Formation Of Sugars Research Articles

Identification of key gene networks controlling organic acid and sugar metabolism during star fruit (Averrhoa carambola) development

The sugar and organic acid content significantly impacts the flavor quality of star fruit, and it undergoes dynamic changes during development. However, the metabolic network and molecular mechanisms governing the formation of sugar and organic acid in star fruit remain unclear. In this study, 23 of 743 components were detected by metabonomic analysis. The highest metabolites contents were organic acids and derivatives. The highest sugar content in the fruit was fructose and glucose, followed by sucrose, which proved that A. carambola is a hexose accumulation type fruit. Genome identification preliminarily screened 141 genes related to glucose metabolism and 67 genes related to acid metabolism. A total of 7,881 unigenes were found in transcriptome data, 6,124 differentially expressed genes were screened, with more up-regulated than down-regulated genes. Transcriptome and metabolome association analysis screened seven core candidate genes related to glucose metabolism and 17 core genes highly related to organic acid pathway, and eight differentially expressed sugar and acid genes were selected for qRT-PCR verification. In addition, 29 bHLHs and eight bZIPs transcription factors were predicted in the glucose metabolism pathway, and 23 MYBs, nine C2H2s transcription factors and one GRAS transcription factor was predicted in the acid metabolism pathway, and transcription factors have both positive and negative regulatory effects on sugar and acid structure genes. This study increased our understanding of A. carambola fruit flavor and provided basic information for further exploring the ornamental and edible values of star fruit.

Epimerization of glucose to rare sugars using Beta zeolite-supported MoOx catalysts

Epimerization of abundant monosaccharides derived from lignocellulosic biomass offers an attractive approach for the synthesis of rare sugars. Molybdenum-based catalysts demonstrate excellent glucose-mannose epimerization performance, but most studies have neglected the synthesis of other sugar epimers and the pathways of their formation. Here, reduced Beta zeolite supported MoOx catalysts (Mo/Beta) with 1.5–10 wt% Mo loading were examined for glucose epimerization in water, specifically focusing on the formation of the rare sugars allose and altrose. The physicochemical structure and the catalytic activity of the catalyst were examined in detail, and the reaction mechanisms for the epimer formation were probed by nuclear magnetic resonance (NMR) spectroscopy. The results demonstrate that 5 wt% Mo/Beta achieved a near-equilibrium mannose yield of 30 % from glucose within 10 min at reaction temperatures below 140 °C, exhibiting a relatively low activation energy (∼67 kJ mol−1). At elevated reaction temperatures (≥ 120 °C), the rare sugars allose and altrose accumulated to combined yields of 24 % at 140 °C. An isotope labelling study using NMR spectroscopy corroborated the catalysis to involve 1,2-carbon shifts that elicit the formation of rare sugars at sufficiently high temperatures. Evaluation of catalyst reuse and regeneration indicated that supported MoOx had higher stability than MoO3, but the stability of the Mo/Beta catalysts under hydrothermal conditions leaves room for improvement.

H-atom-assisted formation of key radical intermediates in interstellar sugar synthesis

Context. Despite the identification of the smallest sugar molecule, glycolaldehyde (GA), in the interstellar medium (ISM), its mechanism of formation in the ISM is still not fully understood. A more profound understanding of the interstellar chemistry of GA and related molecules could provide insights into whether larger sugar molecules can also form and survive under such conditions. Aims. The primary objectives of this research are to delve into the sugar formation mechanism in the ISM, especially in dark molecular clouds; unravel intricate details of H-atom-mediated reactions involving glyoxal (GO), GA, and ethylene glycol (EG); and identify intermediates playing potential roles in the formation of larger sugars or serving as intermediates in the destruction reaction paths of sugar molecules. Methods. The study utilizes the para-H2 matrix isolation method with infrared (IR) spectroscopic detection and quantum chemical computations to investigate H-atom reactions of GO, GA, and EG at a low temperature. Results. Several radical products were spectroscopically identified that might be key active species in the interstellar formation of larger sugar molecules.

Identification of HOC•HC(O)H, HOCH2C•O, and HOCH2CH2O• Intermediates in the Reaction of H + Glycolaldehyde in Solid Para-Hydrogen and Its Implication to the Interstellar Formation of Complex Sugars.

Glycolaldehyde [HOCH2C(O)H, GA], the primitive sugar-like molecule detected in the interstellar medium (ISM), is a potential precursor for the synthesis of complex sugars. Despite its importance, the mechanism governing the formation of these higher-order sugars from GA under interstellar circumstances remains elusive. Radical intermediates HOCH2CH2O• (1), HOCH2C•HOH (2), HOCH2C•O (3), HOC•HC(O)H (4), and O•CH2C(O)H (5) derived from GA could be potential precursors for the formation of glyceraldehyde (aldose sugar), dihydroxyacetone (ketose sugar), and ethylene glycol (sugar alcohol) in dark regions of ISM. However, the spectral identification of these intermediates and their roles were little investigated. We conducted reactions involving H atoms and the Cis-cis conformer of GA (Cc-GA) in solid p-H2 at 3.2 K and identified IR spectra of radicals Cc-HOCH2C•O (3) and Cc-HOC•HC(O)H (4) produced from H abstraction as well as closed-shell HOCHCO (6) produced via consecutive H abstraction of GA. In addition, Cc-HOCH2CH2O• (1) and C•H2OH + H2CO (7) were produced through the H addition and the H-induced fragmentation channels, respectively. In darkness, when only H-tunneling reactions occurred, the formation of (3) was major and that of (1) was minor. In contrast, during IR irradiation to produce H atoms with higher energy, the formation of (4) and C•H2OH + H2CO (7) became important. We also successfully converted most Cc-GA to the second-lowest-energy conformer Trans-trans-GA (Tt-GA) by prolonged IR irradiation at 2827 nm to investigate H + Tt-GA; Tt-HOCH2C•O (3'), Tt-HOC•HC(O)H (4'), HOCHCO (6), Tt-HOCH2CH2O• (1'), and C•H2OH + H2CO (7) were observed. We discuss possible routes for the formation of higher-order sugars or related compounds involving (7), (1), (3), and (4), but neither (2), which was proposed previously, nor (5) plays a significant role in H + GA. Such previously unreported rich chemistry in the reaction of H + GA, with four channels of three distinct types, indicates the multiple roles that GA might play in astronomical chemistry.

Impact of Rye Malt with Various Diastatic Activity on Wholegrain Rye Flour Rheology and Sugar Formation in Scalding and Fermentation Processes.

Amylase activity in rye flour plays a crucial role in the production of rye bread. When preparing a scald in rye bread production, diastatic rye malt is utilized to augment the amylase activity of the rye flour. This study investigated the effects of the diastatic power (DP) and concentration of rye malt on the Falling Number (FN) and the rheological properties of rye flour. Additionally, it examined reducing sugars in the scalding process and fermentation. Mixolab results provided comprehensive data on dough properties at different temperature stages, highlighting significant changes in starch gelatinization and enzyme activity due to varying malt diastatic power and concentrations. The decline in the gelatinization index (C3-C2) indicated faster starch gelatinization with increased diastatic power. Adding rye malt significantly increased maltose content in the saccharified and fermented scald, promoting a favorable environment for lactic acid bacteria and yeasts. FN and Amylograph results showed that less active malt (DP 170, 179 °WK), at a 1.5% concentration, could achieve similar effects as the more active malt (DP 362, 408 °WK) at 0.5%. Adding rye malt to rye flour allows for the regulation of the flour's rheological properties and FN, adjustable based on malt DP and concentration.

Comparing levoglucosan and mannosan ratios in sediments and corresponding aerosols from recent Australian fires

The monosaccharide anhydrides levoglucosan, mannosan, and galactosan are known as ‘fire sugars’ as they are powerful proxies used to trace fire events. Despite their increasing use, their application is not completely understood, especially in the context of tracing past fire events using sediment samples. There are many uncertainties about fire sugar formation, partitioning, transport, complexation, and stability along all stages of the source-to-sink pathway. While these uncertainties exist, the efficacy of fire sugars as fire tracers remains limited. This study compared high-resolution fire sugar fluxes in freshwater sediment cores to known fire records in Tasmania, Australia. Past fire events correlated with fire sugar flux increases down-core, with the magnitude of the flux inversely proportional to the distance of the fires from the study site. For the first time, fire sugar ratios (levoglucosan/mannosan, L/M) in aerosols were compared with those in sediments from the same time-period. The L/M ratio in surface sediments (1.42–2.58) were significantly lower than in corresponding aerosols (5.08–15.62). We propose two hypotheses that may explain the lower average L/M of sediments. Firstly, the degradation rate of levoglucosan is higher than mannosan in the water column, sediment-water interface, and/or sediment. Secondly, the L/M ratio of non-atmospheric emissions during fires may be lower than that of atmospheric emissions from the same fire. Due to the uncertainties about transport partitioning (atmospheric versus non-atmospheric emissions) and fire sugar degradation along all stages of the source-to-sink pathway, we advise caution when inferring vegetation type (e.g. softwood, hardwood, or grasses) based purely on fire sugar ratios in sediments (e.g. L/M ratio). Future investigations are required to increase the efficacy of fire sugars as a complimentary, or standalone, fire tracer in sediments.

Preparation of Acetylenediol (HOCCOH) and Glyoxal (HCOCHO) in Interstellar Analog Ices of Carbon Monoxide and Water

Enols—tautomers of ketones or aldehydes—are considered key intermediates in the formation of prebiotic sugars and sugar acids. Although laboratory simulation experiments suggest that enols should be ubiquitous in the interstellar medium, the underlying formation mechanisms of enols in interstellar environments are largely elusive. Here, we present the laboratory experiments on the formation of glyoxal (HCOCHO) along with its ynol tautomer acetylenediol (HOCCOH) in interstellar ice analogs composed of carbon monoxide (CO) and water (H2O) upon exposure to energetic electrons as a proxy for secondary electrons generated from Galactic cosmic rays. Utilizing tunable vacuum ultraviolet photoionization reflectron time-of-flight mass spectrometry, glyoxal and acetylenediol were detected in the gas phase during temperature-programmed desorption. Our results reveal the formation pathways of glyoxal via radical–radical recombination of two formyl (HĊO) radicals, and that of acetylenediol via keto-enol-ynol tautomerization. Due to the abundance of carbon monoxide and water in interstellar ices, glyoxal and acetylenediol are suitable candidates for future astronomical searches. Furthermore, the detection of acetylenediol in astrophysically relevant ices advances our understanding for the formation pathways of high-energy tautomers such as enols in deep space.

Aeration Alleviated the Adverse Effects of Nitrogen Topdressing Reduction on Tomato Root Vigor, Photosynthetic Performance, and Fruit Development.

To explore the compensation effect of aeration on tomato vegetative and reproductive growth in arid and semi-arid areas, a two-year field experiment was conducted with four micro-nano aeration ratios (0%, 5%, 10%, and 15%) and three nitrogen topdressing levels (80, 60, and 40 kg·ha-1) during the tomato growth period in Ningxia, China. The results showed that increasing the aeration ratio in the range of 0-15% was conducive to the enhancement of tomato root vigor (the ability of triphenyltetrazolium chloride to be reduced, 3-104%) and the leaf net photosynthetic rate (14-63%), favorable to the facilitation of plant dry matter accumulation (3-59%) and plant nitrogen accumulation (2-70%), and beneficial to the improvement of tomato yield (12-44%) and fruit quality. Interestingly, since the aeration ratio exceeded 10%, the increase in the aeration ratio showed no significant effects on the single-fruit weight, tomato yield, and fruit quality. Moreover, with aerated underground drip irrigation, properly reducing the traditional nitrogen topdressing level (80 kg·ha-1) by 25% was favorable for enhancing tomato root vigor (5-31%), increasing tomato yield (0.5-9%), and improving fruit soluble solid accumulation (2-5%) and soluble sugar formation (4-9%). Importantly, increasing the aeration ratio by 5% could compensate for the adverse effects of reducing the nitrogen topdressing level by 25% by improving the leaf photosynthetic rate, promoting plant dry matter accumulation, increasing tomato yield, and enhancing the soluble solid and soluble sugar accumulation in tomato fruits. Synthetically considering the decrease in the nitrogen topdressing amount, leading to plant growth promotion, a tomato yield increase, and fruit quality improvement, a favorable nitrogen topdressing level of 60 kg·ha-1 and the corresponding proper aeration ratio of 10% were suggested for tomato underground drip irrigation in the Yinbei Irrigation District of Ningxia.

Direct Observation of Gas-Phase Hydroxymethylene: Photoionization and Kinetics Resulting from Methanol Photodissociation.

Carbene species play an integral role in high-energy chemistry, transition-metal-carbene chemistry, catalysis, photolytic formation of carbohydrates, and possibly even the formation of interstellar sugars. In 1921, "reactive formaldehyde"─now known as hydroxymethylene (HCOH)─was first implicated as an intermediate in photocatalytic processes. However, due to its transient nature, direct observation of HCOH has predominantly been attained using cryogenic isolation methods. As a result, HCOH gas-phase reactivity measurements have been limited. We directly observed HCOH using photoionization spectroscopy following UV photodissociation of methanol. Our measurements show it reacts slowly with O2 at room temperature. This work provides evidence for the formation mechanism of HCOH from CH3OH and its subsequent reactivity under gas-phase reaction conditions.

Anatomical, chemical and endophytic fungal diversity of a Qi-Nan clone of Aquilaria sinensis (Lour.) Spreng with different induction times.

Recently, some new Qi-Nan clones of Aquilaria sinensis (Lour.) Spreng which intensively produces high-quality agarwood have been identified and propagated through grafting techniques. Previous studies have primarily focused on ordinary A. sinensis and the differences in composition when compared to Qi-Nan and ordinary A. sinensis. There are few studies on the formation mechanism of Qi-Nan agarwood and the dynamic changes in components and endophytic fungi during the induction process. In this paper, the characteristics, chemical composition, and changes in endophytic fungi of Qi-Nan agarwood induced after 1 year, 2 years, and 3 years were studied, and Qi-Nan white wood was used as the control. The results showed that the yield of Qi-Nan agarwood continued to increase with the induction time over a period of 3 years, while the content of alcohol extract from Qi-Nan agarwood reached its peak at two years. During the formation of agarwood, starch and soluble sugars in xylem rays and interxylary phloem are consumed and reduced. Most of the oily substances in agarwood were filled in xylem ray cells and interxylary phloem, and a small amount was filled in xylem vessels. The main components of Qi-Nan agarwood are also chromones and sesquiterpenes. With an increasing induction time, the content of sesquiterpenes increased, while the content of chromones decreased. The most abundant chromones in Qi-Nan agarwood were 2-(2-Phenethyl) chromone, 2-[2-(3-Methoxy-4-hydroxyphenyl) ethyl] chromone, and2-[2-(4-Methoxyphenyl) ethyl] chromone. Significant differences were observed in the species of the endophytic fungi found in Qi-Nan agarwood at different induction times. A total of 4 phyla, 73 orders, and 448 genera were found in Qi-Nan agarwood dominated by Ascomycota and Basidiomycota. Different induction times had a significant effect on the diversity of the endophytic fungal community in Qi-Nan. After the induction of agarwood formation, the diversity of Qi-Nan endophytic fungi decreased. Correlation analysis showed that there was a significant positive correlation between endophytic fungi and the yield, alcohol extract content, sesquiterpene content, and chromone content of Qi-Nan agarwood, which indicated that endophytic fungi play a role in promoting the formation of Qi-Nan agarwood. Qi-Nan agarwood produced at different induction times exhibited strong antioxidant capacity. DPPH free radical scavenging activity and reactive oxygen species clearance activity were significantly positively correlated with the content of sesquiterpenes and chromones in Qi-Nan agarwood.

ФИЗИОЛОГО-БИОХИМИЧЕСКИЕ ИЗМЕНЕНИЯ В ПОБЕГАХ ВИНОГРАДА В ПЕРИОД ЗИМНЕГО ПОКОЯ

The adaptive of the stability of cultivated grape varieties are changing due to the instability of the climate in the Anapa-Taman zone of the Krasnodar region. The purpose of this work is to conduct a comparative analysis of the physiological and biochemical changes occurring in the shoots of grape varieties with different frost resistance during the winter dormancy. The objects of research are grape varieties of various genetic origin: Kristall (control), Dostoynyi, Krasnostop AZOS, Vostorg, Aligote, Zarif. On the basis of generally accepted physiological and biochemical methods, the features of physiological and biochemical changes in grape varieties of different frost resistance in the autumn-winter period 2021-2023 were studied. It was revealed that the ripened shoots of grapes were characterized by both changes in the anatomical structure of tissues (formation of periderm, hardening and lignification of cell walls) and physiological and biochemical changes in the cells of storage tissues – a high content of starch and sugars, as well as a decrease in hydration. It was revealed that the hydration of shoots decreased to a greater extent in frost-resistant varieties Kristall, Dostoynyi, Krasnostop AZOS, Vostorg – by 5.07-5.29 %, in non-frost-resistant varieties Aligote, Zarif – by 1.25-2.04 %. It was found that a more complete conversion of starch into sugar occurred in frost-resistant varieties of Kristall, Dostoynyi, Krasnostop AZOS, Vostorg. Thus, the starch content decreased in varieties: Crystal – by 2.51 times, Dostoynyi – by 2.15 times, Krasnostop AZOS – by 2.21 times, Vostorg – by 2.06 times. In the non-frost-resistant Aligote variety, starch reduction was 1.43 times, and in Zarif – 1.40 times. It was shown that a higher content of organic acids, important antioxidants in protection against oxidative stress, was noted in more frost-resistant varieties – Kristall, Dostoynyi, Krasnostop AZOS, Vostorg. – 10.8-17.2 mg/g of fresh weight, compared with non-frost-resistant Aligote, Zarif – 5.28-7.50 mg/g of fresh weight. The relationship between the content of water, starch, sugars, organic acids and frost resistance of grape varieties has been revealed. The less hydration of the shoots, the greater the degree of sugar formation, the higher the content of organic acids in the tissues of the shoot, the more frost-resistant the variety. Key words: GRAPES, DORMANCY, STARCH, SUGARS, ORGANIC ACIDS, FROST RESISTANCE

Influence of Cellulose-Cellulase Enzyme Digestibility in the Production of Glucose from Lignocellulosic Biomass Waste

A comprehensive understanding of the factors and ability of cellulase enzyme to completely hydrolyze the structural lignocellulosic biomass has been a major research focus over the years. A comparative analysis of cellulose-cellulase digestibility of Kraft-pretreated sawdust from twenty different Nigeria wood wastes was carried out with increasing enzyme (Trichorderma viride) loading of 0.4 mg cm−3, 1.0 mg cm−3, 2.0 mg cm−3, and 4.0 mg cm−3 at constant substrate application of 10 mg cm−3 biomass concentration, temperature of 40°C and 2 h incubation period. This was carried out in order to establish the optimum cellulase-cellulose ratio for maximum biodegradation of the lignocellulosic biomass to produce glucose, a fermentable sugar. The influence of the cellulose-cellulase interaction from 0.4 mg cm−3 to 1.0 mg cm−3 enzyme treatment resulted in 144% increase in glucose yield from E. suaveolen and 121% from S. pustlatas. while 2.0 mg cm−3 cellulase concentration gave 674%, 641% and 617% increase from E.suaveolen, H. ciliate and A. germinans respectively. A general trend of increasing sugar formation was observed with an increasing enzyme loading due to enhanced cellulose accessibility by the cellulase enzyme leading to effective saccharification of the lignocellulosic materials for more sugar production. However, further increase of 4.0 mg cm−3 enzyme concentration failed to produce a commiserate amount of fermentable sugar.

Deconstructing biomass resistance for improving pyrolytic sugars via γ-valerolactone pretreated bamboo coupled with fast pyrolysis

Pyrolytic sugars, as significant fermentable sugars for the production of fuel ethanol, can be fleetly prepared by biomass fast pyrolysis. However, both the biomass inherent resistance and the interaction of compositions restrain the formation of pyrolytic sugars during pyrolysis. To overcome the above bottleneck and improve the yield of pyrolytic sugars, γ-valerolactone (GVL) pretreatment of bamboo coupled with fast pyrolysis was proposed. The effects of reaction temperatures, concentration of acid catalyst, pyrolytic parameters and kinetics on the distributions of sugar compounds were systematically investigated in this process. The experimental results demonstrated that the GVL pretreated biomass effectively eliminated the inherent resistance due to the removal of lignin (16.5 wt%) and hemicellulose (16 wt%). In addition, the content of alkaline and alkaline earth metals significantly decreased from 0.25 wt% of untreated bamboo to 0.01 wt% of the pretreated sample. Subsequently, the selectivity of levoglucosan effectively raised from 9.1 % of untreated bamboo to 70.3 % of GVL pretreated bamboo, and the content of levoglucosan from fast pyrolysis of GVL pretreated bamboo increased 20.2 folds as compared to untreated bamboo.

Contributions of plant‐ and microbial‐derived residuals to mangrove soil carbon stocks: Implications for blue carbon sequestration

Abstract Coastal blue carbon ecosystems, particularly mangroves, are becoming increasingly recognised for their importance in mitigating climate change. Still, the specific patterns and drivers of plant lignin components and microbial necromass accumulation in these ecosystems are unclear. In response, we carried out a study along a 40‐year mangrove restoration chronosequence, measuring lignin phenol and amino sugar concentrations in soil profiles (0–100 cm) as indicators of plant‐based and microbial‐derived residues, respectively. Our results showed that restoration significantly increased plant lignin phenol and amino sugar concentrations, with mature mangroves having much higher concentrations than tidal flats. During restoration, the fungal necromass was greater than the bacterial necromass. The factors influencing the lignin phenols were tree biomass, total nitrogen, pH and salinity, while those influencing the formation of amino sugars were total biomass, soil C: N ratio and pH. While the amino sugars decreased, the lignin phenols increased with the content of SOC, providing evidence of the important role lignin phenol components play in the formation of SOC in mangrove. Synthesis: By separating soil carbon into plant‐based and microbial‐derived components, our results demonstrate that the carbon stock in mangrove sediments is vulnerable to disturbances and that changes from anaerobic to aerobic conditions cause significant carbon mineralisation. The precise identification of soil carbon sources in blue carbon ecosystems could aid in elucidating the mechanisms of soil carbon sequestration and their responses to environmental changes. Read the free Plain Language Summary for this article on the Journal blog.

SUBJECT REVIEW PHASES OF SUGAR METABOLISM AND THE EFFECT OF HORMONES ON IT

Sugar metabolism is the biochemical processes that imply formation, breakdown, and conversion of sugar in human body. Several biological processes are involved during Sugar metabolism. This report discusses comprehensively both sugar metabolism phases and digestion pathways. The biological activities related to sugar metabolism in every relevant human body organs, chemical reactions, hormones and enzymes effects, transport routes and absorption mechanisms have been highlighted.

Influence of the Weak Nuclear Force on Metal-Promoted Autocatalytic Strecker Synthesis of Amino Acids: Formation of a Chiral Pool of Precursors for Prebiotic Peptide and Protein Synthesis.

Natural chiral amino acids typically adopt an L structural configuration. While a preference for specific molecular chiralities is observed throughout biology and cellular chemistry, the origins of this preference are unclear. In a previous report the origin of enantiomeric selectivity was analyzed in terms of an "RNA World" model, and a pathway to a chiral preference for d-ribose was proposed based on the autocatalytic transformation of glyceraldehyde as a precursor to the formation of sugars. Metal-ion-promoted catalysis allows the parity non-conserving (PNC) weak nuclear interaction to influence the chirality of a nascent chiral carbon center. Since the PNC effect is the only natural property with an inherent handedness, it is an obvious candidate to influence enantiomeric preference from a catalytic reaction performed over geologically relevant time scales. The PNC influence requires and emphasizes the important role of catalytic metal ions in primordial chemistry. In this study, the impact of geologically available divalent calcium and higher Z alkaline earth elements are examined as mediators of chiral preference. Detailed calculations of the magnitude of the effect are presented, including the influence of time, temperature, pH, and metal ion identity. It is concluded that metal ions can direct chiral preference for amino acid synthesis via a metal-promoted autocatalytic Strecker reaction within a relatively short geological timeframe, thereby providing a pool of l-amino acids for catalytic chemistry evolving either from an RNA-world model of molecular evolution or alternative pathways to protein synthesis.

STUDY OF DOUGH FERMENTATION PROCESS WITH FLAX SEEDS

Flax seeds are a valuable raw material for the production of functional bakery products. The article investigates the fermentation processes in wheat dough supplemented with whole and crushed flax seeds in dry and soaked states. For a holistic understanding of the fermentation process, the regularities of the kinetics and dynamics of gas formation in the experimental samples were analyzed. It was found that during fermentation in samples with whole flax seeds in dry and soaked states, the amount of carbon dioxide released slightly increases compared to the control. In the samples with crushed dry and soaked flax seeds, the total amount of carbon dioxide released is higher than in the control sample by 16.5% and 19.0%, respectively. In the sample with crushed flax seeds, the nature of the dynamics of carbon dioxide release differs from the control sample, namely, a one-stage fermentation is observed. At the same time, the peak of carbon dioxide release was observed almost 30 minutes later than in the control sample. This may be due to the fact that soaking flaxseed products produces viscous solutions of polysaccharides, which envelop the yeast cells during dough kneading and slow down the supply of nutrients to them. Based on the analysis of the dynamics of carbon dioxide emission, it is recommended to reduce the duration of dough fermentation for the sample with whole flax seeds to 90 minutes, and for the samples with crushed seeds and soaked flax products to 60 minutes, so that the most intense carbon dioxide emission in these experimental samples occurs during the period of proofing of dough pieces. It was found that the introduction of whole and crushed flax seeds in soaked form slows down the rise of the dough due to the thickening of the dough system with water-soluble and insoluble flax dietary fiber, reducing fermentation and the formation of sugars in the dough system.

Exogenous application of ALA enhanced sugar, acid and aroma qualities in tomato fruit.

The content and proportion of sugars and acids in tomato fruit directly affect its flavor quality. Previous studies have shown that 5-aminolevulinic acid (ALA) could promote fruit ripening and improve its aroma quality. In order to explore the effect of ALA on sugar and acid quality during tomato fruit development, 0, 100, and 200 mg L-1 ALA solutions were sprayed on the fruit surface 10 days after pollination of the fourth inflorescence, and the regulation of ALA on sugar, acid metabolism and flavor quality of tomato fruit was analyzed. The results showed that ALA treatment could enhance the activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase (SS), reduce the activity of sucrose phosphate synthase (SPS), up-regulate the expression of SlAI, SlNI and SlSS, change the composition and content of sugar in tomato fruit at three stages, significantly increase the content of sugars in fruit, and promote the accumulation of sugars into flesh. Secondly, ALA treatments increased the activities of phosphoenolpyruvate carboxykinase (PEPC), malic enzyme (ME), and citrate synthase (CS), up-regulated the expression of SlPPC2, SlME1, and SlCS, and reduced the citric acid content at maturity stage, thereby reducing the total organic acid content. In addition, ALA could also increase the number and mass fraction of volatile components in mature tomato fruits. These results indicated that exogenous application of ALA during tomato fruit development could promote the formation of fruit aroma quality and were also conducive to the formation of fruit sugar and acid quality.

Influence of alkali and alkali earth metals on pyrolysis of tobacco waste

The effect of alkali and alkali earth metals on pyrolysis behavior of tobacco was revealed in this paper. Four alkali and alkali earth metal ions (Na+, K+, Ca2+, and Mg2+) were used to impregnate acid-washed tobacco. The addition of alkali and alkali earth metal ions in acid-washed tobacco increases the relative content of ketones, acids, nitrogen containing compounds, and esters, while inhibit the formation of anhydro sugars and aldehydes. The generation of solid residues is enhanced by the presence of alkali and alkali earth metal ions and the increase of K+ concentration. The addition of 0.5 mmol K+/g can increase the yield of solid residues from 13.7 wt% to 20.2 wt%. The increase of K+ concentration promotes the conversion of anhydro sugars to ketones. The effect of hot water-wash, acid-wash, and acid-infuse, which can control the concentration of alkali and alkali earth metal ions in the tobacco, on the product distribution of tobacco pyrolysis were also discussed. Acid-wash method and hot water-wash method promote the production of carbohydrate derivatives and inhibit the generation of nitrogen-containing products. After nitric acid-wash and hot water-wash pretreatment, the relative content of nitrogen-containing products decreased from 52.1% to 6.2% and 4.3%, respectively. Compared with inorganic acid-wash pretreatment method, organic acid-wash pretreatment method has weaker inhibition on nitrogen-containing products. Organic acid-wash pretreatment method promoted the formation of aromatics and aldehydes. Prewash methods facilitate the thermal decomposition of tobacco. The results from this study suggests that feedstock pretreatment could be used as a strategy of controlling aroma compounds formation from tobacco.

Transcriptome Analysis Reveals Brassinolide Signaling Pathway Control of Foxtail Millet Seedling Starch and Sucrose Metabolism under Freezing Stress, with Implications for Growth and Development.

Low-temperature stress limits the growth and development of foxtail millet. Freezing stress caused by sudden temperature drops, such as late-spring coldness, often occurs in the seedling stage of foxtail millet. However, the ability and coping strategies of foxtail millet to cope with such stress are not clear. In the present study, we analyzed the self-regulatory mechanisms of freezing stress in foxtail millet. We conducted a physiological study on foxtail millet leaves at -4 °C for seven different durations (0, 2, 4, 6, 8, 10, and 12 h). Longer freezing time increased cell-membrane damage, relative conductance, and malondialdehyde content. This led to osmotic stress in the leaves, which triggered an increase in free proline, soluble sugar, and soluble protein contents. The increases in these substances helped to reduce the damage caused by stress. The activities of superoxide dismutase, peroxidase, and catalase increased reactive oxygen species (ROS) content. The optimal time point for the response to freezing stress was 8 h after exposure. The transcriptome analysis of samples held for 8 h at -4 °C revealed 6862 differentially expressed genes (DEGs), among which the majority are implicated in various pathways, including the starch and sucrose metabolic pathways, antioxidant enzyme pathways, brassinolide (BR) signaling pathway, and transcription factors, according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. We investigated possible crosstalk between BR signals and other pathways and found that BR signaling molecules were induced in response to freezing stress. The beta-amylase (BAM) starch hydrolase signal was enhanced by the BR signal, resulting in the accelerated degradation of starch and the formation of sugars, which served as emerging ROS scavengers and osmoregulators to resist freezing stress. In conclusion, crosstalk between BR signal transduction, and both starch and sucrose metabolism under freezing stress provides a new perspective for improving freezing resistance in foxtail millet.