Levels Of Polysaccharides Research Articles

Polysaccharides and polyphenol in dried Morinda citrifolia fruit tea after different processing conditions: Optimization analysis using response surface methodology.

The increasing popularity of Morinda citrifolia has many medical and health benefits because of its rich polysaccharides (PSC) and polyphenols (PPN). It has become popular to brew the dry M. citrifolia fruit slice as tea in some regions of China. In this study, optimize the extraction parameters of M. citrifolia fruit tea polysaccharides and polyphenols using response surface methodology. The results indicated the highest PSC yield of 17% at 46 °C for 11 min and the ratio of water/M. citrifolia fruit powder was 78 mL/g. The optimum extraction of PPN was at 95 °C for 10 min and the ratio of water/M. citrifolia fruit powder 90 mL/g, with 8.93% yield. Using dry M. citrifolia fruit slices as a tea is reported for the first time. Based on the results, the maximum level of PSC can be obtained under condition by infusing about four dried M. citrifolia fruit slice with average thickness and size in warm boiled water for 11 min, taking a 300 mL cup (300 mL of water) for example. The maximum level of PPN can be obtained by adding three slices of dried M. citrifolia fruit slice to boiled water for 10 min. Considering the powder used in our study, the further pulverization of cutting into powder is more conducive to material precipitation. This study provides a scientific basis for obtaining PSC and PPN from dry M. citrifolia fruit slice tea by brewing.

Expression of Concern on “DNA Extraction Protocol for Plants with High Levels of Secondary Metabolites and Polysaccharides without Using Liquid Nitrogen and Phenol”

Expression of Concern on “DNA Extraction Protocol for Plants with High Levels of Secondary Metabolites and Polysaccharides without Using Liquid Nitrogen and Phenol”

Powdered activated carbon addition for fouling control in anaerobic membrane bioreactor

The effect of powdered activated carbon (PAC) addition to a conventional anaerobic membrane bioreactor (AnMBR) on removal performance and membrane fouling was explored in this study. The optimal one-off PAC dose could increase average chemical oxygen demand (COD) and total organic carbon (TOC) removal rates up to 15.7% and 15.6%, respectively. The PAC addition exhibited not only lower TMP increase rate, but also reduced soluble microbial product (SMP) and extracellular polymeric substances (EPS). Higher protein to polysaccharide ratio of SMP and higher zeta potential in AnMBR with PAC could enhance hydrophobicity and flocculation ability, thereby effectively alleviating membrane fouling. Lower total membrane resistance and pore blocking resistance indicated that PAC addition could prevent both severe pore blocking and irreversible fouling, due to the lower polysaccharide level in SMP of the cake layer. Moreover, PAC addition facilitated the decrease in fouling-related bacteria such as Cloacibacterium and Paludibacter.

Zinc affects the physiology and medicinal components of Dendrobium nobile Lindl

The growth of Dendrobium nobile is often influenced by zinc. Here, D. nobile was regularly sprayed with different concentrations (0, 50, 100, 200, 400, 800, 1000, 2000 μmol L−1) of zinc to study its effect on the growth and biosynthesis of medicinal components. Samples were taken at 0, 7, 14, and 21 days to detect physiological and medicinal components. The results showed that the net photosynthetic rate, transpiration rate, stomatal conductance, and Chl A and Chl B levels of leaves first increased and then decreased as the concentration of zinc increased. At 400 μmol L−1 concentration, these parameters reached their maximum values. Thus, a certain dose of zinc could promote the photosynthesis of D. nobile. There was an obvious increase in the synthesis of superoxide dismutase (SOD), while the content of ascorbate peroxidase and ascorbic acid (AsA) were the highest after treatment with 400 μmol L−1 zinc. Maximum levels of polysaccharides and polyphenols were observed on day 7 and 14, respectively, at a zinc concentration of 400 μmol L−1. These results suggest that exogenous zinc may promote the accumulation of medicinal components in D. nobile. It was also found that polysaccharides could combine well with zinc to form a polysaccharide-zinc chelate and transform inorganic zinc into organic form, which is stored in the form of polysaccharide-Zn and is known to reduce the damage induced by Zn stress.

Effect of Pre-Fermentative Maceration and Fining Agents on Protein Stability, Macromolecular, and Phenolic Composition of Albariño White Wines: Comparative Efficiency of Chitosan, k-Carrageenan and Bentonite as Heat Stabilisers.

In this work, the effect of pre-fermentative skin maceration (PFSM) on the chemical composition of the macromolecular fraction, polysaccharides and proteins, phenolic compounds, chromatic characteristics, and protein stability of Albariño monovarietal white wines was studied. PFSM increased the extraction of phenolic compounds and polysaccharides and reduced the extraction of pathogenesis-related proteins (PRPs). PFSM wine showed significantly higher protein instability. Sodium and calcium bentonites were used for protein stabilisation of wines obtained with PFSM (+PFSM) and without PFSM (−PFSM), and their efficiencies compared to fungal chitosan (FCH) and k-carrageenan. k-Carrageenan reduced the content of PRPs and the protein instability in both wines, and it was more efficient than sodium and calcium bentonites. FCH was unable to heat stabilise both wines, and PRPs levels remained unaltered. On the other hand, FCH decreased the levels of wine polysaccharides by 60%. Sodium and calcium bentonite also decreased the levels of wine polysaccharides although to a lower extent (16% to 59%). k-Carrageenan did not affect the wine polysaccharide levels. Overall, k-carrageenan is suitable for white wine protein stabilisation, having a more desirable impact on the wine macromolecular fraction than the other fining agents, reducing the levels of the wine PRPs without impacting polysaccharide composition.

Elucidating carbohydrate metabolism in Euglena gracilis: Reverse genetics-based evaluation of genes coding for enzymes linked to paramylon accumulation

Euglena gracilis is a eukaryotic single-celled and photosynthetic organism grouped under the kingdom Protista. This phytoflagellate can accumulate the carbon photoassimilate as a linear β-1,3-glucan chain called paramylon. This storage polysaccharide can undergo degradation to provide glucose units to obtain ATP and reducing power both in aerobic and anaerobic growth conditions. Our group has recently characterized an essential enzyme for accumulating the polysaccharide, the UDP-glucose pyrophosphorylase (Biochimie vol 154, 2018, 176–186), which catalyzes the synthesis of UDP-glucose (the substrate for paramylon synthase). Additionally, the identification of nucleotide sequences coding for putative UDP-sugar pyrophosphorylases suggests the occurrence of an alternative source of UDP-glucose. In this study, we demonstrate the active involvement of both pyrophosphorylases in paramylon accumulation. Using techniques of single and combined knockdown of transcripts coding for these proteins, we evidenced a substantial decrease in the polysaccharide synthesis from 39 ± 7 μg/106 cells determined in the control at day 21st of growth. Thus, the paramylon accumulation in Euglena gracilis cells decreased by 60% and 30% after a single knockdown of the expression of genes coding for UDP-glucose pyrophosphorylase and UDP-sugar pyrophosphorylase, respectively. Besides, the combined knockdown of both genes resulted in a ca. 65% reduction in the level of the storage polysaccharide. Our findings indicate the existence of a physiological dependence between paramylon accumulation and the partitioning of sugar nucleotides into other metabolic routes, including the Leloir pathway’s functionality in Euglena gracilis.

Dietary soluble non-starch polysaccharide level and xylanase supplementation influence performance, egg quality and nutrient utilization in laying hens fed wheat-based diets

The aim of this study was to evaluate the effects of dietary soluble non-starch polysaccharide (sNSP) content and xylanase supplementation on production performance, egg quality parameters, and nutrient digestibility in Hy-line Brown layers from 25 to 32 wk of age. A total of 144 Hy-line Brown laying hens (25 wk of age) were randomly allocated to 1 of 4 wheat-based dietary treatments in a 2 × 2 factorial experimental design, with 36 replicates of individual hens per treatment. The diets were formulated to contain either a high or low sNSP level (at 13.3 or 10.8 g/kg) and were supplemented with either 0 or 12,000 BXU/kg exogenous xylanase. Birds were fed these treatment diets for an 8-wk period, and hen production performance, including daily egg production, average egg weight, daily egg mass, feed conversion ratio and proportion of dirty and abnormal eggs were measured at bird age 25 to 28 wk and 29 to 32 wk. An interaction between sNSP content of the diet and xylanase supplementation was observed on daily egg production from 25 to 28 wk of age (P = 0.018); birds fed the high sNSP diet without xylanase had lower egg production than those fed any other treatment. An interaction between the 2 dietary factors was also observed on hen weight gain at 29 to 32 wk of age (P = 0.014), with birds fed the low sNSP diet with 12,000 BXU/kg xylanase presenting greater weight gain compared to those fed the high sNSP diet with 12,000 BXU/kg xylanase. Feed intake at 29 to 32 wk of age was reduced by xylanase supplementation (P = 0.047). Xylanase supplementation also increased yolk colour score at both 28 and 32 wk of age, and decreased yolk weight at 32 wk of age (P = 0.014, 0.037 and 0.013, respectively). Birds fed the low sNSP diet presented lower protein digestibility (P = 0.024) than those fed the high sNSP diet. Additionally, birds fed high sNSP presented higher shell reflectivity at both 28 and 32 wk of age (P = 0.05 and 0.036, respectively). The influence of duration of feeding the treatment diets on egg quality was also determined. It was observed that egg weight, yolk weight and yolk colour score consistently increased over time, regardless of experimental treatment effects. In contrast, Haugh Unit and albumen height significantly decreased throughout the study period in all treatments, although this was less pronounced in hens fed the treatment with high sNSP and no supplemental xylanase. A reduction in shell breaking strength over time was observed only in hens fed the treatments without xylanase addition, and shell thickness was improved over time only in birds fed the low sNSP diet with xylanase. The impacts of the dietary treatments were largely inconsistent in this study, so a solid conclusion cannot be drawn. However, these findings do indicate that dietary NSP level influences layer production performance, and thus should be considered when formulating laying hen diets. It also proved that further research is warranted into how to optimize the benefits of xylanase application in laying hens.

Urethane Dimethacrylate Influences the Cariogenic Properties of Streptococcus Mutans.

Concerns regarding unbound monomers in dental composites have increased with the increased usage of these materials. This study assessed the biological effects of urethane dimethacrylate (UDMA), a common monomer component of dental composite resins, on the cariogenic properties of Streptococcus mutans. Changes in the growth rate, biofilm formation, interaction with saliva, surface hydrophobicity, adhesion, glucan synthesis, sugar transport, glycolytic profiles, and oxidative- and acid-stress tolerances of S. mutans were evaluated after growing the cells in the presence and absence of UDMA. The results indicated that UDMA promotes the adhesion of S. mutans to the underlying surfaces and extracellular polysaccharide synthesis, leading to enhanced biofilm formation. Furthermore, UDMA reduced the acid tolerance of S. mutans, but enhanced its tolerance to oxidative stress, thus favoring the early stage of biofilm development. UDMA did not significantly affect the viability or planktonic growth of cells, but diminished the ability of S. mutans to metabolize carbohydrates and thus maintain the level of intracellular polysaccharides, although the tendency for sugar transport increased. Notably, UDMA did not significantly alter the interactions of bacterial cells with saliva. This study suggests that UDMA may potentially contribute to the development of secondary caries around UDMA-containing dental materials by prompting biofilm formation, enhancing oxidative tolerance, and modulating carbon flow.

Branched-chain amino acids protect the liver from cirrhotic injury via suppression of activation of lipopolysaccharide-binding protein, toll-like receptor 4, and signal transducer and activator of transcription 3, as well as Enterococcus faecalis translocation

ObjectivesBranched-chain amino acids (BCAAs) are used as nutritional support and for improving prognosis in liver cirrhosis. Here we investigate the molecular mechanisms of BCAA treatment and liver damage focused on pathways related to lipopolysaccharide-binding protein (LBP). MethodsSerum LBP levels were measured in cirrhotic patients and in cirrhotic rats treated with BCAA to examine the correlation between liver function and survival. In cirrhotic rats, liver damage, Enterococcus faecalis translocation, serum capsular polysaccharide, and intestinal tight junction levels were assessed. Damaged HepG2 cells were cultured with BCAA-supplemented, BCAA-deficient, or control amino acid medium, followed by examination of LBP expression. ResultsSerum LBP levels were significantly increased in deceased patients individuals with liver cirrhosis. The survival rate in patients with lower serum LBP (<3.48 μg/mL) was significantly improved. In BCAA-treated rat liver samples, protein expression of LBP, toll-like receptor 4 (TLR4), and phosphorylated signal transduction and activator of transcription 3 (STAT3) were significantly reduced. Also in BCAA-treated rats, intestinal zonula occludens gene expression was increased, whereas hepatic translocation of E. faecalis and serum capsular polysaccharide levels were reduced. In damaged HepG2 cells, lipopolysaccharide-induced elevation of LBP expression was rapidly and strongly repressed in BCAA-enriched medium. ConclusionsSerum LBP level is a prognostic biomarker in liver cirrhosis. BCAA treatment reduced translocation of E. faecalis through intestinal tight junction recovery and reduced LBP expression in the liver, which repressed activation of LBP, toll-like receptor 4, and signal transduction and activator of transcription 3. Our findings suggest that BCAA supplementation protects the liver from damage via multiple pathways.

Organic composition of epilithic biofilms from agricultural and urban watershed in South Brazil.

Active functional groups in biofilms determine the adsorption and desorption of contaminants and nutrients. Epilithic biofilms were characterized in order to understand the association between the chemistry alteration patterns and the surrounding anthropic activities of the Guaporé River watershed. The instrumental analyses included pyrolysis coupled to gas chromatography and mass spectroscopy, spectroscopy in the IR region with attenuated total reflectance, and two-dimensional nuclear magnetic resonance. Spectrometric techniques demonstrated that epilithic biofilms are mainly composed of polysaccharides, nitrogen-containing compounds, lipids, and aromatic and phenolic structures, which have functional groups characteristic of alcohols, esters, ethers, and amides. The polysaccharide levels reflect well the environmental pressures. The chemical composition of epilithic biofilms can be an effective tool for environmental assessment in watercourses, since the different anthropic actions developed in watersheds, mainly agriculture and urban areas, can modify the organic fraction of biofilms.

Heat-induced gel formation by whey protein isolate-Lycium barbarum polysaccharides at varying pHs

Effects of different levels (0, 0.1, 0.5, and 1% w/v) of Lycium barbarum polysaccharides (LBP) were investigated on the gel properties of heat-induced whey protein gels forming at varying pHs (3.0, 5.2 and 7.0). The textural, rheological, hydration properties and microstructure of gels were evaluated. Results exhibited that the composite gel containing 0.1% (w/v) LBP showed the greatest functional valorization, whereas higher concentrations of LBP (1% w/v) yielded hydrogels with higher porosity, which was confirmed by scanning electron microscopy. Moreover, whey protein formed white particulate gels and transparent fibrillar gels at pH values near to and far from the isoelectric point, respectively. As for hydration properties, no difference in water holding capacity and swelling property was observed at all pHs. This study simulated the conditions used in practical production, aiming to provide a theoretical basis for the application of LBP on composite gels and develop tunable gel-type food to satisfy different consumer preferences.

Modulation of human gut microbiota by dietary fibers from unripe and ripe papayas: Distinct polysaccharide degradation using a colonic in vitro fermentation model

Dietary fibers (DFs) consumption promotes a healthier gut through colonic fermentation and the modulation of different types of gut bacteria. The aim of this study is to evaluate the production of short-chain fatty acids (SCFA), metabolization of polysaccharides, and changes in the bacterial profile related to DFs extracted from the pulp of unripe and ripe papayas, using a batch colonic in vitro fermentation model. Our results show that fermentation of DFs from papayas induce the production of SCFAs and are utilized in different ways by intestinal microbiota. DFs from ripe papayas showed faster degradation by human gut microorganisms due to higher level of water-soluble polysaccharides. The fermentation of unripe papaya fibers increased the abundance of microorganisms belonging to family Clostridiaceae and genera Coprobacillus, Bulleidia, and Slackia, whereas both fibers increased Clostridium and Bacteroides, showing fruit ripeness affects the fermentation pattern of fruit fibers and their probable beneficial health aspects.

The effects of temperature shock on the treatment of high-concentration organic wastewater by an Fe0/GO-anaerobic system.

In order to make up for the defects of traditional anaerobic fermentation systems, such as low energy utilization rates and the slow growth and reproduction of microorganisms, an Fe0/GO (zero-valent iron/graphene oxide) anaerobic biological treatment system was used as a treatment process in this paper, and the impact of temperature shock on the system during the treatment of high-concentration organic wastewater was studied. The experimental results showed that temperature shock reduced the CODCr removal rate and gas production level in each system, but the Fe0/GO group maintained a higher level and had the highest CODCr degradation rate after shocking. After temperature shock, the acetic acid content in each system was higher (above 90%), and the volatile fatty acid (VFA) content in the Fe0/GO group was the lowest. The mixed liquor suspended solids (MLSS) in all systems decreased after impact; the decrease was less in the Fe0/GO group and the increase was largest after temperature recovery. After shocking, the extracellular polymer substance (EPS) protein (PN) and polysaccharide (PS) levels in each system were both low. After temperature recovery, the PN/PS ratio of the Fe0/GO group was the highest, showing a strong impact resistance to temperature.

The primary, secondary, and structures of higher levels of pectin polysaccharides.

Pectin is a heteropolysaccharide abundant in the cell wall of plants and is obtained mainly from fruit (citrus and apple), thus its properties are particularly prone to changes occurring during ripening process. Properties of pectin depend on the string-like structure (conformation, stiffness) of the molecules that determines their mutual interaction and with the surrounding environment. Therefore, in this review the primary, secondary, and structures of higher levels of pectin chains are discussed in relation to external factors including crosslinking mechanisms. The review shows that the primary structure of pectin is relatively well known, however, we still know little about the conformation and properties of the more realistic systems of higher orders involving side chains, functional groups, and complexes of pectin domains. In particular, there is lack of knowledge on the influence of postharvest changes and extraction method on the primary and secondary structure of pectin that would affect conformation in a given environment and assembly to higher structural levels. Exploring the above-mentioned issues will allow to improve our understanding of pectin functionality and will help to tailor new functionalities for the food industry based on natural but often biologically variable source. The review also demonstrates that atomic force microscopy is a very convenient and adequate tool for the evaluation of pectin conformation since it allows for the relatively straightforward stretching of the pectin molecule in order to measure the force-extension curve which is directly related to its stiffness or flexibility.

Relationship between the Content of β-D-Glucans and Infection with Fusarium Pathogens in Oat (Avena sativa L.) Plants.

In human nutrition, oats (Avena sativa L.) are mainly used for their dietary fiber, β-D-glucans and protein content. The content of β-D-glucans in oat grain is 2–7% and is influenced by genetic and/or environmental factors. High levels of this cell walls polysaccharide are observed in naked grains of cultivated oat. It the work, the relationship between the content of β-D-glucans in oat grain and the infection with Fusarium graminearum (FG) and Fusarium culmorum (FC) was analyzed. The hypothesis was that oats with higher content of β-D-glucans are better protected and the manifestation of artificial inoculation with Fusarium strains is weaker. In the 22 oat samples analyzed, the content of β-D-glucans was 0.71–5.06%. In controls, the average content was 2.15% for hulled and 3.25% for naked grains of cultivated oats. After the infection, a decrease was observed in all, naked, hulled and wild oats. As an evidence of lower rate of infection, statistically significant lower percentage of pathogen DNA (0.39%) and less deoxynivalenol (DON) mycotoxin (FC infection 10.66 mg/kg and FG 4.92 mg/kg) were observed in naked grains compared to hulled where the level of pathogen DNA was 2.09% and the average DON level was 21.95 mg/kg (FC) and 5.52 mg/kg (FG).

Yellow- and green-cotyledon seeds of black soybean: Phytochemical and bioactive differences determine edibility and medical applications

Black soybean seed (BSS) is a traditional edible and medical food. The cotyledons of BSS are either yellow or green, but that difference's effect on functional and bioactivities are not clear. In the present study, the concentrations of the main functional components, including anthocyanins, isoflavones, fatty acids, protein, and polysaccharides, and in vitro antioxidant activities of yellow-cotyledon and green-cotyledon BSS (YBS and GBS, respectively) were compared. The anti-fatigue activities of the ethanol extract of BSS (EEB) were evaluated using mouse swimming endurance tests. Additionally, a metabolomics comparison between YBS and GBS was done using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) on high doses of EEB-treated mouse plasma. The results indicated that YBS showed significantly higher contents of anthocyanin and protein, and stronger antioxidant activity and anti-fatigue activity than GBS; while GBS showed higher levels of isoflavone, stearic acid, and polysaccharide. By infusing the feed with EEB, the swimming time of mice increased in a dose-dependent manner. The metabolomics results suggested that the anti-fatigue effect of EEB correlated well with serotonin and melatonin biosynthesis in vivo. All of the above results showed that BSS has anti-fatigue potential and might be used as a potential source of functional food ingredients.

Effect of enzymes (phytase and xylanase), probiotics (B. amyloliquefaciens) and their combination on growth performance and nutrient utilisation in Nile tilapia

The increased use of plant ingredients in aquafeeds over the last decades, as replacement for fish meal, has led to rising levels of undesired non-starch polysaccharides (NSP) and phytate. Both NSP and phytate degrading enzymes and probiotics have been widely studied. They can be used as a tool to deal with increasing levels of NSP and phytate in aquafeeds. However, studies combining both probiotics and enzymes are scarce in fish. The main objective of the present study was to assess the impact on Nile tilapia (Oreochromis niloticus) of enzymes and probiotics, as well as their synergistic effect. Parameters measured were: growth; nutrient digestibility; body composition; and the energy, nitrogen (N), P and Ca balance. Diets were supplemented with, and without, an enzyme mix (phytase at 1000 FTU/kg and xylanase at 6000 U/kg) and with, and without, probiotics (three strains of B. amyloliquefaciens at 60 mg/kg feed), according to a 2 × 2 factorial arrangement. This resulted in a control treatment (CON-CON) without enzymes and probiotics, an enzyme treatment (ENZ-CON), a probiotic treatment (CON-PRO) and a treatment with both enzymes and probiotics (ENZ-PRO). In total, 16 tanks (4 replicates/treatment) were used with 35 fish each (mean initial weight 39 g). Fish were restrictively fed equal amounts of dry matter for 42 days. Both enzymes (P < 0.001) and probiotics (P < 0.05) improved growth (g/d) and FCR when applied individually. The combination of enzymes and probiotics showed an interaction effect (P < 0.05) on growth and FCR. Enzymes improved growth to a greater extent than probiotics, whereas the combination of enzymes and probiotics did not further enhance growth. The CON-CON treatment had the highest FCR (1.33), the CON-PRO treatment a slightly lower FCR (1.27); the lowest FCR (1.11) was found for both treatments with enzymes (ENZ-CON and ENZ-PRO). Enzyme supplementation improved the digestibility of all nutrients (P < 0.01), whereas probiotics enhanced fat digestibility (P < 0.01). Additionally, enzyme supplementation increased retained P (mg/d), retained N (mg/d) and N efficiency (P < 0.001). Probiotic supplementation affected the energy requirements for maintenance (kJ/kg0.8/d; P < 0.05). Dietary supplementation of either enzymes or probiotics had positive effects on the measured parameters, but the combination of enzymes and probiotics did not have a synergistic effect.

A Comprehensive Study of the Impacts of Oat β-Glucan and Bacterial Curdlan on the Activity of Commercial Starter Culture in Yogurt.

This study provides important information about the impacts of various levels of oat (OBG) and bacterial (curdlan) β-glucan and fat contents in milk on survivability and metabolism of yogurt starter cultures. The results show that addition of β-glucans in the concentration higher than 0.25% reduced starter bacterial counts during storage and prolonged the milk acidification process. A significant increase in lactose consumption by starter cultures was noted in the yogurt samples with OBG addition up to 0.75%. The highest (by 567% on average) increase in lactic acid content was noted in the control yogurts. Whereas the lowest (by 351%) increase in lactic acid content was noted in yogurts with OBG. After 28-day storage, the acetic aldehyde content was significantly influenced by fat content, type and addition level of polysaccharide. A higher increase in acetoin content was noted in samples with 0.25% than in samples with 1% of polysaccharides. In turn, significantly lower increases in diacetyl and 2,3-pentanedione contents were observed in the yogurt samples with OBG than in these with curdlan, with diacetyl production increase along with the higher concentration of the polysaccharide. The addition of OBG and curdlan to milk contributed to differences in the starter culture metabolism, consequently, in the milk acidification dynamics.

Integrative analyses of transcriptome and metabolome shed light on the regulation of secondary metabolites in pseudobulbs of two Bletilla striata (Thunb.) Reichb.f. varieties

Blettila striata (Thunb.) Reichb.f. is an important ornamental and herbaceous medicinal plant. However, natural resources are endangered and breeding and improvement of the medicinal plant using modern biotechnology are urgently needed. Increasing the harvest biomass is critical to the total yield of bioactive substances. The ‘MBS’ variety of Bletilla striata could be an ideal parental line for genetic and metabolic engineering as the yield of the ‘MBS’ was more than that of the ‘BS’. Nonetheless, its genetic background and metabolic networks remain largely unknown. In this study, integrative analyses of transcriptome and metabolome in pseudobulbs were conducted. Our study establishes a correlation between transcriptome and metabolome in pseudobulbs of Bletilla striata, shedding light on the synthesis pathways in bioactive substances. In total, 11,277 unigenes were differentially expressed in the pseudobulbs of ‘MBS’ and ‘BS’. Moreover, 109 metabolites were identified as differentially accumulated substances. Correlation analysis between differentially expressed genes and differentially accumulated metabolites revealed that genes involved in metabolism might contribute to the different levels of polysaccharides and flavonoids between the two varieties. This study should be helpful in bioresource utilization and crop improvement via genetic and metabolic engineering.

Extension of shelf life of semi-dry longan pulp with gaseous chlorine dioxide generating film

A packaging system using gaseous chlorine dioxide generating film (CDGF) in a sealed container was developed to extend the shelf life of semi-dry longan pulp (moisture content 38.8 wt%; aw0.8). The antimicrobial properties, formation of chloroxyanion residues and effects of CDGF on the quality of semi-dry longan pulp were investigated. CDGF was triggered by the moisture vapor from semi-dry longan pulp in the sealed container and released gaseous ClO2 into the headspace of the container. The antifungal test showed that CDGF significantly inactivated artificially inoculated molds in semi-dry longan pulp and achieved reductions of over 3 log CFU/g after 28 days storage at room temperature (25 °C). CDGF reduced total aerobic bacterial populations by over 6.4 log CFU/g and maintained these population levels at around 2.0 log CFU/g throughout the 180-day storage period at room temperature. The residual concentrations of chloride, chlorate and perchlorate in longan pulp increased and then decreased during the 180-day storage. Residual chloride levels were maintained at 1.5 mg/g after Day 120 and residual chlorate and perchlorate levels were not detected after Day 120 and Day 180, respectively, in CDGF-treated samples. CDGF treatments reduced total polyphenol content but didn't have any significant impact on the levels of polysaccharides in samples. There were no significant differences between CDGF-treated and control samples in color changes during storage. The content of 5-hydroymethylfurfural (5-HMF) in both samples increased during storage, suggesting that the Maillard reaction occurred. This study demonstrated an effective approach to develop a new antimicrobial packaging system for semi-dry longan pulp.