Membrane-based technologies for meeting the recovery of biologically active compounds from foods and their by-products

Mangiferin: A comprehensive review on its extraction, purification and uses in food systems

With the target of fabricating healthier products, food manufacturing companies look for natural-based nutraceuticals that can potentially improve the physicochemical properties of food systems while being nutritive to the consumer and providing additional health benefits (biological activities). In this regard, Mangiferin joins all these requirements as a potential nutraceutical, which is typically contained in Mangifera indica products and its by-products. Unfortunately, knowing the complex chemical composition of Mango and its by-products, the extraction and purification of Mangiferin remains a challenge. Therefore, this comprehensive review revises the main strategies proposed by scientists for the extraction and purification of Mangiferin. Importantly, this review identifies that there is no report reviewing and criticizing the literature in this field so far. Our attention has been targeted on the timely findings on the primary extraction techniques and the relevant insights into isolation and purification. Our discussion has emphasized the advantages and limitations of the proposed strategies, including solvents, extracting conditions and key interactions with the target xanthone. Additionally, we report the current research gaps in the field after analyzing the literature, as well as some examples of functional food products containing Mangiferin.

Glycomacropeptide: A comprehensive understanding of its major biological characteristics and purification methodologies

Glycomacropeptide (GMP) is a bioactive peptide derived from whey protein, consisting of 64 amino acids. It is a phenylalanine-free peptide, making it a beneficial dietary option for individuals dealing with phenylketonuria (PKU). PKU is an inherited metabolic disorder characterized by high levels of phenylalanine in the bloodstream, resulting from a deficiency of phenylalanine dehydrogenase in affected individuals. Consequently, patients with PKU require lifelong adherence to a low-phenylalanine diet, wherein a significant portion of their protein intake is typically sourced from a phenylalanine-free amino acid formula. GMP has several nutritional values, numerous bioactivity properties, and therapeutic effects in various inflammatory disorders. Despite all these features, the purification of GMP is an imperative requirement; however, there are no unique methods for achieving this goal. Traditionally, several methods have been used for GMP purification, such as thermal or acid treatment, alcoholic precipitation, ultrafiltration (UF), gel filtration, and membrane separation techniques. However, these methods have poor specificity, and the presence of large amounts of impurities can interfere with the analysis of GMP. More efficient and highly specific GMP purification methods need to be developed. In this review, we have highlighted and summarized the current research progress on the major biological features and purification methodologies associated with GMP, as well as providing an extensive overview of the recent developments in using charged UF membranes for GMP purification and the influential factors.

Recent advances in membrane technologies applied in oil-water separation

Effective treatment of oily wastewater, which is toxic and harmful and causes serious environmental pollution and health risks, has become an important research field. Membrane separation technology has emerged as a key area of investigation in oil-water separation research due to its high separation efficiency, low costs, and user-friendly operation. This review aims to report on the advances in the research of various types of separation membranes around emulsion permeance, separation efficiency, antifouling efficiency, and stimulus responsiveness. Meanwhile, the challenges encountered in oil-water separation membranes are examined, and potential research avenues are identified.

Application of membrane separation technology in the purification of pharmaceutical components

Traditional Chinese medicine (TCM) is often composed of a variety of natural medicines. Its composition is complex, and many of its components can not be analyzed and identified. The first step in the rational application of TCM is to successfully separate the effective components which is also a great inspiration for the development of new drugs. Among the many separation technologies of TCM, the traditional heating concentration separation technology has high energy consumption and low efficiency. As a new separation technology, membrane separation technology has the characteristics of simple operation, high efficiency, environment-friendly and so on. The separation effect of high molecular weight difference solution is better. The applications of several main membrane separation technologies such as microfiltration, nanofiltration, ultrafiltration and reverse osmosis are reviewed, the methods of restoring membrane flux after membrane fouling are discussed, and their large-scale industrial applications in the future are prospected and summarized.

Innovative applications of whey protein for sustainable dairy industry: Environmental and technological perspectives-A comprehensive review

Industrial waste management is critical to maintaining environmental sustainability. The dairy industry (DI), as one of the major consumers of freshwater, generates substantial whey dairy effluent, which is notably rich in organic matter and thus a significant pollutant. The effluent represents environmental risks due to its high biological and chemical oxygen demands. Today, stringent government regulations, environmental laws, and heightened consumer health awareness are compelling industries to responsibly manage and reuse whey waste. Therefore, this study investigates sustainable solutions for efficiently utilizing DI waste. Employing a systematic review approach, the research reveals that innovative technologies enable the creation of renewable, high-quality, value-added food products from dairy byproducts. These innovations offer promising sustainable waste management strategies for the dairy sector, aligning with economic interests. The main objectives of the study deal with, (a) assessing the environmental impact of dairy sector waste, (b) exploring the multifaceted nutritional and health benefits inherent in cheese whey, and (c) investigating diverse biotechnological approaches to fashion value-added, eco-friendly dairy whey-based products for potential integration into various food products, and thus fostering economic sustainability. Finally, the implications of this work span theoretical considerations, practical applications, and outline future research pathways crucial for advancing the sustainable management of dairy waste.

A Novel Ultrafiltrate Extract of Propolis Exerts Anti-inflammatory Activity through Metabolic Rewiring

Thousands of years ago, humans started to use propolis because of its medicinal properties, and modern science has successfully identified several bioactive molecules within this resinous bee product. However, a natural propolis extract which has been removed the adhesive glue and preserved propolis bioactive compounds is urgently needed to maximise the therapeutic opportunities. In this study, a novel ultrafiltrate fraction from Brazilian green propolis, termed P30K, was demonstrated with anti-inflammatory properties, both in vitro and in vivo. Total flavonoids and total phenolic acids content in P30K were 244.6 mg/g and 275.8 mg/g respectively, while the IC50 value of inhibition of cyclooxygenase-2 (COX-2) was 8.30 μg/mL. The anti-inflammatory activity of P30K was furtherly corroborated in experimental models of lipopolysaccharides (LPS)-induced acute liver and lung injury. Mechanistically, integrated GC-MS and LC-MS based serum metabolomics analysis revealed that P30K modulated citrate cycle (TCA), pyruvate, glyoxylate and dicarboxylate metabolism pathways to inhibit secretion of pro-inflammatory cytokines. Results of network pharmacology and molecular docking suggested that P30K targeted catechol-O-methyltransferases (COMT), 11β-hydroxysteroid dehydrogenases (HSD11B1), and monoamine oxidases (MAOA and MAOB) to promote cellular metabolomic rewiring. Collectively, our work reveals P30K as an efficient therapeutic agent against inflammatory conditions and its efficacy is related to metabolic rewiring.

Membrane-Based Preparation Process and Antioxidant and Anti-AGEs Activities of a Novel Propolis Ultrafiltrate

Propolis is one functional supplement with hundreds of years of usage. However, it's rarely consumed directly for its resinous property. Herein, a pre-treated process which can remove the impurity while preserve its bioactivities is needed to maximise its therapeutic opportunities. In the present study, a membrane-based ultrafiltration process was developed on a KM1812-NF experimental instrument. Using Brazilian green propolis as testing material, all experimental steps and parameters were sequentially optimized. In addition, a mathematical model was developed to fit the process. As a result, the optimum solvent was 60 % ethanol adjusted to pH 8-9, while the optimum MWCO (molecular weight cut-off) value of membrane was 30 KDa. The membrane filtration dynamic model fitted with the function y=(ax+b)/(1+cx+dx2 ). The resulting propolis ultrafiltrate from Brazilian green propolis, termed P30K, contains the similar profile of flavonoids and phenolic acids as raw propolis. Meanwhile, the ORAC (oxygen radical absorbance capacity) value of P30K is 11429.45±1557.58 μM TE/g and the IC50 value of inhibition of fluorescent AGEs (advanced glycation end products) formation is 0.064 mg/mL. Our work provides an innovative alternative process for extraction of active compounds from propolis and reveals P30K as an efficient therapeutic antioxidant.

Membrane Separation of Chicken Byproduct Hydrolysate for Up-Concentration of Bioactive Peptides

Membrane processes, such as microfiltration, ultrafiltration, and nanofiltration, are increasingly used for various applications in both upstream and downstream processing. Membrane-based processes play a critical role in the field of separation/purification of biotechnological products, including protein production/purification. The possibility of using membranes to separate peptides from a chicken byproduct hydrolysate and the effect of the performed downstream processing on the DPP-IV dipeptidyl peptidase IV (DPP-IV) inhibitory activity of mechanical deboning chicken residue (MDCR) has been investigated. The chicken byproduct hydrolysate was prepared by enzymatic hydrolysis followed by microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) separation. Comparing all separation treatments, hydrolysates processed only by MF and UF show the best DPP-IV inhibition (59.5-60.0% at 1 mg/mL and 34.2-40.7% at 0.5 mg/mL). These samples show dose-responsive behavior. Bioactivity was correlated with molecular weight distribution profiles and average molecular weights. The nanofiltration process notably decrease the inhibitory activity, and these permeates show low DPP-IV inhibition (9.5-21.8% at 1 mg/mL and 3.6-12.1% at 0.5 mg/mL). The size-exclusion chromatography-organic carbon detection-organic nitrogen detection (LC-OCD-OND) analysis confirms that NF and RO would retain the bioactive peptides in the concentrate in comparison to MF and UF. Bioactivity was correlated with molecular weight distribution profiles and average molecular weights. Permeates after ultrafiltration show an IC50 value of 0.75 mg/mL, comparable to other potent DPP-IV inhibitors derived from various food sources, and significantly more potent compared to the microfiltration sample, which shows an IC50 value of 1.04 mg/mL. The average molecular weight of the permeates calculated from the SEC chromatograms was 883 g/mol for UF and 1437 g/mol for MF. Of the four membranes studied, the UF membrane shows the best separation properties with respect to maximizing the yield and up-concentration of the bioactive peptides. Overall, UF was demonstrated to be a feasible technology for the removal of the undesired high-molecular-weight substances and up-concentration of small-molecular-weight bioactive peptides from chicken byproduct hydrolysate. These peptides might exhibit biological activity and could offer several health benefits. There is a high potential for the use of bioactive peptides, and more research in this field can lead to promising results that have significant effects in the food and medical industries.

Designing Nutrition for Health-Incorporating Dietary By-Products into Poultry Feeds to Create Functional Foods with Insights into Health Benefits, Risks, Bioactive Compounds, Food Component Functionality and Safety Regulations

This review delves into the concept of nutrition by design, exploring the relationship between poultry production, the utilization of dietary by-products to create functional foods, and their impact on human health. Functional foods are defined as products that extend beyond their basic nutritional value, offering potential benefits in disease prevention and management. Various methods, including extraction, fermentation, enrichment, biotechnology, and nanotechnology, are employed to obtain bioactive compounds for these functional foods. This review also examines the innovative approach of enhancing livestock diets to create functional foods through animal-based methods. Bioactive compounds found in these functional foods, such as essential fatty acids, antioxidants, carotenoids, minerals, vitamins, and bioactive peptides, are highlighted for their potential in promoting well-being and mitigating chronic diseases. Additionally, the review explores the functionality of food components within these products, emphasizing the critical roles of bioaccessibility, bioactivity, and bioavailability in promoting health. The importance of considering key aspects in the design of enhanced poultry diets for functional food production is thoroughly reviewed. The safety of these foods through the establishment of regulations and guidelines was reviewed. It is concluded that the integration of nutrition by design principles empowers individuals to make informed choices that can prioritize their health and well-being. By incorporating functional foods rich in bioactive compounds, consumers can proactively take steps to prevent and manage health issues, ultimately contributing to a healthier society and lifestyle.

Production and Bioconversion Efficiency of Enzyme Membrane Bioreactors in the Synthesis of Valuable Products

The demand for bioactive molecules with nutritional benefits and pharmaceutically important properties is increasing, leading researchers to develop modified production strategies with low-cost purification processes. Recent developments in bioreactor technology can aid in the production of valuable products. Enzyme membrane bioreactors (EMRs) are emerging as sustainable synthesis processes in various agro-food industries, biofuel applications, and waste management processes. EMRs are modified reactors used for chemical reactions and product separation, particularly large-molecule hydrolysis and the conversion of macromolecules. EMRs generally produce low-molecular-weight carbohydrates, such as oligosaccharides, fructooligosaccharides, and gentiooligosaccharides. In this review, we provide a comprehensive overview of the use of EMRs for the production of valuable products, such as oligosaccharides and oligodextrans, and we discuss their application in the bioconversion of inulin, lignin, and sugars. Furthermore, we critically summarize the application and limitations of EMRs. This review provides important insights that can aid in the production of valuable products by food and pharmaceutical industries, and it is intended to assist scientists in developing improved quality and environmentally friendly prebiotics using EMRs.

A comprehensive review on Ginger (Zingiber officinale) as a potential source of nutraceuticals for food formulations: Towards the polishing of gingerol and other present biomolecules

Currently, ginger is one the most consumed plants when dealing with the treatments of various illnesses. So far, it is known that various biologically active molecules, such as gingerols, shogaols and zingerone, among others, are the main responsible for specific biological activities, opening a new window for its utilization as a nutraceutical in foods. In pioneering extraction processes, solvent extraction has been initially used for these applications; however, the drawbacks of this typical extraction method compared with other emergent separation techniques make it possible for the exploration of new extraction pathways, including microwave, ultrasound, supercritical, subcritical and pressurized-assisted extraction, along with three phase partitioning, high-speed counter current chromatography and magnetic solid phase extraction. To the best of our knowledge, there is no report documenting the recent studies and cases of study in this field. Therefore, we comprehensively review the progress and the latest findings (over the last five years) on research developments, including patents and emerging extraction methods, aiming at the purification of biologically active molecules (gingerols, shogaols and zingerone) contained in ginger. Over the course of this review, particular emphasis is devoted to breakthrough strategies and meaningful outcomes in ginger components extraction. Finally, dosage and safety concerns related to ginger extracts are also documented.

A Perspective on Missing Aspects in Ongoing Purification Research towards Melissa officinalis

Melissa officinalis L. is a medicinal plant used worldwide for ethno-medical purposes. Today, it is grown everywhere; while it is known to originate from Southern Europe, it is now found around the world, from North America to New Zealand. The biological properties of this medicinal plant are mainly related to its high content of phytochemical (bioactive) compounds, such as flavonoids, polyphenolic compounds, aldehydes, glycosides and terpenes, among many other groups of substances. Among the main biological activities associated with this plant are antimicrobial activity (against fungi and bacteria), and antispasmodic, antioxidant and insomnia properties. Today, this plant is still used by society (as a natural medicine) to alleviate many other illnesses and symptoms. Therefore, in this perspective, we provide an update on the phytochemical profiling analysis of this plant, as well as the relationships of specific biological and pharmacological effects of specific phytochemicals. Currently, among the organic solvents, ethanol reveals the highest effectiveness for the solvent extraction of precious components (mainly rosmarinic acid). Additionally, our attention is devoted to current developments in the extraction and fractionation of the phytochemicals of M. officinalis, highlighting the ongoing progress of the main strategies that the research community has employed. Finally, after analyzing the literature, we suggest potential perspectives in the field of sustainable extraction and purification of the phytochemical present in the plant. For instance, some research gaps concern the application of cavitation-assisted extraction processes, which can effectively enhance mass transfer while reducing the particle size of the extracted material in situ. Meanwhile, membrane-assisted processes could be useful in the fractionation and purification of obtained extracts. On the other hand, further studies should include the application of ionic liquids and deep eutectic solvents (DES), including DESs of natural origin (NADES) and hydrophobic DESs (hDES), as extraction or fractionating solvents, along with new possibilities for effective extraction related to DESs formed in situ, assisted by mechanical mixing (mechanochemistry-based approach).

A Review on Current Strategies for Extraction and Purification of Hyaluronic Acid

Since it is known that hyaluronic acid contributes to soft tissue growth, elasticity, and scar reduction, different strategies of producing HA have been explored in order to satisfy the current demand of HA in pharmaceutical products and formulations. The current interest deals with production via bacterial and yeast fermentation and extraction from animal sources; however, the main challenge is the right extraction technique and strategy since the original sources (e.g., fermentation broth) represent a complex system containing a number of components and solutes, which complicates the achievement of high extraction rates and purity. This review sheds light on the main pathways for the production of HA, advantages, and disadvantages, along with the current efforts in extracting and purifying this high-added-value molecule from different sources. Particular emphasis has been placed on specific case studies attempting production and successful recovery. For such works, full details are given together with their relevant outcomes.

Processing Agroindustry By-Products for Obtaining Value-Added Products and Reducing Environmental Impact

Over four billion tons of foods are produced annually on the planet, and about a third is wasted. A minimal part of this waste is incinerated or sent to landfills for treatment, avoiding contamination and diseases; the rest is disposed of elsewhere. The current review was aimed at broadening the panorama on the potential of agroindustrial by-products in applications such as biofuels, biomaterials, biocompounds, pharmaceuticals, and food ingredients. It also exposes the main chemical, physical, and biochemical treatments for converting by-products into raw materials with added value through low environmental impact processes. The value of agroindustrial waste is limited due to the scarce information available. There is a need for further research in unexplored areas to find ways of adding value to these by-products and minimizing their contamination. Instead of throwing away or burning by-products, they can be transformed into useful materials such as polymers, fuels, antioxidants, phenols, and lipids, which will effectively reduce food waste and environmental impact.

Use of Membrane Technologies in Dairy Industry: An Overview

The use of treatments of segregated process streams as a water source, as well as technical fluid reuse as a source of value-added recovery products, is an emerging direction of resource recovery in several applications. Apart from the desired final product obtained in agro-food industries, one of the challenges is the recovery or separation of intermediate and/or secondary metabolites with high-added-value compounds (e.g., whey protein). In this way, processes based on membranes, such as microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO), could be integrated to treat these agro-industrial streams, such as milk and cheese whey. Therefore, the industrial application of membrane technologies in some processing stages could be a solution, replacing traditional processes or adding them into existing treatments. Therefore, greater efficiency, yield enhancement, energy or capital expenditure reduction or even an increase in sustainability by producing less waste, as well as by-product recovery and valorization opportunities, could be possible, in line with industrial symbiosis and circular economy principles. The maturity of membrane technologies in the dairy industry was analyzed for the possible integration options of membrane processes in their filtration treatment. The reported studies and developments showed a wide window of possible applications for membrane technologies in dairy industry treatments. Therefore, the integration of membrane processes into traditional processing schemes is presented in this work. Overall, it could be highlighted that membrane providers and agro-industries will continue with a gradual implementation of membrane technology integration in the production processes, referring to the progress reported on both the scientific literature and industrial solutions commercialized.

Techniques for Dealcoholization of Wines: Their Impact on Wine Phenolic Composition, Volatile Composition, and Sensory Characteristics

The attention of some winemakers and researchers over the past years has been drawn towards the partial or total dealcoholization of wines and alcoholic beverages due to trends in wine styles, and the effect of climate change on wine alcohol content. To achieve this, different techniques have been used at the various stages of winemaking, among which the physical dealcoholization techniques, particularly membrane separation (nanofiltration, reverse osmosis, evaporative perstraction, and pervaporation) and thermal distillation (vacuum distillation and spinning cone column), have shown promising results and hence are being used for commercial production. However, the removal of alcohol by these techniques can cause changes in color and losses of desirable volatile aroma compounds, which can subsequently affect the sensory quality and acceptability of the wine by consumers. Aside from the removal of ethanol, other factors such as the ethanol concentration, the kind of alcohol removal technique, the retention properties of the wine non-volatile matrix, and the chemical-physical properties of the aroma compounds can influence changes in the wine sensory quality during dealcoholization. This review highlights and summarizes some of the techniques for wine dealcoholization and their impact on wine quality to help winemakers in choosing the best technique to limit adverse effects in dealcoholized wines and to help meet the needs and acceptance among different targeted consumers such as younger people, pregnant women, drivers, and teetotalers.

Current evidence in high throughput ultrafiltration toward the purification of monoclonal antibodies (mAbs) and biotechnological protein-type molecules

Pressure-driven membrane-based technologies, such as microfiltration (MF), ultrafiltration (UF), and nanofiltration (NF), have been successfully implemented in recovering different types of biomolecules and high-value-added compounds from various streams. Especially, UF membranes meet the requirements for separating specific bioproducts in downstream processes, e.g. monoclonal antibodies (mAbs), which are recognized as proteins produced mainly by plasma cells. According to the importance and functionality of the mAbs, their recovery is a current challenge with these bioseparations. Nevertheless, mAbs recovery using UF-assisted processes has been smartly performed over the last decade. To the best of our knowledge, there are no reviews of the reported developments using UF technology toward mAbs separation. Therefore, the goal of this paper is to collect and elucidate ongoing research studies implemented for the featured separation of mAbs and other biotechnological protein-type molecules (e.g. adenovirus serotype, extracellular vesicles, red fluorescent protein, cyanovirin-N, among others) via ultrafiltration-aided systems. The literature evidence (e.g. research papers, patents, etc.) has been analyzed and discussed according to the purpose of the study. Importantly, the relevant findings and novel approaches are discussed in detail. To finalize this document, the advantages, drawbacks, and guidelines in applying membrane-based techniques for such a recovery are presented.

Comprehensive review of water management and wastewater treatment in food processing industries in the framework of water-food-environment nexus

Food processing is among the greatest water-consuming industries with a significant role in the implementation of sustainable development goals. Water-consuming industries such as food processing have become a threat to limited freshwater resources, and numerous attempts are being carried out in order to develop and apply novel approaches for water management in these industries. Studies have shown the positive impact of the new methods of process integration (e.g., water pinch, mathematical optimization, etc.) in maximizing water reuse and recycle. Applying these methods in food processing industries not only significantly supported water consumption minimization but also contributed to environmental protection by reducing wastewater generation. The methods can also increase the productivity of these industries and direct them to sustainable production. This interconnection led to a new subcategory in nexus studies known as water-food-environment nexus. The nexus assures sustainable food production with minimum freshwater consumption and minimizes the environmental destructions caused by untreated wastewater discharge. The aim of this study was to provide a thorough review of water-food-environment nexus application in food processing industries and explore the nexus from different aspects. The current study explored the process of food industries in different sectors regarding water consumption and wastewater generation, both qualitatively and quantitatively. The most recent wastewater treatment methods carried out in different food processing sectors were also reviewed. This review provided a comprehensive literature for choosing the optimum scenario of water and wastewater management in food processing industries.

Membrane separation processes for enrichment of bovine and caprine milk oligosaccharides from dairy byproducts

Breast milk is an ideal source of human milk oligosaccharides (HMOs) for isolation and purification. However, breast milk is not for sale and at most is distributed to neonatal intensive care units as donor milk. To overcome this limitation, isolating HMOs analogs including bovine milk oligosaccharides (BMOs) and caprine milk oligosaccharides (CMOs) from other sources is timely and significant. Advances in the development of equipment and analytical methods have revealed that dairy processing byproducts are good sources of BMOs and CMOs. Enrichment of these oligosaccharides from dairy byproducts, such as whey, permeate, and mother liquor, is of increasing academic and economic value. The commonly employed approach for oligosaccharides purification is chromatographic technique, but it is only used at lab scale. In the dairy industry, chromatographic methods (large-scale ion exchange, 10,000 L size) are currently routinely used for the isolation/purification of milk proteins (e.g., lactoferrin). In contrast, membrane technology has been proven to be a suitable approach for the isolation and purification of BMOs and CMOs from dairy byproducts. Therefore, this review simply introduces BMOs and CMOs in dairy processing byproducts. This review also summarizes membrane separation processes for isolating and purifying BMOs and CMOs from different dairy byproducts. Finally, the technological challenges and solutions of each processing strategy are discussed in detail.

Techniques and modeling of polyphenol extraction from food: a review

There is a growing demand for vegetal food having health benefits such as improving the immune system. This is due in particular to the presence of polyphenols present in small amounts in many fruits, vegetables and functional foods. Extracting polyphenols is challenging because extraction techniques should not alter food quality. Here, we review technologies for extracting polyphenolic compounds from foods. Conventional techniques include percolation, decoction, heat reflux extraction, Soxhlet extraction and maceration, whereas advanced techniques are ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, high-voltage electric discharge, pulse electric field extraction and enzyme-assisted extraction. Advanced techniques are 32-36% more efficient with approximately 15 times less energy consumption and producing higher-quality extracts. Membrane separation and encapsulation appear promising to improve the sustainability of separating polyphenolic compounds. We present kinetic models and their influence on process parameters such as solvent type, solid and solvent ratio, temperature and particle size.

Potential development of non-synthetic food additives from orange processing by-products—a review

Citrus is the largest fruit crop worldwide. Meanwhile, oranges account for 60 per cent of the total, with their main application in juice production. During orange juice production, only about 50 per cent of the fresh orange weight is transformed into juice, with the remaining 50 per cent comprised of residue (peel, pulp, seeds, orange leaves and whole orange fruits that do not reach the quality requirements). With the resulting tons of orange by-products, there has been an initiative to research possible ways to reutilize and revalorize citrus waste. Orange pomace, the by-product from juicing process, is currently used to extract the essential oils for fragrance and flavor, and a majority of the waste is used as cattle feed; however, these applications do not account for all of the waste or capture all of its potential value. Meanwhile, these by-products are put into landfills at the owner’s expense, and contribute to global warming through carbon emissions. On the other hand, orange by-products still contain many useful nutraceutical components, such as dietary fiber and phytochemicals, which could be utilized for value-added ingredients and new product development. Some research approaches in this area include the production of organic fertilizers and biofuels, or the extraction of essential oils, pectins, and antioxidant compounds. There is little information in the literature and in the food industry in terms of utilizing the orange pomace directly or with some simple treatments. Orange pomace may be used for food product development as a ‘clean-label’, non-synthetic preservative, which rationalizes this review.

Decimeter-Scale Atomically Thin Graphene Membranes for Gas-Liquid Separation

Graphene holds great potential for fabricating ultrathin selective membranes possessing high permeability without compromising selectivity and has attracted intensive interest in developing high-performance separation membranes for desalination, natural gas purification, hemodialysis, distillation, and other gas-liquid separation. However, the scalable and cost-effective synthesis of nanoporous graphene membranes, especially designing a method to produce an appropriate porous polymer substrate, remains very challenging. Here, we report a facile route to fabricate decimeter-scale (∼15 × 10 cm²) nanoporous atomically thin membranes (NATMs) via the direct casting of the porous polymer substrate onto graphene, which was produced by chemical vapor deposition (CVD). After the vapor-induced phase-inversion process under proper experimental conditions (60 °C and 60% humidity), the flexible nanoporous polymer substrate was formed. The resultant skin-free polymer substrate, which had the proper pore size and a uniform spongelike structure, provided enough mechanical support without reducing the permeance of the NATMs. It was demonstrated that after creating nanopores by the O₂ plasma treatment, the NATMs were salt-resistant and simultaneously showed 3-5 times higher gas (CO₂) permeance than the state-of-the-art commercial polymeric membranes. Therefore, our work provides guidance for the technological developments of graphene-based membranes and bridges the gap between the laboratory-scale "proof-of-concept" and the practical applications of NATMs in the industry.

Protein recovery as a resource from waste specifically via membrane technology-from waste to wonder

Economic growth and the rapid increase in the world population has led to a greater need for natural resources, which in turn, has put pressure on said resources along with the environment. Water, food, and energy, among other resources, pose a huge challenge. Numerous essential resources, including organic substances and valuable nutrients, can be found in wastewater, and these could be recovered with efficient technologies. Protein recovery from waste streams can provide an alternative resource that could be utilized as animal feed. Membrane separation, adsorption, and microbe-assisted protein recovery have been proposed as technologies that could be used for the aforementioned protein recovery. This present study focuses on the applicability of different technologies for protein recovery from different wastewaters. Membrane technology has been proven to be efficient for the effective concentration of proteins from waste sources. The main emphasis of the present short communication is to explore the possible strategies that could be utilized to recover or restore proteins from different wastewater sources. The presented study emphasizes the applicability of the recovery of proteins from various waste sources using membranes and the combination of the membrane process. Future research should focus on novel technologies that can help in the efficient extraction of these high-value compounds from wastes. Lastly, this short communication will evaluate the possibility of integrating membrane technology. This study will discuss the important proteins present in different industrial waste streams, such as those of potatoes, poultry, dairy, seafood and alfalfa, and the possible state of the art technologies for the recovery of these valuable proteins from the wastewater.

Spectroscopic, mineral, and antioxidant characteristics of blue colored powders prepared from cornflower aqueous extracts

The present study aimed to prepare blue colored powders from an aqueous extract of cornflower petals. Low temperature (4 °C) aqueous extraction (1:20) and microencapsulation by freeze-drying were performed. A mixture of stabilizers (maltodextrin, guar gum, and lecithin) in a proportion of 10% to the amount of extract was used. The results indicated that the addition of 2% and 4% guar gum to maltodextrin (8-6%) significantly increased the efficiency of the process, but 4% guar gum caused the formation of amorphous particles; therefore, 2% guar gum addition was found to be the most optimal. The FT-IR and FT-Raman band characteristics for guar gum, lecithin, and maltodextrin dominated over those for anthocyanins contained in the powders made from cornflower petals. The blue powders had total phenolic content of 19.5-26.6 mg GAE/g DW. The antioxidant activity of the prepared powders measured by ABTS, CHEL, OH, and RED was high.

Emerging techniques assisting nixtamalization products and by-products processing: an overview

The production of worldwide nixtamalized products has increased in Latin American countries over the last years. For a better maize handling and exploitation of its nutritional elements, maize is subjected to a nixtamalization pretreatment protocol, which produces meaningful chemical, nutritional and quality changes in maize and its derived products, but large amounts of its primary by-product, well-known as 'nejayote', are also produced. Importantly, nejayote is usually discarded into the urbanized sewage with minimal treatment. Today, according to the recent research reports, new emerging techniques and protocols have been implemented to improve the nixtamalization products and by-products processing. New valorization approaches and biotechnological developments (including biotransformations) toward the reuse of nejayote have been developed according to its considerable content of biomolecules. Therefore, the goal of this paper is to provide a comprehensive review of the main development works at assisting nixtamalization products and by-products processing. Herein, particular attention is paid to experimental insights dealing with the valorization of nejayote.

Olive Mill Wastewater Polyphenol-Enriched Fractions by Integrated Membrane Process: A Promising Source of Antioxidant, Hypolipidemic and Hypoglycaemic Compounds

The valorisation of food wastes is a challenging opportunity for the green, sustainable, and competitive development of industry. The recovery of phenols contributes to the sustainability of olive waste sector, reducing its environmental impact and promoting the development of innovative formulations of interest for pharmaceutical, nutraceutical, and cosmeceutical applications. In this work, olive mill wastewater was treated through a combination of microfiltration (MF), nanofiltration (NF), and reverse osmosis (RO) in a sequential design to produce polyphenol-enriched fractions that have been investigated for their chemical profile using ultra-high-performance liquid chromatography (UHPLC), and their potential antioxidant, hypolipidemic, and hypoglycaemic activities. RO retentate exhibited the highest content of hydroxytyrosol, tyrosol, oleuropein, verbascoside, vanillic acid, and luteolin. In particular, a content of hydroxytyrosol of 1522.2 mg/L, about five times higher than the MF feed, was found. RO retentate was the most active extract in all in vitro tests. Interestingly, this fraction showed a 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) radicals scavenging activity with an IC₅₀ value of 6.9 μg/mL and a potential inhibition of lipid peroxidation evaluated by the β-carotene bleaching test with IC₅₀ values of 25.1 μg/mL after 30 min of incubation. Moreover, RO retentate inhibited α-amylase and α-glucosidase with IC₅₀ values of 65.3 and 66.2 μg/mL, respectively.

Biologically active components in by-products of food processing

Food by-products happen at various stages of production and processing at home and on commercial scales. In the recent years, because of the fast-growing food companies and production, food processing by-products have gained a lot of interest and attracted many technical and health professionals as well as policy makers internally and internationally. Also, concerns are increasing about food by-products due to their ecological and environmental impact on the planet. This is particularly of concern when large companies emit. Large quantities of food by-products are thrown into environment in which they can be exploited technically, medicinally, and pharmaceutically. This is due to their chemical component and biologically active compounds of the by-products. Therefore, this systematic review focuses on the food by-product biological compounds present in different parts of the food products, particularly in some common foods such as fruits, vegetables, cereals, dairy products, meat, eggs, nuts, coffee, and tea. Moreover, the review also explains the kind of biologically active compounds and their quantity not just in edible foods, but also in part and types of the by-product which then can be reused and recycled into different processes in order to extract and get benefit from.

Biologically Active Compounds from Goji (Lycium Barbarum L.) Leaves Aqueous Extracts: Purification and Concentration by Membrane Processes

Goji (Lycium barbarum L.) leaves and fruits have been described as a valuable source of bioactive compounds with a great potential for the development of health-promoting formulations. The present study aimed to evaluate the potential of a sustainable process for the recovery of phenolic compounds from Goji leaves through a combination of aqueous extraction and membrane-based operations. Water was used as a safe, cheap, and non-hazardous extraction solvent, and parameters of extraction of dried Goji leaves were optimized in order to maximize the yield of polyphenols, total soluble solids (TSS), and total antioxidants simultaneously. The aqueous extract was clarified by ultrafiltration and then processed with three flat-sheet polyethersulphone (PES) membranes with molecular weight cut-off (MWCO) values in the range of 0.3–4.0 kDa, in order to remove sugar compounds from polyphenols and improve the antioxidant activity of the produced fractions. Among the selected membranes, a 1 kDa membrane exhibited the best performance in terms of purification of polyphenols from the clarified aqueous extract. The rejection by this membrane of TSS and total carbohydrates was in the range of 15.8–25.3%, and was decreased by increasing the volume reduction factor (VRF). On the other hand, the retention values for total polyphenols and total antioxidant activity (TAA) were in the range of 73–80%, and were increased by increasing the VRF.

Membrane separation processes for the extraction and purification of steviol glycosides: an overview

Steviol glycosides (SGs), as natural sweeteners from Stevia rebaudiana, are currently employed for replacing sugar and its derivatives in several food products and formulations. Such compounds play an essential role in human health. Their usage provides a positive effect on preventing diseases related to sugar consumption, including diabetes mellitus, cancer, and lipid metabolism disorders. The traditional extraction of SGs is performed by means of solvent extraction, which limits their application since the removal of residual solvents is a challenging task requiring further downstream purification steps. In addition, the presence of residual solvents negatively affects the quality of such compounds. Today, food technicians are looking for innovative and improved techniques for the extraction, recovery and purification of SGs. Membrane-based technologies, including microfiltration, ultrafiltration, and nanofiltration, have long been proven to be a valid alternative for efficient extraction and purification of several high added-value molecules from natural sources. Such processes and their possible coupling in integrated membrane systems have been successfully involved in recovery protocols of several compounds, such as metabolites, polyphenols, anthocyanins, natural pigments, proteins, from different sources (e.g., agro-food wastes, plant extracts, fruits, fermentation broths, among others). Herein, we aim to review the current progresses and developments about the extraction of SGs with membrane operations. Our attention has been paid to the latest insights in the field. Furthermore, key process parameters influencing the extraction and purification of SGs are also discussed in detail.

Current Advances in Biofouling Mitigation in Membranes for Water Treatment: An Overview

Membranes, as the primary tool in membrane separation techniques, tend to suffer external deposition of pollutants and microorganisms depending on the nature of the treating solutions. Such issues are well recognized as biofouling and is identified as the major drawback of pressure-driven membrane processes due to the influence of the separation performance of such membrane-based technologies. Herein, the aim of this review paper is to elucidate and discuss new insights on the ongoing development works at facing the biofouling phenomenon in membranes. This paper also provides an overview of the main strategies proposed by “membranologists” to improve the fouling resistance in membranes. Special attention has been paid to the fundamentals on membrane fouling as well as the relevant results in the framework of mitigating the issue. By analyzing the literature data and state-of-the-art, the concluding remarks and future trends in the field are given as well.

Flower and Leaf Extracts of Sambucus nigra L.: Application of Membrane Processes to Obtain Fractions with Antioxidant and Antityrosinase Properties

This study aimed at evaluating and comparing the chemical profile as well as the antityrosinase and antioxidant activities of ethanol (EtOH) and methanol (MeOH) extracts of Sambucus nigra L. (Adoxaceae) flowers and leaves in order to discover new candidates for food additives and cosmetic and pharmaceutical products. For this purpose, a novel lower-melting-point ethylene-chlorotrifluoroethylene (LMP ECTFE) nanofiltration (NF) membrane was employed in order to produce the concentrated fractions of S. nigra. Floral extracts were richer in phytochemicals in comparison to the leaf extracts. The High-performance liquid chromatography (HPLC) profile revealed rutin, quercetin, protocateuchic acid, 3,5-dicaffeoylquinic acid, and neochlorogenic acid as the most abundant compounds. Ferric reducing antioxidant power (FRAP), 2,2’-diphenil-1-picrylhydrazil (DPPH) radical scavenging, and 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) tests were used to investigate the antioxidant properties. NF retentate fractions of floral ethanol extracts exerted the highest tyrosinase inhibitory activity with an IC₅₀ of 53.9 µg/mL and the highest ABTS radical scavenging activity (IC₅₀ of 46.4 µg/mL). In conclusion, the present investigation revealed the potential benefits of NF application in S. nigra extracts processing, suggesting the use of retentate fractions as a promising source for antioxidant and tyrosinase inhibitory compounds which could pave the way for future applications.

Recovery of High Value-Added Nutrients from Fruit and Vegetable Industrial Wastewater

The industrial processing water of fruit and vegetables has raised serious environmental concerns due to the presence of many important bioactive compounds being disposed in the wastewater. Bioactive compounds have great potential for the food industry to optimize their process and to recover these compounds in order to develop value-added products and to reduce environmental impacts. However, to achieve this goal, some challenges need to be addressed such as safety assurance, technology request, product regulations, cost effectiveness, and customer factors. Therefore, this review aims to summarize the recent advances of bioactive compounds recovery and the current challenges in wastewater from fruit and vegetable processing industry, including fruit and beverage, soybean by-products, starch and edible oil industry. Moreover, future direction for novel and green technology of bioactive compounds recovery are discussed, and a prospect of bioactive compounds reuse and sustainable development is proposed.

Chemical and bio-chemical reactions assisted by pervaporation technology

Since several decades ago, the application of pervaporation (PV) technology has been mainly aimed at the separation of different types of water-organic, organic-water and organic-organic mixtures, reaching its large-scale application in industry for the dehydration of organics. Today, the versatility and high selectivity toward specific compounds have led its consideration to other types of application such as the assisted chemical and bio-chemical reactions. The focus of this review is to provide a compelling overview on the recent developments of PV combined with chemical and bio-chemical reactions. After a general introduction of PV and its theoretical background, particular emphasis is given to the results obtained in the field for different reactions considered, identifying the key features and weak points of PV in such particular applications. Furthermore, future trends and perspectives are also addressed according to the latest literature reports.

Membrane-Based Clarification and Fractionation of Red Wine Lees Aqueous Extracts

Polyvinylidenefluoride (PVDF) hollow fiber membranes prepared in laboratory through the inversion phase method were characterized and used to clarify an aqueous extract from red wine lees. Steady-state permeate fluxes of 53 kg/m²h were obtained in the treatment of the aqueous extract in selected operating conditions. Suspended solids were completely retained by the hollow fiber membranes while bioactive compounds, including polyphenols, anthocyanins, and resveratrol were recovered in the permeate stream. The clarified stream was then fractionated by nanofiltration (NF). Three different commercial membranes, in flat-sheet configuration (NP010 and NP030 from Microdyn-Nadir, MPF36 from Koch Membrane Systems), were selected and tested for their productivity and selectivity towards sugars and bioactive compounds, including phenolic compounds, anthocyanins, and resveratrol. All selected membranes showed high retention towards anthocyanins (higher than 93%). Therefore, they were considered suitable to concentrate anthocyanins from clarified wine lees extracts at low temperature. On the other hand, NF permeate streams resulted enriched in phenolic compounds and resveratrol. Among the selected membranes, the MPF36 exhibited the lowest retention towards resveratrol (10%) and polyphenols (26.3%) and the best separation factor between these compounds and anthocyanins.

Pervaporation-based membrane processes for the production of non-alcoholic beverages

Nowadays, the interest in manufacturing non-alcoholic or low alcoholic content beverages from alcoholic beverages is a current challenge for food technologists; this is due to the fact that huge consumption of alcoholic beverages may produce health problems in the costumers. In principle, the post-fermentation ethanol removal from alcoholic beverages is carried out by means of evaporation or distillation. Such current dealcoholization methodologies are efficiently removing the ethanol, however, some organoleptic compounds can also be lost during the process. This makes the dealcoholization process highly sensitive in order to preserve the quality properties of the beverages. Thereby, membrane-based technologies, which use perm-selective barriers for the separation, have been highly promoted for such purpose. Pervaporation (PV) technology is indeed one of these technologies aimed for ethanol removal. Herein, the goal of this review is to provide a compelling overview of the most relevant findings for the production of non-alcoholic beverages (such as beer and wine) by means of PV. Particular attention is paid to experimental results which provide compelling feedback about the accurate ethanol removal and minimal changes on physicochemical properties of the beverages. Moreover, some theoretical basis of such technology, as well as key criteria for a more efficient dealcoholization, are also given.