Characterization and human microfold cell assay of fish oil microcapsules: Effect of spray drying and freeze-drying using konjac glucomannan (KGM)-soybean protein isolate (SPI) as wall materials

Improved physicochemical properties and in vitro digestion of walnut oil microcapsules with soy protein isolate and highly oxidized konjac glucomannan as wall materials

This study investigated the effect of the oxidation degrees of oxidized konjac glucomannan (OKGM) on the encapsulation efficiency (EE), physicochemical and in vitro digestive properties of soy protein isolate (SPI)-based microcapsules walnut oil using experimental and computational approaches. Microcapsules had the highest EE when the ratio of OKGM and SPI to oil was 2.5:1. With increasing the oxidation degree of OKGM, the EE of microcapsules was increased and the hygroscopicity was decreased. Molecular dynamics simulation results showed that SPI/oil/highly OKGM had relatively low binding energy (-4.03 × 106 kJ/mol) and strong electrostatic interactions, which may contribute to a higher EE and lower hygroscopicity of microcapsules, respectively. The oxidative stability of the oil was markedly improved by SPI and OKGM, and microcapsules prepared with SPI and highly OKGM had the highest in vitro digestion. This study provided theoretical support for broadening the application of microcapsules prepared with SPI and OKGM.

Microencapsulation of fish oil by spray drying, spray freeze-drying, freeze-drying, and microwave freeze-drying: Microcapsule characterization and storage stability

The objective of this paper was to evaluate the effect of spray drying (SD), spray freeze-drying (SFD), freeze-drying (FD), and microwave freeze-drying (MFD) on the characteristics of fish oil (FO) microcapsules. The physicochemical properties, morphology, fatty acid composition, and stability of the microcapsules were analyzed. The encapsulation efficiencies of microcapsules dried by SD, SFD, FD, and MFD were 86.98%, 77.79%, 63.29%, and 57.89%, respectively. SD microcapsules exhibited superior properties in terms of effective loading capacity, color, and flowability. Conversely, SFD microcapsules demonstrated improved solubility. Microencapsulation positively affected the thermal stability of FO, but the content of unsaturated fatty acids decreased. The findings from the storage experiment indicated that the oxidative stability of SD fish oil microcapsules was marginally lower compared to microcapsules produced through three alternative drying techniques, all of which were based on the FD concept. The comparison of various drying methods and their effects on the quality of FO microcapsules offers valuable insights that can serve as a foundation for the industrial production of high-quality microcapsules.

Preparation and Characterization of Prickly Ash Peel Oleoresin Microcapsules and Flavor Retention Analysis

Prickly ash peel oleoresin (PPO) is a highly concentrated oil of Prickly ash essential oil and has a stronger aroma. However, its low water solubility, high volatility, difficulty in transport and storage, and decomposition by light, heat, and oxygen limit its wider application. To solve this problem, this study used freeze-drying or spray-drying, with soybean protein isolate (SPI) or gum Arabic (GA), combined with aqueous maltodextrin (MD) as the encapsulating agents to prepare four types of PPO microcapsules (POMs). Spray-dried microcapsules with GA as the encapsulating agent achieved a high encapsulation efficiency (EE) of 92.31 ± 0.31%, improved the thermal stability of the PPO, and had spherical morphology. (Headspace solid-phase microextraction/gas chromatography-mass spectrometry) HS-SPME/GC-MS detected 41 volatile compounds in PPO; of these, linalool, β-myrcene, sabinene, and D-limonene were identified as key flavor components. Principal component analysis (PCA) effectively distinguished the significant differences in flavor between PPO, spray-dried SPI/MD microcapsules (SS), and spray-dried GA/MD microcapsules (SG). During 15 days of air-exposure, the loss of flavor from SG (54.62 ± 0.54%) was significantly lower than PPO (79.45 ± 1.45%) and SS (57.55 ± 0.36%). During the air-exposure period, SG consistently had the highest antioxidant capacity, making it desirable for PPO packaging, and expanding its potential applications within the food industry.

Advances in protein-based microcapsules and their applications: A review

Due to their excellent emulsification, biocompatibility, and biological activity, proteins are widely used as microcapsule wall materials for encapsulating drugs, natural bioactive substances, essential oils, probiotics, etc. In this review, we summarize the protein-based microcapsules, discussing the types of proteins utilized in microcapsule wall materials, the preparation process, and the main factors that influence their properties. Additionally, we conclude with examples of the vital role of protein-based microcapsules in advancing the food industry from primary processing to deep processing and their potential applications in the biomedical, chemical, and textile industries. However, the low stability and controllability of protein wall materials lead to degraded performance and quality of microcapsules. Protein complexes with polysaccharides or modifications to proteins are often used to improve the thermal instability, pH sensitivity, encapsulation efficiency and antioxidant capacity of microcapsules. In addition, factors such as wall material composition, wall material ratio, the ratio of core to wall material, pH, and preparation method all play critical roles in the preparation and performance of microcapsules. The application area and scope of protein-based microcapsules can be further expanded by optimizing the preparation process and studying the microcapsule release mechanism and control strategy.

Advances in the construction and application of konjac glucomannan-based delivery systems

Konjac glucomannan (KGM) has been widely used to deliver bioactive components due to its naturalness, non-toxicity, excellent biodegradability, biocompatibility, and other characteristics. This review presents an overview of konjac glucomannan as a matrix, and the types of konjac glucomannan-based delivery systems (such as hydrogels, food packaging films, microencapsulation, emulsions, nanomicelles) and their construction methods are introduced in detail. Furthermore, taking polyphenol compounds, probiotics, flavor substances, fatty acids, and other components as representatives, the applied research progress of konjac glucomannan-based delivery systems in food are summarized. Finally, the prospects for research directions in konjac glucomannan-based delivery systems are examined, thereby providing a theoretical basis for expanding the application of konjac glucomannan in other industries, such as food and medicine.

Comparison of Electrostatic Spray Drying, Spray Drying, and Freeze Drying for Lacticaseibacillus rhamnosus GG Dehydration

Spray drying (SD) is extensively used to encapsulate lactic acid bacteria in large-scale industrial applications; however, bacteria combat several harms that reduce their viability. In this study, a novel technique called electrostatic spray drying (ESD) was used to explore the benefits and disadvantages of using electrostatic charge and lower temperatures in the system. Freeze drying (FD) was used as a reference. The effect of different encapsulation agents, like maltodextrin, arabic gum, and skim milk, on the viability of Lacticaseibacillus rhamnosus GG (LGG) was investigated. The initial cell concentration, particle size distribution, aspect ratio, sphericity, scanning-electron-microscopy images, moisture content, water activity, glass transition, rehydration abilities, and survival during storage were compared. Skim milk was proven to be the best protectant for LGG, regardless of the drying process or storage time. A huge reduction in cell numbers (4.49 ± 0.06 log CFU/g) was observed with maltodextrin using SD; meanwhile, it was protected with minimum loss (8.64 ± 0.62 log CFU/g) with ESD. In general, ESD preserved more LGG cells during processing compared to SD, and provided better stability than FD and SD during storage, regardless of the applied voltage. The ESD product analysis demonstrated an efficient LGG preservation, close to FD; therefore, ESD presented to be a promising and scalable substitute for SD and FD.

Recent Advances in the Microencapsulation of Essential Oils, Lipids, and Compound Lipids through Spray Drying: A Review

In recent decades, the microcapsules of lipids, compound lipids, and essential oils, have found numerous potential practical applications in food, textiles, agricultural products, as well as pharmaceuticals. This article discusses the encapsulation of fat-soluble vitamins, essential oils, polyunsaturated fatty acids, and structured lipids. Consequently, the compiled information establishes the criteria to better select encapsulating agents as well as combinations of encapsulating agents best suited to the types of active ingredient to be encapsulated. This review shows a trend towards applications in food and pharmacology as well as the increase in research related to microencapsulation by the spray drying of vitamins A and E, as well as fish oil, thanks to its contribution of omega 3 and omega 6. There is also an increase in articles in which spray drying is combined with other encapsulation techniques, or modifications to the conventional spray drying system.

Microencapsulation of tomato seed oil using phlorotannins-adducted pea protein isolate-chitosan and pea protein isolate-chitosan complex coacervates

Pea protein isolates (PPI)/phlorotannins (PT)/chitosan (CS) ternary complex and PPI/CS binary complex were synthesized to prepare tomato seed oil (TSO) microcapsules. The concentration of PT was determined to be 0.025% (w/w) based on the solubility, emulsification, and UV-visible spectrum of PPI-PT complex. Subsequently, the optimal pHs associated with the formation of PPI/CS and PPI-PT/CS complex coacervates were determined to be pH 6.6 and 6.1, while the optimal ratios were 9:1 and 6:1, respectively. The coacervate microcapsules were successfully produced by freeze-dried method and those formulated with PPI-PT/CS displayed significantly lower surface oil content (14.57 ± 0.22%), higher encapsulation efficiency (70.54 ± 0.13%), lower particle size (5.97 ± 0.16 μm), and PDI (0.25 ± 0.02) than PPI/CS. The microcapsules were characterized by scanning electron microscopy and Fourier Transform infrared spectroscopy. Furthermore, the encapsulated TSO exhibited enhanced thermal and oxidative stability than that of free oil, along with microcapsules fabricated with PPI-PT/CS ternary complex showed better protection than that of free PT. Overall, PPI-PT/CS complex as an effective wall material in delivery system presented great potential.

Effects of citrus essential oils on the oxidative stability of microencapsulated fish oil by spray-drying

The effects of citrus essential oils (orange, lemon, mandarin, and grapefruit) on the oxidative stability of microencapsulated fish oil by spray-drying were evaluated. The encapsulation efficiency of microcapsules was in the range of 42.25 and 62.43%. Twelve active substances were determined as major volatile components of citrus essential oils. The highest phenolic content was obtained from grapefruit essential oil (44.32 mg GAE/g). Lower values of thiobarbituric acid reactive substances (TBARs) were obtained for microencapsulated fish oils with essential oils compared to control. At the end of storage, the highest peroxide value (PV) was observed in the control group (25.30 meq O₂/kg oil) while the lowest value was in the lemon (13.40 meq O₂/kg oil) and orange group (13.91 meq O₂/kg oil). The results of this study showed that citrus essential oils can be used to improve the oxidative stability of fish oil microcapsules.

Emulsion Properties during Microencapsulation of Cannabis Oil Based on Protein and Sucrose Esters as Emulsifiers: Stability and Rheological Behavior

The effects of different emulsifiers, such as soy protein isolate-sucrose ester (SPI-SE) and whey protein isolate-sucrose ester (WPI-SE), on the properties of the emulsion during the microencapsulation of cannabis oil were studied. The influence of SE concentration on the emulsion properties of the two emulsifying systems was analyzed. The results of the adsorption kinetics show that SE can decrease the interfacial tension, particle size and zeta potential of the emulsions. The results of the interfacial protein concentration show that SE could competitively replace the protein at the oil-water interface and change the strength of the interfacial film. The results of the viscoelastic properties show that the emulsion structure of the two emulsion systems results in the maximum value when the concentration of SE is 0.75% (w/v), and the elastic modulus (G') of the emulsion prepared with SPI-SE is high. The viscosity results show that all emulsions show shear-thinning behavior and the curve fits well with the Ostwald-Dewaele model. The addition of SE in the emulsions of the two emulsion systems can effectively stabilize the emulsion and change the composition and strength of the oil-water interface of the emulsion. The cannabis oil microcapsules prepared with protein-SE as an emulsion system exhibit high quality.

Recent Developments in the Microencapsulation of Fish Oil and Natural Extracts: Procedure, Quality Evaluation and Food Enrichment

Due to the beneficial health effects of omega-3 fatty acids and antioxidants and their limited stability in response to environmental and processing factors, there is an increasing interest in microencapsulating them to improve their stability. However, despite recent developments in the field, no specific review focusing on these topics has been published in the last few years. This work aimed to review the most recent developments in the microencapsulation of fish oil and natural antioxidant compounds. The impact of the wall material and the procedures on the quality of the microencapsulates were preferably evaluated, while their addition to foods has only been studied in a few works. The homogenization technique, the wall-material ratio and the microencapsulation technique were also extensively studied. Microcapsules were mainly analyzed for size, microencapsulation efficiency, morphology and moisture, while in vitro digestion, flowing properties, yield percentage and Fourier transform infrared spectroscopy (FTIR) were used more sparingly. Findings highlighted the importance of optimizing the most influential variables of the microencapsulation procedure. Further studies should focus on extending the range of analytical techniques upon which the optimization of microcapsules is based and on addressing the consequences of the addition of microcapsules to food products.

Microencapsulation of Citrus aurantifolia essential oil with the optimized CaCl2 crosslinker and its antibacterial study for cosmetic textiles†

A functional fabric immobilized by the microcapsules of C. aurantifolia lime essential oil (LO) was prepared and characterized. A varied amount of CaCl₂ crosslinker was optimized to coacervate LO using alginate–gelatin biopolymers and Tween 80 emulsifier. A further evaluation of the immobilized LO microcapsules for the antibacterial effect against both Gram-positive and Gram-negative bacteria was conducted. The optimized alginate/gelatin-based microcapsules were effectively crosslinked by 15% CaCl₂ with an yield, oil content (OC), and encapsulation efficiency (EE) of 39.91 ± 3.10%, 78.33 ± 7.53%, and 90.27 ± 5.84%, respectively. A spherical shape of LO microcapsules was homogeneously found with an average particle size of 1.394 μm. A first-order kinetics mechanism for the release of LO out of the microcapsules was modeled by Avrami's kinetic equation (k = 1.60 ± 3.68 × 10⁻⁵ s⁻¹). The LO microcapsules demonstrated good thermal stability up to 100 °C and maintained 51.07% OC and 43.56% EE at ambient temperature for three weeks. Using a pad dry method and citric acid binder, LO microcapsules were successfully immobilized on a cloth with a % add on 30.60 ± 1.80%. The LO microcapsules and the immobilized one exhibited a moderate ZoI of bacterial growth for Gram-positive S. aureus and S. epidermidis as well as Gram-negative E. coli and K. pneumonia. Further washing test toward the functional fabric showed that the LO microcapsules incorporated into the fabric were resistant to five cycles of normal washing with a mass reduction of 22.01 ± 1.69%.

A functional fabric immobilized by the microcapsules of C. aurantifolia lime essential oil (LO) was prepared and characterized.