Bacteriocin assisted food functional membrane for simultaneous exclusion and inactivation of Alicyclobacillus acidoterrestris in apple juice

Analysis of Metal-Organic Framework and Polyamide Interfaces in Membranes for Water Treatment and Antibacterial Applications

Integrating biocidal nanoparticles (NPs) into polyamide (PA) membranes shows promise for enhancing resistance to biofouling. Incorporating techniques can tailor thin-film nanocomposite (TFN) membranes for specific water purification applications. In this study, silver-based metal-organic framework Ag-MOFs (using silver nitrate and 1,3,5-benzentricarboxylic acid as precursors) are incorporated into PA membranes via three different methods: i) incorporation, ii) dip-coating, and iii) in situ ultrasonic techniques. The characterizations, such as top-surface and cross-section scanning and transmission microscopy, reveal that the incorporation methods for the modified TFN membranes substantially control morphology and surface characteristics. For example, the in situ ultrasonically interlayered Ag-MOFs showed the largest pores (average pore diameter of 14 Å ± 0.1), resulting in the highest water permeance (water flux of 10.9 LMH/bar for Na2SO4). It also show superior antifouling and anti-biofouling performance, with a flux recovery ratio (FRR) of 94.1% in both fouling tests due to its improved surface hydrophilicity and the antibacterial properties of incorporated Ag-MOFs. Conversely, the surface-grafted dip-coated Ag-MOFs offered the highest salt rejection, attributed to its highly negatively charged surface and a dense PA network with narrow pores (average pore diameter of 10 Å ± 0.06).

New Strategy for the Covalent Immobilisation of Phenolic Compounds on Silica Particles to Fight Against Foodborne Pathogens

The immobilisation of essential oil components (EOCs) on food-grade supports is a promising strategy for preserving liquid foods without the drawbacks of direct EOC addition such as poor solubility, high volatility, and sensory alterations. This study presents a novel method for covalently immobilising EOCs, specifically thymol and carvacrol, on SiO2 particles (5-15 µm) using the Mannich reaction. This approach simplifies conventional covalent immobilisation techniques by reducing the steps and reagents while maintaining antimicrobial efficacy and preventing compound migration. The antimicrobial effectiveness of the EOC-SiO2 system, applied as an additive, was tested against foodborne pathogens (Escherichia coli, Salmonella enterica, Staphylococcus aureus, and Listeria monocytogenes) inoculated into phosphate buffer solution and fresh apple juice. The results showed high antimicrobial activity, with inactivation exceeding 4-log reductions, depending on the EOC type, target microorganism, and medium. Moreover, the addition of functionalised particles did not affect the juice organoleptic properties. This study demonstrates that the Mannich reaction is an effective method for developing antimicrobial systems based on the covalent immobilisation of EOCs on silica particles, and offers a practical solution for food preservation without compromising food quality.

Innovative Trends in Modified Membranes: A Mini Review of Applications and Challenges in the Food Sector

Membrane technologies play a pivotal role in various industrial sectors, including food processing. Membranes act as barriers, selectively allowing the passage of one or other types of species. The separation processes that involve them offer advantages such as continuity, energy efficiency, compactness of devices, operational simplicity, and minimal consumption of chemical reagents. The efficiency of membrane separation depends on various factors, such as morphology, composition, and process parameters. Fouling, a significant limitation in membrane processes, leads to a decline in performance over time. Anti-fouling strategies involve adjustments to process parameters or direct modifications to the membrane, aiming to enhance efficiency. Recent research has focused on mitigating fouling, particularly in the food industry, where complex organic streams pose challenges. Membrane processes address consumer demands for natural and healthy products, contributing to new formulations with antioxidant properties. These trends align with environmental concerns, emphasizing sustainable practices. Despite numerous works on membrane modification, a research gap exists, especially with regard to the application of modified membranes in the food industry. This review aims to systematize information on modified membranes, providing insights into their practical application. This comprehensive overview covers membrane modification methods, fouling mechanisms, and distinct applications in the food sector. This study highlights the potential of modified membranes for specific tasks in the food industry and encourages further research in this promising field.

Essential Oil Nanoemulsions-A New Strategy to Extend the Shelf Life of Smoothies

Over the years, consumer awareness of proper, healthy eating has increased significantly, but the consumption of fruits and vegetables remains too low. Smoothie drinks offer a convenient way to supplement daily diets with servings of fruits and vegetables. These ready-to-eat beverages retain the nutritional benefits of the raw ingredients from which they are made. Furthermore, they cater to the growing demand for quick and nutritious meal options. To meet consumer expectations, current trends in the food market are shifting towards natural, high-quality products with minimal processing and extended shelf life. Food manufacturers are increasingly aiming to reduce or eliminate synthetic preservatives, replacing them with plant-based alternatives. Plant-based preservatives are particularly appealing to consumers, who often view them as natural and organic substitutes for conventional preservatives. Essential oils, known for their antibacterial and antifungal properties, are effective against the microorganisms and fungi present in fruit and vegetable smoothies. However, the strong taste and aroma of essential oils can be a significant drawback, as the concentrations needed for microbiological stability are often unpalatable to consumers. Encapsulation of essential oils in nanoemulsions offers a promising and effective solution to these challenges, allowing for their use in food production without compromising sensory qualities.

Strategies to Enhance the Membrane-Based Processing Performance for Fruit Juice Production: A Review

Fruit juice is an essential food product that has received significant acceptance among consumers. Harmonized concentration, preservation of nutritional constituents, and heat-responsive sensorial of fruit juices are demanding topics in food processing. Membrane separation is a promising technology to concentrate juice at minimal pressure and temperatures with excellent potential application in food industries from an economical, stable, and standard operation view. Microfiltration (MF) and ultrafiltration (UF) have also interested fruit industries owing to the increasing demand for reduced pressure-driven membranes. UF and MF membranes are widely applied in concentrating, clarifying, and purifying various edible products. However, the rising challenge in membrane technology is the fouling propensity which undermines the membrane's performance and lifespan. This review succinctly provides a clear and innovative view of the various controlling factors that could undermine the membrane performance during fruit juice clarification and concentration regarding its selectivity and permeance. In this article, various strategies for mitigating fouling anomalies during fruit juice processing using membranes, along with research opportunities, have been discussed. This concise review is anticipated to inspire a new research platform for developing an integrated approach for the next-generation membrane processes for efficient fruit juice clarification.

Immobilization of Natural Antimicrobial Compounds on Food-Grade Supports as a New Strategy to Preserve Fruit-Derived Foods

The use of natural antimicrobials in the food industry is being proposed as an eco-friendly postharvest technology to preserve fruit-derived foods. In this context, this systematic review aims to describe and discuss the application of naturally occurring antimicrobial compounds in the processing of fruit-derived foods by the PRISMA methodology. In a first step, the use of free natural antimicrobials was investigated as an approach to identify the main families of bioactive compounds employed as food preservatives and the current limitations of this dosage form. Then, the use of immobilized antimicrobials, in an innovative dosage form, was studied by distinguishing two main applications: addition to the food matrix as preservatives or use during processing as technological aids. Having identified the different examples of the immobilization of natural antimicrobial compounds on food-grade supports, the mechanisms of immobilization were studied in detail to provide synthesis and characterization guidelines for future developments. Finally, the contribution of this new technology to decarbonization and energy efficiency of the fruit-derived processing sector and circular economy is discussed in this review.

Membrane techniques in the production of beverages

The most important developments in membrane techniques used in the beverage industry are discussed. Particular emphasis is placed on the production of fruit and vegetable juices and nonalcoholic drinks, including beer and wine. This choice was dictated by the observed consumer trends, who increasingly appreciate healthy food and its taste qualities.

Bioactive Peptides: A Promising Alternative to Chemical Preservatives for Food Preservation

Bioactive peptides used for food preservation can prolong the shelf life through bacteriostasis and antioxidation. On the one hand, bioactive peptides can inhibit lipid oxidation by scavenging free radicals, interacting with metal ions, and inhibiting lipid peroxidation. On the other hand, bioactive peptides can fundamentally inhibit the growth and reproduction of microorganisms by destroying their cell membranes or targeting intracellular components. Besides, bioactive peptides are biocompatible and biodegradable in vivo. Therefore, they are regarded as a promising alternative to chemical preservatives. However, bioactive peptides are easily affected by the external environment in practical application, which hinders their commercialization. Currently, the studies to overcome the weakness focus on encapsulation and chemical synthesis. Bioactive peptides have been applied to the preservation of various foods in experimental research, with good results. In the future, with the deepening understanding of their safety and structure-activity relationship, there may be more bioactive peptides as food preservatives.

Stimuli-Responsive Lysozyme Nanocapsule Engineered Microfiltration Membranes with a Dual-Function of Anti-Adhesion and Antibacteria for Biofouling Mitigation

Biofouling remains as a persistent problem impeding the applications of membranes for water and wastewater treatment. Green anti-biofouling of membranes made of natural and environmentally friendly materials and methods is a promising strategy to tackle this problem. Herein, we have developed a functionalized PVDF membrane with stimuli-responsive lysozyme nanocapsules (NCP). These nanocapsules can responsively release lysozyme according to environmental stimuli (pH and redox) induced by bacteria. Results showed that (i) the surface of the functionalized membrane with NCP had enhanced hydrophilicity, reduced roughness, and negative charge, (ii) a remarkable reduction of adsorption of proteins, polysaccharides, and bacteria was achieved by the functionalized membrane, and (iii) the colony forming unit (CFU) of bacteria on a membrane surface was reduced more than 80% within 24 h of contact. In addition, the NCP membrane showed excellent anti-biofouling activity regarding the bacterial viability being 12.5 and 8.3% on the membrane after filtration with 10⁸ CFU mL^-1 Escherichia coli and Staphylococcus aureus solution as feed, respectively. The coating layer and assembled nanocapsules endowed the membrane with improved lysozyme stability, anti-adhesion performance, and antibacterial activity. Stimuli-responsive lysozyme nanocapsule engineered microfiltration membranes show great potential for anti-biofouling in future practical application.

Inactivation of Bacteria Using Bioactive Nanoparticles and Alternating Magnetic Fields

Foodborne pathogens are frequently associated with risks and outbreaks of many diseases; therefore, food safety and processing remain a priority to control and minimize these risks. In this work, nisin-loaded magnetic nanoparticles were used and activated by alternating 10 and 125 mT (peak to peak) magnetic fields (AMFs) for biocontrol of bacteria Listeria innocua, a suitable model to study the inactivation of common foodborne pathogen L. monocytogenes. It was shown that L. innocua features high resistance to nisin-based bioactive nanoparticles, however, application of AMFs (15 and 30 min exposure) significantly potentiates the treatment resulting in considerable log reduction of viable cells. The morphological changes and the resulting cellular damage, which was induced by the synergistic treatment, was confirmed using scanning electron microscopy. The thermal effects were also estimated in the study. The results are useful for the development of new methods for treatment of the drug-resistant foodborne pathogens to minimize the risks of invasive infections. The proposed methodology is a contactless alternative to the currently established pulsed-electric field-based treatment in food processing.