Dominant Sugar Research Articles

Dynamic Analysis of UPLC-MS/MS for Sugar and Organic Acid Components of Pears with Different Flesh Texture Types During Development

Pears are popular among consumers for their juicy and delicious taste. In this study, the sugar and organic acid compositions of pear fruits with different texture types during development were determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), and fruit texture traits were determined by a texture analyzer. The results showed that the dominant sugar in soft and crispy types of pear fruits was fructose. The main difference between pears was the second-highest sugar component; glucose content was higher in crispy-flesh pear fruits while sucrose content was higher in soft-flesh pear fruits. The composition of organic acid components in both texture types of pear fruits was similar. The turning points of changes in the content of sucrose, sorbitol, glucose and quinic acid were different between different-textured pear varieties. A Pearson correlation analysis showed that sugar and organic acid components were significantly correlated with single fruit weight and soluble solid contents (SSCs), respectively. There was a high correlation among texture traits, individual sugars and organic acids. A partial least squares discriminant analysis (PLS-DA) VIP score plot showed that the differential traits with scores greater than 1 were total soluble sugars/total organic acids (TSSs/TAs), fracture and malic acid/citric acid (MA/CA), which could distinguish pear fruits of different texture types better and reflect the uneven quality differences among pear fruits adapted to different origins. The comprehensive analysis results of the flesh texture parameters and sugar and organic acid components are in line with objective reality and will provide a reference for quantitative indicators of the sensory evaluation of pear varieties as well as for molecular mechanism research on trait differences.

Comparison of Some Parts of Cotoneaster coriaceus Franch. Plant in Terms of Phytochemicals and Antioxidant Capacity

Cotoneaster spp. is a plant belonging to the Rosaceae family, which includes different genera and taxa. It is a woody plant that grows from shrubs to trees depending on its height (between 0.2-20 m) and grows in the temperate areas of Europe, North Africa and Asia. Many Cotoneaster species have become highly popular ornamental plants due to their striking leaves, dense flowers, and bright red-black fruits. These species have been used traditionally for the treatment of numerous diseases due to their rich bioactive components present in both their above-ground and below-ground parts. This study investigates the phytochemical and antioxidant properties of the above-ground parts of Cotoneaster coriaceus Franch., including its fruits, stems, and leaves. For this purpose, total phenolic content (TPC) and DPPH radical scavenging activity, organic acid and sugar profile, and mineral distributions were determined. According to the results, the highest amounts of macro-minerals identified were potassium (K) and calcium (Ca), while iron (Fe) and boron (B) were the predominant micro-minerals. The dominant organic acid in the fruit was malic acid, while succinic acid was prevalent in the stems and leaves. Sucrose and fructose, the sugars detected in the fruit, were found in equal levels in the stems and leaves. Fructose was identified as the dominant sugar in the leaves. It was determined that the fruit, stem, and leave parts of the Cotoneaster coriaceus Franch. plant species were rich in TPC, with the stems exhibiting higher antioxidant capacity.

Expanded genome and proteome reallocation in a novel, robust Bacillus coagulans strain capable of utilizing pentose and hexose sugars.

Bacillus coagulans, a Gram-positive thermophilic bacterium, is recognized for its probiotic properties and recent development as a microbial cell factory. Despite its importance for biotechnological applications, the current understanding of B. coagulans' robustness is limited, especially for undomesticated strains. To fill this knowledge gap, we characterized the metabolic capability and performed functional genomics and systems analysis of a novel, robust strain, B. coagulans B-768. Genome sequencing revealed that B-768 has the largest B. coagulans genome known to date (3.94 Mbp), about 0.63 Mbp larger than the average genome of sequenced B. coagulans strains, with expanded carbohydrate metabolism and mobilome. Functional genomics identified a well-equipped genetic portfolio for utilizing a wide range of C5 (xylose, arabinose), C6 (glucose, mannose, galactose), and C12 (cellobiose) sugars present in biomass hydrolysates, which was validated experimentally. For growth on individual xylose and glucose, the dominant sugars in biomass hydrolysates, B-768 exhibited distinct phenotypes and proteome profiles. Faster growth and glucose uptake rates resulted in lactate overflow metabolism, which makes B. coagulans a lactate overproducer; however, slower growth and xylose uptake diminished overflow metabolism due to the high energy demand for sugar assimilation. Carbohydrate Transport and Metabolism (COG-G), Translation (COG-J), and Energy Conversion and Production (COG-C) made up 60%-65% of the measured proteomes but were allocated differently when growing on xylose and glucose. The trade-off in proteome reallocation, with high investment in COG-C over COG-G, explains the xylose growth phenotype with significant upregulation of xylose metabolism, pyruvate metabolism, and tricarboxylic acid (TCA) cycle. Strain B-768 tolerates and effectively utilizes inhibitory biomass hydrolysates containing mixed sugars and exhibits hierarchical sugar utilization with glucose as the preferential substrate.IMPORTANCEThe robustness of B. coagulans makes it a valuable microorganism for biotechnology applications; yet, this phenotype is not well understood at the cellular level. Through phenotypic characterization and systems analysis, this study elucidates the functional genomics and robustness of a novel, undomesticated strain, B. coagulans B-768, capable of utilizing inhibitory switchgrass biomass hydrolysates. The genome of B-768, enriched with carbohydrate metabolism genes, demonstrates high regulatory capacity. The coordination of proteome reallocation in Carbohydrate Transport and Metabolism (COG-G), Translation (COG-J), and Energy Conversion and Production (COG-C) is critical for effective cell growth, sugar utilization, and lactate production via overflow metabolism. Overall, B-768 is a novel, robust, and promising B. coagulans strain that can be harnessed as a microbial biomanufacturing platform to produce chemicals and fuels from biomass hydrolysates.

COMPARISON OF THE CHEMICAL COMPOSITION AND MORPHOLOGICAL CHARACTERISTICS OF DIFFERENT CARROT VARIETIES

Carrot (Daucus carota L.) is a globally significant root vegetable, rich in bioactive and nutritional compounds. Carrot is a crop with a wide range of phenotypic variability including colour, shape, size, and other characteristics. The aim of this work was to determine and compare selected morphological traits and chemical composition of 24 carrot varieties grown under open field conditions in Slovakia. Altogether, 11 qualitative characteristics and 6 quantitative parameters were evaluated. The carrot roots were also analysed for essential chemical constituents including reducing sugars (fructose, glucose, saccharose), carotenoids, dietary fibre, dry matter, ash, and mineral compounds. A wide range of diversity in morphological characteristics and chemical composition indicates a high variability of studied varieties. The root length ranged from 59 to 205 mm, root diameter varied from 17.7 to 39.0 mm and root weight ranged from 21.0 to 74.8 g. Based on the measurement results, saccharose was the dominant sugar ranging from 1.89 to 4.67 g.100 g-1 of fresh weight, carotenoid content varied from 85.94 to 374.24 µg.g-1 of fresh weight, the amount of dietary fibre ranged from 25.67 to 36.02% of dry matter. Considerable differences were also observed in the content of macro and microelements [mg.100 g-1] ranging as follows: P (17.5 - 52.0), K (110.0 – 337.0), Na (65.9 – 186.0), Fe (0.324 – 3.340), Cu (0.042 – 0.126), Zn (0.152 – 0.945) and Mn (0.062 – 0.189). The presented results can provide useful information for carrot growers and consumers in terms of morphological characteristics as well as the chemical composition of individual carrot varieties.

Changes in bioactive compounds and antioxidant activity of Gaziantep and Kastamonu garlic during black garlic production

Garlic (Allium sativum L.), a member of the Alliaceae family, has been widely used in cuisine and traditional medicine since ancient times. Black garlic is produced by fermentation of fresh garlic under controlled conditions for a certain period at high temperature (60-90°C) and high humidity (70-90%). According to the Turkish Statistical Institute (TURKSTAT) data, Kastamonu and Gaziantep garlic varieties are the most cultivated garlic varieties in our country. Changes in protein, sugar content, antioxidant capacity (DPPH and ABTS methods), total phenolic content, 5-hydroxymethylfurfural (HMF) content, and organosulfur compound profiles were investigated in samples taken from Kastamonu and Gaziantep fresh garlic at 7, 14, 21, and 28 days of black garlic production under 65°C temperature and 70% humidity conditions. With these analyses, the differences between black garlic and fresh garlic and the changes in black garlic during the production process were revealed in detail. It was determined that the amount of total phenolic content and antioxidant capacities increased in the black garlic production processes of both regions compared to fresh garlic. While sucrose was fresh garlic’s dominant sugar, fructose was black garlic’s dominant sugar. Among the organosulfur compounds, allicin was dominant in fresh garlic and SAC in black garlic. It was determined that SAC was formed after the enzymatic conversion of ɣ-glutamyl-S-alk(en)yl-L-cysteine and ɣ-glutamyl and the temperature and fermentation time used in black garlic production increased the formation of SAC. The protein content ranging between 5.8%-7.3% in fresh garlic was 13.1-14.2% in black garlic. Fresh and black garlic from the Gaziantep region was determined to have higher total phenolic content, antioxidant capacity, and organosulfur compound contents.

Structural properties of the biologically active Dictyosphaerium chlorelloides exopolysaccharide α-d-manno-α-l-rhamno-α-d-(2-O-methyl)-galactan

Structure of biopolymers produced by microalgae plays an important role for their potential biological activity prediction and applications. Previously isolated and well characterized dominant fractions (Dch5-8) from ion-exchange chromatography separation of the biologically active microalga Dictyosphaerium chlorelloides exopolysaccharide (Dch) were pooled and partially acid hydrolyzed. The dominant sugar components in the combined Dch5-8 fraction were Gal and its 2-O-methyl derivative, Rha and Man, all accounting for about 94 mol% of total amount of sugars. Separation of obtained hydrolysate on Bio-Gel P-2 afforded ten fractions. Their main components were identified by NMR. Based on oligosaccharide structures, the repeating unit of the polysaccharide backbone was identified as →2)-α-L-Rhap-(1→4)-2-O-methyl-[3-O-β-D-Galp]-α-D-Galp-(1→ branched by Man. Furthermore, the higher molecular weight fraction contained glucuronorhamnan. NMR data indicate 1,4-linked Rha units in the backbone in α and β configuration, branched at O2 by 2,4-di-O-methyl-β-d-glucuronic acid.

Sugar composition and transcriptome analysis in developing ‘Fengtang’ plum (Prunus salicina Lindl.) reveal candidate genes regulating sugar accumulation

Sweetness is an important attribute of fruit quality, which directly affects consumers' preference for fresh fruit and is mostly determined by carbohydrate composition. ‘Fengtang’ plum (Prunus salicina Lindl.) is recognized for its high soluble sugar content, but the sugar composition and the molecular mechanisms underlying sugar overproduction are not fully understood. In this work, the sugar components were analyzed using gas chromatography-mass spectrometry combined with transcription profiles from RNA-sequencing and Quantitative Real-time PCR during fruit development. The target metabolic group showed that sucrose was the dominant sugar component in mature fruit, followed by glucose, fructose, and sorbitol. Based on the transcriptome data and qRT-PCR validation, we identified 12 key structural genes that significantly responded to corresponding component accumulation: sucrose synthase (PsSUS4), sucrose phosphate synthase (PsSPS2), neutral invertase (PsNINV1/3/4), phosphoglucomutase (PsPGM1), UTP-glucose-1-phosphate uridylyl transferase (PsUGP1/2), hexose kinase (PsHXK1/3), sugar transport protein (PsSTP1), and Sugars Will Eventually be Exported Transporter (PsSWEET4). In which PsSUS4 and PsSPS2, whose encoding proteins immediately catalyze sucrose synthesis, were selected to be silenced using the virus-induced gene silencing technology. Silencing of PsSUS4 or PsSPS2 resulted in decreased sucrose content by 27.6% and 8%, respectively, compared with the control, verifying their important roles in sucrose accumulation. Subsequently, sugar metabolism networks in this high-sugar plum were constructed with 12 key structural genes, 72 putative transcription factors, and 4 major sugar components. These results might facilitate a better understanding of the molecular mechanisms of sugar accumulation in ‘Fengtang’ plum and provide a framework for future fruit quality improvement.

Eight Typical Aroma Compounds of 'Panguxiang' Pear during Development and Storage Identified via Metabolomic Profiling.

Aroma is an appreciated fruit property, and volatile flavor plays a key role in determining the perception and acceptability of fruit products by consumers. However, metabolite composition that contributes to the aroma in fruit quality is unclear. In this study, we detected 645 volatile organic compounds of 'Panguxiang' pear in total, including esters, alcohols, alkanes, acids, ketones, terpenes and aldehydes. In addition, the levels of sugars, organic acids and amino acids in 'Panguxiang' pear were investigated using high-performance liquid chromatography. In the aroma generation, glucose was the dominant sugar, followed by sucrose and fructose. At the development transferred storage stage, organic acids may not participate in aroma biosynthesis. The amino acids that may play potential roles in aroma substance synthesis are tyrosine and glycine. Through metabolomics analysis at different stages of 'Panguxiang' pear, we selected 65 key metabolites that were significantly related to glucose, sucrose, fructose, tyrosine and glycine, according to the trends of metabolite concentrations. Finally, we chose eight candidate metabolites (e.g., three esters, two aldehydes, one alcohol, one acid and one ketone) as the representative aroma substances of the 'Panguxiang' pear compared to the metabolome of the 'Korla' at stage Z5. Data and results from this study can help better understand the variations in aroma quality among pear varieties and assist in developing breeding programs for pear varieties.

Analysis of physicochemical characteristics, antioxidant activity, and key aroma compounds of five flat peach cultivars grown in Xinjiang

Flat peach is one of the famous and characteristic table fruits in Xinjiang, China, and has attracted an increasing favorite because of its high nutrition and superior flavor. To evaluate the sensory properties and nutritional value of flat peach, functional components, antioxidant capacity, and aromatic compounds of five flat peach cultivars were measured by using high-performance liquid chromatography (HPLC) and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results indicated that sucrose, malic acid, and chlorogenic acid were the dominant sugars, organic acids, and phenolic compounds in flat peaches, respectively. The antioxidant activity ranged from 62 to 505.46 μmol TEs 100 g−1 FW. In addition, multivariate data analysis was used to discern differences in volatile compounds among different flat peach varieties, and 11 key aroma components were identified in combination with OAV analysis. These key aroma compounds interacted to present distinct green, fruity, floral, milk-like, sweet, and peach-like attributes and could be used as characteristic markers to distinguish the aroma of flat peach from other fruits. These results will provide a comprehensive chemical characterization of the edible quality, nutritional composition, and sensory properties of the five flat peach cultivars.

Flavor compounds, free amino acids, and proteins in Agaricus bisporus mushroom powder

Mushrooms contain a remarkable amount of complete protein, indicating potential as a conventional protein alternative. Commercially available mushroom powder would be protein concentrate and isolate starting material, while valorizing all powder molecules is sustainable and economical. This study aimed to quantify taste-related compounds (five soluble sugars, five organic acids, and five 5′-nucleotides), 23 free amino acids, protein, and other proximate compositions in two A. bisporus mushroom powders. The most dominant sugar was mannitol (5.6 and 6.9% dry matter), followed by glucose and sucrose. The major acid was oxalic acid (0.30 and 0.48%), followed by acetic and malic. Among five nucleotides, 5′-GMP (umami taste, 0.08 and 0.11%) was predominant. Total free amino acids were 4.0 and 6.5%, of which Glu (umami taste, 1.1 and 1.4%) was dominant. Asp (umami taste, 0.27 and 0.67%) was lower. The mushroom powders contained all essential and sweet- and bitter-related amino acids along with around 20% protein; the protein included at least six different fractions per SDS-PAGE. The powders were also majorly comprised of carbohydrates, especially fiber. These results demonstrated taste-related compounds and the nutritional composition in mushroom powders, providing evidence for mushroom powder use as a starting material to develop mushroom protein concentrates and isolates.

Physicochemical Characteristics, Antioxidant Activities, and Aroma Compound Analysis of Seven Peach Cultivars (Prunus persica L. Batsch) in Shihezi, Xinjiang

Peaches are tasty and juicy, with a unique flavor. The flavors of peaches always vary with cultivars. To investigate the physicochemical and aroma characteristics of peaches, the sugars, organic acids, total flavonoids, phenols, antioxidant activities, and aroma compounds of seven peach cultivars in Xinjiang were determined using high-performance liquid chromatography (HPLC) and headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME–GC–MS). The results showed that sucrose (59.83 to 87.34%), malic acid (32.41 to 59.14%), and chlorogenic acid (10.43 to 45.50%) were the dominant sugar, organic acid, and phenolic compound in peaches, respectively. The antioxidant activity varied between 147.81 and 394.55 μmol TEs/100 g. The analysis of the aroma structure of peaches found that the volatile composition of peaches was relatively consistent, though the concentration of total aroma and certain separate compounds were different between cultivars. Meanwhile, the aroma fingerprint of the peaches consisted of hexyl acetate, cis-3-hexenyl acetate, γ-decalactone, n-hexanal, 2-hexenal, nonanal, decanal benzaldehyde and 6-pentylpyran-2-one, providing a clear green, sweet, floral, and fruity odor. These results provide complete information on the physicochemical properties, functional ingredients and aroma of the peaches.

Comparative monosaccharide profiling for taxon differentiation: An example of Icelandic edible seaweeds

Edible seaweeds are usually sold as flakes or even powers, and morphological identification of seaweed taxa is difficult. Water-soluble polysaccharides (WSPs) in edible seaweeds are not only interesting functional food ingredients (e.g. gel-forming property, health benefits), but also useful for seaweed taxon differentiation. The current study aims to explore the utility of monosaccharide profiling of WSPs in seaweed differentiation. We developed a high-performance liquid chromatography-photodiode array detection for monosaccharide determination, and characterized monosaccharide profiles of WSPs from five edible seaweeds sold in Iceland (i.e. kombu Iceland – Laminaria hyperborea, sugar kelp – Saccharina latissima, dulse – Palmaria palmata and two types of nori labelled as Porphyra sp. and Pyropia sp.). Monosaccharide profiling data reflected both the complexity and quantitative differences of WSPs. The seaweed dulse showed the highest concentrations of total sugar (ca. 16 mM), followed by kombu (ca. 12 mM). From monosaccharide profiling of red algae, it was found that galactose (ca. 81–87% of total sugars) and xylose (ca. 65–77% of total sugars) are the dominant sugars in nori and dulse, respectively, which reflected the presence of galactans and xylans. In brown algae (i.e. kombu and sugar kelp), glucose (ca. 64–83%) and fucose (13–20%) are the main sugars, and they represent laminarins and fucoidans. The principal component analysis of sugar profiles showed the useful patterns ‘for seaweed taxon differentiation. The dendrogram resulting from hierarchical cluster analysis is congruent with phylogenetic tree, implying the chemotaxonomic value of seaweed monosaccharide profiles. This tool will be more useful in authentication of seaweed taxa when morphological and genetic identifications are not available.

Composition of Buckwheat Honey

Buckwheat has been grown in Virginia since late 1700s; however, today the crop is almost non-existent in Virginia. Since buckwheat flowers profusely in a few weeks after planting, it has potential to support honeybees but there is a lack of information about quality of buckwheat honey produced in Virginia. Our objective was to characterize composition of honey produced by honeybees foraging on buckwheat (Buckwheat honey), compared to that produced by honeybees foraging on wild plants (Wild plant honey). Buckwheat honey differed in composition, antioxidant concentrations, and microbial activities from wild plant honey. Concentrations of fructose, glucose, and melezitos in buckwheat honey were quantitatively lower than that in wild plant honey whereas concentrations of sucrose and maltose exhibited an opposite trend—concentration of maltose being statistical significant. Fructose was the dominant sugar (42 and 52 percent in buckwheat honey and wild plant honey, respectively). Buckwheat honey had significant higher concentrations of K and Cu in comparison to wild plant honey (0.17 and 0.04 percent, and 5.0 and 3.33 ppm, respectively). Concentrations of Trolox and TPC were significantly higher in buckwheat honey than wild plant honey (1.01 and 0.32, and 0.39 and 0.17, respectively). Both types of honeys exhibited anti-microbial activity against gram-positive and gram-negative bacteria. The buckwheat honey was darker in color than the honey from wild plants. We concluded that production of buckwheat as a grain or cover crop can also support honeybees and buckwheat honey might be superior to wild plant honey.

Nuts as functional foods: Variation of nutritional and phytochemical profiles and their in vitro bioactive properties.

The aim of the present study was to examine the nutritional (fat, fatty acids, minerals, sugars) and bioactive compounds (polyphenols, tocochromanols, triterpene) and their influence on in vitro anti-diabetic (pancreatic α-amylase and intestinal α-glucosidase), anti-obesity (pancreatic lipase) and anti-cholinergic (AChE and BuChE) inhibitory activity of 8 different popular nuts-pecan, pine, hazelnuts, pistachio, almonds, cashew, walnuts, and macadamia. The total content of phenolic compounds in nuts ranged from 432.9 (walnuts) to 5.9 (pistachio) mg/100g. The dominant polyphenols are polymeric procyanidins (walnuts - 415.1mg/100g). Nuts are rich in tocochromanols (832.9-4377.5μg/100g), especially α- and γ-tocopherols. The highest content of α-tocopherol (vitamin E) was detected in hazelnuts and almonds (2551.0 and 2489.7μg/100g, respectively) while the lowest amounts were detected in macadamia, cashew and walnuts. The most abundant in nuts are oleanic and pomolic acids (35 and 22% of total, respectively), while betulin, uvaol and erythrodiol are less characteristic triterpenes for nuts (<1%). Pine nuts are the nuts with the highest content of triterpene (690.3mg/100g). Pistachio and almonds are the richest in total fat (>45%), but monounsaturated (17.5-79.3%; hazelnuts, almonds, cashew, macadamia, pistachio and pecan) and polyunsaturated (7.5-69.3%; pine, walnuts) are the dominant fatty acids. Moreover, nuts are low in Cu, Zn, Mn and Na content, but rich in K (464.5-1772.3mg/100g) and Mg (197.0-502.5mg/100g). Macadamia, walnuts and cashew are good sources of Se. Pistachio, almonds and cashew were characterized by the highest content of sugars, but the dominant sugar was saccharose (58.2-2399.3mg/100g). All nuts showed high activity in inhibiting intestinal α-glucosidase (>90%), but lower ability to inhibit pancreatic α-amylase and pancreatic lipase activity. The activity in inhibiting acetyl- and butylcholinesterase was up to 30%. As described above, all nuts contain various compounds that improve the nutritional value. Therefore they should be one of the important components of the daily human diet rich in functional foods.

Polyphenolics and Chemical Profiles of Domestic Norwegian Apple (Malus × domestica Borkh.) Cultivars

Using modern analytical techniques, a comprehensive study of the chemical composition of fruits from apple cultivars grown in Western Norway during 2019 and 2020 was done. Metals, sugars, organic acids, antioxidant tests, and polyphenol content have been observed. In all investigated samples, the most dominant sugars were glucose, fructose, and sucrose. Among 11 tested organic acids, the dominant was malic acid, followed by citric and maleic acid. The most common metal was potassium, followed by magnesium and zinc. The quantification of polyphenols showed that among the 11 quantified polyphenols, chlorogenic acid, quercetin 3-O-rhamnoside, quercetin 3-O-glucoside, quercetin, and phlorizin were the most abundant. A detailed study of the polyphenolic profile of nine investigated apple samples provided 30 identified polyphenolic compounds from the class of hydroxybenzoic and hydroxycinnamic acids, flavonoids, and dihydrochalcones. In addition to the identified 3-O-caffeoylquinic acid, its two isomers of 5-O-caffeoylquinic acid and three esters were also found. Present polyphenols of the tested apples provided significant data on the quality of Norwegian apples, and they contribute to the distinguishing of these apple samples.

How is Trehalulose Formed by Australian Stingless Bees? - An Intermolecular Displacement of Nectar Sucrose.

Trehalulose, a rare sucrose isomer, is a dominant sugar in stingless bee honey, with traces of the trisaccharide erlose. Incubating sucrose solutions with macerated stingless bee parts (head, thorax, and abdomen) from Tetragonula carbonaria, we observed that sucrose isomerization occurs predominantly in the head incubations, with trehalulose constituting 76.2-80.0% of total detected sugar. By contrast, sucrose hydrolysis occurred in stingless bee abdomen incubations, with glucose and fructose observed as 48.6-51.7% and 48.3-49.7%, respectively, of total detected sugar. Incubating glucose/fructose (1:1) solutions with any bee part did not result in trehalulose formation. In addition, by tracing the 13C isotope-labeled monosaccharide moieties throughout the isomerization from sucrose to trehalulose and erlose, for the first time, the mechanism was established as an enzymatic double displacement reaction. Sucrose acts as a glucose donor giving a β-d-glucosyl enzyme intermediate with fructose release as demonstrated by mixed isotope products. Glucosylation of fructose (inter- or intramolecularly) with isomerization forms trehalulose (favorable), while glucosylation of sucrose forms erlose (less favorable).

Alkaline α-galactosidase 2 (CsAGA2) plays a pivotal role in mediating source-sink communication in cucumber.

Sugars are necessary for plant growth and fruit development. Cucumber (Cucumis sativus L.) transports sugars, mainly raffinose family oligosaccharides (RFOs), in the vascular bundle. As the dominant sugars in cucumber fruit, glucose and fructose are derived from sucrose, which is the product of RFO hydrolysis by α-galactosidase (α-Gal). Here, we characterized the cucumber alkaline α-galactosidase 2 (CsAGA2) gene and found that CsAGA2 has undergone human selection during cucumber domestication. Further experiments showed that the expression of CsAGA2 increases gradually during fruit development, especially in fruit vasculature. In CsAGA2-RNA interference (RNAi) lines, fruit growth was delayed because of lower hexose production in the peduncle and fruit main vascular bundle (MVB). In contrast, CsAGA2-overexpressing (OE) plants displayed bigger fruits. Functional enrichment analysis of transcriptional data indicated that genes related to sugar metabolism, cell wall metabolism, and hormone signaling were significantly downregulated in the peduncle and fruit MVBs of CsAGA2-RNAi plants. Moreover, downregulation of CsAGA2 also caused negative feedback regulation on source leaves, which was shown by reduced photosynthetic efficiency, fewer plasmodesmata at the surface between mesophyll cell and intermediary cell (IC) or between IC and sieve element, and downregulated gene expression and enzyme activities related to phloem loading, as well as decreased sugar production and exportation from leaves and petioles. The opposite trend was observed in CsAGA2-OE lines. Overall, we conclude that CsAGA2 is essential for cucumber fruit set and development through mediation of sugar communication between sink strength and source activity.

Changes in &lt;i&gt;Pleurotus ostreatus&lt;/i&gt; nutritional value and heavy metal profile as a result of supplementation with nano-additive

The present study evaluated the effect of Lithovit-Amino25 on the nutrient profile and heavy metal composition of <italic>Pleurotus ostreatus</italic>. The product was tested in two doses applied at three different timings: T2: 3 g kg⁻¹/spawning, T3: 3 g kg⁻¹/after first harvest, T4: 3 g kg⁻¹/spawning and after first harvest, T5: 5 g kg⁻¹/spawning, T6: 5 g kg⁻¹/after first harvest, and T7: 5 g kg⁻¹/spawning and after first harvest. Compared to control (T1: non-treated substrate), mushrooms’ fibers and carbohydrates increased in all treatments, recording the highest values in T4 (4.16%) and T3 (18.42%), respectively. Protein content was higher in mushrooms of substrates treated at spawning, with a 0.33% improvement in T5. Fat content decreased in T3, T4, T6, and T5. Total sugars decreased in mushrooms of treated substrates, and glucose was the dominant sugar in mushrooms. Fructose increased in mushrooms of T3 and T4. Calcium, iron, and potassium decreased in mushrooms of treated substrates. Sodium decreased in T3, T5, and T7, magnesium increased in T2, and phosphorus increased only in T2 and T7. Copper content of all treated mushrooms was in the standard safe limit (&lt; 40 ppm), and it decreased in T2, T4, and T5 by around 2.5, 6.6, and 5.1 ppm, compared to control. However, zinc content increased in mushrooms of all treated substrates, and nickel and lead, increased by respective ranges of 2.8−11.88 ppm and 9.1−21 ppm, higher than the safe limits. The product presented a risk of heavy metal bioaccumulation even with a low dose.

Extraction, phytochemical analysis, monosaccharide composition and functional properties of X. americana seed mucilage

The ability of mucilage to improve the functional and rheological properties of foods has initiated interest in exploiting different plant sources. Ximenia americana seed, disposed after consuming of the fruit pulp, has not been exploited for its mucilage potential to be used in food industry. X. americana seed mucilage was extracted and precipitated with water and ethanol, respectively. This study investigates the phytochemical constituents, antioxidant activities, monosaccharide composition, and morphological features of X.americana seed mucilage. The yield of mucilage obtained from the seed was 17.15%. The amount of total phenol, flavonoid, alkaloid, and tannin extracted with methanol was higher than that of acetone. Saponin was not detected in this mucilage extract. Xylose (50.18%) was the dominant sugar, while sucrose (2.83%) was the least in quantity among monosaccharides. The FTIR result revealed the presence of (OH) group which indicated the hydrophilic nature of the mucilage. The SEM micrograph also showed the amorphous and uneven shapes with cracks. The mucilage had remarkable functional properties in terms of foaming capacity, foam stability, emulsion capacity, emulsion stability, water and oil holding capacity and viscosity. The result indicated that the mucilage from X. americana seed could be a potential ingredient in food industry.

Lactylated acidic exopolysaccharide produced by the cyanobacterium Nostoc cf. linckia

Cyanobacteria produce a wide range of metabolites of interest for industrial or medical use. The cultivation of freshwater Nostoc cf. linckia yielded 5.4 g/L of a crude exopolysaccharide (cEPS) with a molecular weight of 1.31 × 105 g/mol. Ion-exchange chromatography of cEPS yielded two dominant fractions, EPS-1 and EPS-2, differing in molecular weight. The lower molecular weight fraction (EPS-1) was subjected to structural studies. Results of chemical and spectroscopic analyses showed that three of the four dominant sugars, glucose, galactose and xylose are 1,4-linked in the backbone in the following order: [→4)-β-D-Xylp-(1 → 4)-β-D-Glcp-(1 → 4)-α-D-Galp-(1 → 4)-β-D-Glcp-(1→]n. Terminal mannose residues were identified as side chains linked at C3 of every third backbone xylose and every second glucose is branched at C6 by 3-O-lactyl-β-D-glucuronic acid (nosturonic acid). Antioxidant properties of EPS were tested using two in vitro methods. Both assays showed that the cEPS was more active than purified EPS-1 and EPS-2 fractions and deproteinized EPS.