Comparative study of the microencapsulation by complex coacervation of nisin in combination with an avocado antioxidant extract

Bacteriocins sourced from traditional fermented foods for ensuring food safety: the microbial guards

Concerns about food safety have consistently driven the exploration of potent antimicrobials with probiotic origins. Identification of probiotic-derived bacteriocins as robust alternatives to antibiotics has gained traction following the COVID-19 pandemic. Additionally, the global market is witnessing an increasing preference for minimally processed food products free from chemical additives. Another contributing factor to the search for potent antimicrobials is the escalating number of infections caused by antibiotic-resistant bacteria and the need to mitigate the significant damage inflicted on the commensal human microbiota by broad-spectrum antibiotics. As an alternative bio-preservation strategy, there is substantial enthusiasm for the use of bacteriocins or starter cultures producing bacteriocins in preserving a variety of food items. This review specifically focuses on bacteriocins originating from lactic acid bacteria associated with fermented foods and explores their technological applications as nanobiotics. The food-grade antibiotic alternatives, whether utilized independently or in combination with other antimicrobials and administered directly or encapsulated, are anticipated to possess qualities of safety, stability and non-toxicity suitable for application in the food sector. © 2024 Society of Chemical Industry.

Facile fabrication of microfibrillated cellulose-based aerogels incorporated with nisin/β-cyclodextrin microcapsule for channel catfish preservation

In this study, a hydrophobic and antibacterial pad was prepared to preserve Channel Catfish (Ictalurus punctatus). The pad composite the microfibrillated cellulose and β-cyclodextrin/nisin microcapsules. The hydrophobic pad ensures a dry surface in contact with the fish, reducing microbial contamination. The pad has a low density and high porosity, making it lightweight and suitable for packaging applications, while also providing a large surface area for antibacterial activity. Results demonstrated that this antibacterial pad exhibits an ultralow density of 9.0 mg/cm3 and an ultrahigh porosity of 99.10%. It can extend the shelf life of Channel Catfish fillets to 9 days at 4 °C, with a total volatile base nitrogen below 20 mg/100 g. The study proposes a novel solution for preserving aquatic products by combining antibacterial substances with the natural base material aerogel. This approach also extends the utilization of aerogel and nisin in food packaging.

Interaction between liposome and myofibrillar protein in surimi: Effect on gel structure and digestive characteristics

This study investigated the effects of the interaction between liposomes and myofibrillar protein (MP) on tilapia surimi. The strong interaction between liposomes and MP was primarily mediated through hydrogen bonding and hydrophobic interaction. Liposomes caused the unfolding of MP structure, resulting in the decrease of α-helix content and transformation of spatial structure. Notably, the appropriate ratio of liposomes improved the gel properties of tilapia surimi. The water distribution, microstructure, and texture characteristics further confirmed that liposomes strengthened the structure of surimi gel through non-covalent bonds. However, excessive liposomes (1.0 %) weakened gel characteristics and texture. Moreover, the proper ratio of liposomes enhanced the stability of surimi gels during digestion, reducing protein digestibility from 66.0 % to 54.8 %. Curcumin-loaded liposomes in gel matrix notably delayed digestion and improved bioavailability. This delay in digestion was attributed to the ability of liposomes to decrease the interaction between MP and digestive enzymes. This study provides new insight into the application of liposomes in protein-rich food matrixes.

A comparative study on the encapsulation of black carrot extract in potato protein-pectin complexes

This manuscript reveals the effect of the emulsification step on the black carrot extract (BCE) stabilization by potato protein isolate (PPI)-citrus pectin (CP) coacervates. The effect of core-to-wall ratio and concentration of wall material were also investigated. This was the first attempt to compare the characteristics of emulsified core particles (ECP) and non-emulsified core particles (NECP) coated with complex coacervates. Potato protein was used as an encapsulating agent by complex coacervation for the first time, and it showed excellent characteristics for the encapsulation. Non-hygroscopic particles were produced with emulsification while most of NECPs were slightly hygroscopic. The mean particle diameter of powders ranged from 65.05 to 152.47 μm which is suitable with SEM micrographs. ECPs showed lower particle size values with increased wall concentration at the constant core-to-wall ratio. Encapsulation efficiency (EE) increased, and anthocyanin retention (AR) decreased when emulsification was included. EE of NECP and ECP was between 69.26-82.84% and 85.48-90.15% while AR was between 79.08-102.16% and 53.90-83.37%, respectively. FT-IR and ζ-potential values proved the complexation between PPI and CP in ECPs as well as the interaction of PP, CP, and BCE in NECPs. DSC thermograms proved the success of the encapsulation procedure and thermo-stability of the BCE-loaded particles.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05787-z.

Encapsulation of Bioactive Peptides by Spray-Drying and Electrospraying

Bioactive peptides derived from enzymatic hydrolysis are gaining attention for the production of supplements, pharmaceutical compounds, and functional foods. However, their inclusion in oral delivery systems is constrained by their high susceptibility to degradation during human gastrointestinal digestion. Encapsulating techniques can be used to stabilize functional ingredients, helping to maintain their activity after processing, storage, and digestion, thus improving their bioaccessibility. Monoaxial spray-drying and electrospraying are common and economical techniques used for the encapsulation of nutrients and bioactive compounds in both the pharmaceutical and food industries. Although less studied, the coaxial configuration of both techniques could potentially improve the stabilization of protein-based bioactives via the formation of shell-core structures. This article reviews the application of these techniques, both monoaxial and coaxial configurations, for the encapsulation of bioactive peptides and protein hydrolysates, focusing on the factors affecting the properties of the encapsulates, such as the formulation of the feed solution, selection of carrier and solvent, as well as the processing conditions used. Furthermore, this review covers the release, retention of bioactivity, and stability of peptide-loaded encapsulates after processing and digestion.

The Insecticidal Activity of Azadirachta indica Leaf Extract: Optimization of the Microencapsulation Process by Complex Coacervation

The objective of the present work was to optimize the microencapsulation conditions of neem (Azadirachta indica A. Juss) leaf extracts for the biocontrol of Tenebrio molitor. The complex coacervation method was used for the encapsulation of the extracts. The independent factors considered were the pH (3, 6, and 9), pectin (4, 6, and 8% w/v), and whey protein isolate (WPI) (0.50, 0.75, and 1.00% w/v). The Taguchi L9 (33) orthogonal array was used as the experimental matrix. The response variable was the mortality of T. molitor after 48 h. The nine treatments were applied by immersion of the insects for 10 s. The statistical analysis revealed that the most influential factor on the microencapsulation was the pH (73% of influence), followed by the pectin and WPI (15% and 7% influence, respectively). The software predicted that the optimal microencapsulation conditions were pH 3, pectin 6% w/v, and WPI 1% w/v. The signal-to-noise (S/N) ratio was predicted as 21.57. The experimental validation of the optimal conditions allowed us to obtain an S/N ratio of 18.54, equivalent to a T. molitor mortality of 85 ± 10.49%. The microcapsules had a diameter ranging from 1-5 μm. The microencapsulation by complex coacervation of neem leaf extract is an alternative for the preservation of insecticidal compounds extracted from neem leaves.

Microencapsulation for Food Applications: A Review

Food products contain various active ingredients, such as flavors, nutrients, unsaturated fatty acids, color, probiotics, etc., that require protection during food processing and storage to preserve their quality and shelf life. This review provides an overview of standard microencapsulation technologies, processes, materials, industrial examples, reasons for market success, a summary of recent applications, and the challenges in the food industry, categorized by active food ingredients: flavors, polyunsaturated fatty acids, probiotics, antioxidants, colors, vitamins, and others. We also provide a comprehensive analysis of the advantages and disadvantages of the most common microencapsulation technologies in the food industry such as spray drying, coacervation, extrusion, and spray cooling. This review ends with future perspectives on microencapsulation for food applications.

An Overview of Coacervates: The Special Disperse State of Amphiphilic and Polymeric Materials in Solution

Individual amphiphiles, polymers, and colloidal dispersions influenced by temperature, pH, and environmental conditions or interactions between their oppositely charged pairs in solvent medium often produce solvent-rich and solvent-poor phases in the system. The solvent-poor denser phase found either on the top or the bottom of the system is called coacervate. Coacervates have immense applications in various technological fields. This review comprises a concise introduction, focusing on the types of coacervates, and the influence of different factors in their formation, structures, and stability. In addition, their physicochemical properties, thermodynamics of formation, and uses and multifarious applications are also concisely presented and discussed.

Biotechnological use of dairy by-products for the production and microencapsulation of the food preservative enterocin CRL35

Bacteriocins from Gram-positive bacteria have been proposed as natural food preservative and there is a need for large-scale production for commercial purposes. The aim of the present work is to evaluate whey, a cheese industrial by-product, for the production and microencapsulation of enterocin CRL35. Whey proved to be a promising basal medium for bacterial growth although the bacteriocin production was quite low. However, it could be much favored with the addition of yeast extract at concentrations as low as 0.5%. Besides improving bacteriocin production, this peptide was successfully microencapsulated by spray drying using whey protein concentrate and a chitosan derivative as wall materials. Microcapsules averaging 10 ± 5 μm diameter were obtained, with good structural integrity and high antimicrobial activity with a stability of at least 12 weeks at 4°C. In summary, sustainable bacteriocin production and microencapsulation was achieved recycling whey or its derivatives. In addition, the formulation owns high antimicrobial activity with a long shelf life. The development of a food preservative may represent a green solution for handling whey.

Microencapsulation as a Noble Technique for the Application of Bioactive Compounds in the Food Industry: A Comprehensive Review

The use of natural food ingredients has been increased in recent years due to the negative health implications of synthetic ingredients. Natural bioactive compounds are important for the development of health-oriented functional food products with better quality attributes. The natural bioactive compounds possess different types of bioactivities, e.g., antioxidative, antimicrobial, antihypertensive, and antiobesity activities. The most common method for the development of functional food is the fortification of these bioactive compounds during food product manufacturing. However, many of these natural bioactive compounds are heat-labile and less stable. Therefore, the industry and researchers proposed the microencapsulation of natural bioactive compounds, which may improve the stability of these compounds during processing and storage conditions. It may also help in controlling and sustaining the release of natural compounds in the food product matrices, thus, providing bioactivity for a longer duration. In this regard, several advanced techniques have been explored in recent years for microencapsulation of bioactive compounds, e.g., essential oils, healthy oils, phenolic compounds, flavonoids, flavoring compounds, enzymes, and vitamins. The efficiency of microencapsulation depends on various factors which are related to natural compounds, encapsulating materials, and encapsulation process. This review provides an in-depth discussion on recent advances in microencapsulation processes as well as their application in food systems.

Betalain plant sources, biosynthesis, extraction, stability enhancement methods, bioactivity, and applications

Betalains are plant pigments with functional properties used mainly as food dyes. However, they have been shown to be unstable to different environmental factors. This paper provides a review of (1) Betalain plant sources within several plant families such as Amaranthaceae, Basellaceae, Cactaceae, Portulacaceae, and Nyctaginaceae, (2) The biosynthesis pathway of betalains for both betacyanins and betaxanthins, (3) Betalain extraction process, including non-conventional technologies like microwave-assisted, ultrasound-assisted, and pulsed electrical field extraction, (4) Factors affecting their stability, mainly temperature, water activity, light incidence, as well as oxygen concentration, metals, and the presence of antioxidants, as well as activation energy as a mean to assess stability, and novel food-processing technologies able to prevent betalain degradation, (5) Methods to increase shelf life, mainly encapsulation by spray drying, freeze-drying, double emulsions, ionic gelation, nanoliposomes, hydrogels, co-crystallization, and unexplored methods such as complex coacervation and electrospraying, (6) Biological properties of betalains such as their antioxidant, hepatoprotective, antitumoral, and anti-inflammatory activities, among others, and (7) Applications in foods and other products such as cosmetics, textiles and solar cells, among others. Additionally, study perspectives for further research are provided for each section.

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.

Interactions of the molecular assembly of polysaccharide-protein systems as encapsulation materials. A review

Studying the interactions of biopolymers like polysaccharides and proteins is quite important mainly due to the wide number of applications such as the stabilization and encapsulation of active compounds in complex systems. Complexation takes place when materials like proteins and polysaccharides are blended to promote the entrapment of active compounds. The interaction forces between the charged groups in the polymeric chains allow the miscibility of the components in the complex system. Understanding the interactions taking place between the polymers as well as between the wall material and the active compound is important when designing delivery systems. However, some features of the biopolymers like structure, functional groups, or electrical charge as well as extrinsic parameters like pH or ratios might affect the structure and the performance of the complex system when used in encapsulation applications. This work summarizes the recent progress of the polysaccharide/protein complexes for encapsulation and the influence of the pH on the structural modifications during the complexation process.

Vacuum Microwave-Assisted Aqueous Extraction of Polyphenolic Compounds from Avocado (Persea Americana) Solid Waste

The extraction efficacy of avocado fruit peels (AP) and seeds (AS) with the use of vacuum microwave-assisted aqueous extraction (VMAAE) was optimized in this study, with regard to extract’s total phenolic content (TPC), maximum antioxidant activity and minimal operational cost. Temperature (79.64 and 78.11 °C for AP and 43.90 and 45.26 °C for AS), time (11.89 and 11.75 min for AP, 10.18 and 10.28 min for AS), ratio of water to raw material (16.45% and 10.02% for AP, 38.73% and 37.65% for AS) and microwave power (5708.04 and 5699.10 W for AP, 5549.08 and 4797.29 W for AS) were estimated statistically as the optimal conditions in order to achieve high rates of extracts with high TPC and antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH●) scavenging radical methods, respectively. VMAAE performed under these conditions resulted in received extracts with TPC (0.352 gallic acid equivalent-GAE/g fresh AP/min and 0.124 GAE/g fresh AS/min). Furthermore, it was calculated the DPPH● radical scavenging activity was equal to 100 mg/L expressed in L of 0.104 L/min for AP and 0.045 L/min for AS. The results of our study may give a promising solution to avocado processing companies for further utilization of their waste.

Investigation of enhanced oxidation stability of microencapsulated enzymatically produced tuna oil concentrates using complex coacervation

Tuna oil was selectively hydrolysed using Thermomyces lanuginosus lipase for 6 h to prepare omega-3 acylglycerol concentrate with the DHA content significantly increased from 24.9% in tuna oil to 36.3% in the acylglycerol concentrate. The acylglycerol concentrate was subsequently encapsulated into the "multi-core" microcapsules using gelatin-sodium hexametaphosphate complex coacervates as the shell material. Rancimat, Oxipres and thermogravimetric analyses all showed that the microencapsulated acylglycerol concentrate had unexpectedly improved oxidation stability, compared to those produced using tuna oil, even though the concentrated oils themselves were significantly less stable than tuna oil. The incorporation of enzymatic tuna oil acylglycerol concentrate also significantly improved the oxidation stability of microencapsulated standard refined unconcentrated tuna oil. A wide range of characteristics including lipid and fatty acid composition, oil-in-water (O/W) emulsion properties, morphology, nanomechanical strength and physicochemical stability of acylglycerol, acylglycerol oil-in-water (O/W) emulsion and final microcapsules were investigated throughout the preparation. The result suggests that high levels of monoacylglycerol (about 35%) and diacylglycerol (about 8.5%) were produced in the acylglycerol. The acylglycerol O/W emulsion exhibited significantly smaller droplet size, lower zeta-potential and higher surface hydrophobicity, which contributed to the formation of the microcapsule with a significantly smoother surface and more compact structure, finally leading to improved oxidative stability compared to those prepared from native tuna oil.

Effect of the addition of microcapsules with avocado peel extract and nisin on the quality of ground beef

This study evaluated the incorporation of microcapsules containing nisin and avocado peel extract on the shelf life of ground beef. Ten treatments were studied and divided into two groups: one packaged under vacuum and the other in permeable packaging. Each group contained: (a) control, (b) extract, (c) nisin, (d) empty microcapsules (only wall microcapsule system), and (e) microcapsules with extract and nisin. The samples containing the microcapsules presented lower bacterial growth and less oxidation. On day 10, the vacuum-packaged samples with microencapsulated preservative presented a reduction in the oxidation of proteins of approximately 45%, of 30% in the growth of mesophiles, and of 38% in the growth of coliforms, as well as a reduction in the changes in the pH and ɑ W that occur during storage, compared with the permeable control. The combination of microcapsules with vacuum packaging reduced the physicochemical and microbiological changes that occur in the controls.

Microencapsulation of sweet orange essential oil (Citrus aurantium var. dulcis) by liophylization using maltodextrin and maltodextrin/gelatin mixtures: Preparation, characterization, antimicrobial and antioxidant activities

This study evaluated maltodextrin (MD) and gelatin (GEL) in different ratios (SO1, MD only; SO2, MD and GEL = 2:1; and SO3, MD and GEL = 1:1, respectively) as wall materials to microencapsulation of sweet orange essential oil (SOEO, 10% w/w). SOEO microspheres were obtained by emulsification/lyophilization and characterized regarding the microencapsulation yield and efficiency, infrared spectroscopy, ultrastructural aspects (scanning electron microscopy, SEM), thermogravimetric (TG), derivative thermogravimetry (DTG) and differential exploratory calorimetry (DSC) and bioactive properties. Yield and SOEO microencapsulation efficiency (MEE) was of up to 90.19 and 75.75%, respectively. SEM analysis showed SO1, SO2 and SO3 microspheres with irregular shapes. Although improvements in thermal stability of all formulated microspheres were observed, TG and DTG curves indicated slower rates of volatilization and degradation of SOEO in SO1. DSC curves indicated that SO1, SO2 and SO3 microsphere formulations were effective in protecting SOEO, especially in relation to improvements in oxidative stability. Antibacterial and antioxidant properties, as well as total phenolic content of SOEO, were maintained in all formulated microspheres. SOEO microspheres can be prepared using MD and GEL and lyophilization, resulting in high yields, MEE, stability and preservation of antioxidant and antimicrobial properties.

Use of molecular interactions and mesoscopic scale transitions to modulate protein-polysaccharide structures

Mixed protein-polysaccharide structures have found widespread applications in various fields, such as in foods, pharmaceuticals or personal care products. A better understanding and a more precise control over the molecular interactions between the two types of macromolecules leading to an engineering of nanoscale and colloidal building blocks have fueled the design of novel structures with improved functional properties. However, these building blocks often do not constitute the final matrix. Rather, further process operations are used to transform the initially formed structural entities into bulk matrices. Systematic knowledge on the relation between molecular structure design and subsequent mesoscopic scale transitions induced by processing is scarce. This article aims at establishing a connection between these two approaches. Therefore, it reviews not only studies on the underlying molecular interaction phenomena leading to either a segregative or associative phase behavior and nanoscale or colloidal structures, but also looks at the less systematically studied approach of using macroscopic processing operations such as shearing, heating, crosslinking, and concentrating/drying to transform the initially generated structures into bulk matrices. Thereby, a more comprehensive look is taken at the relationship between different influencing factors, namely solvent conditions (i.e. pH, ionic strength), biopolymer characteristics (i.e. type, charge density, mixing ratio, biopolymer concentration), and processing parameters (i.e. temperature, mechanical stresses, pressure) to generate bulk protein-polysaccharide matrices with different morphological features. The need for a combinatorial approach is then demonstrated by reviewing in detail current mixed protein-polysaccharide applications that increasingly make use of this. In the process, open scientific questions that will need to be addressed in the future are highlighted.

Use of gelatin and gum arabic for microencapsulation of probiotic cells from Lactobacillus plantarum by a dual process combining double emulsification followed by complex coacervation

The objectives of this study were i) to microencapsulate probiotic cells of Lactobacillus plantarum through a dual process consisting of emulsification followed by complex coacervation using gelatin and gum arabic, ii) to characterize the lyophilized microcapsules, iii) to evaluate their behavior in simulated in vitro gastrointestinal conditions and iv) to evaluate the survival of microencapsulated probiotic cells during 45 days of storage at 8 °C, 25 °C and -18 °C. The optimized conditions for complex coacervation consisted of a 50:50 biopolymer ratio and pH = 4.0. Emulsification was followed by complex coacervation using gelatin and gum arabic. The microcapsules presented dispersibility of 0.183 ± 0.17 g·mL^-1, moisture content of 4.5%, water activity of 0.34 ± 0.03 and hygroscopicity of 9.20 ± 0.43 g of absorbed water per 100 g. Their size ranged from 66.07 ± 3.04 μm to 105.66 ± 3.24 μm. Viability of the encapsulated L. plantarum cells was 8.6 log CFU·g^-1 and the encapsulation efficiency was 97.78%. After in vitro simulation of gastrointestinal conditions, viability of the encapsulated cells was 80.4% whereas it was only 25.0% for the free cells at 37 °C. Probiotic cell viability was maintained during storage at 8 °C and - 18 °C for 45 days.

Designing biopolymer microgels to encapsulate, protect and deliver bioactive components: Physicochemical aspects

Biopolymer microgels have considerable potential for their ability to encapsulate, protect, and release bioactive components. Biopolymer microgels are small particles (typically 100nm to 1000μm) whose interior consists of a three-dimensional network of cross-linked biopolymer molecules that traps a considerable amount of solvent. This type of particle is also sometimes referred to as a nanogel, hydrogel bead, biopolymer particles, or microsphere. Biopolymer microgels are typically prepared using a two-step process involving particle formation and particle gelation. This article reviews the major constituents and fabrication methods that can be used to prepare microgels, highlighting their advantages and disadvantages. It then provides an overview of the most important characteristics of microgel particles (such as size, shape, structure, composition, and electrical properties), and describes how these parameters can be manipulated to control the physicochemical properties and functional attributes of microgel suspensions (such as appearance, stability, rheology, and release profiles). Finally, recent examples of the utilization of biopolymer microgels to encapsulate, protect, or release bioactive agents, such as pharmaceuticals, nutraceuticals, enzymes, flavors, and probiotics is given.