Role Of Sucrose Research Articles

Role of Sucrose and Benzyladenine in Stevioside Content of Stevia Rebaudiana Leaves in Temporary Immersion Bioreactor

The experiment was carried out in the plant tissue culture laboratory of the Department of Horticulture and landscape gardening from October 2021 to January 2023. micropropagation experiments were conducted using concentrations of BA 0.0, 0.5, 1.0, 1.5 and 2.0 mg L, and an experiment with the addition of three levels of sugar (30, 60 and 90 g L) with two levels of BA (0.0 and 1.0 mg L). The results of the micropropagation showed that the concentration 1.0 mg L giving the highest average number of shoots of 3.5 shoots per plant, and giving the highest average number of leaves of 16.8 leaves of the shoot and the superiority of the comparison treatment in giving the highest average height of shoots amounting to 4.5 cm. The results showed that concentration 60 interacted with BA giving the highest average height of the shoots amounting to 4.3 plant shoots. and the concentration 60 interacted with the comparison treatment in giving the highest average shoot height of 4.4 cm and the concentration 90 interacted with BA in giving the highest average number of leaves amounting to 14.1 leaf shoot. The results indicated that the concentration 90 sucrose interacted with 1.0 mg L BA in giving the highest content of stevioside amounting 171.02

Sugar-sweetened beverages exacerbate high-fat diet-induced inflammatory bowel disease by altering the gut microbiome

High-fat diets (HFDs) and frequent consumption of sugar-sweetened beverages (SSBs) are potential contributors to increasing inflammatory bowel disease (IBD) incidences. While HFDs have been implicated in mild intestinal inflammation, the role of sucrose in SSBs remains unclear. Therefore, we studied the role of SSBs in IBD pathogenesis in a mouse model and humans. C57BL6/J mice were given ad libitum access to a sucrose solution or plain water for 10 weeks, with or without an HFD. Interestingly, sucrose solution consumption alone did not induce gut inflammation in mice; however, when combined with an HFD, it dramatically increased the inflammation score, submucosal edema, and CD45+ cell infiltration. 16S ribosomal RNA gene-sequencing revealed that sucrose solution and HFD co-consumption significantly increased the relative abundance of IBD-related pathogenic bacteria when compared with HFD consumption. RNA sequencing and flow cytometry showed that co-consumption promoted pro-inflammatory cytokine and chemokine synthesis, dendritic-cell expansion, and IFN-γ+TNF-α+CD4+ and CD8+ T-cell activation. Fecal microbiota transplantation from HFD- and sucrose water-fed mice into gut-sterilized mice increased the susceptibility to dextran sulfate sodium-induced colitis in the recipient mice. Consistent herewith, high consumption of SSBs and animal fat-rich diets markedly increased systemic inflammation-associated IBD marker expression in humans. In conclusion, SSBs exacerbate HFD-induced colitis by triggering a shift of the gut microbiome into a pathobiome. Our findings provide new insights for the development of strategies aimed at preventing IBD.

Sucrose accumulation and endodormancy are synchronized events induced by the short-day photoperiod in grapevine buds

At the end of the summer season, grapevine buds (Vitis vinifera L) grown in temperate climates enter a state of winter recess or endodormancy (ED), which is induced by the shortening of the photoperiod, and during this period, the buds accumulate sucrose. In this study, we investigated whether the shortening of the photoperiod regulates the accumulation of sucrose in the buds in the same way as it regulates its entry into the ED. Because sucrose accumulation is regulated by genes that control its transport and degradation, the effect of the SD photoperiod and the transition of buds from paradormancy (PD) to ED on the expression of sucrose transporter (VvSUTs) and invertase genes (VvINVs) was studied. To analyze the possible role of sucrose during ED development, its effect on bud swelling and sprouting was studied on dormant and nondormant buds under forced growth conditions. The results showed that the SD photoperiod upregulates the expression of the VvSUT genes and downregulates that of the VvINV genes in grapevine buds. Additionally, during the transition of buds from PD to ED, the sucrose content increased, the expression of the VvINV genes decreased, and the expression of the VvSUT genes did not change significantly. Sucrose delayed bud swelling and sprouting when applied to dormant buds but had no effect when applied to nondormant buds. Therefore, we concluded that ED development and sucrose accumulation were synchronized events induced by the SD photoperiod and that a sucrose peak marks the end of ED development in grapevine buds.

Structure-Function Relationships in Temperature Effects on Bacterial Luciferases: Nothing Is Perfect

The evaluation of temperature effects on the structure and function of enzymes is necessary to understand the mechanisms underlying their adaptation to a constantly changing environment. In the current study, we investigated the influence of temperature variation on the activity, structural dynamics, thermal inactivation and denaturation of Photobacterium leiognathi and Vibrio harveyi luciferases belonging to different subfamilies, as well as the role of sucrose in maintaining the enzymes functioning and stability. We used the stopped-flow technique, differential scanning calorimetry and molecular dynamics to study the activity, inactivation rate, denaturation and structural features of the enzymes under various temperatures. It was found that P. leiognathi luciferase resembles the properties of cold-adapted enzymes with high activity in a narrow temperature range and slightly lower thermal stability than V. harveyi luciferase, which is less active, but more thermostable. Differences in activity at the studied temperatures can be associated with the peculiarities of the mobile loop conformational changes. The presence of sucrose does not provide an advantage in activity but increases the stability of the enzymes. Differential scanning calorimetry experiments showed that luciferases probably follow different denaturation schemes.

Different Dose of Sucrose Consumption Divergently Influences Gut Microbiota and PPAR-γ/MAPK/NF-κB Pathway in DSS-Induced Colitis Mice.

Sugar reduction and sugar control are advocated and gaining popularity around the world. Sucrose, as the widely consumed ingredient in our daily diet, has been reported a relation to gastrointestinal diseases. However, the role of sucrose in inflammatory bowel disease remains controversial. Hence, our study aimed to elucidate the potential role of three doses of sucrose on DSS-induced colitis in C57BL/6 mice and the underlying mechanisms. The results showed that low-dose sucrose intervention alleviated colitis in mice, reducing the expression of inflammatory cytokines and repairing mucosal damages. In contrast, high-dose sucrose intervention exacerbated colitis. Furthermore, three doses of sucrose administration markedly altered gut microbiota composition. Notably, the low-dose sucrose restored microbial dysfunction and enhanced the production of short chain fatty acids (SCFAs). Specifically, the abundance of SCFAs-producing bacteria Faecalibaculum, Bacteroides, and Romboutsia were increased significantly in the LOW group. Consistently, PPAR-γ, activated by SCFAs, was elevated in the LOW group, thereby inhibiting the MAPK/NF-κB pathway. Together, our study demonstrates the differential effects of sucrose on colitis at different doses, providing a scientific basis for measuring and modifying the safe intake level of sugar and providing favorable evidence for implementing sugar reduction policies.

Combined Transcriptome and Metabolome Analyses Reveal Candidate Genes Involved in Tangor (Citrus reticulata × Citrus sinensis) Fruit Development and Quality Formation

Tangor, an important citrus type, is a hybrid of orange and mandarin and possesses their advantageous characteristics. Fruit quality is an important factor limiting the development of the citrus industry and highly depends on fruit development and ripening programs. However, fruit development and quality formation have not been completely explored in mandarin-orange hybrids. We sequenced the metabolome and transcriptome of three mandarin-orange hybrid cultivars at the early fruiting [90 days after full bloom (DAFB)], color change (180 DAFB), and ripening (270 DAFB) stages. Metabolome sequencing was performed to preliminarily identify the accumulation patterns of primary and secondary metabolites related to fruit quality and hormones regulating fruit development. Transcriptome analysis showed that many genes related to primary metabolism, secondary metabolism, cell wall metabolism, phytohormones, and transcriptional regulation were up-regulated in all three cultivars during fruit development and ripening. Additionally, multiple key genes were identified that may play a role in sucrose, citric acid and flavonoid accumulation, cell wall modification, and abscisic acid signaling, which may provide a valuable resource for future research on enhancement of fruit quality of hybrid citrus. Overall, this study provides new insights into the molecular basis of pulp growth and development regulation and fruit quality formation in mandarin-orange hybrids.

Role of sucrose and phloem\u2013xylem interaction in recovery of water status and hydraulic dehydration impacts in tobacco plants (Nicotiana tabacum)

The role of phloem–xylem interaction via sucrose exchanges in recovery of dehydration impacts, specifically xylem embolism, has not been directly investigated thus far. Most previous studies were indirect approaches leading to suggestive conclusions. We hypothesized that a block in phloem loading and so no exchange of sucrose with xylem affect tolerance and recovery of tobacco plants (Nicotiana tabacum) during dehydration and after the rehydration phase. Transgenic N. tabacum (αNtSUT1-antisense) plants, which showed impaired phloem loading and high accumulation of soluble sugars in leaves, were compared to the wild-type (WT) plants. The water status, osmotic adjustments, leaf turgor, stomatal conductance, xylem cavitation, and stem xylem sucrose content were determined during dehydration and after the rehydration phases. Results showed that retention of sucrose outside phloem conduits highly improved water status, osmotic adjustment and turgidity of the source leaves in the transgenics during drought period. However, no impact occurred on stomata function and tolerance to xylem cavitation in αNtSUT1. After the rehydration period, WT plants with free phloem transport and phloem–-xylem exchange of sucrose recovered better their water status, leaf turgidity, stomatal conductance and xylem functioning than αNtSUT1 plants. The accumulation of sucrose in leaves of transformants ameliorated their tolerance to water deficit by reinforcing the osmotic adjustment mechanism at the leaf level. However, lack of sucrose in phloem sieve resulted in impairment of hydraulic recovery of xylem from drought of αNtSUT1 after rehydration. This suggests a crucial role of the phloem–-xylem exchange of sucrose in refilling of embolized xylem vessels.

The role of sucrose on enhancing properties of graphene oxide reinforced cement composites containing fly ash

Graphene oxide (GO) has been attracted considerable attention due to its remarkable nano-reinforcing effect on cement-based composites. However, GO undergoes severe agglomerations upon contact to cement pore solution and reduces the fluidity of the fresh cement slurry. Although much attention has paid to the dispersion of GO in the matrix, few studies was reported to develop a method to simultaneously improve the dispersion of GO in alkaline cement solution and the workability of GO-blended cement mortar. In this study, the effect of sucrose (S) on the dispersion of GO in simulated cement pore solution and the fluidity, mechanical strength, microstructure and other properties of GO-fly ash–cement mortar were investigated. UV–Vis absorbance, atomic force microscope (AFM) and Zeta potential tests showed that the addition of sucrose significantly improved the uniform dispersion of GO in saturated Ca(OH)2 (CH) solution and the optimal mass ratio of sucrose/GO was 2.5:1. Sucrose could also compensate the fluidity loss of fly ash–cement mortar caused by the addition of GO. At the 0.01 wt% of GO and 0.025 wt% of sucrose, the flexural and compressive strength of GO-fly ash–cement mortar were further enhanced by 15.5%, 7.2% at 3d and 17.6%, 16.2% at 28d, compared to the 0.01 wt%-GO reference sample. The well-dispersion of GO could obviously promote cement hydration process and form the regular cement hydration products, so as to make the microstructure of hardened cement stone more compact, and greatly enhance the mechanical strength. This study might provide a new way to develop one-pot method to improve the dispersion of GO in cement pore solution and the workability of GO-blended cement mortar and had many potential practical applications.

In Silico Analysis of Regulatory cis-Elements in the Promoters of Genes Encoding Apoplastic Invertase and Sucrose Synthase in Silver Birch

This work is a continuation of studies on the role of sucrose in the formation of figured wood of Karelian birch (Betula pendula Roth var. carelica (Merckl. Hamet-Ahti). It was previously established that this type of xylogenesis is accompanied by significant changes in activity of sucrose-metabolizing enzymes, sucrose synthase and invertase, in the birch trunk’s tissues. The results of molecular genetic analysis indicate that the activity of these enzymes is regulated mainly at the level of transcription of the genes encoding them (SUS and CWInv). The genes encoding sucrose synthase and cell-wall invertase in the silver birch genome were identified. In silico analysis of the regulatory cis-elements present in the 2-kb promoter region of these genes revealed a number of motifs involved in the regulation of their expression. The largest (in terms of both the number of individual elements and their occurrence) was the group of elements associated with the influence of abiotic factors, mainly light and drought. A number of tissue-specific motifs, the function of which is associated with gene expression in conducting tissues, were identified. Analysis of hormone-dependent elements showed that the formation of figured wood of Karelian birch, which occurs against the background of high apoplastic invertase activity, is obviously not associated with the activation of CWInv genes by a high level of auxin. In the studied promoter sequences, various elements indicating the direct effect of sugar signaling were found. Two most likely candidates for involvement in the regulation of carbohydrate metabolism in the birch trunk tissues—transcription factors (TF) DOF5.6 (HCA2) and DOF5.8—were identified. The identification and functional characteristics of the DOF family TFs of silver birch are of interest from the point of view of the regulation of alternative scenarios of xylogenesis.

Role of sucrose in modulating the low-nitrogen-induced accumulation of phenolic compounds in lettuce (Lactuca sativa L.).

Phenolic compounds are phytochemicals present in vegetables which contribute to human health. Although nitrogen deficiency and sucrose (Suc) are linked to phenolic production in vegetables, the relationship between them in the regulation of phenolic biosynthesis remains unknown. This study investigated the potential role of Suc in regulating phenolic biosynthesis of lettuce under low-nitrogen (LN) conditions. Our results showed that LN treatment significantly increased Suc content in lettuce by inducing rapid increases in activities of sucrose synthesis-related enzymes. Exogenous Suc further stimulated LN-induced phenolic accumulation in lettuce by upregulating the expression of genes (PAL, CHS, F3H, DFR, F35H and UFGT) involved in phenolic biosynthesis. The opposite effects were true for exogenous 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) application. No changes were observed in chlorophyll content in LN-treated lettuce, in either the presence or absence of Suc application. Notably, exogenous DCMU resulted in decreases of maximum quantum efficiency of photosystem II (PSII) photochemistry, actual efficiency of PSII and electron transport rate in PSII and increase of quantum yield of non-regulated energy dissipation in PSII in lettuce under LN conditions, whereas these effects were reversed on Suc application. Exogenous Suc also increased glutamine synthetase and glutamate synthase activities in LN-treated lettuce. These results suggest that Suc is involved in LN-induced phenolic production in lettuce by enhancing photosynthetic and nitrogen assimilation efficiency to increase the supply of carbon resources and precursors for phenolic biosynthesis. © 2020 Society of Chemical Industry.

Investigation of catalytic and fuel additive applications of copper/copper(I) oxide/copper(II) oxide (Cu/CuO/Cu2O) microspheres synthesized by hydrothermal method using sucrose as template

Role of sucrose in sequential reduction of copper (II) ions is investigated. Copper/copper(I) oxide/copper(II) oxide (Cu/CuO/Cu2O) microspheres are synthesized via hydrothermal method using sucrose as template. Size of microparticles lies in 9–16 μm range. Formation mechanism of spherical architecture is also proposed. Synthesized spheres are used in two major applications: (i) catalyst for degradation of methyl red (MR) and methyl blue (MB) (ii) fuel additive in commercial diesel. The rate constant of degradation of both dyes (MB and MR) is not found equal under similar conditions. Results indicated that increased concentrations of microparticles in diesel significantly affect properties.

Cu(I)/sucrose-catalyzed hydroxylation of arenes in water: the dual role of sucrose.

A protocol for the hydroxylation of aryl halides catalyzed by copper(i) and sucrose in neat water has been developed. The dual role of sucrose, the reaction pathway, and the high selectivity for hydroxylation were investigated using a combination of experimental and theoretical techniques.

Effect of drought stress on sugar metabolism in leaves and roots of soybean seedlings

Sucrose is the main photosynthetic product in plants, and acts as a major energy substrate and signaling regulator of plant growth. Furthermore, sucrose is involved in the responses to various abiotic stresses. However, the role of sucrose in soybean (Glycine max L.) growth and development under drought stress remains largely unknown. In this study, the two soybean cultivars, Shennong8 (CV.SN8) and Shennong12 (CV.SN12), were grown in pot culture and subjected to three water treatments for 15 days: soil moisture contents of 75 ± 5% (CK), 45 ± 5% (MD), and 30 ± 5% (SD) of field capacity. Under drought stress, the reduction in shoot biomass was more pronounced than the reduction of biomass in the root of both soybean cultivars, resulting in higher root/shoot (R/S) ratio. Drought stress increased the contents of soluble sugar and sucrose in the leaves, but decreased starch content; in the roots, all of these parameters were increased. This may be related to the enhanced carbohydrate metabolism activity under drought stress, including notable changes in the activities of sugar metabolism enzymes and expression levels of GmSPS, GmSuSy, GmC-INV, GmA-INV, GmAMY3, and GmBAM1. Furthermore, the expression levels of sucrose transporter genes (GmSUC2, GmSWEET6, and GmSWEET15) in leaves and roots of soybean seedlings were up-regulated under drought stress. In conclusion, our results highlight that the increase in R/S ratio caused by the changes of sugar allocation, metabolism, and transport under drought stress contributes towards drought resistance of soybean.

Photomorphogenesis of the root system in developing sunflower seedlings: a role for sucrose

The domestic sunflower (Helianthus annuus L. cv. 'Giganteus') has been used since the 19th century as a model plant for the study of seedling development in darkness and white light (WL) (scoto- versus photomorphogenesis). However, most pertinent studies have focused on the developmental patterns of the hypocotyl and cotyledons, whereas the root system has been largely ignored. In this study, we analysed entire sunflower seedlings (root and shoot) and quantified organ development in the above- and belowground parts of the organism under natural (non-sterile) conditions. We document that seedlings, raised in moist vermiculite, are covered with methylobacteria, microbes that are known to promote root development in Arabidopsis. Quantitative data revealed that during photomorphogenesis in WL, the root system expands by 90%, whereas stem elongation is inhibited, and hook opening/cotyledon expansion occurs. Root morphogenesis may be mediated via imported sucrose provided by the green, photosynthetically active cotyledons. This hypothesis is supported by the documented effect of sucrose on the induction of lateral root initials in sunflower cuttings. Under these experimental conditions, phytohormones (auxin, cytokinin, brassinolide) exerted little effect on root and cotyledon expansion, and no hormone-induced initiation of lateral roots was observed. It is concluded that sucrose not only acts as an energy source to fuel cell metabolism but is also a shoot-derived signalling molecule that triggers root morphogenesis.

Role of sucrose, pacifier and their combination as pain reliever among preterm neonates during painful procedures

Background/Objective: The role of sucrose and/or non-nutritive sucking (NNS) has been evaluated for relieving procedural pain in newborn infants with satisfactory results however there was a controversy regarding the synergestic effect of their combination.}Methods: This quasi-experimental study was conducted in the neonatal intensive care unit in Assiut University Children Hospital including 120 preterm neonates who were divided into 4 groups (20 neonates each). Control group received routine hospital care; sucrose group received oral sucrose solution (OS); pacifier group received pacifier; and last group received oral sucrose solution and pacifier during painful procedures. All were assessed regarding socio-demographic and clinical data in addition to application of Premature Infant Pain Profile (PIPP) scale to assess the levels of pain and mean pain scores pre and post-intervention.Results: The 4 groups were similar regarding soci-demographic and clinical data. The application of the OS and/or pacifier, led to significant improvement of the levels of pain and reduction of the mean score of pain among preterm neonates during painful procedures. In addition, combined pacifier and OS was superior to OS alone and comparable to pacifier alone regarding their effect on the reduction of pain level and mean score of pain.Conclusions: OS and pacifier are effective as pain reliever during painful procedures among preterm neonates. Combined OS and pacifier is superior to OS and pacifier alone.

Effect of sucrose exposure on the xylem anatomy of three temperate species

ABSTRACTThis study is a continuation of research on the role of sucrose in figured wood formation in temperate trees. Different concentrations of sucrose solutions were administered for 7 weeks to trunk tissues ofBetula pendulaRoth, Alnus incana(L.) Moench andPopulus tremulaL. Then xylem anatomy was examined with particular emphasis to the number of vessels and the spatial orientation of xylem elements. InB. pendulaandA. incanaa high level of exogenous sucrose caused a reduction in the number and size of xylem vessels, even to the point of absence of vessels. Sucrose concentrations of 100 and 200 g l-1induced the formation of curly grain and anomalous club-shaped rays in xylem ofB. pendula.Populus tremulaxylem was not significantly altered by the experiment; the xylem anatomy was more seriously affected by wounding than by sucrose. InB. pendulaandA. incanathe wood formed during the experiment was similar to figured wood of these species. The decrease in the number and size of vessels in the xylem formed during the experiment possibly suggests that high concentrations of sucrose lead to a decline in the level of physiologically active auxin. Changes in the orientation of xylem elements points to a disruption of basipetal auxin transport. Further biochemical and physiological studies are needed to provide more comprehensive understanding of the relationship between sucrose and auxin during the development of figure in wood.

Sucrose breakdown within guard cells provides substrates for glycolysis and glutamine biosynthesis during light-induced stomatal opening.

Sucrose has long been thought to play an osmolytic role in stomatal opening. However, recent evidence supports the idea that the role of sucrose in this process is primarily energetic. Here we used a combination of stomatal aperture assays and kinetic [U-13 C]-sucrose isotope labelling experiments to confirm that sucrose is degraded during light-induced stomatal opening and to define the fate of the C released from sucrose breakdown. We additionally show that addition of sucrose to the medium did not enhance light-induced stomatal opening. The isotope experiment showed a consistent 13 C enrichment in fructose and glucose, indicating that during light-induced stomatal opening sucrose is indeed degraded. We also observed a clear 13 C enrichment in glutamate and glutamine (Gln), suggesting a concerted activation of sucrose degradation, glycolysis and the tricarboxylic acid cycle. This is in contrast to the situation for Gln biosynthesis in leaves under light, which has been demonstrated to rely on previously stored C. Our results thus collectively allow us to redraw current models concerning the influence of sucrose during light-induced stomatal opening, in which, instead of being accumulated, sucrose is degraded providing C skeletons for Gln biosynthesis.

Characterization of SWEET family members from loquat and their responses to exogenous induction

The plant SWEET family is a sugar transporter family that plays a significant role in plant development. Here, seven loquat SWEET family members were identified by RNA-seq. These were designated as EjSWEET1, EjSWEET2a, EjSWEET2b, EjSWEET2c, EjSWEET4, EjSWEET15, and EjSWEET17. Phylogenetic and predictive functional annotation analyses suggest that the loquat SWEETs are classified as having sucrose, glucose and fructose transportation features. The in vivo responses of loquat SWEETs to exogenous sugar or NaCl was investigated by applying high concentrations of sugar or salt to 7-month-old loquat seedlings cultured in a nutrient medium. The results showed that most loquat SWEET genes can respond to exogenous applications of sucrose, glucose, fructose and salt. The response of EjSWEET1 to exogenous fructose was faster than the others, indicating that EjSWEET1 is more sensitive to exogenous fructose compared with other loquat SWEETs. EjSWEET15 can be induced by sucrose, but is suppressed by glucose. This indicates its possible role in sucrose transporting. The response of loquat SWEETs to NaCl showed broadly similar patterns compared to sugars. However, after a longer time of NaCl treatment, most loquat SWEETs are upregulated, especially EjSWEET15. This indicates its long-term response to high salinity.

Revisiting the role of sucrose in PLGA-PEG nanocarrier for potential intranasal delivery

The efficient design of nanocarriers is a major challenge and must be correlated with the route of administration. Intranasal route is studied for local, systemic or cerebral treatments. In order to develop nanocarriers with suitable properties for intranasal delivery, to achieve brain and to market the product, it is extremely important the simplification of the formulation in terms of raw materials. Surfactants and cryoprotectants are often added to improve structuration and/or storage of polymeric nanoparticles. PLGA-PEG nanocarriers were prepared by nanoprecipitation method evaluating the critical role of sucrose as surfactant-like and cryoprotectant, with the aim to obtain a simpler formulation compared to those proposed in other papers. Photon correlation spectroscopy and Turbiscan analysis show that sucrose is a useful excipient during the preparation process and it effectively cryoprotects nanoparticles. Among the investigated nanocarriers with different degree of PEG, PEGylated PLGA (5%) confers weak interaction between nanoparticles and mucin as demonstrated by thermal analysis and mucin particle method. Furthermore, in vitro biological studies on HT29, as epithelium cell line, does not show cytotoxicity effect for this nanocarrier at all texted concentrations. The selected nanosystem was also studied to load docetaxel, as model drug, and characterized by a technological point of view.

New Insight into the Role of Sucrose in the Generation of α-Diketones upon Coffee Roasting.

The origin and formation pathways of the buttery-smelling α-diketones 2,3-butanedione and 2,3-pentanedione upon coffee roasting were studied by means of biomimetic in-bean experiments combined with labeling experiments. For this purpose natural sucrose in the coffee bean was replaced by fully or partially 13C-labeled sucrose or by a mixture of unlabeled and fully 13C-labeled sucrose (CAMOLA approach). The obtained data point out that sucrose contributes to both α-diketones; however, its importance and reaction pathways clearly differ. Whereas the major part of 2,3-pentanedione originates from sucrose (about 76%), its contribution to 2,3-butanedione is much lower (about 35%). Formation from intact sugar skeleton is the major pathway generating 2,3-pentanedione from sucrose, whereas 2,3-butanedione is mainly generated by recombination of sucrose fragments. The contribution of glucose and fructose moieties of sucrose to both α-diketones is comparable. Finally, kinetic experiments with fully labeled sucrose showed that the contribution of sucrose changes during roasting.