Use of proteins for the delivery of flavours and other bioactive compounds

Fabrication and characterization of Karaya gum-based films reinforced with bacterial nanocellulose stabilized valerian root extract Pickering emulsion for lamb meat preservation

A novel biodegradable film was fabricated by incorporating bacterial nanocellulose stabilized valerian root extract (VRE) Pickering emulsion into karaya gum with better antioxidant and antibacterial properties for lamb meat preservation. The valerian root extract Pickering emulsion (VPE) exhibited 98 ± 1.84 % encapsulating efficiency and excellent physical stability with an average particle size of 274.6 nm. The incorporation of VPE-5 into the film matrix increased its elongation at break (EAB), and improved water resistance and barrier properties against oxygen, water vapor, and UV light. Moreover, the antioxidant and anti-bacterial properties against S.aerous and E. coli were also improved based on VPE-5 concentration. The SEM images showed a uniform distribution of VPE-5 while FTIR and XRD revealed its compatibility with karaya gum, which improved its thermal stability. The active films showed a significant preservative effect by reducing the pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable count (TVC) value of lamb meat and maintained its texture and color during the storage period of 9 days at 4 °C. These results demonstrated the inclusion of VPE-5 into Karaya gum was a promising technique and offers a great potential application as a bioactive material in food packaging.

The effect of Maillard reaction on the lactose crystallization and flavor release in lactose/WPI/inulin encapsulation

The crystallization of lactose usually causes the structural collapse and core material escape of flavor encapsulations. The objective of this study was to investigate the effects of different grafting degrees of WPI-inulin Maillard reaction products on the lactose crystallization and the subsequent release behaviors. Ethyl acetate was chosen as the model volatile flavor and the encapsulations were prepared by freeze-drying. The results found that the encapsulation efficiency was significantly increased from 30% to over 80% by using MRPs as wall materials. Those microparticles showed the greater flavor retention and lower moisture adsorption. In addition, the encapsulations produced by the proper Maillard reaction times (e.g., 48 h and 72 h) could effectively delay the lactose crystallization and thus improve the structural stability of the matrix. This innovation finding aims to use the Maillard reaction to control the crystallization behaviors and enhance the usefulness of high-lactose containing products in encapsulation systems.

Flavour encapsulation: A comparative analysis of relevant techniques, physiochemical characterisation, stability, and food applications

Flavour is an important component that impacts the quality and acceptability of new functional foods. However, most flavour substances are low molecular mass volatile compounds, and direct handling and control during processing and storage are made difficult due to susceptibility to evaporation, and poor stability in the presence of air, light, moisture and heat. Encapsulation in the form of micro and nano technology has been used to address this challenge, thereby promoting easier handling during processing and storage. Improved stability is achieved by trapping the active or core flavour substances in matrices that are referred to as wall or carrier materials. The latter serve as physical barriers that protect the flavour substances, and the interactions between carrier materials and flavour substances has been the focus of many studies. Moreover, recent evidence also suggests that enhanced bioavailability of flavour substances and their targeted delivery can be achieved by nanoencapsulation compared to microencapsulation due to smaller particle or droplet sizes. The objective of this paper is to review several relevant aspects of physical-mechanical and physicochemical techniques employed to stabilize flavour substances by encapsulation. A comparative analysis of the physiochemical characterization of encapsulates (particle size, surface morphology and rheology) and the main factors that impact the stability of encapsulated flavour substances will also be presented. Food applications as well as opportunities for future research are also highlighted.

Production of Innovative Essential Oil-Based Emulsion Coatings for Fungal Growth Control on Postharvest Fruits

This work assessed the antimicrobial potential of natural essential oils (EOs) from cinnamon (CEO), zataria (ZEO), and satureja (SEO), applied natively or as coatings against Penicillium expansum and Botrytis cinerea during both in vitro and in vivo (on apple fruits) experiments. The induced inhibitory effect towards fungal growth, as a function of both EO type and concentration (75–1200 μL/L), was preliminarily investigated to select the most suitable EO for producing bacterial cellulose nanocrystals (BCNCs)/fish gelatin (GelA)-based emulsions. CEO and ZEO exhibited the best performances against P. expansum and B. cinerea, respectively. None of the pristine EOs completely inhibited the fungal growth and “disease severity”, properly quantified via size measurements of lesions formed on fruit surfaces. As compared to pristine CEO, coating emulsions with variable CEO concentration (75–2400 µL/L) curbed lesion spreading on apples, owing to the controlled CEO release during a 21-day temporal window. The strongest effect was displayed by BCNCs/GelA-CEO emulsions at the highest CEO concentration, upon which lesions on fruit skins were barely detectable. This work demonstrated the capability of EOs embedded in BCNCs/GelA-based nanocapsules to efficiently slow down microbial spoilage on postharvest fruits, thus offering viable opportunities for developing innovative antimicrobial packaging systems.

Emerging drying techniques for food safety and quality: A review

The new trends in drying technology seek a promising alternative to synthetic preservatives to improve the shelf-life and storage stability of food products. On the other hand, the drying process can result in deformation and degradation of phytoconstituents due to their thermal sensitivity. The main purpose of this review is to give a general overview of common drying techniques with special attention to food industrial applications, focusing on recent advances to maintain the features of the active phytoconstituents and nutrients, and improve their release and storage stability. Furthermore, a drying technique that extends the shelf-life of food products by reducing trapped water, will negatively affect the spoilage of microorganisms and enzymes that are responsible for undesired chemical composition changes, but can protect beneficial microorganisms like probiotics. This paper also explores recent efficient improvements in drying technologies that produce high-quality and low-cost final products compared to conventional methods. However, despite the recent advances in drying technologies, hybrid drying (a combination of different drying techniques) and spray drying (drying with the help of encapsulation methods) are still promising techniques in food industries. In conclusion, spray drying encapsulation can improve the morphology and texture of dry materials, preserve natural components for a long time, and increase storage times (shelf-life). Optimizing a drying technique and using a suitable drying agent should also be a promising solution to preserve probiotic bacteria and antimicrobial compounds.

Encapsulation of volatile compounds in liquid media: Fragrances, flavors, and essential oils in commercial formulations

The first marketed example of the application of microcapsules dates back to 1957. Since then, microencapsulation techniques and knowledge have progressed in a plethora of technological fields, and efforts have been directed toward the design of progressively more efficient carriers. The protection of payloads from the exposure to unfavorable environments indeed grants enhanced efficacy, safety, and stability of encapsulated species while allowing for a fine tuning of their release profile and longer lasting beneficial effects. Perfumes or, more generally, active-loaded microcapsules are nowadays present in a very large number of consumer products. Commercial products currently make use of rigid, stable polymer-based microcapsules with excellent release properties. However, this type of microcapsules does not meet certain sustainability requirements such as biocompatibility and biodegradability: the leaking via wastewater contributes to the alarming phenomenon of microplastic pollution with about 4% of total microplastic in the environment. Therefore, there is a need to address new issues which have been emerging in relation to the poor environmental profile of such materials. The progresses in some of the main application fields of microencapsulation, such as household care, toiletries, cosmetics, food, and pesticides are reviewed herein. The main technologies employed in microcapsules production and the mechanisms underlying the release of actives are also discussed. Both the advantages and disadvantages of every technique have been considered to allow a careful choice of the most suitable technique for a specific target application and prepare the ground for novel ideas and approaches for encapsulation strategies that we expect to be proposed within the next years.

Microencapsulation of carotenoid-rich materials: A review

Carotenoids are natural pigments that present several bioactive properties, including antioxidant, anticarcinogenic and provitamin A activities. However, these compounds are susceptible to degradation when exposed to a number of conditions (e.g. light, heat, oxygen), leading to loss of benefits and hampering their application in food products. Their hydrophobicity also makes incorporation into water-based foods more difficult. Microencapsulation techniques have been applied for decades to provide stability to carotenoid-rich extracts under typical conditions of processing and storage of foods, besides offering several other advantages to the use and application of these materials. This work reviews the recent advances in the microencapsulation of carotenoid-rich extracts, oils and oleoresins from varying sources, evidencing the technologies applied to encapsulate these materials, the effects of encapsulation on the obtained particles, and the impact of such processes on the bioaccessibility and release profile of carotenoids from microparticles. Moreover, recent applications of carotenoid-rich microparticles in food products are discussed. Most of the applied processes were effective in improving different aspects of the encapsulated materials, especially the stability of carotenoids during storage, resulting in microparticles with promising properties for future applications in food products. However, the lack of information about the effects of microencapsulation on carotenoids during processing of model foods, the sensory acceptance of enriched food products and the bioaccessibility and bioavailability of microencapsulated carotenoids reveals gaps that should be explored in the future.

Spray drying encapsulation of bioactive compounds within protein-based carriers; different options and applications

Spray-drying is known as a common and economical technique for the encapsulation of various nutrients and bioactive compounds. However, shear and thermal tensions during atomization and dehydration, as well as physicochemical instability during storage, result in a loss of these compounds. As a solution, bioactives are stabilized into different carriers, among which proteins and peptides are of particular importance due to their functional properties, surface activity, and film/shell formability around particles. Given the importance of stabilization of bioactive compounds during spray drying, this paper focuses on the role of composition and type of carriers, as well as the characteristics and efficiency of various protein-based carriers in the encapsulation and maintaining of physicochemical, structural, and functional properties, along with biological activity of bioactive compounds (e.g., oleoresins, sterols, polyphenols, anthocyanins, carotenoids, probiotics, and peptides), and nutrients (e.g., vitamins, fatty acids and minerals) alone or in combination with other biopolymers.

Novel Controlled Release Microspheric Soil Conditioner Based on the Temperature and pH Dual-Stimuli Response

A novel type of temperature and pH dual-stimuli-responsive microspheric soil conditioner was prepared for the controlled release of urea. First, poly(N-isopropylacrylamide-co-methacrylic acid) [P(NIPAM-co-MAA)] was synthesized, and the microspheric soil conditioner was prepared on the basis of chitosan-coated P(NIPAM-co-MAA) via the emulsion cross-linking method. The structure and morphology of the microsphere were characterized by Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance, polarization optical microscopy, and scanning electron microscopy. The microsphere showed controlled release behavior in different temperature and pH conditions, indicating good stimuli responsiveness. The plant experiment revealed that the microsphere can effectively promote plant growth in acidified soil and high-temperature conditions, and the pH value of acidified soil could be improved. In addition, the microsphere possessed good biodegradation property in the soil. Therefore, the multi-responsive microspheric soil conditioner owns a great potential value to amend soil conditions and promote plant growth in agriculture applications.

Performance of oil-in-water emulsions stabilized by different types of surface-active components

The emulsion stability depends on the physicochemical properties of the dispersed phase and their interaction with the continuous phase. Surface-active compounds (SAC) are added in emulsions to reduce the interfacial tension (IT) between these phases and keep the oil droplets stabilized. Moreover, small amounts of SAC can occupy intermolecular voids in the dried matrix, reducing the oxidation. However, the formulation must reflect a trade-off between protection and emulsion stabilization. Therefore, this work aimed to identify the minimum concentration of SAC (modified starch-MS, gelatin-GE, and whey protein isolate-WPI) ranging from 0.48 to 6 % (w/w) to form and stabilize droplets of an unsaturated triglyceride (fish oil-FO) or a volatile oil (orange essential oil-OEO). GE did not change the IT (6.7 mN/m) and stabilized the emulsions only through an increase of the viscosity (∼42 mPas for FO-emulsions and ∼97 mPas for OEO-emulsions), presenting high droplet size (∼10 μm) and low surface charge (∼1.5 mV). WPI reduced the IT to a limit value (4.5 mN/m at 1.2 % w/w for OEO and 5.3 mN/m at 2.4 % w/w for FO), whereas MS reduce constantly the IT with the increase of the concentration for both oils (∼4.2 mN/m at 6 % w/w). Both WPI and MS-emulsions presented similar droplet size (∼2.0 μm), but WPI presented higher surface charge of WPI-emulsions (-45 mV) than MS-emulsions (-30 mV). This study allowed to gain a consistent understanding of structure-property relationships on the use of SAC in emulsions.

Advances in the Application of Microcapsules as Carriers of Functional Compounds for Food Products

Natural bioactive compounds and living cells have been reported as promising products with beneficial properties to human health. The constant challenge regarding the use of these components is their easy degradation during processing and storage. However, their stability can be improved with the microencapsulation process, in which a compound sensitive to adverse environmental conditions is retained within a protective polymeric material. Microencapsulation is a widely used methodology for the preservation and stabilization of functional compounds for food, pharmaceutical, and cosmetic applications. The present review discusses advances in the production and application of microcapsules loaded with functional compounds in food products. The main methods for producing microcapsules, as well as the classes of functional compounds and wall materials used, are presented. Additionally, the release of compounds from loaded microcapsules in food matrices and in simulated gastrointestinal conditions is also assessed.

Preparation and application of flavor and fragrance capsules

The preparation methods and applications of flavor and fragrance capsules based on polymeric, inorganic and polymeric–inorganic wall materials are summarized.