Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 586
Filter
1.
Journal of Biomedical Engineering ; (6): 973-981, 2023.
Article in Chinese | WPRIM | ID: wpr-1008923

ABSTRACT

Ultra-rapid cooling and rewarming rate is a critical technical approach to achieve ice-free cells during the freezing and melting process. A set of ultra-rapid solid surface freeze-thaw visualization system was developed based on a sapphire flim, and experiments on droplet freeze-thaw were carried out under different cryoprotectant components, volumes and laser energies. The results showed that the cooling rate of 1 μL mixed cryoprotectant [1.5 mol/L propylene glycol (PG) + 1.5 mol/L ethylene glycol (EG) + 0.5 mol/L trehalose (TRE)] could be 9.2×10 3 °C/min. The volume range of 1-8 μL droplets could be vitrified. After comparing the proportions of multiple cryoprotectants, the combination of equal proportion mixed permeability protectant and trehalose had the best vitrification freezing effect and more uniform crystallization characteristics. During the rewarming operation, the heating curve of glassy droplets containing gold nanoparticles was measured for the first time under the action of 400-1 200 W laser power, and the rewarming rate was up to the order of 10 6 °C/min. According to the droplet images of different power rewarming processes, the laser power range for ice-free rewarming with micron-level resolution was clarified to be 1 400-1 600 W. The work of this paper simultaneously realizes the ultra-high-speed temperature ramp-up, transient visual observation and temperature measurement of droplets, providing technical means for judging the ice free droplets during the freeze-thaw process. It is conducive to promoting the development of ultra-rapid freeze-thaw technology for biological cells and tissues.


Subject(s)
Freezing , Vitrification , Cryopreservation/methods , Trehalose , Gold , Rewarming , Metal Nanoparticles , Cryoprotective Agents , Lasers
2.
Braz. j. oral sci ; 21: e225757, jan.-dez. 2022. ilus
Article in English | LILACS, BBO | ID: biblio-1366215

ABSTRACT

Aim: This study aimed to evaluate the effect of frozen storage on the physical properties of a silicone-based test food material, highly used to evaluate the masticatory performance in research settings. Methods: A total of 1,666 silicone cubes of Optosil Comfort® with 5.6-mm edges were shaped and stored at -18°C. The cubes were subsequently tested for flexural strength (maximum force, displacement, stress, and strain) before breaking (n = 136), changes in weight and size (n = 170), and masticatory performance (n = 1360) at eight timepoints: immediately after cube preparation (baseline, no freezing), and 1, 2, 3 and 4 weeks, and 2, 4 and 6 months after frozen storage. The cubes were thawed 8 h before each assessment. Results: The maximum force, stress, maximum displacement, and deformation values for the cubes were not affected by freezing (P > 0.05). At all of the time points, the cubes exhibited similar weight (P = 0.366) and size (identical values). The masticatory performance for the cubes also showed no differences from baseline through 6 months (P = 0.061). Conclusion: Freezing Optosil Comfort® silicone cubes did not alter the physical and mechanical properties of the material, being suitable to optimize the assessment of masticatory parameters for research purposes


Subject(s)
Humans , Male , Adult , Silicone Elastomers , Materials Testing/methods , Freezing , Flexural Strength , Mastication , Time Factors
3.
Chinese Journal of Biotechnology ; (12): 1490-1505, 2022.
Article in Chinese | WPRIM | ID: wpr-927795

ABSTRACT

Intrinsically disordered proteins (IDPs) are proteins or protein regions that fail to get folded into definite three-dimensional structures but participate in various biological processes and perform specific functions. Defying the traditional protein "sequence-structure-function" paradigm, they enrich the protein "structure-function" diversity. Ubiquitous in organisms, they show extreme hydrophilicity, charged amino acids, and highly repetitive amino acid sequences, with simple arrangement. As a result, they feature highly variable binding affinities and high coordination, which facilitate their functions. IDPs play an important role in cell stress response, which can improve the tolerance to a variety of stresses, such as freezing, high salt, heat shock, and desiccation. In this study, we briefed the characteristics, classifications, and identification of IDPs, summarized the molecular mechanism in improving cell stress resistance, and described the potential applications.


Subject(s)
Freezing , Intrinsically Disordered Proteins/metabolism , Protein Conformation
4.
Rio de Janeiro; rBLH; 2 rev; set. 2021. [8] p. ilus.(Normas técnicas BLH-IFF/NT, 1, 38). (BLH-IFF/NT 38.21).
Monography in Spanish, Portuguese | LILACS, BVSAM | ID: biblio-1436526

ABSTRACT

Esta Norma Técnica tem por objetivo estabelecer as orientações necessárias para o controle de temperatura dos freezers em Bancos de Leite humano e Postos de Coleta de Leite Humano, visando a garantia da qualidade em Bancos de Leite Humano e sua certificação.


Esta Norma Técnica tiene como objetivo establecer las directrices necesarias para el control de la temperatura de los congeladores en los Bancos de Leche Humana y en los Centros de Recolección de Leche Humana con el fin de asegurar la calidad en los Bancos de Leche Humana y su certificación.


Subject(s)
Temperature , Thermometers/standards , Milk Banks/standards , Freezing , Milk, Human
5.
Rio de Janeiro; rBLH; 2 rev; set. 2021. [7] p. ilus.(Normas técnicas BLH-IFF/NT, 1, 36). (BLH-IFF/NT 36.21).
Monography in Spanish, Portuguese | LILACS, BVSAM | ID: biblio-1436521

ABSTRACT

Esta Norma Técnica tem por objetivo estabelecer as condições necessárias para o congelamento do leite humano ordenhado pasteurizado, visando a garantia da qualidade em Bancos de Leite Humano e sua certificação.


Esta Norma Técnica tiene por objetivo establecer las condiciones necesarias para la congelación de la leche humana extraída pasteurizada, con el fin de garantizar la calidad de los Bancos de Leche Humana y su certificación.


Subject(s)
Milk Banks/standards , Breast Milk Expression , Pasteurization/standards , Freezing , Milk, Human
6.
Rio de Janeiro; rBLH; 3 rev; set. 2021. [7] p. ilus.(Normas técnicas BLH-IFF/NT, 1, 24). (BLH-IFF/NT 24.21).
Monography in Portuguese | LILACS, BVSAM | ID: biblio-1392250

ABSTRACT

Esta Norma Técnica tem por objetivo estabelecer os critérios necessários para o degelo do leite humano ordenhado cru, visando a garantia da qualidade em Bancos de Leite Humano e sua certificação.


Subject(s)
Milk Banks/standards , Breast Milk Expression , Freezing , Milk, Human , Brazil
7.
Prensa méd. argent ; 107(4): 219-230, 20210000. tab, graf
Article in Spanish | LILACS, BINACIS | ID: biblio-1359445

ABSTRACT

Antecedentes: el tratamiento del CBC con menor tasa de recurrencia es el quirúrgico. Debido a la ausencia de lesión residual en cirugía de ampliación de márgenes y la utilidad de la congelación intraoperatoria se propuso analizar la utilidad de las retomas intraoperatorias. Objetivo: analizar el impacto de las retomas intraoperatorias en los resultados oncológicos y cosméticos de los pacientes operados de CBC. Secundariamente analizar la extensión subclínica, el valor de la congelación intraoperatoria y las tácticas reconstructivas empleadas. Lugar de aplicación: Hospital de atención terciaria de tumores. Material y métodos: trabajo observacional retrospectivo. Se incluyeron 84 resecciones durante 3 años y se realizó un análisis comparativo en términos de recurrencia, defecto quirúrgico y utilización de colgajos entre tumores sin retoma vs con retoma. Resultados: no hubo diferencias significativas en cuanto a recurrencia y uso de colgajos. El promedio de defecto para los tumores retomados fue 27,8mm y para los no retomados 22,8mm, siendo la diferencia estadísticamente significativa (p=0.002). En el subgrupo de lesiones retomadas se encontró tumor residual en solo 2,9% de las mismas. Conclusiones: las retomas adicionaron en promedio 5mm de defecto por lesión sin aportar beneficios en términos de recurrencia. Un uso más conservador de las mismas podría traducirse en mejores resultados funcionales y cosméticos


Background: the lowest recurrence rates for basal cell carcinoma are achieved by surgical treatment. Low rates of residual tumour in specimens after incomplete excisions plus intraoperative frozen section accuracy are the rationale for analyzing the value of intraoperative re-excisions during basal cell carcinoma standard surgery. Objective: to analyse intraoperative oncologic and cosmetic results of re-captures in patients surgically treated of basal-cells carcinoma. Secondary to analyse subclinic extention, the value of frozen intraoperative sections and reconstructive conducts employed. Setting: tertiary care Hospital of tumours. Methods: observational retrospective study. During a 3-year period 84 tumours were resected. A comparative analysis in terms of recurrence, surgical defect and use of flaps was done between intraoperatively re-excised and not re-excised tumours. Results: there were no statistical difference regarding recurrence rate and use of flaps. Mean surgical defect for re-excised and not re-excised specimens was 27,8mm and 22,8mm respectively, being the difference statistically significant (p=0.002). Residual tumour was found in only 2,9% of re-excised specimens. Conclusions: re-excisions added on average 5mm to surgical defect per specimen and did not contribute to any benefit in terms of recurrence rates. A more conservative use of intraoperative re-excisions could improve functional and cosmetic outcomes


Subject(s)
Humans , Recurrence , Carcinoma, Basal Cell/surgery , Retrospective Studies , Cohort Studies , Plastic Surgery Procedures/methods , Freezing , Head and Neck Neoplasms/surgery
8.
Acta Academiae Medicinae Sinicae ; (6): 193-198, 2021.
Article in Chinese | WPRIM | ID: wpr-878719

ABSTRACT

Objective To investigate the effects of self-made carriers on the cryopreservation of ovarian tissue of sheep. Methods Thirty-two ovaries were randomly assigned to fresh group,programmed freezing group,self-made carrier I vitrification group,and self-made carrier Ⅱ vitrification group.The morphology,proliferation,apoptosis,and estrogen level of the ovarian tissue in each group were observed. Results After cryopreservation,the morphology normal rate of the primordial follicles in programmed freezing group,self-made carrier I vitrification group,and self-made carrier Ⅱ vitrification group were 74.2%,72.8%,and 72.3%,respectively,lower than that(83.7%)in the fresh group(χ


Subject(s)
Animals , Female , Cryopreservation , Freezing , Ovarian Follicle , Ovary , Sheep , Vitrification
9.
Rev. Inst. Adolfo Lutz ; 80: e37320, dez. 2021. tab, ilus
Article in English | LILACS, CONASS, ColecionaSUS, SES-SP, VETINDEX, SESSP-ACVSES, SESSP-IALPROD, SES-SP, SESSP-IALACERVO | ID: biblio-1368348

ABSTRACT

Freezing is an important strategy to keep fish quality and make the species available the whole year. Its effects on the nutritional value of 17 fish species were studied in samples of entire fish, fillets or pieces. One portion of homogenized flesh was analyzed just after purchase (fresh sample). The other portion was packed in polyethylene bag, sealed, quick frozen (-80°C), stored properly at -18°C and analyzed after 12 months (frozen sample). Moisture, ash and protein content were tested using Brazilian Supply, Livestock and Agriculture Ministry methodologies. Lipid content was analyzed through Bligh and Dyer method. Carbohydrate content and caloric value were calculated, using NIFEXT fraction and Atwater coefficient, respectively. When fresh and frozen samples were compared, moisture and ash content showed significant difference (p<0.05) for 17.65% and 11.77% species, respectively. Lipid and protein contents were the most affected parameters, as they were altered in 29.40% of the studied species (p<0.05), and therefore, highlighted the importance of the conservation technology used on nutritional quality of fishery products. Mullet (M. brasiliensis) and Atlantic salmon (S. salar) had their nutritional composition more affected by freezing process with five and four altered parameters, respectively, from the six studied. (AU)


O congelamento é estratégia importante para manter a qualidade do peixe e tornar inúmeras espécies disponíveis o ano todo. Seus efeitos sobre o valor nutricional de 17 espécies foram estudados em amostras de peixes inteiros, filés ou postas. A porção cárnea homogeneizada foi analisada logo após a aquisição (amostra fresca). Outra parte foi embalada em polietileno, selada, rapidamente congelada (-80°C) e analisada após 12 meses de armazenamento a -18°C (amostra congelada). O teor de umidade, cinzas e proteína foram testados com metodologias do Ministério de Agricultura, Pecuária e Abastecimento e teor de lipídios com método de Bligh e Dyer. Conteúdo de carboidrato e valor calórico foram calculados, utilizando fração NIFEXT e coeficiente de Atwater, respectivamente. Quando se comparou amostras frescas e congeladas, teor de umidade e cinzas evidenciaram diferenças significativas (p<0,05) para 17,65% e 11,77% das espécies, respectivamente. O teor de lipídios e de proteínas foram alterados em 29,40% das espécies estudadas (p<0,05), sendo os parâmetros mais afetados pelo congelamento e destacaram a importância da tecnologia de conservação utilizada sobre a qualidade nutricional do pescado. Tainha (M. brasiliensis) e salmão (S. salar) foram as mais afetadas pelo congelamento, com 5 e 4 parâmetros alterados, respectivamente, após estocagem sob congelamento. (AU)


Subject(s)
Animals , Food Quality , Fishes , Food Preservation/methods , Freezing , Food Supply , Nutritive Value
10.
Journal of Forensic Medicine ; (6): 11-14, 2021.
Article in English | WPRIM | ID: wpr-985186

ABSTRACT

Objective To investigate the stability of IgE in postmortem plasma and hemolyzed samples under different storage conditions and freezing-thawing. Methods Thirty nine cardiac blood samples were collected from non-frozen corpses with the postmortem interval of less than 48 hours, including 20 plasma samples and 19 hemolyzed samples taken from whole blood. The samples were stored at -20 ℃, 4 ℃ and 25 ℃ for 28 d and at -80 ℃ for 1 year to evaluate the stability of IgE under different storage conditions. Repeated freezing-thawing treatment was conducted for 5 times to explore the stability of IgE in postmortem plasma and hemolyzed samples. IgE concentration in plasma and hemolyzed samples was detected by electroluminescence before and after treatment. Results The degradation rates of IgE in plasma samples under the three storage conditions, -20 ℃, 4 ℃ and 25 ℃ were close. After 28 d, the mean value was about 15%, the degradation speed of IgE in hemolyzed samples was faster than that of plasma under the same condition (P<0.05) and the degradation rate was faster than other two conditions under 25 ℃ (P<0.05). The differences in the concentration of plasma samples after freezing at -80 ℃ for 1 year and that before freezing had no statistical significance ( P>0.05), while the concentration of hemolyzed samples was degraded after freezing at -80 ℃ for 1 year (P<0.05). The differences between the detection results of plasma and hemolyzed samples after repeated freezing-thawing for 5 times and that before freezing-thawing showed no statistical significance ( P>0.05). Conclusion IgE has good freezing-thawing stability in postmortem plasma and hemolyzed samples. Stability of IgE is better in postmortem plasma samples than hemolyzed samples, thus it is recommended to separate plasma from postmortem blood samples as soon as possible in forensic practice.


Subject(s)
Autopsy , Forensic Medicine , Freezing , Immunoglobulin E , Plasma
11.
Rev. bras. ortop ; 55(6): 778-782, Nov.-Dec. 2020. graf
Article in English | LILACS | ID: biblio-1156183

ABSTRACT

Abstract Objectives The present paper aims to evaluate and compare the histological features of fresh and frozen menisci stored in a tissue bank for 1 month and for 5 years. Methods The meniscal grafts were subjected to a histological study. A total of 10 menisci were evaluated; 2 were frozen for 5 years, 4 were frozen for 1 month, and 4 were fresh, recently harvested specimens. Histological properties were evaluated in sections stained with hematoxylin and eosin and Masson trichrome methods. Results The menisci frozen for 1 month showed partially preserved collagen fiber structure and no significant hydropic tissue degeneration. The menisci frozen for 5 years presented an evident dissociation of collagen fibers and multiple foci of hydropic degeneration. Discussion Degeneration was much more significant in menisci stored for 5 years, indicating that a long freezing period results in substantial progression of tissue deterioration. This may suggest that the 5-year period, considered the maximum time for graft storage before transplant, is too long. Conclusion Grafts stored for 1 month showed a slight degenerative change in collagen fibers, whereas menisci frozen for 5 years presented significant tissue degeneration.


Resumo Objetivos Avaliar e comparar as características histológicas de meniscos frescos e meniscos congelados armazenados em banco de tecidos por 1 mês e por 5 anos. Métodos Foi feito um estudo histológico com enxertos meniscais. Avaliamos 10 meniscos, sendo 2 que ficaram armazenados sob congelamento por 5 anos, 4 armazenados congelados por 1 mês, e 4 frescos, recém captados. Foram feitos cortes histológicos corados com hematoxilina e eosina e Tricrômico de Masson, para avaliação das propriedades histológicas. Resultados Os meniscos congelados por 1 mês apresentaram preservação parcial da estrutura das fibras colágenas, sem degeneração hidrópica significativa do tecido. Nos meniscos congelados por 5 anos, observamos dissociação evidente das fibras colágenas, com presença de múltiplos focos de degeneração hidrópica. Discussão Encontramos degeneração bem mais significativa nos meniscos armazenados por 5 anos, o que indica que o longo período de congelamento leva à progressão significativa da degeneração do tecido. Isto pode sugerir que o período de 5 anos, considerado período máximo que o enxerto pode permanecer armazenado antes de ser transplantado, é um período muito longo. Conclusão Nos enxertos armazenados por 1 mês, existiu apenas discreta alteração degenerativa das fibras colágenas, enquanto que nos meniscos com 5 anos de congelamento foi observada degeneração significativa do tecido. Tibiais


Subject(s)
Tissue Banks , Wounds, Penetrating , Collagen , Eosine Yellowish-(YS) , Transplants , Meniscus , Freezing , Goals , Hematoxylin
12.
Arq. bras. med. vet. zootec. (Online) ; 72(5): 1713-1718, Sept.-Oct. 2020. graf, ilus
Article in English | LILACS, VETINDEX | ID: biblio-1131538

ABSTRACT

A total of 480 milk samples were analyzed in four repetitions with four preservative treatments (no preservative, Bronopol, Bronolat and Brononata), three storage times at temperatures up to 4 °C (24, 48 and 72hours after reception), five different water additions (0.0, 2.5, 5.0, 7.5 and 10.0%) and two analytical instruments (electronic cryoscope and FTIR). The objective of this study was to evaluate the effect of these parameters in the determination of the freezing point by the reference method and by Fourier transform infrared spectroscopy, thus determining the best analytical conditions and establishing a mathematical equation for electronic determination by FTIR spectroscopy. Bronolat was the best preservative and Brononata was the worst and is not recommended to analyze freezing point by FTIR. The storage time of the samples did not interfere in the analytical determinations by the precision method and by FTIR.(AU)


Foram analisadas 480 amostras de leite em quatro repetições em relação a quatro tratamentos por conservantes (sem conservante, bronopol, bronolat e brononata), três tempos de armazenamento, em temperatura até 4ºC desde a recepção da amostra (24, 48 e 72 horas), cinco porcentagens de adição de água (0,0; 2,5; 5,0; 7,5 e 10,0%) e dois instrumentos analíticos (crioscópio eletrônico e FTIR). O objetivo foi avaliar o efeito desses parâmetros na determinação do índice crioscópico pelo método de precisão em crioscópio eletrônico e por espectroscopia com transformada de Fourier no infravermelho, determinando-se, assim, as melhores condições analíticas. Entre os conservantes utilizados, bronolat foi o melhor e brononata foi o menos eficiente, não sendo, portanto, recomendado para análise de crioscopia por FTIR. O tempo de armazenamento das amostras não interferiu nas determinações analíticas pelo método de precisão e por FTIR.(AU)


Subject(s)
Milk/chemistry , Raw Foods/analysis , Food Preservatives , Freezing , Frozen Foods/analysis , Spectroscopy, Fourier Transform Infrared
13.
Chinese Medical Journal ; (24): 800-805, 2020.
Article in English | WPRIM | ID: wpr-877958

ABSTRACT

BACKGROUND@#It is currently unknown whether patients with a fever after controlled ovulation during egg retrieval could increase the risk of pelvic infection or not, and fever itself may affect endometrial receptivity or embryo quality with poor pregnancy outcomes. The aim of this study was to analyze the outcomes of patients with fever during oocyte retrieval after the first frozen-thawed embryo transfer (FET) cycle.@*METHODS@#This was a 1:3 retrospective paired study matched for age. In this study, 58 infertility patients (Group 1) had a fever during the control ovulation, and the time of the oocyte retrieval was within 72 hours, they underwent ovum pick up and whole embryo freezing ("freeze-all" strategy). The control subjects (Group 2) are 174 patients matched for age who underwent whole embryo freezing for other reasons. The baseline characteristics, clinical data of ovarian stimulation, and outcomes, such as the clinical pregnancy rate, ongoing clinical pregnancy rate were compared between the two groups in the subsequent FET cycle.@*RESULTS@#All patients had no pelvic inflammatory disease after oocyte retrieval. Anti-Mullerian hormone (AMH) levels (4.2 vs. 2.2, P <0.001) were higher in group 2, and the number of oocytes retrieved, and fertilization rate were lower in group 1 (P < 0.001), but the endometrial thickness, the number of embryo transfers, and the type of luteal support supplementation were similar between the two groups. Regarding pregnancy outcomes in the subsequent FET cycle, the implantation rate, clinical pregnancy rate, early spontaneous rate, ectopic pregnancy rate, and ongoing pregnancy rate were all not significantly different. Further regression analyses showed that the clinical pregnancy rate and ongoing pregnancy rate were also not significantly different.@*CONCLUSIONS@#Transvaginal ultrasound-guided follicular puncture for oocyte retrieval is a safe and minimally invasive method for patients with fever. Moreover, the fever had almost no effect on embryo quality.


Subject(s)
Female , Humans , Pregnancy , Cryopreservation , Fertilization in Vitro , Freezing , Infertility , Oocyte Retrieval , Oocytes , Ovulation Induction , Pregnancy Outcome , Pregnancy Rate , Retrospective Studies
14.
Journal of the Korean Ophthalmological Society ; : 200-204, 2020.
Article in Korean | WPRIM | ID: wpr-811322

ABSTRACT

PURPOSE: To report a case of corneal collagen cross-linking for corneal ulcer caused by the Moraxella group.CASE SUMMARY: A 77-year-old male had decreased visual acuity for several days in his right eye. The patient showed severe stromal ring infiltrates with a corneal epithelial defect measuring (5.0 × 7.0 mm), a corneal endothelial plaque, and a hypopyon measuring less than 1.0 mm in height in the anterior chamber of the right eye. There was no abnormal finding in the right eye using B-scan ultrasonography. Before starting treatment, a corneal culture was conducted. The culture tests showed the presence of the Moraxella group. Because the patient was diagnosed with a corneal ulcer caused by the Moraxella group, corneal collagen cross-linking (CXL) was performed. The antimicrobial susceptibility test confirmed that this Moraxella group was sensitive to ceftazidime, so the patient was treated with 5% ceftazidime eye drops and 0.5% moxifloxacin eye drops every 2 hours for 9 months after corneal collagen CXL. The uncorrected visual acuity was 0.1 in the right eye, and there was almost no corneal stromal melting on anterior segment optical coherence tomography.CONCLUSIONS: This is the first known case of a corneal ulcer, in the Republic of Korea, caused by the Moraxella group and treated with corneal collagen CXL. Corneal collagen CXL should be considered as a surgical treatment for patients who have an impending corneal perforation due to a corneal ulcer because it is a simple procedure and causes fewer serious complications than other treatments.


Subject(s)
Aged , Humans , Male , Anterior Chamber , Ceftazidime , Collagen , Cornea , Corneal Perforation , Corneal Ulcer , Freezing , Moraxella , Ophthalmic Solutions , Republic of Korea , Tomography, Optical Coherence , Ultrasonography , Visual Acuity
15.
São Paulo med. j ; 137(5): 407-413, Sept.-Oct. 2019. tab
Article in English | LILACS | ID: biblio-1059102

ABSTRACT

ABSTRACT BACKGROUND: Vegetables have some beneficial effects on human health due to their antioxidant compounds, like polyphenols. Cooking leads to many physical and chemical changes to plant structure that can alter the phytochemical compounds of vegetables. OBJECTIVES: To investigate the effects of heat treatment and freezing on the antioxidant properties of garlic, onion, broccoli and cauliflower. DESIGN AND SETTING: Experimental in vitro study in a university laboratory. METHODS: Fresh broccoli (Brassica oleracea var. italica), cauliflower (Brassica oleracea var. botrytis), garlic (Allium sativum) and onion (Allium cepa) were obtained from a local store. These vegetables were divided into three treatment groups: raw, heated and frozen. The heat treatment consisted of heating them in a drying oven at 150 °C for 20 minutes. The freezing treatment consisted of keeping them frozen at -20 °C until analysis. The total phenolic content, antioxidant activity and malondialdehyde levels of the vegetables were measured using the Folin-Ciocalteu phenol reagent, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and thiobarbituric acid reactive substances, respectively. RESULTS: Heat treatment had deleterious effects on the antioxidant properties of onion and garlic; and it decreased the antioxidant activity of broccoli. Freezing improved the antioxidant activity of broccoli and garlic, but had detrimental effects for cauliflower and onion. CONCLUSIONS: Heat treatment and freezing exhibit different effects on the antioxidant properties of broccoli, cauliflower, garlic and onion. Convenient cooking and storage patterns should be identified for each vegetable, to obtain the best nutritional benefit from the antioxidant compounds of vegetables.


Subject(s)
Vegetables/chemistry , Allium/chemistry , Food Handling/methods , Food Preservation/methods , Malondialdehyde/analysis , Antioxidants/analysis , In Vitro Techniques , Brassica/chemistry , Plant Extracts/chemistry , Onions/chemistry , Freezing , Garlic/chemistry , Heating , Nutritive Value
16.
Electron. j. biotechnol ; 41: 88-94, sept. 2019. tab, ilus, graf
Article in English | LILACS | ID: biblio-1087247

ABSTRACT

Background: In industrial yeasts, selection and breeding for resistance to multiple stresses is a focus of current research. The objective of this study was to investigate the tolerance to multiple stresses of Saccharomyces cerevisiae obtained through an adaptive laboratory evolution strategy involving a repeated liquid nitrogen freeze­thaw process coupled with multi-stress shock selection. We also assessed the related resistance mechanisms and very high-gravity (VHG) bioethanol production of this strain. Results: Elite S. cerevisiae strain YF10-5, exhibiting improved VHG fermentation capacity and stress resistance to osmotic pressure and ethanol, was isolated following ten consecutive rounds of liquid nitrogen freeze­thaw treatment followed by plate screening under osmotic and ethanol stress. The ethanol yield of YF10-5 was 16% higher than that of the parent strain during 35% (w/v) glucose fermentation. Furthermore, there was upregulation of three genes (HSP26, HSP30, and HSP104) encoding heat-shock proteins involved in the stress response, one gene (TPS1) involved in the synthesis of trehalose, and three genes (ADH1, HXK1, and PFK1) involved in ethanol metabolism and intracellular trehalose accumulation in YF10-5 yeast cells, indicating increased stress tolerance and fermentative capacity. YF10-5 also showed excellent fermentation performance during the simultaneous saccharification and fermentation of VHG sweet potato mash, producing 13.40% (w/ v) ethanol, which corresponded to 93.95% of the theoretical ethanol yield. Conclusions: A multiple-stress-tolerant yeast clone was obtained using adaptive evolution by a freeze­thaw method coupled with stress shock selection. The selected robust yeast strain exhibits potential for bioethanol production through VHG fermentation.


Subject(s)
Saccharomyces cerevisiae/physiology , Ethanol/chemical synthesis , Saccharomyces cerevisiae/genetics , Selection, Genetic , Stress, Physiological , Trehalose , Yeasts , Breeding , Adaptation, Physiological , Hypergravity , Fermentation , Real-Time Polymerase Chain Reaction , Freezing , Heat-Shock Proteins
17.
Int. j. morphol ; 37(2): 533-540, June 2019. tab
Article in Spanish | LILACS | ID: biblio-1002255

ABSTRACT

Desde la antigüedad se han desarrollado técnicas para el estudio del cerebro con fines didácticos o neuroquirúrgicos. Hacia 1934 Josef Klingler desarrolla una técnica de preparación de hemisferios cerebrales que basada en la fijación con formalina y el congelamiento para aislar los tractos cerebrales. El objetivo de la presente artículo ha sido analizar los métodos de preparación utilizados para la disección de tractos en cerebros humanos y de animales. Se realizó una revisión de la literatura en las bases de datos Web of Science, Scopus, Pubmed, Medline y Scielo, utilizando como descriptores: Disección, Cerebro, Tracto, con el operador booleano "AND" entre ellos, en los idiomas inglés y español, hasta junio de 2018. Fueron seleccionados 26 documentos, para el análisis se determinaron las variables: espécimen, número de hemisferios cerebrales, concentración de formalina, tiempo de fijación, temperatura, tiempo de congelamiento y tractos identificados. En la literatura seleccionada, un total de 410 hemisferios cerebrales fueron analizados, 372 de humanos y 38 de animales; 330 fueron conservados en formalina al 10 %, 20 en formalina al 5 % y el resto en otras concentraciones. El tiempo de fijación fue variable entre 10 y 180 días, así como la temperatura y tiempo de congelación (-10 ºC y -20 ºC, entre 8 y 30 días). En todos los casos se reportó que, en su totalidad o parcialmente, los fascículos cerebrales de asociación fueron aislados. En la preparación de hemisferios cerebrales para disección de tractos, Ludwig & Klingler (1956) recomiendan que en la fijación de los especímenes se utilice formalina al 5 %, sin embargo, el 80 % de los hemisferios utilizados fueron fijados en formalina al 10%, y en esta concentración, el tiempo de fijación, temperatura y tiempo de congelación fue variable, lográndose, en todos los casos analizados, la disección parcial o total de los tractos.


Since ancient times, techniques for the study of the brain have been developed for didactic or neurosurgical purposes. By 1934, Josef Klingler developed a cerebral hemisphere preparation technique based on formalin fixation and freezing to isolate the cerebral tracts. The aim of this article was to analyze the preparation methods used for tracts dissection in human and animal brains. A review of the literature using Web of Science, Scopus, Pubmed, Medline and Scielo databases, with the following descriptors: Dissection, Brain, Tract, with the boolean operator "AND" among them, also in spanish, until June 2018. Twenty-six documents were selected, and we analized the following variables: specimen, number of cerebral hemispheres, formalin concentration, fixing time, temperature, freezing time and tracts. In the selected literature, a total of 410 cerebral hemispheres were analyzed, 372 from humans and 38 from animals; 330 were preserved in 10 % formalin, 20 in 5 % formalin and the rest in other concentrations. The fixation time was variable between 10 and 180 days, as well as the temperature and freezing time (-10 ºC and -20 ºC, between 8 and 30 days). In all cases it was reported that, in whole or in part, the cerebral fascicles of association were isolated. In the preparation of cerebral hemispheres for dissection of tracts, Klingler recommend that 5 % formalin for the fixation of specimens; however, 80 % of the hemispheres used were fixed in 10 % formalin, and in this concentration, the time of fixation, temperature and time of freezing was variable, achieving, in all the cases analyzed, the partial or total dissection of the tracts.


Subject(s)
Humans , Animals , Histocytological Preparation Techniques/methods , Dissection/methods , Cerebrum/anatomy & histology , Time Factors , Tissue Preservation/methods , Fixatives , Formaldehyde/chemistry , Freezing
18.
Hig. aliment ; 33(288/289): 671-675, abr.-maio 2019. tab, ilus
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1482019

ABSTRACT

O objetivo deste trabalho foi testar diferentes aditivos naturais na formulação do sorvete de maracujá e avaliar a influência do congelamento lento (-18ºC) e rápido (-80ºC). Foram preparadas 3 formulações do sorvete, variando apenas o aditivo (F1: Superliga Neutra, F2: Gelatina e F3: Ágar). Estas amostras foram avaliadas com relação a composição nutricional e propriedades físicas e químicas. O congelamento rápido conferiu as 3 formulações uma uniformidade na velocidade de derretimento (p>0,05). A formulação F2 foi a que apresentou melhor resultado quando avaliado a resistência ao derretimento, overrun e composição centesimal. Embora todas as formulações tenham apresentado resultados positivos, a F2 associado ao ultracongelamento apresentou o melhor perfil de sorvete.


Subject(s)
Food Composition , Freezing , Excipients , Chemical Phenomena , Ice Cream , Food, Formulated , Thickeners , Passiflora
19.
Hig. aliment ; 33(288/289): 1012-1016, abr.-maio 2019. tab, ilus
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1482089

ABSTRACT

O objetivo deste trabalho foi comparar a capacidade dos colorímetros Nix Color Sensor Pro (NIX) e CM-5 (MINOLTA) para detectar a variação de cor em amostras de carne bovina submetidas a diferentes taxas de congelamento (lento x rápido) e diferentes tempos de maturação (0 e 14 dias). Todos os índices de cor mensurados foram maiores (P<0,05) no colorímetro MINOLTA do que no colorímetro NIX, que registra a cor das amostras cárneas como sendo mais escuras, com menor intensidade e com tonalidade menos vermelha. A variação nos índices de cor medida pelos aparelhos não foi compatível, indicando efeitos diferentes pelos tratamentos avaliados. Conclui-se que o NIX não pode ser considerado comparável ao MINOLTA ao medir a cor da carne bovina.


Subject(s)
Animals , Cattle , Red Meat/analysis , Colorimetry/instrumentation , Colorimetry/methods , Freezing/adverse effects , Color , Food Quality
20.
Hig. aliment ; 33(288/289): 1050-1054, abr.-maio 2019. tab
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1482097

ABSTRACT

Foram utilizadas amostras de peito de frangos de corte acometidos pela miopatia “White Striping” (estrias brancas em seus diferentes graus de severidade) para análise de coloração (L*, a* e b*), lipídeos totais e concentração de colágeno. Amostras de filés acometidos pela miopatia foram avaliadas logo após o abate e outras foram armazenadas congeladas (-20°C) durante três meses. Com a severidade da miopatia ocorre o aumento da concentração de gordura e, consequentemente, alteração da coloração da superfície do peito, além da redução do percentual de colágeno. O congelamento da carne de peito por três meses provoca alterações de cor da superfície dos filés. A produção de exsudato, oriunda do descongelamento, resulta no aumento da concentração de componentes como colágeno solúvel e lipídeos.


Subject(s)
Animals , Meat/analysis , Collagen/analysis , Freezing/adverse effects , Color , Muscular Diseases/veterinary , Lipids/analysis , Food Storage , Chickens
SELECTION OF CITATIONS
SEARCH DETAIL