RESUMO

In this study, mixed matrix hollow fiber polymeric membranes were prepared using polyethersulfone (PES) and polyvinylidene fluoride (PVDF) as polymers in their composition. N-methyl-2-pyrrolidone (NMP) was used as a solvent and demineralized water with an electrical conductivity below 3 µS·cm-1 was used as a non-solvent. A new approach to producing enhanced polymeric hollow fiber membranes based on the preparation of a simple blend PVDF/PES solution, and on the conformation of the composite membranes through the extrusion technique followed by the phase inversion process in a non-solvent bath, was applied. The investigation focused on the preparation of polymeric membranes with different polymer ratios and further assessment of the effects of these proportions on the membrane performance and in specific physical properties. The amount of PVDF ranged from 10 to 90% with 10% steps. The presence of PVDF, although it increased the membranes' plasticity, had a negative effect on the overall mechanical properties of the composite membranes. Scanning electron microscopy (SEM) results showed good dispersion of both polymers in the polymeric matrix. Furthermore, the membrane permeability showed a slight negative correlation with contact angle, suggesting that membrane hydrophilicity played an important role in membrane permeability. Finally, it was found that membranes with low ratios of PVDF/PES may have potential for water treatment applications, due to the combined advantageous properties of PES and PVDF.

RESUMO

Food processing industries have led to several environmental impacts due to their high water and energy consumption, as well as soil and water bodies' contamination through improper waste disposal. Membrane Separation Processes (MSP) emerge as an important alternative to enable the adoption of sustainable processes by food industries, since satisfying the requests of innovative processes and equipment design, such as smaller, cleaner, more energy-efficient processes (mild conditions) without the usage of chemical agents. Membrane-based processes fulfill these requirements, and their potential has been broadly recognized in the last few years. This review provides a comprehensive and up-to-date overview of the application of MSP in sustainable processes in the different segments of the food industry over the last 10 years. Waste and wastewater treatment, recovery of valuable compounds and water for reuse, and alternatives to high energy consumption processes were identified as sustainable processes in this context. One trend found is the potential for adding value to production chains by obtaining valuable compounds that have not been explored yet. As a perspective for future research, this review showed that it is advisable to implement MSP in different industrial environments in order to make current processes environmentally sustainable and less polluting.

Assuntos

RESUMO

The interest in microalgae production deals with its role as the third generation of feedstock to recover renewable energy. Today, there is a need to analyze the ultimate research and advances in recovering the microalgae biomass from the culture medium. Therefore, this review brings the current research developments (over the last three years) in the field of harvesting microalgae using membrane-based technologies (including microfiltration, ultrafiltration and forward osmosis). Initially, the principles of membrane technologies are given to outline the main parameters influencing their operation. The main strategies adopted by the research community for the harvesting of microalgae using membranes are subsequently addressed, paying particular attention to the novel achievements made for improving filtration performance and alleviating fouling. Moreover, this contribution also gives an overview of the advantages of applying membrane technologies for the efficient extraction of the high added-value compounds in microalgae cells, such as lipids, proteins and carbohydrates, which together with the production of renewable biofuels could boost the development of more sustainable and cost-effective microalgae biorefineries.

RESUMO

The objective of this study was to evaluate the microbiological, physicochemical and functional quality of an innovative goat whey orange juice beverage (GOB) processed by microfiltration. The microfiltration (0.2 µm) of the GOBs had a variation on the feed temperature (20, 30, 40, 50 °C) and were compared to the conventional heat treatment LTLT (63 °C/30 min). Microbiological (aerobic mesophilic bacteria, mold and yeast and lactic bacteria), physicochemical (pH, color, rheology and volatile compounds) bioactive compounds (acid ascorbic, total phenolics) and functional activity (DPPH, ACE, α-amilase and α-glucosidase) analysis were performed. The GOB processed by microfiltration using at least 30 °C presented adequate microbial counts (less than 4, 3 and 4 log CFU/mL, for AMB, molds and yeasts and LAB, respectively). In general, the pH, color parameters, volatile and bioactive compounds were not influenced by microfiltration temperature, but presented a difference from the LTLT processing. The rheological parameters were influenced by MF temperature and the utilization of temperatures of 20° and 30 °C maintained the consistency similar to the LTLT sample, preserving the compounds responsible for the texture. Therefore, it is suggested a processing of GOB by microfiltration using mild temperatures (between 30° and 40 °C) to preserve consistency and also obtain a desirable microbial quality, beyond the preservation of many functional properties and volatile compounds.

Assuntos

RESUMO

Bibliometric studies allow to collect, organize and process information that can be used to guide the development of research and innovation and to provide basis for decision-making. Paraffin/olefin separations constitute an important industrial issue because cryogenic separation methods are frequently needed in industrial sites and are very expensive. As a consequence, the use of membrane separation processes has been extensively encouraged and has become an attractive alternative for commercial separation processes, as this may lead to reduction of production costs, equipment size, energy consumption and waste generation. For these reasons, a bibliometric survey of paraffin/olefin membrane separation processes is carried out in the present study in order to evaluate the maturity of the technology for this specific application. Although different studies have proposed the use of distinct alternatives for olefin/paraffin separations, the present work makes clear that consensus has yet to be reached among researchers and technicians regarding the specific membranes and operation conditions that will make these processes scalable for large-scale commercial applications.

RESUMO

El calostro bovino es una secreción mamaria que se genera aproximadamente siete días antes del parto para alimentar al becerro. El contenido de sus componentes puede llegar a ser 100 veces mayor que en la leche cruda y estudios de otros autores señalan los beneficios alimenticios y medicinales que este presenta. En tal virtud, se estudió el efecto de la aplicación de microfiltración tangencial sobre la concentración de proteínas de calostro bovino como una fuente alimenticia y medicinal. El estudio consideró vacas de la raza Holstein y sus entrecruzamientos, desarrolladas en el cantón Cayambe. Los análisis químicos (grasa, proteína total, inmunoglobulinas totales, lactosa, sólidos totales y sólidos no grasos) fueron analizados en un equipo MilkoScan, los microbiológicos (contaje de células somáticas y contaje total) en un analizador Bacto Scan, la cuantificación de inmunoglobulina G con un cromatógrafo líquido Varian y la influencia de la aplicación de microfiltración tangencial con membranas de 0,45 µm de poro. Los resultados mostraron que en la mayoría de los casos las concentraciones de los parámetros en estudio a las primeras horas presentaron elevados valores (23 a 76 % de aumento con respecto a las 36 horas). El análisis factorial mostró que las condiciones de crianza y las horas después del parto, son los factores que mayormente influyeron sobre los parámetros físico-químicos. Finalmente, la microfiltración concentró la inmunoglobulina G en un 27 %, este concentrado podría ser empleado en la elaboración de nuevos productos que presenten beneficios a la salud de los humanos.

Assuntos

RESUMO

The application of milk ultrafiltration technology for cheese manufacture presents several advantages. However, it also influences proteolysis and, consequently, cheese ripening. The effects of five different processing methods for Prato cheese were evaluated with respect to the time evolution of the extent and depth of proteolysis indexes (EPI and DPI). The following treatments (T) for cheese production were studied: T1 - without ultrafiltration (standard); T2, T3, T4 and T5 - using milk concentrated by ultrafiltration (UFCM) and respectively: T2 - without pre-fermentation of the UFCM; T3 - pre-fermentation of 10% of the UFCM; T4 - pre-fermentation of 20% of the UFCM, and T5 - pre-fermentation of 20% of the UFCM plus indirect heating. Treatments affected the EPI and DPI of the cheeses (T1 lower values for EPI and DPI and T4 higher values for EPI and DPI). The time influenced the extent and depth of proteolysis indexes.

A aplicação da tecnologia de ultrafiltração do leite para fabricação de queijos apresenta inúmeras vantagens, porém, ela também influi na proteólise, e conseqüentemente na maturação dos queijos. Foram avaliados os efeitos de cinco diferentes métodos de processamento de queijo Prato sobre a evolução dos índices de extensão e profundidade da proteólise (EPI e DPI). Os seguintes tratamentos (T) para produção de queijo foram estudados: T1 - sem ultrafiltração (padrão); T2, T3, T4 e T5 - usando leite concentrado por ultrafiltração (UFCM) e respectivamente: T2 - sem pré-fermentação do UFCM, T3 - pré-fermentação de 10% do UFCM; T4 - pré-fermentação de 20% do UFCM e T5 - pré-fermentação de 20% do UFCM com aquecimento indireto. O tratamento afetou o EPI e o DPI dos queijos (T1 menores valores para EPI e DPI e T4 maiores valores para EPI e DPI). O tempo influenciou os índices de extensão e profundidade da proteólise.

RESUMO

The application of milk ultrafiltration technology for cheese manufacture presents several advantages. However, it also influences proteolysis and, consequently, cheese ripening. The effects of five different processing methods for Prato cheese were evaluated with respect to the time evolution of the extent and depth of proteolysis indexes (EPI and DPI). The following treatments (T) for cheese production were studied: T1 - without ultrafiltration (standard); T2, T3, T4 and T5 - using milk concentrated by ultrafiltration (UFCM) and respectively: T2 - without pre-fermentation of the UFCM; T3 - pre-fermentation of 10% of the UFCM; T4 - pre-fermentation of 20% of the UFCM, and T5 - pre-fermentation of 20% of the UFCM plus indirect heating. Treatments affected the EPI and DPI of the cheeses (T1 lower values for EPI and DPI and T4 higher values for EPI and DPI). The time influenced the extent and depth of proteolysis indexes.

A aplicação da tecnologia de ultrafiltração do leite para fabricação de queijos apresenta inúmeras vantagens, porém, ela também influi na proteólise, e conseqüentemente na maturação dos queijos. Foram avaliados os efeitos de cinco diferentes métodos de processamento de queijo Prato sobre a evolução dos índices de extensão e profundidade da proteólise (EPI e DPI). Os seguintes tratamentos (T) para produção de queijo foram estudados: T1 - sem ultrafiltração (padrão); T2, T3, T4 e T5 - usando leite concentrado por ultrafiltração (UFCM) e respectivamente: T2 - sem pré-fermentação do UFCM, T3 - pré-fermentação de 10% do UFCM; T4 - pré-fermentação de 20% do UFCM e T5 - pré-fermentação de 20% do UFCM com aquecimento indireto. O tratamento afetou o EPI e o DPI dos queijos (T1 menores valores para EPI e DPI e T4 maiores valores para EPI e DPI). O tempo influenciou os índices de extensão e profundidade da proteólise.