Vacuum steam pulsed blanching (VSPB) was employed as a novel blanching technology on Cornus officinalis to soften the tissue for subsequent coring and dehydration. The current work aims to explore ...its effect on mass transfer behavior, PPO inactivation, drying characteristics, physicochemical properties, antioxidant capacity, and microstructure of C. officinalis. Results showed that VSPB increased water loss, decreased solid gain, and increased weight reduction with increased blanching cycles. Besides, VSPB significantly changed physical properties and extensively reduced drying time which was attributed to the cell wall components dissolving and cell turgor pressure decreasing, also verified by observing microstructure alteration. PPO was completely denatured after blanching in 6 cycles, but phenolic compounds were still diffused or degraded. Notably, the content of flavonoids and antioxidant capacity significantly increased compared to fresh samples probably due to increased extractability caused by the disrupting cell structure. Besides, the carotenoids and ascorbic acid could be well preserved.
The fabrication of van der Waals (vdWs) heterostructures mainly extends to two-dimensional (2D) materials. Nevertheless, the current processes for obtaining high-quality 2D films are mainly ...exfoliated from their bulk counterparts or by high-temperature chemical vapor deposition (CVD), which limits industrial production and is often accompanied by defects. Herein, we first fabricated the type-II p-PdSe2/n-InSe vdWs heterostructure using the ultra-high vacuum laser molecular beam epitaxy (LMBE) technique combined with the vertical 2D stacking strategy, which is reproducible and suitable for high-volume manufacturing. This work found that the introduction of 365 nm UV light illumination can significantly improve the electrical transport properties and NO2 sensing performance of the PdSe2/InSe heterojunction-based device at room temperature (RT). The detailed studies confirm that the sensor based on the PdSe2/InSe heterojunction delivers the comparable sensitivity (Ra/Rg = ∼2.6 at 10 ppm), a low limit of detection of 52 ppb, and excellent selectivity for NO2 gas under UV light illumination, indicating great potential for NO2 detection. Notably, the sensor possesses fast response and full recovery properties (275/1078 s) compared to the results in the dark. Furthermore, the mechanism of enhanced gas sensitivity was proposed based on the energy band alignment of the PdSe2/InSe heterojunction with the assistance of investigating the surface potential variations. This work may pave the way for the development of high-performance, room-temperature gas sensors based on 2D vdWs heterostructures through the LMBE technique.
Kiwifruit undergoes rapid quality changes after harvest, which has an important influence on quality grading and processing. The effects of postharvest ripening on water status, distribution, drying ...characteristics, and the effects of ripening and drying on volatile profiles, phytochemical contents, antioxidant capacity, and microstructure of kiwifruit were investigated. During postharvest storage, the water binding ability decreased, the water distribution, migration path, and the microstructure changed, which led to the shortening of drying time first and then prolongation. Ripeness affected kiwifruit's volatile composition, phytochemical composition and antioxidant capacity, and the drying process after storage reduced the differences of nutrients and volatile components caused by different postharvest ripeness. The findings in current work provide practical implications for the quality classification and effective drying of kiwifruit during post-harvest ripening.
•Postharvest ripening affected physicochemical properties and drying characteristics.•Changes in water binding state and microstructure led to differences in drying rate.•Ripeness of kiwifruit affected the heat transfer during drying process.•Both postharvest ripening and drying significantly affected the volatile profiles.•Storage and drying progress affected phytochemical and antioxidant activity.
A new drying technology, far-infrared radiation heating assisted pulsed vacuum drying (FIR-PVD) was applied to process blueberries. Influences of drying temperature, vacuum pressure duration (VPD), ...and ambient pressure duration (APD) on drying characteristics and quality attributes of blueberries were investigated under FIR-PVD. Results showed that drying temperature, APD, and VPD had significant influence on drying time and quality attributes of dried blueberries expect for color and cohesiveness. Compared to hot air dried blueberries, FIR-PVD seriously damaged the cellular walls of blueberries during drying at 65 °C. The highest total phenolics (TP) and total monomeric anthocyanins (TMA) contents of dried blueberries were obtained at 65 °C with pulsed ratio of 15 min: 4 min and 15 min: 2 min, respectively. The FIR-PVD products obtained lower color difference, better mechanical properties and rehydration performance and maintained higher antioxidant capacity by shortening drying time, reducing exposure to oxygen, and modifying the microstructure compared to hot air drying.
Blueberry is a popular function fruit around the world. With high moisture content and tender tissue, fresh blueberry is very susceptible to microbial infection even under low temperature storage conditions. Drying is a good alternative to extend the shelf life and increase the availability of fresh blueberries. However, the existence of waxy hydrophobic layer covered the surface of blueberries inhibits moisture diffusion during drying. Chemical dipping and thermal blanching pretreatments were usually used to reduce the influence of skin hydrophobicity and promote moisture diffusion. Nevertheless, the chemical additive residue leads to food safety risk and it's a big challenge to deal with the corrosive waste chemical solutions, while thermal blanching resulted a high loss of bioactive compounds. FIR-PVD is a recent developed emerging drying technology to process berries with waxy layer beyond pretreatments. Results indicated that FIR-PVD is a very promising technology for processing blueberries with the improvement of drying efficiency and quality attributes.
Display omitted
•FIR-PVD promoted drying process and preserved blueberry quality.•FIR-PVD seriously damaged the cellular walls of blueberries.•FIR-PVD samples maintained higher antioxidant capacity.•More porous microstructures were observed in FIR-PVD products.•FIR-PVD products showed better mechanical properties and rehydration performance.
As a new type of blanching technology, vacuum-steam pulsed blanching (VSPB) has higher blanching efficiency and quality, but the mechanism of this technology on texture softening and drying ...enhancement is still unclear. In this study, the mechanism was revealed from texture, pectin, nanostructure, cell ultrastructure, calcium, and water state. Results revealed that VSPB treatment reduced the hardness and chewiness, increased water-soluble pectin, decreased sodium‑carbonate-soluble and chelate-soluble pectin concentration, and resulted in depolymerization and degradation of pectin nanostructure. However, transmission electron microscopy showed that blanching damaged the cell wall structure and the integrity of the middle layer. Scanning electron microscope - Energy dispersive X-ray spectroscopy measurement observations indicated that lipid droplets containing calcium ions were formed under the action of VSPB. In addition, low field nuclear magnetic resonance showed that the redistribution of moisture in carrot was facilitated by VSPB. The findings reveal the mechanism of texture softening and drying rate enhancement driven by blanching.
Thermal blanching is an essential thermal treatment for many fruits and vegetables processing. Hot water blanching and steam blanching are the two most frequently employed blanching methods due to simple to establish and easy to operate. However, hot water and steam blanching holds several disadvantages, e.g., hot water blanching requires a huge amount of water and generates an excessive amount of wastewater, particularly loss of water-soluble nutrients during blanching due to leaching and diffusion, while for steam blanching, the existence of air and water vapor among the piled materials leads to low blanching efficiency and un-uniform heating. VSPB is an innovative steam blanching method. In the VBSP process, the air and water vapor are expelled by the vacuum pump to facilitate steam deep penetration in the materials, particularly the piled materials, so as to improve blanching efficiency and uniformity. Previous study indicated VSPB could soften texture and reduce the drying time of carrot, but the mechanism was not clear. The current work reveal that VSPB softens texture and enhances drying rate of carrot via micro-, ultra-structure modification, pectin polysaccharides degradation and changes of water state. The findings have important implications for understanding and controlling the blanching triggered texture formation and drying enhancement.
•A new blanching technology, vacuum-steam pulsed blanching technology was developed.•SEM, TEM, AFM, EDX and LF-NMR were used for quality analysis during VSPB of carrot.•Micro, ultra, nanostructure and ion changes clarify the mechanism of tissue softening.•Tissue softening and moisture variation clarify the reason of accelerated drying rate.•Pectin content and structure affect texture, microstructure, water state, calcium ion.
Molybdenum disulfide (MoS2), a transition metal dichalcogenide (TMD), is conventionally regarded as a promising room-temperature sensing material due to its unique physical and chemical properties. ...However, the gas sensors based on pure MoS2 films do not seem to achieve the expectation. In this study, we fabricated the unique structure of dispersed Co and Zn atoms doped on the MoS2/graphite (Co–Zn/MG) composite and investigated the gas-sensing properties. We find that the sensor based on the Co–Zn/MG composite shows high responses toward NO2 gas (Ra/Rg = ∼1.3 at 50 ppb and ∼5.5 at 5 ppm) at room temperature, which is significantly higher than that of the pristine MoS2 sensor in our work. In addition, the Co–Zn/MG sensor has a low limit of detection of 6.2 ppb, fast response–recovery time (118/383 s toward 1 ppm NO2), and long-term stability. Compared with other gases, including NO, NH3, H2, CO, and ethanol, the sensor exhibits good selectivity toward NO2 due to its lower activation energy. Furthermore, the enhanced gas-sensing mechanism can be attributed to the modulation of Schottky barrier height, enriched oxygen adsorption, and catalysis. This work may open a new avenue to achieve NO2 sensors with absolutely competitive performance at room temperature.
Autism is a pervasive neurodevelopmental disorder,thought to be caused by a combination of genetic heritability and environmental risk factors. Some autistic-like traits have been reported in mothers ...of autistic children. We hypothesized that dysregulation of oxytocin (OXT), Arg-vasopressin (AVP) and sex hormones, found in autistic children, may also exist in their mothers.
We determined plasma levels of OXT (40 in autism vs. 26 in control group), AVP (40 vs. 17) and sex hormones (61 vs. 47) in mothers of autistic and normal children by enzyme immunoassay and radioimmunoassay, respectively and investigated their relationships with the children's autistic behavior scores (Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC)).
Significantly lower plasma concentrations of OXT (p<0.001) and AVP (p<0.001), as well as a higher level of plasma testosterone (p<0.05), were found in mothers of autistic children vs. those of control. The children's autistic behavior scores were negatively associated with maternal plasma levels of OXT and AVP.
These results suggest that dysregulation of OXT, AVP and/or testosterone systems exist in mothers of autistic children, which may impact children's susceptibility to autism.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Autism spectrum disorder(ASD) is defined by impairments of social interaction and the presence of obsessive behaviors. The ‘‘twin’’ nonapeptides oxytocin(OXT) and arginine-vasopressin(AVP) are known ...to play regulatory roles in social behaviors. However, the plasma levels and behavioral relevance of OXT and AVP in children with ASD have seldom been investigated. It is also unknown whether their mothers have abnormal plasma peptide levels. Here, using well-established methods of neuropeptide measurement and a relatively large sample size, we determined the plasma levels of the two neuropeptides in 85 normal children, 84 children with ASD, and 31 mothers from each group of children.As expected, children with ASD had lower plasma OXT levels than gender-matched controls(P = 0.028). No such difference was found for plasma AVP concentrations. Correlation analysis showed that ASD children with higher plasma OXT concentrations tended to have less impairment of verbal communication(Rho =-0.22,P = 0.076), while those with higher plasma AVP levels tended to have lower levels of repetitive use of objects(Rho =-0.231, P = 0.079). Unlike the findings in children, maternal plasma OXT levels showed no group difference. However, plasma AVP levels in the mothers of ASD children tended to be lower than in the mothers of normal children(P = 0.072). In conclusion, our results suggest that the OXT system is dysregulated in children with ASD, and that OXT and AVP levels in plasma seem to be associated with specific autistic symptoms. The plasma levels of OXT or AVP in mothers and their ASD children did not seem to change in the same direction.
Mitochondrial bioenergetics is dynamically coupled with neuronal activities, which are altered by hypoxia‐induced respiratory neuroplasticity. Here we report structural features of postsynaptic ...mitochondria in the pre‐Bötzinger complex (pre‐BötC) of rats treated with chronic intermittent hypoxia (CIH) simulating a severe condition of obstructive sleep apnea. The subcellular changes in dendritic mitochondria and histochemistry of cytochrome c oxidase (CO) activity were examined in pre‐BötC neurons localized by immunoreactivity of neurokinin 1 receptors. Assays of mitochondrial electron transport chain (ETC) complex I, IV, V activities, and membrane potential were performed in the ventrolateral medulla containing the pre‐BötC region. We found significant decreases in the mean length and area of dendritic mitochondria in the pre‐BötC of CIH rats, when compared to the normoxic control and hypoxic group with daily acute intermittent hypoxia (dAIH) that evokes robust synaptic plasticity. Notably, these morphological alterations were mainly observed in the mitochondria in close proximity to the synapses. In addition, the proportion of mitochondria presented with enlarged compartments and filamentous cytoskeletal elements in the CIH group was less than the control and dAIH groups. Intriguingly, these distinct characteristics of structural adaptability were observed in the mitochondria within spatially restricted dendritic spines. Furthermore, the proportion of moderately to darkly CO‐reactive mitochondria was reduced in the CIH group, indicating reduced mitochondrial activity. Consistently, mitochondrial ETC enzyme activities and membrane potential were lowered in the CIH group. These findings suggest that hypoxia‐induced respiratory plasticity was characterized by spatially confined mitochondrial alterations within postsynaptic spines in the pre‐BötC neurons. In contrast to the robust plasticity evoked by dAIH preconditioning, a severe CIH challenge may weaken the local mitochondrial bioenergetics that the fuel postsynaptic activities of the respiratory motor drive.
Pulsed pressure pickling is an emerging highly efficient osmotic dehydration technique. However, the immobility of the pickling liquid and the material, the formation of layers, and the uneven ...pickling efficiency in different sections make it difficult to use industrially. This work aims at improving and optimizing the conditions of fluid flow in the pickling tank with a liquid-cycle system to reduce the unevenness in the production process. Fluid flow around the eggs was numerically investigated by solving three-dimensional Reynolds-averaged Navier–Stokes equations within the flow regime, adopting different angles and positions at the inlet and outlet. The simulation results show that the inlet with a radial deflection of 35° and the outlet with axial direction were characterized by the best flow efficiency. Under these conditions, the average flow velocity and the global uniformity index were 0.153 m/s and 0.407, respectively. Furthermore, the experiments were carried out using an equivalent scale model of the pulsed pressure equipment with liquid circulation. The experimental results showed that, under optimal conditions, the salt content in all four layers of the egg white was about 2.8% after 48 h. This study provides a solution to ensure the constant salinity of different layers of pickled eggs and to improve pickling efficiency, especially in industrial-scale production.
PDF
