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1.
Water Sci Technol ; 82(1): 27-38, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32910790

RESUMO

The present study describes a pilot-scale experimental validation of a forced-convection greenhouse solar dryer, combined with a biofilter, for controlled atmospheric emissions. This set-up was applied to the dewatering of sewage sludge from a biological plant that treated process wastewater in a commercial Mediterranean winery. Experiments were performed after the harvest, from September onwards, during the peak generation of sludge. The average drying rate during the first 10 days of operation ranged from 1.17 to 2.24 kg m-2 d-1, depending on the measurement method, during which the water content of the sludge was reduced from 90% down to 67%. Biofiltration was quite inefficient against greenhouse gases (methane and dinitrous oxide), and direct emissions during the drying process were on average 57 g CO2-eq m-2 d-1. Ammonia and volatile organic compounds were removed with average efficiencies of 71% and 35%, but ammonia losses through volatilization represented less than 2% of the initial nitrogen content. The sludge was dried further during November, to the lowest possible water content of 14%. Both the intermediate and final sludge dried materials were characterized for their agronomical value as organic fertilizers.


Assuntos
Dessecação , Esgotos , Fazendas , Nutrientes , Águas Residuárias
2.
Acta Odontol Latinoam ; 33(2): 135-142, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920616

RESUMO

This study evaluated the influence of the mode and time of solvent evaporation on the tensile strength (TS), flexural strength (FS) and elastic modulus (EM) of two adhesive systems: Scotchbond Multipurpose (SBMP) and Clearfil SE (CSEB). For this purpose, rectangular samples (2x1x7 mm) were prepared with 10 µL of primer and the solvents were evaporated with air spray at (23±1) ºC, (40±1) ºC and negative control (without spray). For each temperature, the times of 5, 20, 30, and 60 seconds were investigated. The statistical results showed that evaporation at 40±1ºC resulted in better EM for the two adhesives tested and all the evaporation times evaluated. However, there were no significant differences between the times and modes of evaporation for TS. The results of this study indicate that evaporation at a temperature of (40±1) °C could improve the elastic modulus of both adhesives tested, regardless of the evaporating time.


Assuntos
Adesivos/química , Cimentos Dentários/química , Adesivos Dentinários/química , Solventes/farmacologia , Resistência à Tração , Dessecação , Humanos , Teste de Materiais , Volatilização
3.
Am J Bot ; 107(8): 1177-1188, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32754914

RESUMO

PREMISE: The young seedling life stage is critical for reforestation after disturbance and for species migration under climate change, yet little is known regarding their basic hydraulic function or vulnerability to drought. Here, we sought to characterize responses to desiccation including hydraulic vulnerability, xylem anatomical traits, and impacts on other stem tissues that contribute to hydraulic functioning. METHODS: Larix occidentalis, Pseudotsuga menziesii, and Pinus ponderosa (all ≤6 weeks old) were imaged using x-ray computed microtomography during desiccation to assess seedling biomechanical responses with concurrently measured hydraulic conductivity (ks ) and water potential (Ψ) to assess vulnerability to xylem embolism formation and other tissue damage. RESULTS: In non-stressed samples for all species, pith and cortical cells appeared circular and well hydrated, but they started to empty and deform with decreasing Ψ which resulted in cell tearing and eventual collapse. Despite the severity of this structural damage, the vascular cambium remained well hydrated even under the most severe drought. There were significant differences among species in vulnerability to xylem embolism formation, with 78% xylem embolism in L. occidentalis by Ψ of -2.1 MPa, but only 47.7% and 62.1% in P. ponderosa and P. menziesii at -4.27 and -6.73 MPa, respectively. CONCLUSIONS: Larix occidentalis seedlings appeared to be more susceptible to secondary xylem embolism compared to the other two species, but all three maintained hydration of the vascular cambium under severe stress, which could facilitate hydraulic recovery by regrowth of xylem when stress is relieved.


Assuntos
Pseudotsuga , Traqueófitas , Dessecação , Secas , Plântula , Água , Xilema
4.
An Acad Bras Cienc ; 92(2): e20190072, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785423

RESUMO

To preserve freshness and nutritional quality of fruits and vegetables is required large energy expenditure due to most storage techniques require low temperatures, making the product difficult to transport and store. PURPOSE: To reduce energy expenditure, dehydration processes are being improving by pretreatments and changing frozen stage. METHOD: Alkaline emulsion pretreatment was introduced to freeze-drying method to reduce the drying time of grapes and obtain significant energy savings. RESULTS: Dehydration process for untreated fresh grape samples was 22 hours, using industrial freeze-drying equipment. It was obtained a high quality product with range 3 % to 7% of final humidity, without losing natural characteristics and organoleptic properties of the grapes. CONCLUSIONS: it was found by modifying standard equipment frozen method, using dry ice (CO2) and applied coconut oil alkaline emulsion pretreatment, a 54% energy saving. Even more the dehydration process decreased the microbial load in the fruit. A product with low number of microorganisms may be consumed by patients with low defenses as cereals, nutritional bars, salads, yogurts, etc. Finally, if all enterprises involved in this field take into account these findings and improve constantly their process they will stop emitting several kg of CO2 into the atmosphere.


Assuntos
Vitis , Dessecação , Liofilização
5.
PLoS One ; 15(7): e0236492, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735613

RESUMO

Scientific and reasonable treatment of dredged silt can not only protect the ecological environment but also play an essential role in the utilization of silt resources. Due to high water content, low permeability and high organic matter content of the silt, a large amount of bacteria and harmful gases are often produced during the process of silt sedimentation. Thermal drying has been taken as a technically attractive method for harmless treatment of contaminated dredged silt. In this study, ultrasound technology is introduced to shorten the time needed for silt drying. A preliminary laboratory study is carried out to assess the effectiveness of ultrasound on thermal drying. A series of thermal drying tests, with and without ultrasound, were conducted on kaolin soil specimens that were prepared by settling and self-weight consolidation. The test results show that the length of drying time can be shortened by increasing temperature and ultrasound power. The drying time plays a dominant role in the determination of the total energy consumption. This is because reduction of drying time leads to significant decrease in energy consumption for thermal drying, and the energy consumption for additional ultrasound is relatively marginal. For thermal drying at temperatures 60 and 100°C, when combined with 100 W ultrasound, the length of drying time was shortened by 44.19% and 45.16%, and the energy consumption was saved by 30.07% and 38.16%, respectively; when combined with 60 W ultrasound, the length of drying time was shortened by 4.65% and 6.45%, but the energy consumption was increased by 9.79% and 0.48%, respectively. The combination of thermal drying and 100 W ultrasound is found to be optimal in terms of drying rate and energy consumption for silt drying.


Assuntos
Fenômenos Ecológicos e Ambientais , Metabolismo Energético/efeitos da radiação , Água/química , Dessecação , Temperatura Alta , Caulim/efeitos da radiação , Solo/química , Ultrassonografia
6.
Proc Natl Acad Sci U S A ; 117(32): 19209-19220, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32723826

RESUMO

Some organisms have evolved a survival strategy to withstand severe dehydration in an ametabolic state, called anhydrobiosis. The only known example of anhydrobiosis among insects is observed in larvae of the chironomid Polypedilum vanderplanki Recent studies have led to a better understanding of the molecular mechanisms underlying anhydrobiosis and the action of specific protective proteins. However, gene regulation alone cannot explain the rapid biochemical reactions and independent metabolic changes that are expected to sustain anhydrobiosis. For this reason, we conducted a comprehensive comparative metabolome-transcriptome analysis in the larvae. We showed that anhydrobiotic larvae adopt a unique metabolic strategy to cope with complete desiccation and, in particular, to allow recovery after rehydration. We argue that trehalose, previously known for its anhydroprotective properties, plays additional vital roles, providing both the principal source of energy and also the restoration of antioxidant potential via the pentose phosphate pathway during the early stages of rehydration. Thus, larval viability might be directly dependent on the total amount of carbohydrate (glycogen and trehalose). Furthermore, in the anhydrobiotic state, energy is stored as accumulated citrate and adenosine monophosphate, allowing rapid reactivation of the citric acid cycle and mitochondrial activity immediately after rehydration, before glycolysis is fully functional. Other specific adaptations to desiccation include potential antioxidants (e.g., ophthalmic acid) and measures to avoid the accumulation of toxic waste metabolites by converting these to stable and inert counterparts (e.g., xanthurenic acid and allantoin). Finally, we confirmed that these metabolic adaptations correlate with unique organization and expression of the corresponding enzyme genes.


Assuntos
Dípteros/metabolismo , Proteínas de Insetos/metabolismo , Monofosfato de Adenosina/metabolismo , Animais , Dessecação , Dípteros/química , Dípteros/genética , Secas , Glicogênio/genética , Glicogênio/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/genética , Larva/química , Larva/genética , Larva/metabolismo , Metaboloma , Transcriptoma , Trealose/metabolismo , Água/metabolismo
7.
PLoS One ; 15(7): e0235712, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32634165

RESUMO

A better understanding of plant cell micromechanics would enhance the current opinion on "how things are happening" inside a plant cell, enabling more detailed insights into plant physiology as well as processing plant biomaterials. However, with the contemporary laboratory equipment, the experimental investigation of cell micromechanics has been a challenging task due to diminutive spatial and time scales involved. In this investigation, a three-dimensional (3-D) coupled Smoothed Particle Hydrodynamics (SPH) and Coarse-Grained (CG) computational approach has been employed to model micromechanics of single plant cells going through drying or dehydration. This meshfree-based computational model has conclusively demonstrated that it can effectively simulate the behaviour of stress and strain in a plant cell being compressed at different levels of dryness: ranging from a fresh state to an extremely dried state. In addition, different biological and physical circumstances have been approximated through the proposed novel computational framework in the form of different turgor pressures, strain rates, mechanical properties and cell sizes. The proposed computational framework has potential not only to study the micromechanical characteristics of plant cellular structure during drying, but also other equivalent, biological structures and processes with relevant modifications. There are no underlying difficulties in adopting the model to replicate other types of cells and more sophisticated micromechanical phenomena of the cells under different external loading conditions.


Assuntos
Biologia Computacional , Células Vegetais/fisiologia , Parede Celular/fisiologia , Simulação por Computador , Dessecação , Hidrodinâmica , Modelos Biológicos , Pressão , Estresse Fisiológico , Fatores de Tempo
8.
Proc Natl Acad Sci U S A ; 117(29): 17438-17445, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32636259

RESUMO

Among green plants, desiccation tolerance is common in seeds and spores but rare in leaves and other vegetative green tissues. Over the last two decades, genes have been identified whose expression is induced by desiccation in diverse, desiccation-tolerant (DT) taxa, including, e.g., late embryogenesis abundant proteins (LEA) and reactive oxygen species scavengers. This up-regulation is observed in DT resurrection plants, mosses, and green algae most closely related to these Embryophytes. Here we test whether this same suite of protective genes is up-regulated during desiccation in even more distantly related DT green algae, and, importantly, whether that up-regulation is unique to DT algae or also occurs in a desiccation-intolerant relative. We used three closely related aquatic and desert-derived green microalgae in the family Scenedesmaceae and capitalized on extraordinary desiccation tolerance in two of the species, contrasting with desiccation intolerance in the third. We found that during desiccation, all three species increased expression of common protective genes. The feature distinguishing gene expression in DT algae, however, was extensive down-regulation of gene expression associated with diverse metabolic processes during the desiccation time course, suggesting a switch from active growth to energy-saving metabolism. This widespread downshift did not occur in the desiccation-intolerant taxon. These results show that desiccation-induced up-regulation of expression of protective genes may be necessary but is not sufficient to confer desiccation tolerance. The data also suggest that desiccation tolerance may require induced protective mechanisms operating in concert with massive down-regulation of gene expression controlling numerous other aspects of metabolism.


Assuntos
Adaptação Fisiológica/genética , Clorófitas/genética , Clorófitas/fisiologia , Dessecação , Regulação da Expressão Gênica de Plantas , Clorofíceas/genética , Clorofíceas/fisiologia , Regulação para Baixo , Extremófilos/fisiologia , Ontologia Genética , Genes de Plantas/genética , Fatores de Transcrição , Transcriptoma , Regulação para Cima
9.
AAPS PharmSciTech ; 21(5): 181, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32607628

RESUMO

Cocrystals have gained a lot of consideration regarding its superior role in enhancement of solubility and dissolution of the included API. Cocrystals could be converted to coamorphous systems via different techniques like milling and quench cooling; however, the use of spray-drying technique has not been investigated before. So, the aim of this study was to explore the effect of spray drying on the amorphization of indomethacin/nicotinamide, INDNIC, as model cocrystals. Spray-drying operating parameters were optimized using the Taguchi design of experiment for maximum powder yield and low moisture content. The obtained INDNIC spray-dried cocrystals were characterized for their degree of crystallinity, morphology, moisture content, and dissolution performance. In addition, stability study was performed at different temperature and humidity conditions. Experimental design results delineate that spray-drying inlet temperature and cocrystal concentrations as the most influential factors for maximum powder yield and low moisture content. Powder X-ray diffraction and differential scanning calorimetry studies revealed the conversion of INDNIC cocrystals to a partial coamorphous or coamorphous structure without dissociation of INDNIC molecular structure. INDNIC coamorphous powders showed a significantly higher release of IND compared with cocrystals and remain physically stable for 2 months when stored in the refrigerator.


Assuntos
Dessecação/métodos , Estabilidade de Medicamentos , Indometacina/química , Niacinamida/química , Varredura Diferencial de Calorimetria , Composição de Medicamentos/métodos , Estrutura Molecular , Pós/química , Solubilidade , Difração de Raios X
10.
Food Chem ; 332: 127407, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32645677

RESUMO

This study aimed to investigate the difference between ginger slices (vertically cut) and splits (horizontally cut) during microwave-vacuum drying (MVD) procedures. MVD ginger slices showed a higher shrinkage rate and a higher hardness value, with a more porous structure of the surface layer. MVD ginger splits had higher rehydration rates at the first 15 min of the rehydration. Nine optimal wavelengths were selected by regression coefficients (RC) from the partial least squares regression (PLSR) model based on the raw data. A simplified PLSR model based on optimal wavelengths showed a good performance with a coefficient of determination in prediction (Rp2) of 0.973 and a root mean square error in prediction (RMSEP) of 4.63%. Texture features of grey level co-occurrence matrix (GLCM) of moisture prediction maps demonstrated a more uniform moisture distribution in MVD ginger slices than that in splits in the original geometry.


Assuntos
Dessecação/métodos , Gengibre/fisiologia , Micro-Ondas , Gengibre/química , Análise dos Mínimos Quadrados , Microscopia Eletrônica de Varredura , Vácuo , Água/química
11.
Pestic Biochem Physiol ; 168: 104637, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32711771

RESUMO

Cytochrome P450 monooxygenases (CYPs) serve many functions in insects, from the regulation of development to xenobiotic detoxification. Several conserved CYPs have been shown to play a role in insect growth and development. CYP303A1 is a highly conserved CYP with a single ortholog in most insects, but its underlying molecular characteristics and specific physiological functions remain poorly understood. In Drosophila melanogaster and Locusta migratoria, CYP303A1 is indispensable for eclosion to adult. Here, we report additional functions of the locust gene LmCYP303A1 in nymphal molts, cuticular lipid deposition and insecticide penetration. RT-qPCR revealed that LmCYP303A1 had a high expression level before ecdysis and was highly expressed in integument, wing pads, foregut and hindgut. Suppression of LmCYP303A1 expression by RNA interference (RNAi) caused a lethal phenotype with molting defect from nymph to nymph. In addition, LmCYP303A1 RNAi resulted in locusts being more susceptible to desiccation and to insecticide toxicity. Furthermore, knockdown of LmCYP303A1 efficiently suppressed the transcript level of key genes (ELO7, FAR15 and CYP4G102) responsible for cuticular hydrocarbon (CHC) synthesis, which led to a decrease in some CHC levels. Taken together, our results suggest that one of the functions of LmCYP303A1 is to regulate the biosynthesis of CHC, which plays critical roles in protecting locusts from water loss and insecticide penetration.


Assuntos
Inseticidas , Locusta migratoria , Animais , Dessecação , Drosophila melanogaster , Hidrocarbonetos , Proteínas de Insetos
12.
J Environ Manage ; 268: 110730, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32510451

RESUMO

Solar drying is one of the most efficient and cost-effective, renewable, and sustainable technologies to conserve agricultural products in Asian and sub-Saharan African (SSA) countries. This review paper presents the different types of solar dryers that are widely used in Africa and Asia. In addition, the pre-eminent effects of their use on product quality, as well as their economic, environmental, and social impacts, are highlighted. Since financial, external, and structural factors play a key role in the adoption and scaling of solar dryers, this paper also discusses the impact of these factors on the effectiveness of solar drying technologies in selected Asian and SSA countries.


Assuntos
Agricultura , Luz Solar , África , Ásia , Dessecação
13.
Food Chem ; 329: 127178, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32502746

RESUMO

A betacyanin rich extract was obtained from the flowers of Gomphrena globosa L. by ultrasound-assisted extraction and dried either by lyophilization or spray-drying, was tested as a natural colourant in cookies and compared to a commercial colourant. The extracts were characterized in terms of betacyanin content and antioxidant potential. The effects of the colourants incorporation in the cookies were assessed through proximate composition, soluble sugars, fatty acids, color, texture and microbial load, over a shelf life of 30 days. Considering all the assays and analyzing the results through a 2-way analysis of variance, the cookies incorporated with spray-dried colourant showed the most intense pink coloration while cookies incorporated with lyophilized extract lost less color intensity over time. Thus, betacyanin extracts have potential as pink natural alternatives to synthetic colourants in the food industry.


Assuntos
Amaranthaceae/química , Betacianinas/química , Doces/análise , Corantes/química , Amaranthaceae/metabolismo , Antioxidantes/química , Betacianinas/isolamento & purificação , Dessecação , Flores/química , Flores/metabolismo , Liofilização , Valor Nutritivo , Extratos Vegetais/química , Sonicação
14.
Int J Food Microbiol ; 330: 108696, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32502760

RESUMO

Synthetic preservatives can have harmful effects on the body, so plant essential oils appear to be an attractive natural alternative. However, the use of essential oils is limited due to the low stability and possible negative effects on the sensory properties of food. Oil encapsulation was suggested as a way to overcome these drawbacks. The objective of this study was to encapsulate thyme essential oil and to evaluate its antioxidant and antimicrobial potential in vitro and in situ in of hamburger-like meat products. The casein-maltodextrin capsules produced by spray-drying were assessed for encapsulation efficiency, thermal stability, chemical compounds and morphology. Antioxidant activity was evaluated by DPPH, hydroxyl and nitric oxide methods, while antimicrobial activity was evaluated in vitro against four bacteria and in situ in hamburger-like products. The capsule showed high encapsulation efficiency and thermal stability, and spherical and irregular morphology. The casein-maltodextrin encapsulated essential oil showed antioxidant and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Salmonella Typhimurium tested in vitro and against thermotolerants coliforms and Escherichia coli in situ, showing potential for application as a natural preservative in food.


Assuntos
Antibacterianos/farmacologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Produtos da Carne/microbiologia , Óleos Voláteis/farmacologia , Thymus (Planta)/química , Antibacterianos/química , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Dessecação , Microbiologia de Alimentos , Conservantes de Alimentos/química , Temperatura Alta , Óleos Voláteis/química
15.
Food Chem ; 331: 127201, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32562976

RESUMO

Volatile compounds in Chinese jujubes dried by different methods - hot-air (HAD), heat-pump (HPD), infrared radiation (IRD), vacuum (VD), vacuum freeze (VFD) and instant controlled pressure drop (DIC) drying - were analyzed using GC-MS, MOS e-nose, and flash GC e-nose. Acids comprised more than 90% of the aroma compounds in the dried jujubes, of which acetic, butanoic, propanoic, hexanoic, octanoic and decanoic acids were the most common. Jujubes dried using VFD had the highest content of total aroma compounds (1061.6 µg/kg), while DIC-dried jujubes had the most diverse profile (26 species). HPD-, IRD-, HAD- and VD-dried jujubes had similar aroma profiles based on GC-MS and flash GC e-nose results. Although the results of GC-MS, MOS e-nose, and flash GC e-nose were significant different (p < 0.05), their combination could characterize aroma profiles more comprehensively.


Assuntos
Nariz Eletrônico , Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Orgânicos Voláteis/análise , Ziziphus/química , Dessecação , Análise de Alimentos/métodos , Liofilização , Odorantes/análise
16.
Ecotoxicol Environ Saf ; 201: 110729, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485491

RESUMO

The transformation of carbosulfan (CSN) in apples was investigated during oven-drying, microwave drying, and sun-drying. CSN transformed primarily into carbofuran (COA) during these drying processes. The conversion kinetics of CSN and COA was fitted by curve regression and mainly conformed to quadratic models (R2 = 0.70-0.97). Oven-drying promoted the transformation of CSN into COA. Microwave drying resulted in the highest scavenging capacity against CSN and COA (41%-100%). Moreover, a transformation mechanism was proposed on the basis of density functional theory (DFT) calculation. The COA originated from a series of chemical reactions involving hydroxyl substitution, cleavage, and oxidation; this result was further confirmed on the basis of molecular electrostatic potential (MEP) and molecular orbital theory. Furthermore, the toxicity and stability of CSN and COA were evaluated with the T.E.S.T. program. COA was less toxic than CSN to aquatic organisms but more toxic than CSN to rats. Therefore, COA production should be avoided during drying. Microwave drying was found to be the optimum choice for drying apples.


Assuntos
Carbamatos/metabolismo , Dessecação/métodos , Manipulação de Alimentos/métodos , Malus/química , Animais , Organismos Aquáticos/efeitos dos fármacos , Carbamatos/química , Carbamatos/toxicidade , Carbofurano/química , Carbofurano/metabolismo , Carbofurano/toxicidade , Dessecação/instrumentação , Manipulação de Alimentos/instrumentação , Depuradores de Radicais Livres/análise , Ratos
17.
Int J Food Microbiol ; 329: 108662, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32505890

RESUMO

Listeria monocytogenes is a foodborne pathogen whose biofilm formation and desiccation tolerance may contribute to its survival in the food industry. L. monocytogenes possesses three cold-shock domain family proteins (CspA, CspB and CspD) known to be essential for adaptation against various food-relevant stress conditions including cold growth. The role of Csps in desiccation tolerance and biofilm formation was investigated in csp mutants as well as twenty-one other wild-type (WT) strains. Mutants with a single (ΔcspA) or multiple (ΔcspAB, ΔcspAD and ΔcspABD) deletions of csp genes, in a desiccation sensitive WT background (L. monocytogenes EGD-e) were immotile and exhibited an elevated desiccation tolerance compared to the parent strain. However, deletion of cspA in the more desiccation resistant food and outbreak related L. monocytogenes strains 568 and 08-5578 had no impact on desiccation tolerance although compared to the parent strains the mutants were also immotile. A correlation between lower motility and higher desiccation tolerance was observed among the 20 WT strains (Spearman rank correlation, rs = -0.56, p = 0.01), although exceptions occurred indicating that multiple factors influence the diverse desiccation tolerance among L. monocytogenes strains. Expression of cspA was upregulated in WT EGD-e, 568 and 08-5578 strains after desiccation for seven days, while the 568 and 08-5578 ΔcspA mutants expressed elevated levels of cspD and cspB (>30 fold higher) compared to their WTs. This indicates that upregulation of the other csps compensates for the deleted cspA gene. Although biofilm formation was improved in all EGDe csp mutants relative to the WT strain, the opposite was observed for 568 and 08-5578 WT strains and their cspA deletion mutants. Only motile strains formed biofilm in the peg lid assay but a significant negative correlation (rs = -0.60, p = 0.01) was seen between higher motility and higher biofilm formation of WT strains. In conclusion, the survival of L. monocytogenes strains in the food processing environment may depend on the control of motility, which is a necessity for biofilm formation but disadvantageous for desiccation survival.


Assuntos
Biofilmes/crescimento & desenvolvimento , Proteínas e Peptídeos de Choque Frio/metabolismo , Microbiologia de Alimentos , Listeria monocytogenes/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas e Peptídeos de Choque Frio/genética , Dessecação , Manipulação de Alimentos , Deleção de Genes , Deleção de Sequência
18.
J Food Sci ; 85(6): 1717-1724, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32406950

RESUMO

This study evaluated the influence of different fluidized-bed drying temperatures (20, 60, and 100 °C) on the cooking properties, in vitro starch digestibility, and phenolic bioaccessibility of black rice. The results indicated that the formation of fissures in the grains dried at or above 60 °C reduced the physical integrity of the grains after cooking, increasing the starch digestion and the rehydration ratio, and reduced the cooking time, the hardness and adhesiveness. Due to the higher digestibility of grains dried at higher temperatures, an increase in the bioaccessibility of ferulic acid, which was previously associated with the polysaccharides, was observed. Caffeic acid was the only phenolic compound whose levels decreased when the drying temperature increased. At high temperatures and in the gastric phase, cyanidin chalcones were formed due to the deglycosylation of cyanidin-3-O-glucoside. PRACTICAL APPLICATION: The results of this study provide information to the food industry about the effects of different fluidized-bed drying temperatures on the rice structure after cooking and that, consequently, affect the availability of bioactive compounds after digestion and the glycemic index of black rice.


Assuntos
Dessecação/métodos , Oryza/química , Fenóis/química , Amido/química , Antocianinas/química , Antocianinas/metabolismo , Culinária , Digestão , Manipulação de Alimentos , Glucosídeos/química , Glucosídeos/metabolismo , Índice Glicêmico , Humanos , Modelos Biológicos , Oryza/metabolismo , Fenóis/metabolismo , Amido/metabolismo , Temperatura
19.
AAPS PharmSciTech ; 21(5): 143, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424702

RESUMO

This work aims to improve the functionality of Rosmarinus officinalis L. (rosemary) polyphenols by encapsulation in an optimized proliposome formulation. A 23 Box-Wilson central composite design (CCD) was employed to determine lone and interaction effects of composition variables on moisture content (Xp); water activity (Aw); concentration and retention of rosemary polyphenols-rosmarinic acid (ROA), carnosol (CAR), and carnosic acid (CNA); and recovery of spray-dried proliposomes (SDP). Processing conditions which generate proliposomes with optimum physicochemical properties were determined by multi-response analysis (desirability approach). Antioxidant and antifungal activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH•) sequestering and minimum inhibitory concentration (MIC)/minimum fungicidal concentration (MFC) assays, respectively. SDP exhibited high polyphenol retention, ranging from 62.0 to 100.0% w/w, showing dependence on composition variables and polyphenol lipophilicity. SDP recovery ranged from 20.1 to 45.8%, with Xp and Aw of 1.7 ± 0.14-2.5 ± 0.23% w/w and 0.30 ± 0.004-0.47 ± 0.003, respectively, evidencing product with good chemical and microbiological stability. Optimum liposomal composition was determined, namely, lipid concentration (4.26% w/w), lyophilized extract (LE) concentration (4.48% w/w), and drying aid:(lipid+extract) ratio (7.55% w/w) on wet basis. Relative errors between experimental and predicted values for SDP properties showed concurrence for all responses except CAR retention, being 22% lower. SDP showed high antioxidant activity with IC50 of 9.2 ± 0.2 µg/mL, superior to results obtained for LE (10.8 µg/mL) and butylated hydroxytoluene (BHT), a synthetic antioxidant (12.5 µg/mL). MIC and MFC against Candida albicans (ATCC1023) were 312.5 µg/mL and 1250 µg/mL, respectively, a moderate antimicrobial activity for phytochemical-based products. SDP is shown as a veritable tool to encapsulate hydrophilic and lipophilic rosemary polyphenols generating a product with optimal physicochemical and biological properties.


Assuntos
Lipossomos/química , Polifenóis/química , Rosmarinus/química , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Candida albicans/efeitos dos fármacos , Cápsulas , Dessecação , Composição de Medicamentos , Liofilização , Humanos , Lipídeos/química , Testes de Sensibilidade Microbiana , Folhas de Planta/química , Polifenóis/administração & dosagem , Polifenóis/farmacologia , Água/análise
20.
J Vis Exp ; (159)2020 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-32420989

RESUMO

Artificial lipid-containing tear formulations are developed to reduce tear evaporation by the restoration of a deficient tear lipid layer. Artificial tear formulations that prevent cell desiccation will result in ocular surface protection and the maintenance of cell metabolic activity. During dehydration, cells undergo the process of loss of metabolic activity and subsequently cell death. This work describes a method for assessing the efficacy of artificial tear formulations. The metabolic dye (i.e., alamarBlue) changes from a low fluorescent molecule resazurin to a fluorescent molecule resorufin in viable cells. The biological performance of an artificial tear formulation is measured as the ability of the formulation to (a) maintain cell viability and (b) provide cell protection from desiccation. Growth media and saline are used as controls for the cell viability/desiccation tests. Cells are incubated with test solutions for 30 min and then desiccated for 0 or 5 min at 37 °C and 45% relative humidity. Cell metabolic activity after initial exposure and after cell desiccation is then determined. The results show the comparative effects of eye drop formulations on cell metabolic activity and desiccation protection. This method can be used to test dry eye formulations that are designed to treat individuals with evaporative dry eye.


Assuntos
Córnea/citologia , Dessecação , Células Epiteliais/metabolismo , Lubrificantes Oftálmicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Análise de Dados , Síndromes do Olho Seco/metabolismo , Células Epiteliais/efeitos dos fármacos , Humanos , Lipídeos/análise
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