Dehydration Procedure Research Articles

Reconstruction of the Permittivity of Ex Vivo Animal Tissues in the Frequency Range 1-20 GHz Using a Water-Based Dielectric Model.

Several medical techniques are based on the application of electromagnetic fields (EMFs) on the human body with therapeutic and/or diagnostic aims. The response of human tissues to the applied EMF is mediated by the tissues' dielectric properties, which must therefore be characterized at the frequencies of the considered technique. Due to the heterogeneity and complexity of biological tissues, it is necessary to know their properties in vivo for the specific condition of interest. Traditional techniques for the dielectric characterization of biological tissues are invasive and, as such, not adoptable for this aim. Accordingly, alternative sensors and/or sensing methods are needed. Recently, a new wideband spectroscopy technique was proposed, based on quantities derived from the Magnetic Resonance (MRI) signal. Among these quantities, the water content was proposed to evaluate the dielectric properties at frequencies around a few GHz. This work verifies the possibility of deriving tissues' dielectric properties in the frequency range of 1-20 GHz based on knowledge of the water content. The water content was retrieved through a dehydration procedure for five different ex vivo tissues. The achieved results were compared with references from the literature.

Enabling one-step regeneration of LiBH4 with self-sustaining hydrogen in its spent fuel – One pathway to storing renewable hydrogen

LiBH4 (LB in short) with a hydrogen capacity as high as 18.5 wt% and a low molecular weight (21.78 g mol−1) is among the most promising candidates for the hydrogen-based economy. However, current major technologies in (re)generation of LB rely heavily on energy-intensive processes, which greatly prohibits practical scaling-up of applications. Here we report a sustainable and effective approach to (re)generate LB via converting renewable H+ in crystalline water into H-, achieving a desirable yield of ∼50%. This one-step synthesis method relies on the reaction between spent fuels, specifically LiBO2·xH2O, and Mg-based alloys to form LB under ambient atmosphere. Notably, our approach surpasses the efficiency of other conventional method, such as LiH-B-H2 and MgH2-LiBO2 systems, which not only bypasses the energy-intensive dehydration procedure of LiBO2·xH2O (∼470 ℃) but also eliminates the use of costly hydrides or high-pressure H2. Our findings indicate that Mg participated in the regeneration process prior to Al in Mg-Al alloys and [BH4]- is gradually evolved from other intermediate species [BHx(OH)4-x]- (x = 0, 1, 2, 3). By combining hydrogen release and efficient storage of hydrogen-rich substrate in a closed materials cycle, this study may shed light on a promising step toward application of renewable hydrogen in a fuel cell-based hydrogen economy.

Remediation of waste water through natural coagulants such as lemon and banana peel

Water is not only necessary for survival, but it also adds significantly to the quality of our lives. The rapid increase in population, economic expansion, and industrialization in developing nations has led to an unexpected need for water in cities. The capacity for water uses and wastewater generation in residential sectors has significantly risen during the past few decades. Wastewater treatment is an essential procedure in the sanitation system. Reusing resources and adhering to environmental regulations require efficient treatment and pollution management of municipal wastewater resources. The most preferred method for treating wastewater among the many options currently available is the coagulation and flocculation processes. People widely use this treatment due to its low energy consumption, reliability, affordability, and ease of use. This study evaluated the use of banana and lemon peels as coagulants in water treatment using coagulation-flocculation procedures as a potential substitute for alum. We determined the pH and coagulant dose for both banana and lemon peel combinations. The results of this experiment show that lemon peel works well as a coagulant to absorb biological oxygen demand. It has been discovered that the dehydration procedure works better with peels from bananas and lemons. The ideal duration of contact between lemon and banana peels is 90 minutes. For peels of bananas and lemons, the optimal particle size is 300μm, and the ideal dosage of adsorbent is 0.3g.

Stacking transfer of wafer-scale graphene-based van der Waals superlattices

High-quality graphene-based van der Waals superlattices are crucial for investigating physical properties and developing functional devices. However, achieving homogeneous wafer-scale graphene-based superlattices with controlled twist angles is challenging. Here, we present a flat-to-flat transfer method for fabricating wafer-scale graphene and graphene-based superlattices. The aqueous solution between graphene and substrate is removed by a two-step spinning-assisted dehydration procedure with the optimal wetting angle. Proton-assisted treatment is further used to clean graphene surfaces and interfaces, which also decouples graphene and neutralizes the doping levels. Twist angles between different layers are accurately controlled by adjusting the macroscopic stacking angle through their wafer flats. Transferred films exhibit minimal defects, homogeneous morphology, and uniform electrical properties over wafer scale. Even at room temperature, robust quantum Hall effects are observed in graphene films with centimetre-scale linewidth. Our stacking transfer method can facilitate the fabrication of graphene-based van der Waals superlattices and accelerate functional device applications.

Evaporative Dry Powders Derived From Cellulose Nanofiber Organogels to Fully Recover Inherent High Viscosity and High Transparency of Water Dispersion.

Water containing low amounts of cellulose nanofiber (CNF) has been widely used as a thickening agent owing to its three unique properties: high transparency, viscosity, and controllable viscosity based on the shear rate. CNF dry powders are used to reduce the transportation and storage costs or expand applications as a thickening agent. Herein, we report the preparation of CNF dry powders that can be used to obtain redispersions while maintaining the aforementioned properties. In this regard, we discuss the dehydration and vaporization procedures for a CNF water dispersion without using additives. When dry powders are prepared by removing water by boiling, their redispersions do not exhibit all their unique properties because of dense aggregations. However, when their redispersions are vigorously stirred to break the dense aggregations, they become transparent, although they do not recover their initial viscosity. Freeze-dried powders recover all their initial properties after redispersion. Nevertheless, their large volume does not reduce the transportation and storage costs. When the liquid is evaporated from the solvent-exchanged CNF organogels, their redispersions also fully recover all their properties. Furthermore, the evaporative dry powders with dense small volumes and good handling contribute to reducing the transportation and storage costs. This article is protected by copyright. All rights reserved.

Use of X-Ray Photoelectron Spectroscopy as an analytical tool for the study of contamination by Teflon in the synthesis of Mo(VI)Cl2O2Bipy/TiO2 catalysts

The preparation of catalysts can involve various sources of contamination, which can seriously affect the quality of the prepared materials. In the present work, a case of fluorine contamination in a set of catalyst samples was studied, in which using the X-Ray Photoelectron Spectroscopy (XPS) technique, it was evidenced by the F 1s signal that this element was present in the form of Teflon, since its binding energy corresponded mainly to the CF2 species. Furthermore, using the C 1s signal, it was also possible to corroborate the presence of the CF2 group, which is associated with the main component of the Teflon carbon chains. The use of this information made it possible to identify that the solvent dehydration procedure (previous step to obtaining the catalysts) could lead to contamination with Teflon since it involved various accessories with Teflon, organic solvents and high temperature; the Teflon tape and the magnetic stirrer being the possible sources of contamination.

Kinetic and isotherm studies of Acid Orange 7 dye absorption using sulphonated mandarin biochar treated with TETA

This study contributes to the current state of knowledge by highlighting the physical–chemical interactions between biochar and dyes. The removal of Acid Orange 7 (AO7) dye by a modified biochar obtained from the wastes of mandarin peels (MPs) has been investigated in this work. A dehydration procedure with 80% H2SO4 under reflux was applied to produce an innovative biochar from MPs and then boiled with H2O2 and followed by boiling with triethylenetetramine to make mandarin biochar-C-TETA (MBCT). FTIR, SEM, EDX, BJH, BET, TGA, and DTA analyses were applied to investigate the MBCT. FTIR analysis showed an additional peak that confirmed the addition of the NH2 group to the MBCT structure. An amorphous carbon structure was also confirmed by XRD analysis. The AO7 dye solution pH was proved to give the best absorption at pH 2.0. Significant removal of AO7 dye 99.07% using an initial concentration of 100 mg/L of AO7 dye and a 0.75 g/L MBCT. The Langmuir (LNR) and Freundlich (FRH) isotherm models investigated the experimental results. The LNR was best suited to handle the working MBCT data. The maximum adsorption capacity (Qm) calculated for the MBCT was 312.5 mg/g using 0.25 g/L of the MBCT. Kinetic studies were conducted using the intraparticle diffusion (IND), film diffusion (FD), pseudo-first-order (PFOR), and pseudo-second-order (PSOR) models. The absorption rate was calculated using the ultimate value of the linear regression coefficient (R2 > 0.99), and the PSOR rate model was found to ideally describe the absorption process. The point of zero charge (pHPZC) was found to be 10.17. The electrostatic attractive-forces between the sorbent surface positively charged sites and negatively charged anionic dye molecules were the primary mechanism of the MBCT sorption of the AO7 dye’s anion absorption. The results indicate that the manufactured MBCT adsorbent may be useful for removing the AO7 dye from wastewater. MBCT can be used repeatedly for up to six cycles without dropping its absorption efficiency.

Mass transfer kinetics (soluble solids gain and water loss) of ultrasound-assisted osmotic dehydration of apple slices

Ultrasound (sonication) treatment can be used directly for dehydration or pre-treatment before the osmotic dehydration (OD) procedure of fruit or vegetable particles. The combination of this technique with the OD technique can further improve the dehydration process efficiencies by increasing the mass transfer rates and enhancing final product quality. In this study, apple slices were osmotically dehydrated in different hypertonic sucrose solutions and assisted with or without ultrasound. Sucrose concentrations (in three levels of 30, 40, and 50° Brix), sonication power (in three levels of 0, 75, and 150 W), and treatment time (in six time intervals: 10, 20, 30, 40, 50, and 60 min) were the factors investigated concerning weight reduction, soluble solids gain, water loss and rehydration. Also, mass transfer kinetics were modelled according to Page, Newton, Midilli, Logarithmic, Verma, and Two terms equations. Increased sucrose solution concentration resulted in higher weight reduction, soluble solids gain and water loss. Also, increased sonication power levels resulted in higher weight reduction, soluble solids gain and water loss. The average rehydration ratio of apple slices decreased from 237.7 to 177.5%, by increasing osmotic solution concentration from 30 to 50%. The Page equation showed the best fitting for water loss data. The effective moisture diffusivity (Deff) of apple slices during OD calculated using Fick’s second law applied to a slab geometry was found to be in the range of 1.48 × 10–10 and 4.62 × 10–10 m2s−1 for water loss.

Cryopreservation of Endangered Ornamental Plants and Fruit Crops from Tropical and Subtropical Regions.

Simple SummaryThe protection of biodiversity, i.e., the biological variety and variability of life on Earth, is of great importance for the present and future generations. Maintaining variation at the genetic and ecosystem levels is indispensable in breeding programs and creation of new cultivars. Currently, numerous plant species, wild varieties, and local forms of ornamental and fruit plants are endangered with extinction. Cryopreservation, i.e., the storage of biological samples in tanks filled with liquid nitrogen is considered as the most effective long-term preservation method of plant genetic resources. Nonetheless, the establishment of efficient cryogenic procedures is a difficult task, requiring consideration of several factors. The impact of cryopreservation on the stability and homogeneity of the stored samples is of particular interest. The aim of this article is to evaluate some traditional and modern cryopreservation methods and their utility for the storage and exchange of genetic sources of tropical and subtropical horticultural crops.Horticultural crops comprise various economic species extending from fruits, nuts, vegetables, spices and condiments, ornamentals, aromatic, and medicinal plants. Ornamental and fruit plants are produced mainly for their nutritional and aesthetic values, respectively. Unfortunately, many tropical and subtropical species are in danger of extinction because of climate change and (a)biotic stresses. It is imperative to preserve the germplasms of these species for the present and future genetic improvement programs. Cryopreservation, i.e., maintenance of tissues at the ultralow temperature of liquid nitrogen, is a promising long-term preservation technique, alternative to seed or in vitro banks, which can be applied for both vegetatively and generatively (through seeds) propagated crops, including those with recalcitrant seeds. It is a technology of choice not only for the preservation of plant biodiversity but also for virus elimination in the proficient administration of large-scale micropropagation. The main advantages of cryopreservation are the lowering of in vitro culture expenditures, needed space, contamination risk, and operator errors. However, tropical species are temperature delicate and one of the foremost challenging issues is preconditioning treatments that stimulate physiological reactions to sufficiently enhance tolerance to dehydration and cryogenic procedures. In recent years, several cryopreservation methods based on encapsulation-vitrification, droplet-vitrification, the use of aluminum cryo-plates, and cryo-mesh have been established. Combined cryo-techniques, gene/DNA conservation, as well as studies on perceiving bio-molecular events and exploring the multistage process from the beginning to end of cryopreservation are receiving more emphasis. The development of cryobiomics delivers a conceptual framework to assess the significance of cell signaling mechanisms on cellular functions, the influence of cryoinjury factors on sample viability, and the implications for genetic stability following cryo-storage. The aim of this mini-review article is to provide a succinct synthesis of the developed cryogenic procedures and their use for the storage and exchange of genetic resources of tropical and subtropical horticultural crops, particularly fruit crops and ornamental plants under the threat of extinction.

Volatile Flavor Compounds of Pugionium cornutum (L.) Gaertn. Before and After Different Dehydration Treatments.

Pugionium cornutum (L.) Gaertn (also Pugionium) is a special Mongolian vegetable, belonging to the Cruciferous family, growing in arid and semi-arid areas of northern China, with a unique flavor and potential health benefits. This article aims to describe the profile of volatile flavor compounds in fresh and different dehydrated samples, establish the fingerprint, and identify the characteristic compounds. The fresh Pugionium sample and 3 kinds of dehydrated samples were analyzed. Headspace/gas chromatography-ion migration spectrometry (HS/GC-IMS) and solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) were used for identification and relative quantification. HS/GC-IMS identified 78 compounds, whereas SPME/GC-MS identified 53 compounds. Principal component analysis (PCA), clustering analysis, and partial least squares discriminant analysis (PLS-DA) were used as appropriate to investigate variations in volatile compounds among Pugionium samples and identify distinctive compounds. The first two principal components described 76.5% and 69.5% of the variance of the data from HS/GC-IMS and SPME/GC-MS, respectively. By clustering analysis, 4 kinds of Pugionium samples could be classified into four independent groups. The similarity between fresh Pugionium and natural dehydration Pugionium was higher than the other two dehydrated samples, indicating that natural dehydration can better preserve the flavor of Pugionium. Most aldehydes and alcohols increased following different dehydration procedures, whereas esters decreased, and the dehydrated Pugionium samples have more harmonious and less pungent aroma than the fresh Pugionium. PLS-DA model analysis revealed that the marker compounds (VIP scores > 1) discriminating the flavor of the four samples for HS/GC-IMS and SPME/GC-MS were 24 and 15 compounds, respectively, such as 2-phenylethyl isothiocyanate, 1-butene-4-isothiocyanate and other isothiocyanates, 2-propanone, nonanal, gamma-butyrolactone, 2,3-butanediol, 3-methyl-2-butenenitrile, and pentanal. Analysis of volatile compounds might be useful for monitoring the quality of Pugionium and guiding the cooking methods and processing technologies. More study is required to discover if the various volatile flavor compounds have biological or physiological impacts on nutrition.

Substantiation of a rational method for drying granules in a fluidized bed and the hydrodynamic regime of their interaction with a fluidizing agent

Gluten is produced from wheat grains and is used in the food industry as an improver in flour baking properties. On the basis of a comparative analysis of the methods of dehydration of frozen granules of wheat gluten with a surface dry crust, a rational method of drying them in a fluidized bed has been selected. In the process of calculating units with a fluidized bed, its hydrodynamic parameters have been determined: loss of the pressure of the fluidizing agent; the speed at the transition of the bed from the state of rest to the pseudo-boiling mode; layer porosity; the rate of entrainment of particles in unrestricted conditions roughly corresponding to the rate of soaring, at which a single particle is in equilibrium in the gas flow. During the dewatering operation, the rate of entrainment of the granules varies; therefore, it is advisable to use the passing fluidization mode depending on the decrease in their moisture content. In the variant of the active hydrodynamic regime in the drying unit, the dehydration procedure is intensified without a noticeable decrease in the economic efficiency of its functioning and high quality indicators of the finished product with the given final moisture are provided, which is due to the specific conditions of contact of the granules with the coolant. For granules with a moisture content of 0.19 kg/kg, the values of hydrodynamic characteristics have been determined: the area of critical pseudo-boiling rates is 4.1-5.5 m/s; the carryover rate of the fines is 12.5-14.5 m/s. As a result of the study, the choice has been substantiated in favor of drying the studied granules in a fluidized bed due to the prevalence of its advantages over the dehydration of the object in drum dryers.

Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH4 from its Hydrolytic Product

AbstractSodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.

Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH4 from its Hydrolytic Product.

Sodium borohydride (NaBH4 ) is among the most studied hydrogen storage materials because it is able to deliver high-purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2 , forming Na2 B4 O7 ⋅10 H2 O and Na2 CO3 , both of which are ball-milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2 , bypasses the energy-intensive dehydration procedure to remove water from Na2 B4 O7 ⋅10 H2 O, and does not require high-pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.

Long term conservation of embryonic axes of genipap accessions

The ex situ conservation of seeds in cryobanks demands previous studies of dehydration procedures for the adjustment of the adequate moisture that makes long-term conservation possible. The objective of this work was to evaluate the effect of dehydration time on the regenerative capacity of embryonic axes of two genipap accessions (Umbaúba and Núcleo Bandeirante). Seeds were submitted to desiccation in policarbonate box containing silica gel for 0, 12, 16 and 20 h at room temperature and after each period, seed moisture content was determined. Seeds were inoculated in germination medium and samples were inserted into cryotubes and immersed in liquid nitrogen (-196ºC). Desiccation in silica gel was efficient in reducing the moisture content in both accessions. Umbaúba accession presented 100% germination at all desiccation treatments before cryopreservation and Núcleo Bandeirante was more sensitive to desiccation with 10% germination in 20 h. Umbaúba accession showed a reduction of growth variables with increased desiccation time. The treatments tested did not affect the growth variables of Núcleo Bandeirante accession. The desiccation, although changes observed in the ultra-structures of embryonic axis, did not influence the regeneration percentage of cryopreserved accessions.

Evaluation and Safety Validation of Dehydrating Methods for Goat Meat in Rural Malawi

ObjectivesThis study was conducted to evaluate the dehydration methods of goat meat based in Malawi and the effects on food safety.Materials and MethodsGoat meat was prepared as ground, minced, and whole muscle strips. Samples were treated with 6% lemon juice marinade, 6% vinegar marinade, or salt rub. During phase 1, dehydration of the meat was performed with a solar dehydrator (n = 108), electric oven (n = 108) or drum oven (n = 108). Qualitative data on the three drying methods was collected from a panel of students from Mzuzu University, Malawi, on the practicality of each method in a local rural setting. Additionally, visual observations were conducted 30 d prior to drying for the presence of mold and insects to give an indication of shelf life. Phase 2 was performed at Texas Tech University in Lubbock, Texas where whole muscle strips of lamb were submerged in a five-strain Escherichia coli surrogate cocktail of Escherichia coli for 5 min, allowed 30 min for cell attachment, then dried using an electric and drum oven, replicating the dehydration procedure in Malawi. For each replicate (n = 2), attachment samples (n = 10), samples dried in the electric oven (n = 10) and samples dried in drum oven samples (n = 10) were aseptically plated on MacConkey agar with a TSA overlay and enumerated for E. coli.ResultsIn phase 1, mold growth was observed on 15.7% (34/216) of samples dried in the solar dehydrator and drum oven. Of those positive for mold, 32.4% (n = 11) were minced, and 67.6% (n = 23) were whole muscle strips. No samples dried using the electric oven displayed mold (0/108). No samples displayed insects. Based on qualitative data that was gathered, top reasons to dry goat meat using the drum oven include “not requiring electricity” and “drum ovens are a common piece of equipment in villages”. Top reasons against using a drum oven include “unequal distribution of heat” and “high level of oversight required during drying”. Top reasons to dry goat meat using electric oven include “fast drying time”, “uniform distribution of heat”, and “limited oversight required”. Top reasons against using electric oven to dry goat meat include “requiring electricity” and “low knowledge of electric oven operation in a community setting”. Top reasons to use the solar dehydrator to dry goat meat include “not requiring electricity or firewood” and “limited oversight required”. Top reasons against using the solar dehydrator to dry goat meat include “slow drying time” and “uneven heat distribution due to time of day and shadows”. In phase 2, a 5-log reduction was observed for all electric oven treatment replicates (100%, 2/2) and half drum oven (50%, 1/2) replicates. However, variation in the reduction of E.coli is a direct result of weather and fuel provided to the drum oven.ConclusionElectric drying oven displayed the most consistent results for shelf life and safety. However, in rural Malawi, dehydrating methods should be chosen on a case by case basis.

Evaluation and Safety Validation of Dehydrating Methods for Goat Meat in Rural Malawi

ObjectivesThis study was conducted to evaluate the dehydration methods of goat meat based in Malawi and the effects on food safety.Materials and MethodsGoat meat was prepared as ground, minced, and whole muscle strips. Samples were treated with 6% lemon juice marinade, 6% vinegar marinade, or salt rub. During phase 1, dehydration of the meat was performed with a solar dehydrator (n = 108), electric oven (n = 108) or drum oven (n = 108). Qualitative data on the three drying methods was collected from a panel of students from Mzuzu University, Malawi, on the practicality of each method in a local rural setting. Additionally, visual observations were conducted 30 d prior to drying for the presence of mold and insects to give an indication of shelf life. Phase 2 was performed at Texas Tech University in Lubbock, Texas where whole muscle strips of lamb were submerged in a five-strain Escherichia coli surrogate cocktail of Escherichia coli for 5 min, allowed 30 min for cell attachment, then dried using an electric and drum oven, replicating the dehydration procedure in Malawi. For each replicate (n = 2), attachment samples (n = 10), samples dried in the electric oven (n = 10) and samples dried in drum oven samples (n = 10) were aseptically plated on MacConkey agar with a TSA overlay and enumerated for E. coli.ResultsIn phase 1, mold growth was observed on 15.7% (34/216) of samples dried in the solar dehydrator and drum oven. Of those positive for mold, 32.4% (n = 11) were minced, and 67.6% (n = 23) were whole muscle strips. No samples dried using the electric oven displayed mold (0/108). No samples displayed insects. Based on qualitative data that was gathered, top reasons to dry goat meat using the drum oven include “not requiring electricity” and “drum ovens are a common piece of equipment in villages”. Top reasons against using a drum oven include “unequal distribution of heat” and “high level of oversight required during drying”. Top reasons to dry goat meat using electric oven include “fast drying time”, “uniform distribution of heat”, and “limited oversight required”. Top reasons against using electric oven to dry goat meat include “requiring electricity” and “low knowledge of electric oven operation in a community setting”. Top reasons to use the solar dehydrator to dry goat meat include “not requiring electricity or firewood” and “limited oversight required”. Top reasons against using the solar dehydrator to dry goat meat include “slow drying time” and “uneven heat distribution due to time of day and shadows”. In phase 2, a 5-log reduction was observed for all electric oven treatment replicates (100%, 2/2) and half drum oven (50%, 1/2) replicates. However, variation in the reduction of E.coli is a direct result of weather and fuel provided to the drum oven.ConclusionElectric drying oven displayed the most consistent results for shelf life and safety. However, in rural Malawi, dehydrating methods should be chosen on a case by case basis.

Pulsed Electric Field as an Alternative Pre-treatment for Drying to Enhance Polyphenol Extraction from Fresh Tea Leaves

Drying is an essential pre-treatment prior to extraction of tea polyphenols from tea leaves, which is a time and energy-intensive process. In this study, pulsed electric field (PEF) was utilized to replace the conventional thermal dehydration procedure before the phenolic extraction. The influence of different PEF conditions on total polyphenol yield from fresh tea leaves combined with a solid-liquid extraction were compared. PEF treatment at 1.00 kV/cm electric field strength, 100 pulses of 100 μs pulse duration, and 5 s pulse repetition, which delivered 22 kJ/kg and induced 1.5 °C of temperature increase, was used for further study on the extraction kinetics of green tea catechins. The results indicated that compared to oven drying, PEF pre-treatment increased the extraction rate by approximately two times, without significantly altering the phenolic profiles, as revealed by using liquid chromatography combined with mass spectrometry. Scanning electron microscopy imaging revealed that PEF pre-treatment induced the formation of inhomogeneously distributed pores and protuberances on the surface of leaf tissues, which might facilitate the penetration of extraction solvent and the migration of phenolics. This study demonstrates that PEF as a time and energy efficient processing method is a promising alternative for the conventional drying process before further tea polyphenol extraction.

Methyltrimethoxysilane as a stabilising agent for archaeological waterlogged wood differing in the degree of degradation

Abstract Experiments using archaeological wooden remains of a medieval “Poznan” bridge from the Lednica Lake, Wielkopolska Region, Poland, were performed to evaluate the stabilisation effect of methyltrimethoxysilane on waterlogged oak wood varied in the degree of degradation. Moreover, two types of treatment were compared: the soaking method and the oscillating pressure method, preceded by the ethanol dehydration procedure. The results suggest that the silane in question can effectively penetrate wood cell walls, causing their bulking and thus enhancing wood dimensional stability. Exceptionally satisfying results were obtained for severely decayed sapwood (loss of wood substance about 80%), for which an overall anti-shrink efficiency oscillated around 100%, regardless of the applied treatment method. In the case of almost non-degraded heartwood, resistant to impregnation, the obtained anti-shrink efficiency of over 60% could also be considered as quite satisfactory. Comparable values of weight percent gain and anti-shrink efficiency for silane-treated specimens clearly show that there is no significant difference in the efficacy of the soaking and the oscillating pressure method applied. The obtained results show that the methyltrimethoxysilane treatment preceded by wood dehydration could be a reliable method for stabilisation of small archaeological waterlogged wooden artefacts, providing their good dimensional stability of wood differing in the degree of degradation.

Cryopreservation of rhizome buds of Asparagus officinalis L. (cv. Morado de Huétor) and evaluation of their genetic stability

We describe an encapsulation–dehydration procedure with prefreezing steps for the cryopreservation of rhizome bud explants of Asparagus officinalis L. cv. Morado de Huetor. With this procedure, survival of Rhizome buds was at least 84 and 42% developed to complete plantlets at 8 weeks. Flow cytometry and EST-SSR molecular markers were used to assess genetic stability of the regenerated material. Effects of preculture time in a medium rich in sucrose and prefreezing treatments (0 °C or/and − 20 °C) on plant recovery were evaluated. Rhizome Buds of the “Morado de Huetor” landrace were incubated in preculture medium (MS + 0.3 M sucrose) for 48 h, encapsulated in alginate beads and desiccated until a water content of 35%, prefrozen for one hour at 0 °C plus one hour at − 20 °C, followed by cryopreservation in liquid nitrogen, and then were rewarmed and recovered in ARBM medium for 6 weeks and finally incubated in ARBM-0 for 4 weeks. Analyses of ploidy and molecular stability of plantlets recovered from cryopreserved rhizome buds of two selected genotypes showed no differences compared with the mother plants. Cryopreservation of RB explants of A. officinalis with this Encapsulation–Dehydration procedure will be useful in long-term preservation programs.

Effects of Antarctic krill oil on lipid and glucose metabolism in C57BL/6J mice fed with high fat diet

BackgroundObesity and other metabolic diseases have become epidemic which greatly affect human health. Diets with healthy nutrition are efficient means to prevent this epidemic occurrence. Novel food resources and process technology were needed for these purpose. In this study, Antarctic krill oil (KO) extracted from a dry krill by a procedure of hot pump dehydration in combined with freezing-drying was used to investigate health effect in animals including the growth, lipid and glucose metabolism.MethodsC57BL/6J mice were fed with a lard based high fat (HF) diet and substituted with KO for a period of 12 weeks in comparison with low fat normal control (NC) diet. Mice body weight and food consumption were recorded. Serum lipid metabolism - of C57BL/6J mice serum was measured. A glucose tolerance tests (GTTs) and pathology analysis of mice were performed at the end of the experiment.ResultsThe KO fed mice had less body weight gain, less fat accumulation in tissue such as adipose and liver. Dyslipidemia induced by high fat diet was partially improved by KO feeding with significant reduction of serum low density lipoprotein-cholesterol (LDL-C) content. Furthermore, KO feeding also improved glucose metabolism in C57BL/6J mice including a glucose tolerance of about 22% vs. 32% of AUC (area under the curve) for KO vs HF diet and the fast blood glucose level of 8.5 mmol/L, 9.8 mmol/L and 9.3 mmol/L for NC, HF and KO diet groups, respectively. In addition, KO feeding also reduced oxidative damage in liver with a decrease of malondialdehyde (MDA) content and increase of superoxide dismutase (SOD) content.ConclusionThis study provided evidence of the beneficial effects of KO on animal health from the processed technology, particularly on lipid and glucose metabolism. This study confirmed that as the Antarctic krill was extracted with a procedure of efficient energy, it might make it possible for Krill oil to be available for food industry.