Sucrose Hydrolysis Research Articles

Polysaccharides of nutritional interest in jicama (Pachyrhizus erosus) during root development.

Jicama root applications have focused on their nutraceutical properties without clearly specifying which compounds are related to this effect. Thus, the aim of the present study was to identify the changes in polysaccharides of nutraceutical interest in two commercial jicama roots (YS – Yellow Seed; PS – Purple Seed) during four stages of maturation, focusing on starch, fructooligosaccharides, and pectin (via galacturonic acid), and on their glycemic index, with the goal of determining, if possible, the best cost‐effectiveness between jicama growing stages and nutraceutical effect. Both materials (YS, PS) presented similar growth rates (0.069 and 0.072 cm/day) and final sizes (12.7 ± 1.25, 12.3 ± 1.63 cm). Changes in size were accompanied by changes in protein, fiber, ashes, lipids, and carbohydrates, after 106 or 127 days of growing. It was also found that fructose content was higher than glucose during the maturing stages, possibly because of the hydrolysis of fructooligosaccharides or sucrose for starch production. Concerning inulin, its levels decreased (<6.0%), after the first days (YS: 13.4% ± 0.7%; PS: 8.4% ± 0.2%, 106 days); however, during development, the presence of other fructooligosaccharides was observed (nystose‐YS 106 days 15.8% ± 0.9% and PS‐106 days 18.5% ± 0.1%), while galacturonic acid and native starch levels increased, which must be related to the jicama's low glycemic index found (<25%), and their nutraceutical properties. This work proves the presence of inulin in jicama roots by analytical methods, its dependence on root development and classifies jicama as a low glycemic index food, supporting its nutraceutical character.

High Power Sugar Fuel Cells Using PEDOT*PSS, CNT and PtRu Composite Anode

Abstract Output characteristics of sugars/KOH fuel cells using PEDOT*PSS, CNT, and PtRu composite (anode)/cellophane/Pt (cathode)/air have been studied. The maximum power density of glucose demonstrated 60 mWcm−2, being the best in the world. The relative outputs were 1, 0.37, 0.51, 0.42, and 0.006 for glucose, fructose, lactose, maltose, and sucrose, respectively, depending on the reducibility of sugars. The hydrolysis of sucrose with acids resulted in the enhancement of output. The coulombic and energetic conversion efficiencies are discussed comparing experimental and theoretical estimations.

Effect of membrane purification and concentration of sucrose in sugar beet molasses for the production of 5-hydroxymethylfurfural

Production of 5-hydroxymethylfurfural from sugar beet molasses as feed-stock should in theory be a straight-forward process: first, hydrolysis of sucrose, followed by dehydration of fructose, but is in reality challenging. The enzyme-catalysed sucrose hydrolysis is inhibited by impurities and the dehydration of fructose has low conversions. In this study, pretreatment of crude molasses through purification using membrane filtration was investigated. The pretreatment process was evaluated with respect to the sucrose hydrolysis reaction rates and for the downstream 5-hydroxymethylfurfural production. Results from the ultra-/nanofiltration experiments showed good filtration fluxes (11–34 L/m2 h bar), high flux recovery after being heavily fouled (>80%) and ability to purify sucrose. The sucrose hydrolysis results showed an improved reaction rate for nanofiltered molasses (concentrate), while the ultrafiltration permeate showed no major difference from the crude molasses, indicating that the inhibitory compounds are of low molecular weight. Furthermore, the ultrafiltered molasses showed highly efficient fructose conversion (near 100%) and 5-hydroxymethylfurfural selectivity of 57% in the biphasic acid-catalysed dehydration, in contrast to only 49% fructose conversion in the crude molasses.

Acid hydrolysis of sucrose in sweet sorghum syrup followed by succinic acid production using a genetically engineered Escherichia coli

Acid hydrolysis of sucrose was studied as a method to convert sucrose in sweet sorghum syrup into glucose and fructose before fermentation with the genetically engineered succinic acid-producing Escherichia coli strain AFP184. Successful hydrolysis of sucrose in sweet sorghum syrup was achieved without noticeable formation of degradation products using moderate temperatures, 65–85 °C, with 0.24–0.48 M HCl in less than 30 min. The measured sucrose hydrolysis rates were lower than previously reported for sweet sorghum molasses. The E. coli strain AFP184 consumed all the sugars (glucose and fructose) in the sweet sorghum syrup hydrolysate. The products were predominately succinic and acetic acid. The final concentration of succinic acid was 27 g/L, but the organism was shown to produce higher levels of succinic acid (60 g/L), when grown under optimal conditions on pure glucose. Note that the fermentation results during scale-up should be seen as preliminary, as initial sugar content, aeration, agitation, and duration of initial aerobic growth phase were not optimized. Thus, improved results closer to those experienced with glucose are expected.

Extraction, purification and characterization of invertase from Candida guilliermondii isolated from peach solid wastes

Abstract The best conditions for in vitro sucrose hydrolysis based on invertase from Candida guilliermondii (ICg) were studied and the kinetic parameters KM,Vmax, and thermal stability of ICg were determined. Candida guilliermondii (Cg) yeast isolated and lyophilized from peach solid wastes was identified using the API 20C AUX method. Subsequently, the Cg was submitted to an autolysis process using NaHCO3 at 200 mM under 200 rpm stirring and 40 °C for 24 h. The enzyme extracts obtained were recovered through precipitation with acetone followed by dialysis and ion-exchange chromatography. The extract purified through precipitation with acetone had activity of 27.7 U.mg-1 and 56% recovery whereas the chromatography process yielded 46.5 U.mg-1 and 44.8%. The optimal sucrose hydrolysis conditions were pH 5.0 and 50 °C, resulting in KM of 30.5 mM and 28.7 mM sucrose, respectively, at 25 °C and 50 °C, both with Michaelian behavior. Thermal inactivation of ICg exhibited first-order apparent kinetics and its residual activity was typically linear between 40 °C and 70 °C. Three isoenzymes were detected through electrophoresis.

Metabolic regulation of subcellular sucrose cleavage inferred from quantitative analysis of metabolic functions

Quantitative analysis of experimental metabolic data is frequently challenged by non-intuitive, complex patterns which emerge from regulatory networks. The complex output of metabolic regulation can be summarised by metabolic functions which comprise information about dynamics of metabolite concentrations. In a system of ordinary differential equations, metabolic functions reflect the sum of biochemical reactions which affect a metabolite concentration, and their integration over time reveals metabolite concentrations. Further, derivatives of metabolic functions provide essential information about system dynamics and elasticities. Here, invertase-driven sucrose hydrolysis was simulated in kinetic models on a cellular and subcellular level. Both Jacobian and Hessian matrices of metabolic functions were derived for quantitative analysis of kinetic regulation of sucrose metabolism. Model simulations suggest that transport of sucrose into the vacuole represents a central regulatory element in plant metabolism during cold acclimation which preserves control of metabolic functions and limits feedback-inhibition of cytosolic invertases by elevated hexose concentrations.

Effects of single and combined exogenous application of abscisic acid and melatonin on cotton carbohydrate metabolism and yield under drought stress

Drought is a major abiotic factor that adversely affects plant growth and crop productivity. Abscisic acid (ABA) and melatonin (MT) are two commonly used hormones, whose exogenous application has been shown to improve crop drought tolerance under water deficiency, when used separately; however, studies on the effects of their combined application on crops are scarce. To amend this, pot studies were conducted to study the effects of exogenous ABA and MT application (single or combined) on cotton leaf photosynthetic carbon metabolism and yield under drought. Results revealed that single ABA or MT application significantly improved plant water status under drought by different pathways, which curtailed drought-induced yield losses. ABA+MT application effects on plant water status were similar to those of MT, however, ABA+MT application had synergistic effects on alleviating drought-induced yield losses. ABA spraying had no effects on the net photosynthetic rate (Pn) of drought-stressed leaves, but MT application improved Pn by increasing stomatal conductance and CO2 fixation, and ABA+MT was more effective than MT in alleviating the Pn. Furthermore, ABA application reduced leaf sucrose synthesis by decreasing sucrose synthase (SuSy) activity, and MT and ABA+MT application also inhibited sucrose synthesis by reducing SuSy and sucrose phosphate synthase activities. Extra ABA down-regulated acid invertase activity to inhibit the hydrolysis of sucrose to hexose, but MT spraying decreased both acid and alkaline invertases activities of drought-stressed leaves, and ABA+MT had similar effects as MT. Although ABA or MT down-regulated GhSWEET5, GhSWEET20 and GhSWEET55 expression, thus repressing sucrose transport to the cell wall, their application up-regulated GhSUT3A/D and GhSUT4 expression in drought-stressed leaves, improving in that way sucrose transport to the sieve-companion cell complex and ultimately benefiting yield formation. Similarly, ABA+MT application had additive effects on GhSUT3A/D and GhSUT4 expression under drought. Consequently, ABA or MT application decreased sucrose content in drought-stressed leaves, while ABA+MT application showed a synergistic effect. Hexose, as the substrate for starch biosynthesis, content decreased in ABA- or MT-treated leaves under drought, however, starch accumulation was not affected by ABA application, and MT spraying increased starch content of drought-stressed leaves, by increasing ADP-glucose pyrophosphorylase activity. Nevertheless, ABA+MT application was more effective in increasing starch synthesis under drought than either single hormone application. In conclusion, the effects of ABA+MT on photosynthetic carbon metabolism of cotton leaves were more similar to those of MT under drought, but there were significant synergistic effects in mitigating the negative effects of drought on Pn, sucrose accumulation, sucrose transport, starch synthesis as well as final yield.

Sucrose Hydrolysis in a Continuous Packed-Bed Reactor with Auto-immobilise Aspergillus niger Biocatalyst Obtained by Solid-State Fermentation.

Invertase from Aspergillus niger C28B25 was produced by solid-state fermentation (SSF). Fermented solids were used directly as a biocatalyst for batch and continuous hydrolysis of sucrose in a packed-bed reactor under different operational conditions with various temperatures, sucrose concentrations, and feed flow rates. The SSF allowed obtaining a biocatalyst with an invertase activity of 82.2 U/g db. The biocatalyst maintained its activity in the range of 40 to 70°C for at least 70h of continuous operation. In a 20-mL packed bed reactor, the highest hydrolysis rate (12.3g/g db h) was obtained at 40°C with 2M sucrose. Continuous hydrolysis in 20-mL and 200-mL reactors at 60°C led to sucrose hydrolysis above 60% (8.5 residence times) and above 55% (4.5 residence times), respectively. The auto-immobilised biocatalyst produced by SSF without recovery, purification, and immobilisation stages offers an economical alternative for developing accessible biocatalysts that can be applied in batch or continuous sucrose hydrolysis processes. This study shows the potential of biocatalyst production by SSF for other enzymatic systems.

Formulation of gluten-free biscuits with reduced glycaemic index: Focus on in vitro glucose release, physical and sensory properties

Gluten-free (GF) biscuits based on buckwheat, sorghum and lentil flours were produced in an industrial plant. These flours are very little exploited in commercial products. In addition, since there is growing attention on glycaemic index (GI) of cereal based products. Sucrose replacers, mainly maltitol and inulin, and type 2 resistant starch (RS) were used to substitute sucrose and flours, respectively, in the view of reducing GI of biscuits. Ingredients were used in amounts established on the basis of previous experiments and European Regulations on nutritional claims. This study aimed at the evaluation of the effect of maltitol, inulin and RS on physico-chemical and sensory characteristics of biscuits. In particular, glucose released by sucrose and starch hydrolysis during in vitro digestion was placed under the spotlight.The use of sucrose contributed to the reduction of in vitro glucose release and consequently of predicted glycaemic index (pGI) with values decreasing from 84 to 67. Despite some slight differences in the sensory profile of the biscuits, reformulated products had a reduced friability and sweetness, and increased adhesiveness and nuts odour, all the formulations scored well above the threshold of acceptability (from 6.5 to 7.6) by consumers used to eat biscuits made with alternate flours.

Real-time monitoring of the sucrose hydrolysis process based on two-photon coincidence measurements.

Real-time measurement of the biochemical reaction process has important application scenarios. Due to the chirality of a large number of life-sustaining molecules, many parameters of the reaction kinetics involving these chiral molecules, such as the reaction rate and the reagents concentrations, could be tracked by monitoring the optical activity of the substrate and/or product molecules. However, the optical activity of photosensitive biomolecules does not allow traditional laser-based real-time measurement due to the vulnerability of their biochemical properties under high-intensity light regimes. Here we introduce a real-time tracking technique of the sucrose hydrolysis reaction based on two-photon coincidence measurements. The two-photon source is generated based on a spontaneous parametric down-conversion process. During the reaction, the kinetic parameters are obtained by the real-time measurement of the change of the polarization of the photons when operating at extremely low-light regimes. Compared with single-photon counting measurements, two-photon coincidence measurements have higher signal-to-noise ratios and better robustness, which demonstrates the potential value in monitoring the photosensitive biochemical reaction processes.

Comparison of Spathaspora passalidarum and recombinant Saccharomyces cerevisiae for integration of first- and second-generation ethanol production.

First-generation ethanol (E1G) is based on the fermentation of sugars released from saccharine or starch sources, while second-generation ethanol (E2G) is focused on the fermentation of sugars released from lignocellulosic feedstocks. During the fractionation process to release sugars from hemicelluloses (mainly xylose), some inhibitor compounds are released hindering fermentation. Thus, the biggest challenge of using hemicellulosic hydrolysate is selecting strains and processes able to efficiently ferment xylose and tolerate inhibitors. With the aim of diluting inhibitors, sugarcane molasses (80% of sucrose content) can be mixed to hemicellulosic hydrolysate in an integrated E1G-E2G process. Cofermentations of xylose and sucrose were evaluated for the native xylose consumer Spathaspora passalidarum and a recombinant Saccharomyces cerevisiae strain. The industrial S. cerevisiae strain CAT-1 was modified to overexpress the XYL1, XYL2 and XKS1 genes and a mutant ([4-59Δ]HXT1) version of the low-affinity HXT1 permease, generating strain MP-C5H1. Although S. passalidarum showed better results for xylose fermentation, this yeast showed intracellular sucrose hydrolysis and low sucrose consumption in microaerobic conditions. Recombinant S. cerevisiae showed the best performance for cofermentation, and a batch strategy at high cell density in bioreactor achieved unprecedented results of ethanol yield, titer and volumetric productivity in E1G-E2G production process.

Xylooligosaccharides and their chemical stability under high-pressure processing combined with heat treatment

Xylooligosaccharides (XOS) are emerging prebiotic ingredients used for enriching food products due to their health-promoting properties. This study investigated XOS chemical stability after high-pressure processing (HPP) combined with heat treatment. First, orange juice was enriched with XOS (xylobiose, xylotriose, xylotetraose, xylopentaose, and xylohexaose), and then HPP-treated at 100, 300, and 600 MPa applying non-thermal (30 °C) and thermal (100 °C) conditions. Ascorbic acid (vitamin C) degradation was monitored to evaluate the extend of the severity of the treatments due to its low stability under high-energy process conditions. Also, quality attributes associated with fruit juices such as physicochemical properties (pH, soluble solid content, and ζ-potential), organic acid content (malic and citric acids), total phenolic content, antioxidant activity, and sugar content (glucose, fructose, and sucrose) were determined. The use of HPP combined with heat treatment degraded ascorbic acid up to 37% and promoted sucrose hydrolysis into glucose and fructose. However, our findings demonstrated that the XOS were chemically stable to HPP in the range of 100–600 MPa even applying thermal treatment. Therefore, XOS are promising ingredients for the formulation of functional plant-based beverages since their integrity was preserved under high mechanical and thermal stress conditions of 600 MPa and 100 °C.

Extraction and purification of Aspergillus tamarii β-fructofuranosidase with transfructosylating activity using aqueous biphasic systems (PEG/phosphate) and magnetic field

β-fructofuranosidases (FFases) are enzymes involved in sucrose hydrolysis and fructo-oligosaccharides’ production which are of great interest for the food industry. FFase from Aspergillus tamarii URM4634 was extracted using PEG/Phosphate Aqueous Biphasic Systems (ABS), and the impact of magnetic field on the extraction behavior was evaluated. A 24-full experimental design was employed to study the influence of molar mass of PEG, concentrations of PEG and phosphate and pH on the selected response variables, i.e., partition coefficient (K), purification factor (PF), activity yield (Y) and selectivity (S). The influence of magnetic field during partition and NaCl concentration on the same responses was also studied. The best results of FFase extraction without magnetic field (K = 0.50, PF = 4.05, Y = 72.66% and S = 0.06) were observed at pH 8.0 using 12.5% (w/w) PEG 400 and 25% (w/w) NaH2PO4/K2HPO4. Application of the magnetic field allowed improving the performance, with the best results being obtained at the longest distance between magnets (lowest magnetic field) and absence of NaCl (K = 0.93, PF = 4.22, Y = 83.79% and S = 0.09). The outcomes obtained demonstrate that ABS combination with low intensity magnetic field can be used as an efficient FFase pre-purification method.

Fully integrated sampler and dilutor in an electrochemical paper-based device for glucose sensing

An electroanalytical platform capable to take and dilute the sample has been designed in order to fully integrate the different steps of the analytical process in only one device. The concept is based on the addition of glass-fiber pads for sampling and diluting to an electrochemical cell combining a paper-based working electrode with low-cost connector headers as counter and reference electrodes. In order to demonstrate the feasibility of this all-in-one platform for biosensing applications, an enzymatic sensor for glucose determination (requiring a potential as low as −0.1 V vs. gold-plated wire by using ferrocyanide as mediator) was developed. Real food samples, such as cola beverages and orange juice, have been analyzed with the bioelectroanalytical lab-on-paper platform. As a proof-of-concept, and trying to go further in the integration of steps, sucrose was successfully detected by depositing invertase in the sampling strip. This enzyme hydrolyzes sucrose into fructose and glucose, which was determined using the enzymatic biosensor. This approach opens the pathway for the development of devices applying the lab-on-paper concept, saving costs and time, and making possible to perform decentralized analysis with high accuracy.Graphical abstract

Genome-wide analysis of the invertase genes in strawberry (Fragaria×ananassa)

Sugar is an important material basis in fruit development, and strawberry fruit flavour and sweetness largely depend on the sugar content and variety. Invertases (INVs) play an important role in the regulation of sugar accumulation because they irreversibly catalyse the hydrolysis of sucrose into the corresponding nucleoside diphosphate-glucose, glucose or fructose in fruit. In this work, we provided a comprehensive analysis of the INV gene family in octoploid strawberry (Fragaria×ananassa), including the gene structure, chromosomal locations, conserved domains, and gene evolution and expression profiles during strawberry fruit development. Our study revealed that polyploid events resulted in the abundant amplification (almost three- or four-fold) of the INV gene in the F.×ananassa genome, and these amplified INV genes showed dominant expression in strawberry fruit. More than half of the FaINVs transcripts with low expression had incomplete coding sequences by alternative splicing. Previous studies have shown that cell wall invertases (CWINV) are involved in the regulation of phloem unloading and sink strength establishment. The expression of FaCWINV1 was markedly upregulated during fruit development and strongly expressed in ripe fruit. Moreover, a significant correlation was observed between the total sugar content and the FaCWINV1 expression level. These findings suggest that FaCWINV1 may be involved in sugar accumulation in strawberry fruit. Taken together, the results of our study will be beneficial for further research into the functions of INVs in the regulation of fruit ripening.

A cell wall invertase controls nectar volume and sugar composition.

Nectar volume and sugar composition are key determinants of the strength of plant-pollinator mutualisms. The main nectar sugars are sucrose, glucose and fructose, which can vary widely in ratio and concentration across species. Brassicaspp. produce a hexose-dominant nectar (high in the monosaccharides glucose and fructose) with very low levels of the disaccharide sucrose. Cell wall invertases (CWINVs) catalyze the irreversible hydrolysis of sucrose into glucose and fructose in the apoplast. We found that BrCWINV4A is highly expressed in the nectaries of Brassica rapa. Moreover, a brcwinv4a null mutant: (i) has greatly reduced CWINV activity in the nectaries; (ii) produces a sucrose-rich nectar; but (iii) with significantly less volume. These results definitively demonstrate that CWINV activity is not only essential for the production of a hexose-rich nectar, but also support a hypothetical model of nectar secretion in which its hydrolase activity is required for maintaining a high intracellular-to-extracellular sucrose ratio that facilitates the continuous export of sucrose into the nectary apoplast. The extracellular hydrolysis of each sucrose into two hexoses by BrCWINV4A also likely creates the osmotic potential required for nectar droplet formation. These results cumulatively indicate that modulation of CWINV activity can at least partially account for naturally occurring differences in nectar volume and sugar composition. Finally, honeybees prefer nectars with some sucrose, but wild-type B.rapa flowers were much more heavily visited than flowers of brcwinv4a, suggesting that the potentially attractive sucrose-rich nectar of brcwinv4a could not compensate for its low volume.

Comparative studies on the physicochemical profile and potential hypoglycemic activity of different tea extracts: Effect on sucrase-isomaltase activity and glucose transport in Caco-2 cells

Tea is one of the most popular beverages in the world and is believed to be beneficial for health. The main components in tea change greatly depending on different processes, and thus, the effects of different teas on human health may differ. In this study, we compared the effect of green, oolong, black, and dark tea extracts on sucrase-isomaltase (SI) activity and glucose transport, which are two intervention options for postprandial blood glucose control, using Caco-2 cells as a model. Theaflavin-rich black tea extracts showed the highest inhibition of SI activity and retardation of the hydrolysis of sucrose, maltose, and isomaltose, with IC50 values of 8.34 μg/mL, 16.10 μg/mL, and 21.63 μg/mL, respectively. All four kinds of tea extracts caused a dose-dependent inhibition of glucose transport, which were closely related to the catechin content. Green tea extracts showed the highest inhibition of glucose transport and was more effective against sodium-dependent glucose cotransporter 1 (SGLT1) than glucose transporter 2 (GLUT2) in the management of glucose transport. Black tea extracts also inhibited glucose transport despite low level of catechins. The reason could partly lie in the suppression of Na+/K+-ATPase, which reduced the energy needed for SGLT1 to actively transport glucose. Furthermore, the mRNA level of SI, SGLT1, GLUT2, and Na+/K+-ATPase in Caco-2 cells were significantly reduced after treatment with tea extracts for 2 h. These in vitro studies suggested that tea could be used as a functional food in the diet to modulate postprandial hyperglycaemia for diabetic patients.

Hydrolysis of Sucrose over Sulfonic Acid Resins

AbstractSucrose hydrolysis on acidic ion‐exchange resins is a long‐established process in the sugar industry, but the formation of side products is less understood. A resin typically used in the industrial process (C124SH, Purolite) was investigated in a broad range of sucrose concentration (7 to 75 % w/w) and temperatures from 25 to 80 °C. Fructose is converted to 5‐hydroxymethylfurfural (HMF) due to a 1/2 order reaction. This is explained by the formation of a fructose disaccharide (monoanhydride) as an intermediate decomposing to HMF and fructose. Difructose dianhydrides (DFAs) are separately formed as prevailing by‐products. The color of the product mixture is correlated to HMF and found to be reduced by size exclusion inside the resins. Diffusional limitations of the total reaction are investigated by comparison of the entire resin bead with its size‐reduced forms obtained by milling. Without diffusion limitation the catalytic activity increases with the sugar concentration while the diffusion control leads to a maximal activity around 40 % w/w sugar. Diffusion coefficients of sucrose are calculated.

Rice spikelet formation inhibition caused by decreased sugar utilization under high temperature is associated with brassinolide decomposition

Rice (Oryza sativa) spikelet formation is dependent on carbohydrate metabolism. High temperature inhibits young panicle growth and spikelet formation, and brassinolides (BRs) are involved in the regulation of spikelet formation. Elucidation of the mechanism by which endogenous BRs mediate carbohydrate metabolism to influence spikelet formation under high temperature may provide a theoretical and technical basis to alleviate heat injury. In this study, rice cultivar ‘IR36’ was subjected to high temperature (HT; 40 °C) or normal temperature (NT; 33 °C) for 7 days at the panicle initiation stage in conjunction with application of exogenous 2, 4-epibrassinolide (EBR) and brassinazole (BRZ) at the beginning of the treatments. HT inhibited spikelet differentiation and aggravated spikelet degeneration to reduce the number of spikelets per panicle. Exogenous EBR reduced the decrease in spikelet number induced by HT, whereas exogenous BRZ enhanced the reduction in spikelet number. Analyses of the transcript levels of genes associated with BR biosynthesis and decomposition showed that HT promoted BR decomposition to reduce the endogenous BR content. HT blocked sucrose transport from leaves to young panicles, and inhibited the activities of crucial enzymes involved in sucrose hydrolysis, glycolysis, and the tricarboxylic acid cycle to reduce sugar utilization. In addition, HT reduced the activities of antioxidant enzymes and increased the contents of hydrogen peroxide and malondialdehyde. Exogenous EBR application promoted sucrose transport to young panicles and improved sucrose utilization under NT and HT, whereas application of BRZ resulted in the opposite physiological response. These results show that inhibition of spikelet formation owing to decreased sugar utilization under HT is associated with BR decomposition.

Biotechnology of families’ strength influence on the processes of sucrose inversion, dehydration and accumulation of monosaccharides

The purpose of the work is an experimental substantiation of biotechnological processes that ensure the maturation of honey during the processing of nectar by bees. During the whole period (7–9 days) of nectar treatment by bees there is a simultaneous partial dehydration of the liquid and biochemical transformations, among which the hydrolysis of sucrose and the accumulation of monosaccharides have the most significant effect on the quality of the mature product. In all series of experiments, the maturity of processed honey in the beehive at the water limit of less than 20 % occurs after 5–6 days of treatment by bees. The mature product in terms of water content remains open in almost completely filled cells for another 3–5 days, slightly reducing the water content from 19.78–20.07 % up to 16.40–18.38 %. Dynamic changes in the ratio of monosaccharides and sucrose in the process of nectar processing by bees, starting from the honey stomach during gathering from flowers to sealing in honeycomb cells have been detected. At the honey stomach-cell stage, a small amount of sucrose is hydrolyzed during the incomplete first day of processing and, as a rule, 0.48–4.11 % of monosaccharides calculated relative to the dry weight of the product are added. Sucrose inversion is more intense during the next 5–6 days, when a total of 12.94–31.42 % of splitted sugars are added, depending on their initial number and strength of families. The main processes of conversion of nectar into honey by bees are characterized by the advance of the reduction of water content in comparison with the splitting of sucrose and the accumulation of monosaccharides. According to the water content (less than 20 %), honey becomes suitable for pumping 3–5 days before it is sealed in the cells. The influence of the mass of bees of different families on the intensity of sucrose inversion in the cells and the accumulation of monosaccharides in the product has been experimentally proved. The maturity of honey in the ratio of sugars in the beehives of strong families is better than in weak ones.