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Food gels are viscoelastic substances used in various gelled products manufactured around the world. Polysaccharides are the most common food gelling agents. The aim of this work was the production and characterization of a gel produced in a blue corn flour fermentation process, where different proportions were used of blue corn (Zea mays L.) flour and Czapek Dox culture medium (90 mL of culture medium with 10 g of blue corn flour, 80 mL of culture medium with 20 g of blue corn flour, and 70 mL of culture medium with 30 g of blue corn flour) and were fermented for three different durations (20, 25, and 30 days) with the Colletotrichum gloeosporioides fungus. A characterization of the gel was carried out studying the rheological properties, proximal analysis, toxicological analysis, microscopic structure, and molecular characterization, in addition to a solubility test with three different organic solvents (ethanol, hexane, and ethyl acetate, in addition to water). The results obtained showed in the rheological analysis that the gel could have resistance to high temperatures and a reversible behavior. The gel is soluble in polar solvents (ethanol and water). The main chemical components of the gel are carbohydrates, especially polysaccharides, and it was confirmed by FT-IR spectroscopy that the gel may be composed of pectin.

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This study aimed to evaluate the effectiveness of pH control, water activity (Aw), and the addition of lactic acid bacteria (LAB) on the proliferation of Escherichia coli in the curd during the manufacturing of Chihuahua cheese. Milk proved to be an excellent culture medium for E. coli, allowing it to develop at concentrations up to 109 cfu/g. However, the presence of LAB, the pH control, Aw, and especially the use of the Cheddarization process during the Chihuahua cheese production proved to be important obstacles that inhibited the proliferation of E. coli under the conditions studied. Moreover, reducing the water activity of the curd as quickly as possible is presented as the most powerful tool to inhibit the development of E. coli during the Chihuahua cheese-making process.

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RESUMEN El presente trabajo es una reseña original sobre el libro "Medicine-Based Informatics and Engineering" publicado en la colección Lecture Notes in Bioengineering de Springer, en 2022, cuyos editores son los investigadores Franco Simini y Pedro Bertemes-Filho. La reseña busca sintetizar el contenido de los trabajos presentados en los capítulos centrándose en las soluciones desarrolladas. Los editores, a partir de la diversidad de los aportes, vislumbran la integración de visiones, en lo que denominan "Ingeniería Médica".

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ABSTRACT This paper is an original review of the book "Medicine-Based Informatics and Engineering" published in Springer's Lecture Notes in Bioengineering collection, in 2022, whose editors are Franco Simini and Pedro Bertemes-Filho. The review aims to synthesize the content of the papers presented in the chapters focusing on the solutions developed. The editors, from the diversity of the contributions, envision the integration of visions, in what they call "Medical Engineering".

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There is little information on the milk coagulation process by plant proteases combined with chymosins. This work is aimed at studying the capability of protease enclosed in the ripe fruits of Solanum elaeagnifolium (commonly named trompillo) to form milk gels by itself and in combination with chymosin. For this purpose, proteases were partially purified from trompillo fruits. These proteases had a molecular weight of ~60 kDa, and results suggest cucumisin-like serine proteases, though further studies are needed to confirm this observation. Unlike chymosins, trompillo proteases had high proteolytic activity (PA = 50.23 UTyr mg protein-1) and low milk-clotting activity (MCA = 3658.86 SU mL-1). Consequently, the ratio of MCA/PA was lower in trompillo proteases (6.83) than in chymosins (187 to 223). Our result also showed that milk gels formed with trompillo proteases were softer (7.03 mPa s) and had a higher release of whey (31.08%) than the milk gels clotted with chymosin (~10 mPa s and ~4% of syneresis). However, the combination of trompillo proteases with chymosin sped up the gelling process (21 min), improved the firmness of milk gels (12 mPa s), and decreased the whey release from milk curds (3.41%). Therefore, trompillo proteases could be combined with chymosin to improve the cheese yield and change certain cheese features.

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BACKGROUND: Some studies have employed machine learning (ML) methods for mobility prediction modeling in older adults. ML methods could be a helpful tool for life-space mobility (LSM) data analysis. AIM: This study aimed to evaluate the predictive value of ML algorithms for the restriction of life-space mobility (LSM) among elderly people and to identify the most important risk factors for that prediction model. METHODS: A 2-year LSM reduction prediction model was developed using the ML-based algorithms decision tree, random forest, and eXtreme gradient boosting (XGBoost), and tested on an independent validation cohort. The data were collected from the International Mobility in Aging Study (IMIAS) from 2012 to 2014, comprising 372 older patients (≥ 65 years of age). LSM was measured by the Life-Space Assessment questionnaire (LSA) with five levels of living space during the month before assessment. RESULTS: According to the XGBoost algorithm, the best model reached a mean absolute error (MAE) of 10.28 and root-mean-square error (RMSE) of 12.91 in the testing portion. The variables frailty (39.4%), mobility disability (25.4%), depression (21.9%), and female sex (13.3%) had the highest importance. CONCLUSION: The model identified risk factors through ML algorithms that could be used to predict LSM restriction; these risk factors could be used by practitioners to identify older adults with an increased risk of LSM reduction in the future. The XGBoost model offers benefits as a complementary method of traditional statistical approaches to understand the complexity of mobility.

Assuntos

Fragilidade , Aprendizado de Máquina , Humanos , Idoso , Algoritmos , Fatores de Risco , Envelhecimento

RESUMO

Background: Primary screening with Human Papilloma Virus (HPV) testing was introduced in Colombia in 2014 for individuals between 30 and 65 years of age. When the result is positive, cytology triage is performed for colposcopy referral. The convenience of initiating HPV-DNA testing for screening at 25 years of age is currently a subject of discussion. Therefore, the objective of this health technology assessment (HTA) is to analyze the available evidence regarding safety, efficacy, cost-effectiveness, values and preferences, ethical dilemmas and considerations pertaining to the implementation of the HPV-DNA test as a cervical screening strategy in women under 30 years of age in the Colombian context. Domains to be assessed: Clinical efficacy and safety 1. Cumulative rate of cervical intraepithelial neoplasia (CIN) grade 2 or high-er after 2 screening rounds. 2. Cumulative rates of invasive cancer of the uterine cervix after 2 screening rounds. 3. Safety: referral to colposcopy. Cost-effectiveness Cost-effectiveness for Colombia. Other domains considered Ethical considerations associated with cervical screening in women under 30 years of age. Organizational and individual considerations. Barriers and facilitators pertaining to the implementation of cervical screening in women under 30 years of age in the Colombian context. Methods: Clinical efficacy and safety assessment A systematic literature search of systematic reviews and clinical trials was conducted in MEDLINE, Embase and CENTRAL. The body of evidence was rated using the GRADE approach. An interdisciplinary team was then convened to create a working group to review the retrieved evidence. This led to the discussion and construction of the conclusions following the guidelines of a formal consensus in accordance with the RAND/UCLA methodology. Economic study Systematic literature research of studies that had assessed cost-effectiveness for Colombia. Results: Clinical outcomes An integrative analysis of 5 randomized clinical trials that met the inclusion critera was performed. Compared with cytology, primary HPV-DNA testing in women under 30 years of age could be associated with a lower frequency of CIN+2 lesions during the first screening round (RR: 1.57; CI: 1.20 to 2.04; low evidence certainty), and a lower incidence of CIN+2 (RR: 0.67; CI: 0.48 to 0.92; low evidence certainty). Moreover, it is associated with a lower frequency of invasive carcinoma at the end of follow-up (RR: 0.19; CI: 0.07 to 0.53; high evidence certainty). Economic results From the financial point of view, the use of HPVDNA testing plus cytology-based triage starting at 25 years of age is perhaps the most cost-effective option for Colombia (incremental cost-effectiveness ratio, COP 8,820,980 in 2013). Other implications Two studies suggest that barriers to implementation attributable to intermediation, public unrest and geographic considerations could be overcome with the use of new screening technologies or strategies. It is important to consider administration and service provision alternatives in order to overcome some acceptability and access barriers. Any cervical screening program must take into consideration ethical principles of nonmaleficence, beneficence, autonomy and equity. Future studies should focus on analyzing new screening techniques with emphasis on the population under 30 years of age. Conclusions: The use of HPV-DNA testing as a screening strategy in women under 30 years of age is a potentially efficacious and cost-effective intervention for Colombia. Future studies should focus on analyzing new screening technologies, with emphasis on the population under 30 years of age.

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Antecedentes: A partir del 2014 en Colombia se incorporó la Tamización primaria con prueba de Virus del Papiloma Humano (VPH) desde los 30 hasta los 65 años, cuando la prueba es positiva se hace triage con citología para remisión a colposcopia. Actualmente se discute la conveniencia de iniciar la tamización con prueba de ADN de VPH a partir de los 25 años. De esta manera, el objetivo de esta evaluación de tecnologías sanitarias es analizar la evidencia disponible en torno a la seguridad, efectividad, costoefectividad, valores y preferencias, dilemas éticos y aspectos relacionados con la implementación para el contexto colombiano de la prueba ADN-VPH como estrategia de tamización cervical en mujeres menores de 30 años. Dominios a evaluar: Eficacia clínica y seguridad 1. Tasa acumulada de neoplasia intraepitelial cervical (NIC) grado 2 o más avanzado luego de 2 rondas de tamización. 2. Tasas acumuladas de cáncer invasor de cérvix luego de 2 rondas de tamización. 3. Seguridad: remisión a colposcopia. Costo-efectividad Costo efectividad para Colombia. Otros dominios considerados Aspectos éticos asociados a la tamización cervical en mujeres menores de 30 años. Aspectos organizacionales y del individuo. Barreras y facilitadores relacionados con la implementación en el contexto colombiano de la tamización cervical en mujeres menores de 30 años. Métodos: Evaluación de efectividad y seguridad clínicas Se realizó una búsqueda sistemática de la literatura en MEDLINE, Embase y CENTRAL de revisiones sistemáticas y ensayos clínicos. Se calificó el cuerpo de la evidencia con la aproximación GRADE. Posteriormente, se convocó a un grupo interdisciplinario a una mesa de trabajo en donde se presentó la evidencia recuperada, dando paso a la discusión y a la construcción de las conclusiones, siguiendo los lineamientos de un consenso formal acorde a la metodología RAND/UCLA. Estudio económico Se hizo una búsqueda sistemática de la literatura de estudios que hubieran evaluado el costo-efectividad para Colombia. Resultados: De 7.659 referencias recuperadas se incluyeron 8 estudios. Resultados clínicos Se realizó un análisis integrativo de 5 ensayos clínicos aleatorizados que cumplieron con los criterios de inclusión. Cuando se compara frente a la citología, la tamización primaria con ADN-VPH en mujeres menores de 30 años, podría asociarse con una mayor frecuencia de detección de lesiones NIC2+ durante la primera ronda de cribado (RR: 1.57; IC: 1,20 a 2,04; certeza en la evidencia baja), con una menor incidencia de NIC2+ (RR:0,67; IC: 0,48 a 0,92; certeza en la evidencia baja) y se asocia con una menor frecuencia de carcinoma invasor al término del seguimiento (RR: 0,19; IC: 0,07 a 0,53; certeza en la evidencia alta). Resultados económicos Desde el punto de vista económico, la alternativa de ADN-VPH y triage con citología desde los 25 años quizás representa la alternativa más costo-efectiva para Colombia (razón costo-efectividad incremental $8.820.980 COP año 2013). Otras implicaciones Dos estudios sugieren que las barreras de implementación, atribuibles a circunstancias de intermediación, de orden público y de carácter geográfico, podrían ser solventadas por nuevas tecnologías o estrategias de cribado. Es importante considerar alternativas de forma de administración y de prestación de servicios para solventar algunas barreras de aceptabilidad y acceso. Todo programa de tamización cervical debe contemplar los principios éticos de no maleficencia, beneficencia, autonomía y equidad. Futuros estudios deben enfocarse en analizar nuevas tecnologías de cribado con énfasis en población menor de 30 años. Conclusiones: El uso de la prueba ADN-VPH como estrategia de tamización en mujeres menores de 30 años es una intervención probablemente efectiva y costoefectiva para Colombia. Futuros estudios deben enfocarse en analizar nuevas tecnologías de cribado con énfasis en población menor de 30 años.

Assuntos

Infecções por Papillomavirus , Tecnologia Biomédica , Colo do Útero , DNA , Feminino , Humanos , Programas de Rastreamento

RESUMO

Requeson cheese is obtained from whey proteins. The production of this cheese is the most economical way to recover and concentrate whey proteins, which is why it is frequently made in some Latin American countries. Four requeson cheese treatments were prepared with different concentrations and combinations of salts (sodium chloride and/or potassium chloride) and were conventionally or vacuum packed. Proteolysis, peptide concentration, angiotensin-converting enzyme (ACE) inhibitory and antioxidant (DPPH and ABTS) activities were evaluated over time (one, seven and fourteen days). Requeson cheese presented antioxidant and ACE inhibitory activities, however, these values vary depending on salt addition, type of packaging and time of storage. The highest values of antioxidant activity (ABTS) were found in cheese added with 1.5% NaCl and 1.5% (NaCl/KCl, 1:1). Cheese without added salt and vacuum packed presented the highest ACE inhibition percentage at day seven. Therefore, it can be concluded that requeson cheese elaborated exclusively of sweet whey, presents antioxidant and ACE inhibition activity. However, for a cheese with ACE inhibitory capacity, it is recommended not to add salts or add at 1% (NaCl) and vacuum pack it. Additionally, for a cheese with antioxidant activity, it is recommended to add salt at 1.5% either NaCl or (1:1) NaCl/KCl and pack it either in a polyethylene bag or vacuum. In conclusion, requeson cheese elaborate with 100% sweet whey is a dairy product with antioxidant and ACE inhibition activity, being low in salt and fat.

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Lecithins are a phospholipid-rich mixture recovered from the degumming process of crude vegetable oils. Since the nineteenth century, this by-product of oil processing has been used as a food and pharmaceutical ingredient. Lecithins' popularity as an ingredient in the pharmaceutical and food industries arises from their particular properties, such as their hydrophilic-lipophilic balance, critical micellar concentration, and assembly properties. However, there is limited knowledge of the use of lecithins to formulate pharmaceutical- and food-grade microemulsions. Unlike conventional emulsions, microemulsions are thermodynamically stable systems that offer long-term stability. Besides, microemulsions show nano-sized droplets, transparency, ease of preparation and scale-up, and do not require expensive equipment. This review aims to provide a comprehensive overview of lecithins, their properties, and their use in formulating microemulsions, a promising method to incorporate, protect, and deliver bioactive compounds in pharmaceutical and food products. PRACTICAL APPLICATIONS: Lecithins are a phospholipid-rich mixture recovered from the degumming process of crude vegetable oils. Since the nineteenth century, this by-product of oil processing has been used as a food ingredient. Lecithin phospholipids are commonly used as emulsifier agents in the food and pharmaceutical industries because of their particular properties. However, there is limited knowledge of the use of lecithins to formulate pharmaceutical- or food-grade microemulsions. Unlike conventional emulsions, microemulsions are stable systems that offer long-term stability, nano-sized droplets, transparency, ease of preparation and scale-up, and do not require expensive equipment. This review aims to provide a comprehensive overview of lecithins, their properties, and their use in formulating microemulsions, a promising method to incorporate, protect, and deliver bioactive compounds such as vitamins, flavors, antioxidants, nutrients, colors, antimicrobials, and polyphenols.

Assuntos

Lecitinas , Óleos de Plantas , Emulsões , Tamanho da Partícula , Fosfolipídeos

RESUMO

Glutathione peroxidase 3 (GPx3) is the only extracellular selenoprotein (Sel) that enzymatically reduces H2O2 to H2O and O2. Two GPx3 (CqGPx3) cDNAs were characterized from crayfish Cherax quadricarinatus. The nerve cord CqGPx3a isoform encodes for a preprotein containing an N-terminal signal peptide of 32 amino acid residues, with the mature Sel region of 192 residues and a dispensable phosphorylation domain of 36 residues. In contrast, the pereiopods CqGPx3b codes for a precursor protein with 19 residues in the N-terminal signal peptide, then the mature 184 amino acid residues protein and finally a Pro-rich peptide of 42 residues. CqGPx3 are expressed in cerebral ganglia, pereiopods and nerve cord. CqGPx3a is expressed mainly in cerebral ganglia, antennulae and nerve cord, while CqGPx3b was detected mainly in pereiopods. CqGPx3a expression increases with high temperature and hypoxia; meanwhile, CqGPx3b is not affected. We report the presence and differential expression of GPx3 isoforms in crustacean tissues in normal conditions and under stress for high temperature and hypoxia. The two isoforms are tissue specific and condition specific, which could indicate an important role of CqGPx3a in the central nervous system and CqGPx3b in exposed tissues, both involved in different responses to environmental stressors.

Assuntos

Astacoidea , Selênio , Aminoácidos/genética , Animais , Astacoidea/genética , Astacoidea/metabolismo , Clonagem Molecular , DNA Complementar/genética , Peróxido de Hidrogênio/metabolismo , Hipóxia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Sinais Direcionadores de Proteínas/genética , Selênio/metabolismo , Temperatura

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Even though the field of Learning Analytics (LA) has experienced an expressive growth in the last few years. The vast majority of the works found in literature are usually focusing on experimentation of techniques and methods over datasets restricted to a given discipline, course, or institution and are still few works manipulating region and countrywide datasets. This may be since the implementation of LA in national or regional scope and using data from governments and institutions poses many challenges that may threaten the success of such initiatives, including the same availability of data. The present article describes the experience of LA in Latin America using governmental data from Elementary and Middle Schools of the State of Norte de Santander - Colombia. This study is focusing on students' performance. Data from 2013 to 2018 was collected, containing information related to 1) students' enrollment in school disciplines provided by Regional Education Secretary, 2) students qualifications provided by educational institutions, and 3) students qualifications provided by the national agency for education evaluation. The methodology followed includes a process of cleaning and integration of the data, subsequently a descriptive and visualization analysis is made and some educational data mining techniques are used (decision trees and clustering) for the modeling and extraction of some educational patterns. A total of eight patterns of interest are extracted. In addition to the decision trees, a feature ranking analysis was performed using xgboost and to facilitate the visual representation of the clusters, t-SNE and self-organized maps (SOM) were applied as result projection techniques. Finally, this paper compares the main challenges mentioned by the literature according to the Colombian experience and proposes an up-to-date list of challenges and solutions that can be used as a baseline for future works in this area and aligned with the Latin American context and reality.

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The effect of extrusion cooking on bioactive compounds in third-generation snacks (TGSE) and microwave-expanded snacks (MWSE) prepared using black bean, blue maize, and chard (FBCS) was evaluated. FBCS was extruded at different moisture contents (MC; 22.2-35.7%), extrusion temperatures (ET; 102-142 °C), and screw speeds (SP; 96-171 rpm). Total anthocyanin content (TAC), contents of individual anthocyanins, viz., cyanidin-3-glucoside, malvidin-3-glucoside, pelargonidin-3-glucoside, pelargonidin-3-5-diglucoside, and delphinidin-3-glucoside chloride, total phenolic content (TPC), antioxidant activity (AA), and color parameters were determined. TAC and individual anthocyanin levels increased with the reduction in ET. ET and MC affected the chemical and color properties; increase in ET caused a significant reduction in TPC and AA. Microwave expansion reduced anthocyanin content and AA, and increased TPC. Extrusion under optimal conditions (29% MC, 111 rpm, and 120 °C) generated products with a high retention of functional compounds, with high TAC (41.81%) and TPC (28.23%). Experimental validation of optimized process parameters yielded an average error of 13.73% from the predicted contents of individual anthocyanins. Results suggest that the TGSE of FBCS obtained by combining extrusion and microwave expansion achieved significant retention of bioactive compounds having potential physiological benefits for humans.

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Invasive species can reach high abundances and dominate native environments. One of the most impressive examples of ecological invasions is the spread of the African subspecies of the honey bee throughout the Americas, starting from its introduction in a single locality in Brazil. The invasive honey bee is expected to more negatively impact bee community abundance and diversity than native dominant species, but this has not been tested previously. We developed a comprehensive and systematic bee sampling scheme, using a protocol deploying 11,520 pan traps across regions and crops for three years in Brazil. We found that invasive honey bees are now the single most dominant bee species. Such dominance has not only negative consequences for abundance and species richness of native bees but also for overall bee abundance (i.e., strong "numerical" effects of honey bees). Contrary to expectations, honey bees did not have stronger negative impacts than other native bees achieving similar levels of dominance (i.e., lack of negative "identity" effects of honey bees). These effects were markedly consistent across crop species, seasons and years, and were independent from land-use effects. Dominance could be a proxy of bee community degradation and more generally of the severity of ecological invasions.

Assuntos

Produtos Agrícolas , Espécies Introduzidas , Animais , Abelhas , Brasil , Estações do Ano

RESUMO

It has been reported that polysaccharides like carrageenan can change the crystallization of lactose. However, it is still unclear whether changes in lactose mutarotation, solubility, and super-solubility are involved in carrageenans' effect on lactose crystallization. It has been established that the conversion of α- to ß-lactose forms (mutarotation) in an aqueous solution has a significant impact on lactose crystallization. Similarly, lactose solubility changes lead to changes in the metastable zone (MZ), a region between the solubility and super-solubility of lactose. The width of this MZ determines the temperature drop necessary to induce lactose nucleation. This work aimed to study the effect of carrageenans on lactose mutarotation and solubility. For this purpose, lactose solutions were added with ι and κ- carrageenan at two concentrations: 50 and 100 mg L-1. Optical rotation measurements estimated the proportion of ß/α isomers in lactose solutions. Besides, solubility and super- solubility was determined to build the MZ. The presence of carrageenans changed both the time to reach the mutarotation balance and the proportion of ß/α isomers at mutarotation equilibrium. Carrageenans decreased the solubility of lactose in a range of temperatures between 10 and 60 °C and reduced the metastable zone width (MZW).

Assuntos

Lactose , Carragenina , Cristalização , Solubilidade , Temperatura

RESUMO

Lactic acid bacteria (LAB) are an important source of bioactive metabolites and enzymes. LAB isolates from fresh vegetable sources were evaluated to determine their antimicrobial, enzymatic, and adhesion activities. A saline solution from the rinse of each sample was inoculated in De Man, Rogosa and Sharpe Agar (MRS Agar) for isolates recovery. Antimicrobial activity of cell-free supernatants from presumptive LAB isolates was evaluated by microtitration against Gram-positive, Gram-negative, LAB, mold, and yeast strains. Protease, lipase, amylase, citrate metabolism and adhesion activities were also evaluated. Data were grouped using cluster analysis, with 85% of similarity. A total of 76 LAB isolates were recovered, and 13 clusters were formed based on growth inhibition of the tested microorganisms. One cluster had antimicrobial activity against Gram-positive bacteria, molds and yeasts. Several LAB strains, PIM4, ELO8, PIM5 and CAL14 strongly inhibited the growth of L. monocytogenes and JAV15 and TOV9 strongly inhibited the growth of F. oxysporum. Based on enzymatic activities, 5 clusters were formed. Seven isolates hydrolyzed starch, 46 proteins, 14 lipids, and 36 metabolized citrate. LAB isolates with the best activities were molecularly identified as Leuconostoc mesenteroides, Enterococcus mundtii and Enterococcus faecium. Overall, LAB isolated from vegetables showed potential technological applications and should be further evaluated.

RESUMO

Compounds from spices and herbs extracts are being explored as natural antibacterial additives. A plant extract used in traditional folk medicine is Hibiscus sabdariffa L., also known as Roselle. Therefore, the potential use of a phenolic hibiscus extract as antibacterial or natural food preservative was analyzed in vitro and in situ. A phenolic extract was obtained from hibiscus calyces and fractionated, and then the fractions were tested against foodborne pathogen bacteria. Liquid-liquid extraction and solid-phase extraction were used to fractionate the hibiscus extract, and HPLC was employed to analyze the fractions' phenolic composition. Minimum bactericidal concentration (MBC) and minimal inhibitory concentration (MIC) were calculated for brute hibiscus phenolic extract, each of the fractions and pure commercial phenolic compounds. Bacteria tested were Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The fraction obtained after liquid-liquid extraction presented the best performance of MBC and MIC against the bacteria tested. Furthermore, a hibiscus ethanolic extract was employed as a natural preservative to extend the shelf-life of beef. Microbiological, color and sensory analyses were performed to the meat during the shelf-life test. The application of the phenolic hibiscus extract also showed an increase of the duration of the meat`s shelf life.

RESUMO

Manganese peroxidases (MnP) from the white-rot fungi Phanerochaete chrysosporium catalyse the oxidation of Mn2+ to Mn3+, a strong oxidizer able to oxidize a wide variety of organic compounds. Different approaches have been used to unravel the enzymatic properties and potential applications of MnP. However, these efforts have been hampered by the limited production of native MnP by fungi. Heterologous expression of MnP has been achieved in both eukaryotic and prokaryotic expression systems, although with limited production and many disadvantages in the process. Here we described a novel molecular approach for the expression and purification of manganese peroxidase isoform 1 (MnP1) from P. chrysosporium using an E. coli-expression system. The proposed strategy involved the codon optimization and chemical synthesis of the MnP1 gene for optimised expression in the E. coli T7 shuffle host. Recombinant MnP1 (rMnP1) was expressed as a fusion protein, which was recovered from solubilised inclusion bodies. rMnP1 was purified from the fusion protein using intein-based protein purification techniques and a one-step affinity chromatography. The designated strategy allowed production of an active enzyme able to oxidize guaiacol or Mn2+.

Assuntos

Escherichia coli/metabolismo , Expressão Gênica , Peroxidases/isolamento & purificação , Phanerochaete/enzimologia , Sequência de Aminoácidos , Ensaios Enzimáticos , Vetores Genéticos/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Padrões de Referência , Solubilidade

RESUMO

Maize silks have been used in Mexico for centuries as a natural-based treatment for various illnesses, including obesity and diabetes. It has been shown in mice that intake of maize silk extracts reduces the levels of blood glucose. However, it is not clear how or what maize silk compounds are involved in such an effect. A hypothesized mechanism is that some maize silk compounds can inhibit carbohydrate hydrolyzing enzymes like α-glucosidases. This work aimed to assess the capability of both saccharides and phenolic compounds from maize silks to inhibit intestinal α-glucosidases. Results showed that saccharides from maize silks did not produce inhibition on intestinal α-glucosidases, but phenolics did. Maize silk phenolics increased the value of Km significantly and decreased the Vmax slightly, indicating a mixed inhibition of α-glucosidases. According to the molecular docking analysis, the phenolics maysin, methoxymaysin, and apimaysin, which had the highest predicted binding energies, could be responsible for the inhibition of α-glucosidases. PRACTICAL APPLICATIONS: The International Diabetes Federation (IDF) reported in 2017 that diabetes affects over 424 million people worldwide, and caused 4 million deaths. Non-insulin-dependent diabetes or type 2 diabetes mellitus (T2DM) accounts for ∼90% of cases. T2DM is characterized by insulin resistance and pancreatic ß-cell failure. Therapy for T2DM includes the use of sulfonylureas, thiazolidinediones, biguanides, and α-glucosidase inhibitors. Regarding the α-glucosidase inhibitors, only few are commercially available, and these have been associated with severe gastrointestinal side effects. This work aimed to assess the capability of both saccharides and phenolic compounds from maize silks to inhibit intestinal α-glucosidases. Results from this work evidenced that maize silk polyphenols acted as effective inhibitors of intestinal rat α-glucosidases. Computational analysis of maize silk polyphenols indicated that maysin, a particular flavonoid from maize silks, could be responsible for the inhibition of α-glucosidases.

Assuntos

Diabetes Mellitus Tipo 2/tratamento farmacológico , Flores/química , Inibidores de Glicosídeo Hidrolases/farmacologia , Hipoglicemiantes/farmacologia , Fenóis/farmacologia , Zea mays/química , alfa-Glucosidases/metabolismo , Glicemia/efeitos dos fármacos , Flavonoides/química , Flavonoides/farmacologia , Glucosídeos/química , Glucosídeos/farmacologia , Inibidores de Glicosídeo Hidrolases/química , Hipoglicemiantes/química , Intestinos/enzimologia , Cinética , Simulação de Acoplamento Molecular , Fenóis/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Polifenóis/química , Polifenóis/farmacologia

RESUMO

Lactose is recovered by crystallization from cheese whey that is a by-product of cheesemaking. The whey used for the recovery of lactose usually has a residual content of protein that alters the crystallization of lactose. In addition, the pH of whey may fluctuate depending on the cheese variety. However, there is little information on how the pH modifies the effect that whey proteins have on lactose crystallization. Accordingly, this work aimed to evaluate the individual and combined effect of whey proteins and pH on the kinetics of crystallization, the crystal size distribution and the crystallinity of lactose. The addition of whey proteins in lactose solutions (25% v/v) modified the process of lactose crystallization. However, the effect that whey proteins had on lactose crystallization heavily depended on the pH. The number of crystals per milliliter as well as the growth and size distribution of crystals was the most affected with the changes in pH (pHs of 7, 5.5 and 4) and the addition of whey proteins (0 and 0.63%). All the treatment produced mostly α-lactose monohydrated but some treatments also generated crystals of ß-lactose (pH 5.5, 0% of proteins). Amorphous lactose was observed mainly in lactose solutions adjusted at pH 7 and added with whey proteins. This particular treatment also incorporated the highest amount of protein into the lattice of lactose crystals. The results of this work highlight the importance of controlling the pH of lactose crystallization, especially if there is a presence of whey proteins.

Assuntos

Lactose/química , Proteínas do Soro do Leite/química , Proteínas Sanguíneas , Cristalização/métodos , Concentração de Íons de Hidrogênio , Cinética , Tamanho da Partícula

RESUMO

Cream cheese is a fresh acid-curd cheese with pH values of 4.5⁻4.8. Some manufacturers add a small volume of rennet at the beginning of milk fermentation to improve the texture of the cream cheese. However, there is no information about the effect that proteases other than chymosin-like plant-derived proteases may have on cream cheese manufacture. This work aimed to describe some proteolytic features of the protease extracted from fruits of Solanum elaeagnifolium Cavanilles and to assess the impact that this plant coagulant has on the viscoelastic properties of cream cheeses. Results showed that caseins were not hydrolyzed extensively by this plant-derived coagulant. In consequence, the ratio of milk clotting units (U) to proteolytic activity (U-Tyr) was higher (1184.4 U/U-Tyr) than reported for other plant proteases. The plant coagulant modified neither yield nor composition of cream cheeses, but viscoelastic properties did. Cream cheeses made with chymosin had a loss tangent value (tan δ = 0.257) higher than observed in cheeses made with 0.8 mL of plant-derived coagulant per liter (tan δ = 0.239). It is likely that casein fragments released by the plant-derived coagulant improve the interaction of protein during the formation of acid curds, leading to an increase in the viscoelastic properties of cream cheese.

RESUMO

Boneless strip loins from mature cows (50 to 70 months of age) were vacuum impregnated (VI) with an isotonic solution (IS) of sodium chloride. This study sought to determine the vacuum impregnation and microstructural properties of meat from cull cows. The experiments were conducted by varying the pressure, p 1 (20.3, 71.1 kPa), and time, t 1 (0.5, 2.0, 4.0 h), of impregnation. After the VI step, the meat was kept for a time, t 2 (0.0, 0.5, 2.0, 4.0 h), in the IS under atmospheric pressure. The microstructural changes, impregnation, deformation, and porosity of the meat were measured in all the treatments. Impregnation and deformation levels in terms of volume fractions of the initial sample at the end of the vacuum step and the VI processes were calculated according to the mathematical model for deformation-relaxation and hydrodynamic mechanisms. Scanning electron microscopy (SEM) was used to study the microstructure of the vacuum-impregnated meat samples. Results showed that both the vacuum and atmospheric pressures generated a positive impregnation and deformation. The highest values of impregnation X (10.5%) and deformation γ (9.3%) were obtained at p 1 of 71.1 kPa and t 1 of 4.0 h. The sample effective porosity ( ε e ) exhibited a significant interaction (p < 0.01) between p 1 × t 1 . The highest ε e (14.0%) was achieved at p 1 of 20.3 kPa and t 1 of 4.0 h, whereas the most extended distension of meat fibers (98 μm) was observed at the highest levels of p1, t1, and t2. These results indicate that meat from mature cows can undergo a vacuum-wetting process successfully, with an IS of sodium chloride to improve its quality.