Is sugar extracted from plants less healthy than sugar consumed within plant tissues? The sugar anomaly.

There are dilemmas in the minds of consumers with respect to sugar consumption - they would like to consume sugars for sweetness, but in a healthy (and perhaps guilt free!) way. In a sense, consumers believe that if sugar does not appear as an ingredient on the product label, but is intrinsic in the food (and will appear as a nutrient), it is 'good'. As an ingredient, however, it is viewed as a 'bad chemical' associated with tooth decay and obesity. The reality is that unless processing induced modifications have occurred, the sugar molecule within a plant tissue is the same molecule structure as present in purified sugar. The same calorific value. However, there is an argument that humans eat too refined food and that if sugars were eaten in their natural context (e.g. within a fruit), their presence and concentration would be in harmony (where different nutrients complement and balance the sugar concentration) with the human body. This reflects the process of eating, satiety, presence of other nutrients (including water) and the associated impact of the indigestible components of plant foods on the transit/nutrient bioavailability control and thus benefits through the gut. The authors explore these issues in this article and seek to provide a scientific basis to different sides of the argument - sugar is good or bad depending on how (in which format and how much/how concentrated) it is consumed. More importantly perhaps, how should sugar consumption - an important nutrient - be managed to optimize the benefits but reduce the disadvantages? © 2020 Society of Chemical Industry.

Biobutanol production from apple pomace: the importance of pretreatment methods on the fermentability of lignocellulosic agro-food wastes.

Apple pomace was studied as a possible raw material for biobutanol production. Five different soft physicochemical pretreatments (autohydrolysis, acids, alkalis, organic solvents and surfactants) were compared in a high-pressure reactor, whose working parameters (temperature, time and reagent concentration) were optimised to maximise the amount of simple sugars released and to minimise inhibitor generation. The pretreated biomass was subsequently subjected to a conventional enzymatic treatment to complete the hydrolysis. A thermal analysis (DSC) of the solid biomass indicated that lignin was mainly degraded during the enzymatic treatment. The hydrolysate obtained with the surfactant polyethylene glycol 6000 (PEG 6000) (1.96% w/w) contained less inhibitors than any other pretreatment, yet providing 42 g/L sugars at relatively mild conditions (100 °C, 5 min), and was readily fermented by Clostridium beijerinckii CECT 508 in 96 h (3.55 g/L acetone, 9.11 g/L butanol, 0.26 g/L ethanol; 0.276 gB/gS yield; 91% sugar consumption). Therefore, it is possible to optimise pretreatment conditions of lignocellulosic apple pomace to reduce inhibitor concentrations in the final hydrolysate and perform successful ABE fermentations without the need of a detoxification stage.

Prospects of using hyperbranched stationary phase based on poly(styrene-divinylbenzene) in mixed-mode chromatography.

Evaluation of the chromatographic properties of covalently bonded hyperbranched stationary phase based on poly(styrene-divinylbenzene) (PS-DVB) and containing zwitterionic fragments in the structure of functional layer was conducted in suppressed ion chromatography (IC), reversed phase high performance liquid chromatography (RP HPLC), and hydrophilic interaction liquid chromatography (HILIC) modes. Besides the possibility of resolving 20 inorganic anions and organic acids using KOH eluent in suppressed IC, prepared resin provided the separation of alkylbenzenes in RP HPLC, water-soluble vitamins, amino acids, and sugars in HILIC mode. Trends in the retention of hydrophobic and polar analytes on the prepared stationary phase indicated the dominating effect of analyte nature on the retention mechanism and proved satisfactory hydrophilization of PS-DVB surface with hyperbranched functional layer for retaining polar compounds. The obtained results revealed good prospects of using hydrophobic PS-DVB substrate for preparing stationary phases for mixed-mode chromatography.

Purification of the mother liquor sugar from industrial stevia production through one-step adsorption by non-polar macroporous resin.

Steviol glycosides (SGs)-enriched mother liquor sugar (MLS) used to be considered as a by-product of industrial stevia production. This work developed an efficient purification strategy to remove impurities from MLS. A non-polar macroporous adsorption resin (MAR) NDR-1 was selected as the adsorbent and ethanol solution was used as the mobile phase. The adsorption ratio of SGs and impurities was highly affected by ethanol concentration (v/v) due to the polarity difference and competition. In particular, in 25% (v/v) ethanol solution, SGs were mostly adsorbed on NDR-1 while impurities were completely dissolved in ethanol solution. After static adsorption in 25% ethanol solution and desorption in pure ethanol, the impurity content of MLS was decreased from 34.15% to 12.88%, with a high adsorption ratio of 92.24%. At the same condition, dynamic adsorption presented a better purification result with low impurity content of 4.78% and high SGs recovery rate of 89.88%.

Combined dilute hydrochloric acid and alkaline wet oxidation pretreatment to improve sugar recovery of corn stover.

Two-stage dilute hydrochloric acid (DA)/aqueous ammonia wet oxidation (AWO) pretreatment was used to recover the sugars of corn stover. The morphology characterizations of samples were detected by SEM, BET and SXT. The results showed that DA-AWO process demonstrated a positive effect on sugar recovery compared to AWO-DA. 82.8% of xylan was recovered in the first stage of DA-AWO process at 120 °C for 40 min with 1 wt% HCl. The second stage was performed under relative mild reaction conditions (130 °C, 12.6 wt% ammonium hydroxide, 3.0 MPa O2, 40 min), and 86.1% lignin could be removed. 71.5% of glucan was achieved with a low enzyme dosage (3 FPU·g-1) in the following enzymatic hydrolysis. DA-AWO pretreatment was effective due to its sufficient hydrolysis of hemicellulose in the first stage and remarkably removal of the lignin in the second stage, resulting in high sugar recovery with a low enzyme dosage.

Two-Step Pretreatment of Corn Stover Silage Using Non-ionic Surfactant and Ferric Nitrate for Enhancing Sugar Recovery and Enzymatic Digestibility of Cellulose.

Corn stover silage (CSS) is regarded as a promising feedstock for bioethanol production. The two-step pretreatment using a sequential non-ionic surfactant and ferric nitrate pretreatment was investigated for improving the enzymatic hydrolysis of CSS. The first-step pretreatment using non-ionic surfactant (Tween-80, 2.0 wt.%) at 60 °C for 60 min achieved 30.48% the removal of lignin. Compared with the raw material, the cellulose content of first-step treated CSS increased by 15.86%. The second step using ferric nitrate resulted in 94.56% hemicellulose removal and achieved 72.53% cellulose purity at 130 °C for 30 min, while the yields of furfural and HMF were only 0.36 and 0.32 g/100 g dry material, respectively. The maximum enzymatic digestibility of the two-step treated CSS was 90.98% with a low cellulose dosage (15 FPU/g-glucan), which was approximately 32.07% higher than that of the first-step pretreatment only with Tween-80.

Fluorescent Probes for Sugar Detection.

Herein, a new class of polymerizable boronic acid (BA) monomers are presented, which are used to generate soft hydrogels capable of accurate determination of saccharide concentration. By exploiting the interaction of these cationic BAs with an anionic fluorophore, 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (pyranine), a two-component sugar-sensing system was realized. In the presence of such cationic BAs ( o-BA, m-BA, and p-BA), the fluorescence of pyranine becomes quenched because of the formation of a nonfluorescent BA-fluorophore complex. Upon addition of saccharides, formation of a cyclic boronate ester results in dissociation of the nonfluorescent complex and recovery of the pyranine fluorescence. The response of this system was examined in solution with common monosaccharides, such as glucose, fructose, and galactose. Subsequent polymerization of the BA monomers yielded cross-linked hydrogels which showed similar reversible recovery of fluorescence in the presence of glucose.

Acid mediated chemical treatment to remove sugar from waste acid stream from nano-crystalline cellulose manufacturing process.

Nano-crystalline cellulose (NCC) is a nano-scale biomaterial derived from highly abundant natural polymer cellulose. It is industrially produced by concentrated acid hydrolysis of cellulosic materials. However, presences of as high as 5-10% of sugar monomers in spent sulphuric acid during the manufacturing process, makes it unsuitable for such recycling or reuse of sulphuric acid. Currently, the industry has been using membrane and ion exchange technology to remove such sugars, however, such technologies cannot achieve the target of 80-90% removal. In the current investigation, thermal treatment and acid mediated thermal treatment have been evaluated for sugar removal from the spent sulphuric acid. Almost complete removal of sugar has been achieved by this approach. Maximum sugar removal efficiency (99.9%) observed during this study was at 120±1°C for 60min using 0.8 ratio (sample: acid) or at 100±1°C for 40min using 1.5 ratio.

Tunable separations based on a molecular size effect for biomolecules by poly(ethylene glycol) gel-based capillary electrophoresis.

We report novel capillary gel electrophoresis (CGE) with poly(ethylene glycol) (PEG)-based hydrogels for the effective separations of biomolecules containing sugars and DNAs based on a molecular size effect. The gel capillaries were prepared in a fused silica capillary modified with 3-(trimethoxysilyl)propylmethacrylate using a variety of the PEG-based hydrogels. After the fundamental evaluations in CGE regarding the separation based on the molecular size effect depending on the crosslinking density, the optimized capillary provided the efficient separation of glucose ladder (G1 to G20). In addition, another capillary showed the successful separation of DNA ladder in the range of 10-1100 base pair, which is superior to an authentic acrylamide-based gel capillary. For both glucose and DNA ladders, the separation ranges against the molecular size were simply controllable by alteration of the concentration and/or units of ethylene oxide in the PEG-based crosslinker. Finally, we demonstrated the separations of real samples, which included sugars carved out from monoclonal antibodies, mAbs, and then the efficient separations based on the molecular size effect were achieved.