insect interaction between Linaria vulgaris (Plantaginaceae) and stem-galling weevil, Rhinusa pilosa (Mecinini, Curculionidae) with the aim to distinguish carbohydrate allocation patterns in response to herbivory, gall formation (G1, 24 h after oviposition), and gall development (G2, 7 days after oviposition) under controlled conditions. The hypothesis is that herbivory and galling induce distinct responses in both leaves and stems, and that shifts in carbon allocations are regulated by signaling sugars. Systemic response to herbivory was accumulation of T6P and maltose. The main feature of G1 in the stems was accumulation of trehalose, accompanied by increased T6P, turanose and glucose content, oppositely to the leaves. In G2, galls had 3-folds higher weight than controls, with further accumulation of fructose, glucose, turanose, and total water-insoluble carbohydrates (TIC), while the sucrose/hexose ratio decreased. Analysis of fast chlorophyll fluorescence kinetic (OJIP) transients in G2 showed a slight decrease in quantum yield of electron transport flux from QA to QB, and towards photosystem I acceptor side, correlated with the decreased content of photosynthetic pigments and hexoses accumulation. Redistribution of photosynthates, and accumulation of T6P were induced in response to herbivory, indicating its signaling role. The results support the hypothesis that R. pilosa can induce plant reprogramming towards the accumulation of beneficial carbohydrates in developing gall by mechanisms which include both T6P and trehalose.

Antarctica is considered one of the most extreme environments on Earth because of its low temperatures, dryness, high incidence of solar radiation and low nutrient availability. Nevertheless, microorganisms including yeast have successfully colonized Antarctica; however, little is known about Antarctic yeast. In this study, cultivable yeast from soil samples collected from several islands of the South Shetland archipelago and Antarctic Peninsula were identified and characterized at different levels. Most yeasts were psychrotolerant and belonged to eleven genera, with the majority belonging to the Cryptococcus genus. Most yeasts were able to oxidize dextrin, α-d-glucose, sucrose and d-trehalose and to assimilate turanose, d-xylose, dextrin, d-trehalose, α-d-glucose and salicin. Evaluation of twelve hydrolytic enzymes revealed that yeast isolates displayed four to seven different enzyme activities, with lipase, alkaline phosphatase and invertase activities being observed in the majority of isolates. The isolates identified as Cryptococcus gastricus, Cryptococcus victoriae, Cryptococcus gilvencens, Leucosporidium sp. and Rhodotorula mucilaginosa displayed toxicity against other yeast isolates via the secretion of a protein factor. These results reflect the adaptation of yeast to their environment. The yeasts identified in this study have the potential for use as a biosource for the production of enzymes for industrial applications that require high enzyme activities at low temperatures.

Turanose is a sucrose isomer naturally existing in honey and a promising functional sweetener due to its low glycemic response. In this study, the extrinsic fructose effect on turanose productivity was examined in Neisseria amylosucrase reaction. Turanose was produced, by increasing the amount of extrinsic fructose as a reaction modulator, with high concentration of sucrose substrate, which resulted in 73.7% of production yield. In physiological functionality test, lipid accumulation in 3T3-L1 preadipocytes in the presence of high amounts of pure glucose was attenuated by turanose substitution in a dose-dependent manner. Turanose treatments at concentrations representing 50%, 75%, and 100% of total glucose concentration in cell media significantly reduced lipid accumulation by 18%, 35%, and 72%, respectively, as compared to controls. This result suggested that turanose had a positive role in controlling adipogenesis, and enzymatic process of turanose production has a potential to develop a functional food ingredient for controlling obesity and related chronic diseases.

Sugar profiles of 45 Korean honey samples (15 acacia, 15 multi-floral, 10 chestnut, and 5 artificial honey samples), which are commercially available in the Korean markets, were analyzed using gas chromatography/mass spectrometry (GC/MS) through TMS-oxime and TMS-methoxime derivatization. The average invert sugar contents in acacia, multi-floral, chestnut, and artificial honey samples were 71.2±1.05, 68.7±3.26, 63.2±1.85, and 68.0±2.10%, respectively. Fourteen disaccharides were detected from the samples, and the average content of major disaccharides was higher in order of turanose, maltulose, maltose, trehalulose, kojibiose, isomaltose, and nigerose. The average content of total disaccharides was highest in chestnut and lowest in acacia. Seven trisaccharides were detected from the samples, and the average content of trisaccharides was the highest in artificial honeys, which had high erlose content. The total content of disaccharides and trisaccharides was highest (16.0±2.03%) in chestnut honey and lowest (9.70±1.75%) in acacia honey.