The effect of ε-poly-l-lysine treatment on molecular, physiological and biochemical indicators related to resistance in longan fruit infected by Phomopsis longanae Chi.

Postharvest longan fruits are subjected to Phomopsis longanae Chi (P. longanae) infection that lead to fruit quality deterioration. We hypothesized that ε-poly-l-lysine (ε-PL) could enhance fruit disease resistance in longans. Through physiological and transcriptomic analyses, the results showed that, compared to P. longanae-infected longan fruit, ε-PL + P. longanae treatment reduced the disease development of longan fruits. Additionally, ε-PL + P. longanae treatment increased the contents of disease-resistant substances (lignin and H2O2) and the activities of disease-resistance enzymes (CHI, PAL, PPO, C4H, CAD, GLU, 4CL, and POD). Furthermore, the expressions of genes relevant to the phenylpropanoid biosynthesis pathway and plant-pathogen interaction pathway (Rboh, FLS2, WRKY29, FRK1, and PR1) were up-regulated by ε-PL + P. longanae treatment. These findings demonstrated that ε-PL treatment inhibited the disease development of postharvest longan fruits were associated with the increased accumulation of disease-resistant related substances, as well as the raised activities and genes expressions of disease-resistance related enzymes.

Acidic electrolyzed water treatment suppresses Phomopsis longanae Chi-induced the decreased storability and quality properties of fresh longans through modulating energy metabolism.

Longan fruit loses its market value rapidly due to postharvest pathogenic infestation and quality deterioration. Here, we hypothesized that acidic electrolyzed water (AEW) could maintain higher quality of P. longanae-inoculated longans via regulating energy metabolism. Results indicated that AEW reduced fruit disease index and decay incidence. Significantly, AEW treatment retained higher levels of ATP, ADP, and energy charge, and higher activities of Ca2+-ATPase, Mg2+-ATPase, and H+-ATPase in the membranes of plasma, vacuole, and mitochondria, which maintained the structural and functional integrity of cell membrane. Furthermore, indirectly sustaining cell membrane function via AEW treatment could maintain the storability and quality properties of longans, including keeping higher values of color chromaticity (L*, a*, and b*), higher amounts of vitamin C, total soluble solids, sucrose, and total soluble sugars, lower titratable acid and reducing sugar contents. This work elucidated the potential regulation of AEW on the balance of energy metabolism and fruit quality.

DNP and ATP modulate the developments of pulp softening and breakdown in Phomopsis longanae Chi-infected fresh longan through regulating the cell wall polysaccharides metabolism.

Compared with P. longanae-infected longan, 2, 4-dinitrophenol (DNP) treatment for P. longanae-infected longan displayed the lower levels of pulp firmness, cell wall materials, ionic-soluble pectin, covalent-soluble pectin, hemicellulose, or cellulose, but the higher amount of water-soluble pectin, the higher activities of cell wall-degrading enzymes (CWDEs) (PG, ß-Gal, PME, Cx, and XET), and the higher transcript levels of CWDEs-related genes (DlPG1, DlPG2, Dlß-Gal1, DlPME1, DlPME2, DlPME3, DlCx1, and DlXET30). On the contrary, ATP treatment for P. longanae-infected longan exhibited opposite effects. The above results imply that DNP accelerated P. longanae-induced pulp softening and breakdown of fresh longan, which was because DNP up-regulated the transcript levels of CWDEs-related genes, enhanced the CWDEs activities, and accelerated the degradation of cell wall polysaccharides (CWP). However, ATP suppressed longan pulp softening and breakdown caused by P. longanae, because ATP down-regulated the transcript levels of CWDEs-related genes, lowered the CWDEs activities, and reduced the CWP degradation.

Chitosan postharvest treatment suppresses the pulp breakdown development of longan fruit through regulating ROS metabolism.

The influences of Kadozan, a novel chitosan formulation, on the pulp breakdown and ROS metabolism in postharvest 'Fuyan' longans were studied. Compared with control longans, the longans treated with 1:500 Kadozan dilution (VKadozan: VKadozan + Water) exhibited the suppressed development of pulp breakdown, higher AsA and GSH amounts, higher activities of ROS-scavenging enzymes like SOD, CAT, APX and POD, higher reducing power, and higher scavenging ability for DPPH radical, but a lower MDA amount, lower levels of ROS including O2- and H2O2. These findings indicated that the application of 1:500 Kadozan dilution (VKadozan: VKadozan + Water) for harvested longans could enhance the ROS-scavenging capacity to decrease the generation and accumulation of ROS, and a lower level of ROS could slow down the peroxidation progress of membrane lipids, alleviate the damage of longan pulp cellular membrane structure, and ultimately suppress pulp breakdown occurrence of harvested longans.

Effects of hydrogen peroxide treatment on pulp breakdown, softening, and cell wall polysaccharide metabolism in fresh longan fruit.

Longan (Dimocarpus longan Lour.) is prone to pulp softening and pulp breakdown, leading to a loss of its nutrients including polysaccharides. ROS is one main factor affecting fruit quality. This work intended to explicate the influences of hydrogen peroxide, acting as a ROS, on pulp softening, pulp breakdown, and cell wall polysaccharides metabolism in longan fruit during storage. Contrasted to the control group, hydrogen peroxide-treated samples exhibited lower firmness, lower amounts of CWM, ISP, CSP, hemicellulose and cellulose, but higher breakdown index, WSP amount, expression levels of DlPG, DlPE, Dlß-Gal, DlCx and DlXET and activities of their corresponding enzymes (PG, PE, ß-Gal, Cx, XET). These results suggested that hydrogen peroxide reduced longan pulp firmness due to the increased gene expression levels and enzymes activities related to cell wall polysaccharide degradation to boost their decomposition, thereby led to the accelerated pulp softening and the expedited pulp breakdown of harvested longans.

Effect of roasting and in vitro digestion on phenolic profiles and antioxidant activity of water-soluble extracts from sesame.

The effects of roasting and in vitro digestion on total phenolic content (TPC), total flavonoid content (TFC), phenolic profiles, and antioxidant activity of water-soluble extracts from six varieties of sesame were investigated in this study. Our results showed that the major phenolic compounds in raw, roasted and digested sesame were gallic acid (GA), protocatechuic acid (PA), 4-hydroxybenzoic acid (4 HBA), ferulic acid (FA) and quercetin (Quer). Roasting significantly increased the TPC, pinoresinol diglucoside (PD), sesamol, as well as the content of phenolic compounds (especially GA, PA, 4 HBA and Quer) in sesame, but kept or reduced the TFC, sesamin and sesamolin. After roasting, the antioxidant potency composite index (ACI) of six varieties of sesame was significantly increased by 29.8%-216.6%. Additionally, the ACI of gastric digestion was significantly higher than that of oral and intestinal digestion during the in vitro digestion of the roasted-sesame, except for the varieties of Ganzhi 9 and Ganzhi 17. This study showed that five phenolic compounds (GA, PA, 4 HBA, p-coumaric acid, Quer) and sesamol of the water-soluble extracts contributed to the antioxidant activities of the digestive products of sesame.

Effects of acidic electrolyzed water treatment on storability, quality attributes and nutritive properties of longan fruit during storage.

The aim of this study was to use acidic electrolyzed water (AEW) to treat longan fruit and evaluate the effects of AEW treatment on storability, quality attributes and nutritive properties of longans during storage. The data indicated that, as compared to the control samples, AEW treatment could effectively reduce the respiration rate and pericarp cell membrane permeability, retard the occurrences of pericarp browning, pulp breakdown and fruit disease, keep a higher rate of commercially acceptable fruit. Additionally, AEW treatment could suppress the decrease of chromaticity values of L*, a* and b* of the fruit surface, keep higher amounts of pericarp carotenoid, chlorophyll, flavonoid and anthocyanin, maintain higher amounts of pulp total soluble solid (TSS), total soluble sugars, sucrose and vitamin C. These results demonstrated that AEW treatment at pH of 2.5, ACC of 80 mg/L could maintain higher quality attributes and nutritive properties, and display better storability of harvested longans.

Cellulose nanofibers coated with silver nanoparticles as a flexible nanocomposite for measurement of flusilazole residues in Oolong tea by surface-enhanced Raman spectroscopy.

Cellulose nanofibers (CNF) coated with inorganic nanoparticles are novel hybrid nanocomposites that have great potential in various areas including agriculture and food science. The objectives of this study were to synthesize nanocomposites consisted of CNF coated with silver nanoparticles (AgNPs), which can be used as a surface-enhanced Raman spectroscopy (SERS) platform for measuring pesticides in Oolong tea. CNF were coated with AgNPs to form uniform CNF-AgNP nanocomposites that were investigated by transmission electron microscopy. Three-dimensional and porous CNF structures were loaded with AgNPs with an average size of 41 nm. CNF-AgNP substrates were applied in characterization and measurement of flusilazole in Oolong tea samples by SERS. A detection limit of 0.5 mg/kg for flusilazole was obtained based on partial least squares (PLS) regression analysis. These results indicate that CNF-AgNP nanocomposites combined with SERS is an accurate, sensitive, and efficient technique for identification and quantification of pesticide residues in Oolong tea.

A spectroscopic approach to detect and quantify phosmet residues in Oolong tea by surface-enhanced Raman scattering and silver nanoparticle substrate.

There have been increasing concerns among consumers about pesticide residues in Oolong tea. This study aimed to establish surface-enhanced Raman scattering (SERS) method for rapid measurement of chemical contaminants in Oolong tea. Synthesis of SERS substrate was achieved by synthesizing silver nanoparticles (AgNPs) via a reduction method. AgNPs were spherical and highly monodispersed, which created remarkable electromagnetic fields during SERS activities to measure phosmet in the methanol-water solution and Oolong tea. Partial least squares regression models were established to predict the concentrations of phosmet in the methanol-water solution (r = 0.934; slope = 0.880; RMSEP = 1.001 mg/L) and Oolong tea samples (r = 0.927; slope = 0.938; RMSEP = 1.157 mg/kg) with the detection limit of 0.1 mg/kg. The results indicate that SERS coupled with silver nanoparticles is a fast, sensitive, and reliable method for detection and characterization of pesticide contaminants in Oolong tea products.

Effects of chitosan treatment on the storability and quality properties of longan fruit during storage.

Effects of various concentrations of Kadozan (chitosan) treatment on storability and quality properties of harvested 'Fuyan' longans were investigated. Compared to the control samples, Kadozan treated-longans displayed lower fruit respiration rate, lower pericarp cell membrane permeability, pericarp browning index, pulp breakdown index, fruit disease index, and weight loss, but higher rate of commercially acceptable fruit, higher levels of pericarp chlorophyll, carotenoid, anthocyanin, flavonoid and total phenolics, higher amounts of pulp total soluble sugar, sucrose, total soluble solids, and vitamin C. These results revealed Kadozan treatment could increase storability and retain better quality of harvested longan fruit. Among different concentrations of Kadozan, the dilution of 1:500 (VKadozan: VKadozan + Water) showed the best results in storability and maintained the best quality of longans during storage. These findings demonstrated that Kadozan could be a facile and eco-friendly postharvest handling approach for increasing storability and lengthening shelf-life of harvested 'Fuyan' longan fruit.

Detection and quantification of carbendazim in Oolong tea by surface-enhanced Raman spectroscopy and gold nanoparticle substrates.

The contamination of pesticide residues in Oolong tea has raised much concern in recent years. The objective of this study was to synthesize gold nanoparticles (AuNPs) and develop surface-enhanced Raman spectroscopy (SERS) methods for detection and quantification of pesticides in Oolong tea. Facile synthesis of spherical and monodispersed AuNPs with an average diameter of 15 nm was achieved, which induced strong electromagnetic fields in SERS analysis. AuNP substrates were employed for rapid detection and quantification of carbendazim in Tieguanyin Oolong tea. Partial least squares (PLS) analysis and leave-one-out cross validation were utilized in spectral data analysis. The PLS results for Oolong tea samples were obtained: R value = 0.964; the detection limit = 100 µg/kg. These results demonstrate that SERS coupled with gold nanoparticle substrate is a simple, rapid, and sensitive analytical tool for measurement and quantification of carbendazim residues in Oolong tea.

A novel chitosan alleviates pulp breakdown of harvested longan fruit by suppressing disassembly of cell wall polysaccharides.

Longan pulp is an excellent source of polysaccharides and other nutrients that have many health benefits. However, longans is susceptible to pulp breakdown after harvest and loses its nutrition values. To solve this problem, this study aimed to study the effects of a novel chitosan, Kadozan, on pulp breakdown index, contents of pectin, cellulose and hemicelluloses, and activities of enzymes in longan pulp relating to disassembly of polysaccharides (XET, PE, PG, ß-Gal, and cellulase). The data illustrated that, compared to the control longans, chitosan-treated longans contained higher amounts of CWM, CSP, ISP, cellulose and hemicelluloses, but exhibited lower pulp breakdown index, lower activities of cell wall-disassembling enzymes, and contained lower WSP amount. These results suggested that Kadozan with a dilution of 1:500 (VKadozan: VKadozan + Water) could significantly decrease activities of disassembling-enzymes and depolymerization of polysaccharides in cell wall, and subsequently alleviate pulp breakdown and prolong storage-life of postharvest longans.

Compound K producing from the enzymatic conversion of gypenoside by naringinase.

Compound K is a type of protopanaxadiol-type ginsenosides (PPDs) that has strong bioactivities due to fewer glycosyls. However, compound K is not present in raw and unprocessed ginseng. Some PPDs have the same structure with gypenosides, and could be obtained from Gynostemma pentaphyllum. The enzymolysis of PPD-type gypenosides of G. pentaphyllum by naringinase has been reported for the first time in this research. In addition, isolation and identification of enzymolysis end product, and the optimization of enzymolysis parameters were investigated. The results showed that compound K was produced from the enzymolysis of PPD-type gypenosides by naringinase, and could be isolated and purificated by HP-20 macroporous resin and C-18 column chromatography. The optimum enzymolysis conditions determined by the response surface methodology (RSM) are pH 4.1, 50 °C, and 71 h, with a yield of 65.44 ±â€¯4.52% for compound K. These results demonstrated that enzymolysis could be a promising method for producing compound K from the biotransformation of PPD-type gypenosides of G. pentaphyllum.

A novel chitosan formulation treatment induces disease resistance of harvested litchi fruit to Peronophythora litchii in association with ROS metabolism.

This study aimed to investigate the effects of a novel chitosan formulation (Kadozan) treatment on disease development, response of disease resistance, metabolism of reactive oxygen species (ROS) in Peronophthora litchii-inoculated "Wuye" litchis. Compared with P. litchii-inoculated litchis, Kadozan-treated P. litchii-inoculated litchis exhibited lower fruit disease index, higher lignin content, higher activities of disease resistance-related enzymes (CHI, GLU and PAL), lower O2- generating rate and malondialdehyde content, higher activities of ROS scavenging enzymes (SOD, CAT and APX), higher contents of ascorbic acid and glutathione, and higher levels of reducing power and DPPH radical scavenging activity. These results suggest that Kadozan can be used to inhibit the growth of P. litchii in harvested litchis owning to the enhancement of disease resistance and ROS scavenging capacity, and decreases in O2- accumulation and membrane lipid peroxidation. Kadozan treatment can be used as a facile and novel method for suppressing postharvest pathogenic disease of litchis.

Green synthesis of silver nanoparticles using turmeric extracts and investigation of their antibacterial activities.

This study aimed to develop an environmentally friendly and cost-effective approach to synthesize green silver nanoparticles (AgNPs) from silver precursors. Green synthesis of AgNPs was accomplished using the aqueous extract of turmeric powder, in which plant biomaterials were used as a reducing as well as a capping agent. After 24 h of reaction, the yellow color of the extract was changed to dark brown-reddish due to the reduction of silver ions to AgNPs. AgNPs were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The maximum absorbance of the UV-vis spectra was at 432 nm. TEM analysis reveals that the shape of most of the biosynthesized AgNPs was spherical forms and the average particle size was 18 ± 0.5 nm. EDS analysis exhibits strong signals of silver element. In addition, green synthesized AgNPs show high and efficient antimicrobial activities against two food-borne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes). TEM and scanning electron microscopic images reveal that there were significant shrinkage and damage of bacterial cell wall, and leakage or loss of bacterial intracellular contents. A significant reduction (P ≤ 0.05) of bacterial counts just after 4 h of exposure was observed. These results indicate that green synthesized AgNPs can be utilized as an antimicrobial means to inhibit the growth of pathogenic bacteria for applications in agricultural and food industries.

Effects of paper containing 1-MCP postharvest treatment on the disassembly of cell wall polysaccharides and softening in Younai plum fruit during storage.

Disassembly of cell wall polysaccharides accompanied with softening is very common in harvested fruits. To develop a facile postharvest approach, which can be used at ambient temperature, for suppressing softening and maintaining higher nutritive cell wall polysaccharides of Younai plums, influences of paper containing 1-methylcyclopropene (1-MCP) on firmness, activities of cell wall-degrading enzymes, and contents of cell wall polysaccharide in Younai plums during storage at 25 ±â€¯1 °C were investigated. As compared to the control plums, 1.2 µL·L-1 1-MCP-treated plums exhibited higher firmness, lower activities of cell wall-degrading enzymes (pectinesterase, polygalacturonase, cellulase and ß-galactosidase), higher contents of cell wall polysaccharides (sodium carbonate-soluble pectin, chelate-soluble pectin, cellulose, and hemicelluloses), and lower content of water-soluble pectin. The results suggested that paper containing 1-MCP, which was convenient to apply under ambient temperature, could significantly inhibit activities of cell wall degrading-enzymes and decrease disassembly of cell wall polysaccharides, and subsequently retard softening in Younai plums.

Raman spectroscopic characterization of structural changes in heated whey protein isolate upon soluble complex formation with pectin at near neutral pH.

The mechanism leading to an alteration of heat aggregation of whey protein isolate (WPI) in the presence of pectin was investigated by assessing structural changes of proteins using Raman spectroscopy. WPI solutions were heated without or with pectin at 0.015-0.2 pectin to WPI weight ratios and pH 6.0-6.4. In the absence of pectin, thermal denaturation resulted in a loss of α-helical structure and an increase in ß-structure and random coils of protein. At pH 6.0 and 6.2, heat aggregation of WPI was suppressed when pectin (0.05-0.15 pectin to WPI ratios) was present as shown by a decrease in turbidity and particle size. Concomitantly, changes in the secondary structures were reduced, indicating the enhanced stability of protein structure by pectin. Raman results also revealed that α-helix and ß-sheet are dominant structures in heated WPI--pectin soluble complexes, and hydrogen bonding between biopolymers increased. The effect of pectin was pH dependent, indicating the involvement of electrostatic interaction.

Investigating antibacterial effects of garlic (Allium sativum) concentrate and garlic-derived organosulfur compounds on Campylobacter jejuni by using Fourier transform infrared spectroscopy, Raman spectroscopy, and electron microscopy.

Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy were used to study the cell injury and inactivation of Campylobacter jejuni from exposure to antioxidants from garlic. C. jejuni was treated with various concentrations of garlic concentrate and garlic-derived organosulfur compounds in growth media and saline at 4, 22, and 35°C. The antimicrobial activities of the diallyl sulfides increased with the number of sulfur atoms (diallyl sulfide < diallyl disulfide < diallyl trisulfide). FT-IR spectroscopy confirmed that organosulfur compounds are responsible for the substantial antimicrobial activity of garlic, much greater than those of garlic phenolic compounds, as indicated by changes in the spectral features of proteins, lipids, and polysaccharides in the bacterial cell membranes. Confocal Raman microscopy (532-nm-gold-particle substrate) and Raman mapping of a single bacterium confirmed the intracellular uptake of sulfur and phenolic components. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to verify cell damage. Principal-component analysis (PCA), discriminant function analysis (DFA), and soft independent modeling of class analogs (SIMCA) were performed, and results were cross validated to differentiate bacteria based upon the degree of cell injury. Partial least-squares regression (PLSR) was employed to quantify and predict actual numbers of healthy and injured bacterial cells remaining following treatment. PLSR-based loading plots were investigated to further verify the changes in the cell membrane of C. jejuni treated with organosulfur compounds. We demonstrated that bacterial injury and inactivation could be accurately investigated by complementary infrared and Raman spectroscopies using a chemical-based, "whole-organism fingerprint" with the aid of chemometrics and electron microscopy.

Penile replantation, complication management, and technique refinement.

We describe a case of complete guillotine-type penile amputation at the proximal penile shaft. The blood flow was established 10 h after trauma. Circulation in the replanted penis was quite good but there was progressive prepuce necrosis after the hematoma. Cosmetic and urinary outcome was good 6 weeks later. The repair of deep dorsal penile vessels helps in corpus tissue healing and glans circulation. The blood supply from the corpus tissue is sufficient for the survival of the replanted penis even when the repaired dorsal vessels were occluded. Surgical pitfalls in replantation procedures and complication management are discussed.