Characterization of spray-dried tuna oil emulsified in two-layered interfacial membranes prepared using electrostatic layer-by-layer deposition

Tuna oil-in-water emulsions containing droplets stabilized by lecithin–chitosan membranes were produced using an electrostatic layer-by-layer deposition process. Corn syrup solids were added to the emulsions and then the emulsions were spray-dried, which produced a powder consisting of spheroid microcapsules (diameter = 5–30 μm) containing tuna oil droplets (diameter <1 μm) embedded within a carbohydrate wall matrix. The powders had relatively low moisture contents (<3%), high oil retention levels (>85%) and rapid water dispersibility (<1 min). The structure of the microcapsules was unaffected by drying temperature from 165 to 195 °C. We have demonstrated that a novel interfacial engineering technology, based on production of multilayer membranes around oil droplets, is effective for producing spray-dried encapsulated tuna oil. The powdered tuna oil produced by this method has good physicochemical properties and dispersibility, which may lead to its more widespread utilization as a food additive.     

Tuna oil and Mentha piperita oil emulsions and microcapsules stabilised by whey protein isolate and inulin: characterisation and stability

Whey protein isolate (WPI) and its polysaccharide complexes have been widely used to prepare oil‐in‐water emulsions. The aim of this study was to evaluate the emulsions and spray‐dried microcapsules containing tuna oil and/or mint oil and stabilised by combination of WPI with inulin in terms of physicochemical characteristics and storage stability. Stable emulsions were formed before drying. Tuna oil + Mentha piperita oil emulsions had smaller viscosity, surface tension and size than did tuna oil emulsions. Surface morphology showed that spray‐dried microcapsules were spheres but had many dents and apparent shrinkage. During storage, tuna oil and tuna oil + M. piperita oil microcapsules became larger. In the blend oil microcapsules, menthone was reduced to form menthol, loss of DHA and EPA was slightly less, the degree of oxidation characterised using peroxide value and headspace propanal was less but basically greater than half of that of WTI microcapsules.     

Ultrasound-assisted encapsulation of annatto seed oil: Retention and release of a bioactive compound with functional activities

This paper brings forward the encapsulation of annatto seed oil (rich in geranylgeraniol) assisted by high intensity ultrasound using gum Arabic (GA) as stabilizing agent. We studied the effects of time (min) and ultrasonication power (W) over the emulsion characteristics. After forming microparticles from the best emulsion using freeze-drying (FD) and spray-drying (SD) techniques, we evaluated particle size distribution, moisture, water activity, surface oil, entrapment efficiency, encapsulation efficiency, geranylgeraniol retention, oxidative stability and kinetic release of geranylgeraniol, a biocompound with functional activities. The combined intensification of time and ultrasonication power reduced the superficial mean diameter (D₃₂) and polydispersity (PDI) of emulsions. Drying the continuous phase of the optimized emulsion (smallest D₃₂ = 0.69 ± 0.03 μm) using FD and SD formed microparticles with different morphological characteristics, Brouckere diameter (D₄₃), particle size distribution, moisture and water activity. SD process led to microparticles with the highest oil encapsulation efficiency (85.1 ± 0.1 wt.%) as a consequence of their lowest surface oil (SO). However, GA-FD microparticles presented the highest oil entrapment efficiency (97 ± 1 wt.%). Geranylgeraniol retention (80–86 wt.%) was similar for both drying techniques. GA-FD microparticles were more stable against oxidation through accelerated test Rancimat, even though presenting higher SO. This behavior is associated with the likely phase transition on the GA-SD matrix. The difference on the kinetic release of geranylgeraniol is linked to the difference on the particles morphology and particle size distribution.     

Optimisation of the microencapsulation conditions and physicochemical properties of enteric‐coated lactase microcapsules

Enteric double‐coated lactase microcapsules were developed, and the encapsulation conditions were optimised using response surface methodology. The optimum concentration of the enteric coating material was 4.85 g/100 mL, and the amount of core material was 1.85 mL. The particle size of the zein‐coated microcapsules was 2.868 μm, which was smaller than that of the other microcapsules. All microcapsules showed high zeta‐potential values between pH 6 and 8. The in vitro release rates of hydroxypropyl methyl cellulose phthalate (HPMCP)‐ and shellac‐coated microcapsules were superior to that of the zein‐coated microcapsules. Finally, the microcapsules were barely hydrolysed in simulated gastric fluid; however, almost all the microcapsules coated with HPMCP or shellac released their contents in simulated intestinal fluid within 2 h (93.23 and 97.27%, respectively).     

Zein/tannic acid complex nanoparticles‐stabilised emulsion as a novel delivery system for controlled release of curcumin

The present work was aimed to evaluate the potential of the gel‐like Pickering emulsions (50%, v/v, oil) stabilised by zein/tannic acid (TA) complex colloidal particles (ZTPE) as a new encapsulation system of lipophilic ingredients. Compared with sodium caseinate‐stabilised emulsions (SCE) and bulk oil, the better protective effects of ZTPE on the chemical stability of curcumin were observed when they suffered from UV light, and the lipid oxidation rate remarkably reduced in ZTPE. Also, the zein particle layers loaded with TA around the oil droplets can provide protection against harsh gastric environment, facilitating to slow down the release of free fatty acids (FFA) and curcumin during in vitro simulated digestion. These findings show that ZTPE have a good potential to act as an efficient encapsulating agent to protect functional ingredients from degradation and control their release during digestion, which can further improve the bioavailability of bioactive ingredients.     

Manipulating oral behaviour of food emulsions using different emulsifiers

This study aims to investigate the assumption that the presence of α-amylase in the human saliva will interact instantly with starch and will lead to very different oral behaviour and enhanced flavour release. Hence, orange oil flavoured emulsion was prepared with whey protein isolates (WPI) and modified starch (MS). The stability and flavour release of emulsions were examined through in vitro and in vivo studies. MS emulsion mixed with artificial saliva containing α-amylase resulted in more pronounced changes in mean particle size from 0.185 to 2.35 μm and a significant increase in viscosity. Morphology and turbidity revealed strong flocculation, coalescence and creaming. However, WPI emulsion exhibited very little changes in stability and behaviour. Similar results were observed during oral digestion (in vivo) for both emulsion systems. Moreover, a higher intensity of flavour release (37%) was observed in MS emulsion than WPI. This work demonstrated that a starch-stabilised emulsion has a very different oral behaviour to that of a protein-stabilised emulsion.     

A synbiotic marine oligosaccharide microcapsules for enhancing Bifidobacterium longum survivability and regulatory on intestinal probiotics

A novel synbiotic multiparticulate microparticle containing alginate oligosaccharide (AOS), chitosan oligosaccharide (COS) and Bifidobacterium longum CICC 6259 was produced in the current study to expand the synbiotic industrial applications. The influences of these treatments on encapsulation yield, size, morphology, protective effect and stability of microcapsules and on mice gut microbiome were studied in vitro and in vivo. In vitro experiments detected no significant difference (P > 0.05) in encapsulation yield with different types of microcapsules. However, the microcapsule diameter of marine oligosaccharide was approximately 60 μm greater, and these microcapsules increased the number of surviving cells by more than 3 log cfu/g after treatment with simulated gastrointestinal juices, compared to basic alginate microcapsules. In vivo, these microcapsules significantly increased the content of Bifidobacterium and Lactobacillus and reduced the content of Enterococcus and Escherichia in mice gut microbiome. Marine oligosaccharide probiotic microcapsules are promising as a novel functional food ingredient.     

CuO nanoparticles/Indonesian cedarwood essential oil-loaded chitosan coating film: characterisation and antifungal improvement against Penicillium spp.

A novel formulation of composite coating comprising 0.8% chitosan (Chi) incorporating 0.025% CuO nanoparticles (CuO) and 0.5% Indonesian cedarwood essential oil (CEO) was fabricated by casting method. Fourier transform infrared, confocal laser scanning microscopy and scanning electron microscopy analyses were employed to characterise the biocompatibility of each formulation. Additionally, the physico-chemically properties of the composite coatings were characterised. The colour (L*), light transmission, zeta potential and roughness of Chi were significantly (P < 0.05) altered negatively by the presence of CuO or CEO; the colour (a*, b* and ∆E), apparent viscosity and transparency also changed positively as a consequence of CuO and CEO incorporation. The antifungal features of a pure Chi coating against Penicillium italicum and Penicillium digitatum were improved synergistically by CuO and CEO, confirmed by in vitro and in vivo assays. Composite coatings obtained in this work may have potential applications for active primary food packaging, particularly for fresh postharvest commodities.     

The influence of drying methods on the stabilization of fish oil microcapsules: Comparison of spray granulation, spray drying, and freeze drying

The stability of microencapsulated fish oil prepared using various drying methods is investigated. The fish oil with ratio of 33/22, eicosapentaenoic acid (EPA):docosahexaenoic acid (DHA), is emulsified with four combinations of matrices, and emulsions are dried by spray granulation (SG), spray drying (SD), and freeze drying (FD) to produce 25% oil powders. The objective is to identify the most critical factors to determine powder stability and to further examine the superiority of the SG process compared to other drying processes. The stability is examined by measurement of peroxide values (PV) and GC-headspace propanal after 8-week’s storage at room temperature (±21 °C)The best matrices are a combination of 10% soybean soluble polysaccharide (SSPS) and 65% octenyl succinic anhydride (OSA-starch). Microencapsulation of 620 mg/g omega−3 fish oil with these matrices then dried by SG is able to produce powder having a very low propanal content and with a shelf life of 5 weeks at ±21 °C. The results indicate that microcapsules produced by SG are actually formed firstly by agglomeration of seed particles. These agglomerated particles are then covered by successive layers. The particle enlargement is determined by mechanism of the layer growth. Therefore, the SG process produces “multiple encapsulations” granules which provide maximum protection to the oil droplets.Comparison of the SG, SD, and FD processes confirms that combination of matrices, drying temperature, microcapsule morphology, and processing time are among the most critical factors governing stability. Exposure to heat is proved to be a limiting factor for drying unstable emulsion.     

Digestive protection of probiotic Lacticaseibacillus rhamnosus in Ricotta cheese by monoglyceride structured emulsions

This research aimed at studying the potential use of monoglyceride (MG) structured emulsions (MSEs) as delivery and protective systems for probiotic bacteria in Ricotta cheese. To this purpose, a low-fat commercial Ricotta cheese was added with MSEs formulated with milk, as water phase, and sunflower oil (MSE-SO) or anhydrous milk fat (MSE-AMF), as lipid phase. A commercial whole milk Ricotta cheese (W-RC) was considered as reference. A probiotic Lacticaseibacillus rhamnosus strain was inoculated as free cells in W-RC or embedded into the MSEs and added to the low-fat Ricotta at the same reference fat content. After physico-chemical characterisation, L. rhamnosus viability and sample destructuring behaviour upon in vitro digestion were evaluated. At the end of in vitro digestion, both W-RC and sample containing MSE-SO were unable to protect cells. By contrast, sample with AMF ensured a sufficient probiotic viability, even after 14 days of storage at 4 °C. This result was attributed to system composition and structure. During the gastric phase, the presence of caseins and MG-AMF mixed structures induced the formation of clots, entrapping and protecting cells against the acidic pH of the stomach, as confirmed by confocal micrographs and particle size. During the intestinal phase, cell viability was guaranteed by the formation of mixed micelles promoted by MG. It was demonstrated that microbial cells located near MG structures where they found protection.     

Designing emulsion droplets of foods and beverages to enhance delivery of lipophilic bioactive components – a review of recent advances

Lipophilic bioactive compounds such as lipids, vitamins and phytochemicals serve important antioxidant, functional, nutritional and structural roles in the human body. Colloidal systems such as emulsions are particularly suitable matrices for the protection and delivery of these compounds. This article summarises the principal lipophilic bioactives important for human health and challenges associated with their delivery. It discusses the compositional and physical characteristics of emulsions in relation to bioactive delivery, and chemical stability aspects to consider when engineering efficient emulsion delivery systems. The literature shows that aspects such as oil type, droplet size, interfacial composition and solubilisation capacity impact bioactive availability and that their effects are bioactive specific. Therefore, emulsions must be tailored to the bioactives delivered. Much of the present knowledge is based on in vitro studies, and more data from animal and human models are required to better understand the relationship between emulsion characteristics and bioavailability of lipophilic bioactives.     

Spray-drying microencapsulation of pomegranate juice increases its antioxidant activity after in vitro digestion

Most of the work on pomegranate antioxidant and antibacterial activity has been carried out with solvent extracts of different plant or fruit parts. Biosensitive compounds in juice may be subject to oxidation, reducing their biological activities. Microencapsulation can be used to protect compounds, allowing its incorporation into functional foods. This study aimed at investigating antioxidant activity after in vitro digestion of microencapsulated juice. Pomegranate juice was encapsulated by spray drying its maltodextrin and gum arabic. The average diameter of the microcapsules was 10–50 µm. We evaluated the bioaccessibility of microencapsulated phenolic compounds by using an in vitro enzymatic digestion. The total phenolic content in digested microencapsulated juice was three times greater than in undigested, indicating that the compounds were made bioaccessible. Digestion also increased antioxidant activity, as measured by ABTS●+ or by DPPH●. Additionally, microencapsulated pomegranate juice showed antibacterial activity against the nine bacteria species tested.     

Modification of chitosan using hydrogen peroxide and ascorbic acid and its physicochemical properties including water solubility,oil entrapment and in vitro lipase activity

Chitosan was modified using H₂O₂ and ascorbic acid with different incubation temperatures (4–40 °C). The properties of modified chitosan, including its oil entrapment ability, water solubility and the lipase-resistant activities, using in vitro intestine model system were determined. Nuclear magnetic resonance analysis showed that ascorbic acid was bound to modified chitosan. All of the modified chitosan from 4 to 40 °C demonstrated improved water solubility (even in pH 7) compared to non-modified chitosan, which was only soluble at pH 4. Modified chitosan from 4 °C exhibited 27.40% of oil entrapment ability which was approximately four times higher than 6.87% of non-modified chitosan. Modified chitosan from 4 and 40 °C had increased resistance against lipase activity compared to other biopolymers, including beeswax, carnauba wax and non-modified chitosan. Modified chitosan could be used as a new food ingredient due to their high water solubility, oil-entrapping ability and resisting lipase activity.     

Fabrication of chitosan nanoparticles incorporated with Pistacia atlantica subsp. kurdica hulls’ essential oil as a potential antifungal preservative against strawberry grey mould

Essential oil was extracted from Pistacia atlantica subsp. kurdica hulls and encapsulated in chitosan nanoparticles (NPs) by an emulsion-ionic gelation method. A desirable retention rate (43.3–61.5%) of P. atlantica subsp. kurdica hulls’ essential oil (PAHEO) encapsulated in chitosan NPs was confirmed. In addition, the Fourier transform infrared spectroscopy and X-ray diffraction analysis results revealed the success of PAHEO encapsulation. The formed NPs illustrated a shrunk and spherical shape with a size range of 187.2–632.5 nm as indicated by scanning electron microscopy and dynamic light scattering. The encapsulated PAHEO had a high antifungal activity against Botrytis cinerea under both the in vitro and in vivo conditions. It also significantly decreased the incidence and disease severity of grey mould on strawberries during storage. The spoilage process was postponed by the 8th days of storage at 4 °C in the strawberry fruit treated by PAHEO-incorporated chitosan NPs. These findings imply that NP-encapsulated PAHEO will have promising novel applications in food industries.     

Hydroxypropyl methylcellulose-modified whey protein concentrate microcapsules for the encapsulation of tangeretin

The oral bioavailability of tangeretin is limited by its low water solubility and high crystallisation. In the present study, tangeretin was entrapped in whey protein concentrate (WPC)-stabilised emulsions to enhance its bioaccessibility. Hydroxypropyl methylcellulose (HPMC) was added to modify the interface of the emulsion droplets, and Ca²⁺-crosslinking was used to induce the gel formation. Spray drying of the emulsions or gels enabled to produce microcapsules. The physicochemical characteristics and in vitro digestion behavior of the microcapsules were investigated. Results indicated that HPMC modification and Ca²⁺-crosslinking increased the average particle size, altered the microstructure, ameliorated the quality of the WPC-based microcapsules and improved the encapsulation efficiency of tangeretin. Furthermore, the in vitro studies showed that HPMC modified and Ca²⁺-added microcapsules could control the release of free fatty acid. HPMC greatly increased the bioaccessibility of tangeretin from around 28% to 80%. Overall, these results confirmed that HPMC-modified WPC microcapsules could be a promising carrier to protect hydrophobic functional ingredients and improve their oral bioavailability.     

Fabrication,characterization and lipase digestibility of food-grade nanoemulsions

The behavior of nanoemulsion-based delivery systems within the gastrointestinal tract determines their functional performance. In this study, the influence of particle radius (30–85 nm) on the in vitro digestion of nanoemulsions containing non-ionic surfactant stabilized lipid (corn oil) droplets was examined using simulated small intestine conditions. Nanoemulsions were prepared by a combination of high-pressure homogenization and solvent (hexane) displacement. Lipid droplets with different sizes were prepared by varying the oil-to-solvent ratio in the disperse phase prior to homogenization. The fraction of free fatty acids (FFA) released from emulsified triacylglycerols (TG) during digestion was measured by an in vitro model (pH-Stat titration). Nanoemulsions exhibited a lag-period before any FFA were released, which was explained by inhibition of lipase adsorption to the oil–water interface by free surfactant. After the lag-period, the digestion rate increased with decreasing oil droplet diameter (increasing specific surface area). The total amount of FFA released from the emulsions increased from 61% to 71% as the mean droplet radius decreased from 86 nm to 30 nm. The incomplete digestion of the emulsified lipids could be explained by inhibition of lipase activity by the release of fatty acids and/or by interactions between lipase and surfactants molecules.     

In vitro caecum fermentation and in vivo (Gallus gallus) of calcium delivery systems fabricated by desalted duck egg white peptides and chitosan oligosaccharide on gut health

As calcium supplements, two novel calcium delivery systems were prepared with desalted duck egg white peptides (DPs) and chitosan oligosaccharide (COS) by Amadori-linkage and transglutaminase (TGase)-induced reaction, with high calcium-binding ability of promoting calcium absorption in vivo and in vitro. However, there are relatively few studies on the gut health of calcium delivery systems. In this experiment, in vitro caecum fermentation experiment and Gallus gallus intra amniotic feeding model were used to assess the gut health of calcium delivery systems and phytic acid. Results showed that two calcium delivery systems improved the microbial community structure by inhibiting the proliferation of Escherichia coli, and promoting the proliferation of Bifidobacterium and Lactobacillus. The addition of calcium delivery systems significantly increased short chain fatty acids (SCFAs) and improved the boundary membrane function of brush nutrients by significantly increasing villi structure, surface area, cup cell expansion and production of associated genes (P < 0.05). Moreover, calcium delivery systems present significant reverse of the inhibitory effect of phytic acid on gut health through in vitro and in vivo experiments. This study suggested that DPs-COS-Ca systems were superior to the commercially available calcium supplement CaCO₃ and had excellent calcium absorption and gut health regulating effects.     

Antioxidative and antimicrobial effects of low molecular weight shrimp chitosan and its derivatives on seasoned-dried Pangasius fillets

This study was performed to evaluate the efficacy and applicability of low molecular weight shrimp chitosan (LMWC) and its derivatives (chitosan nanoparticles, CN; chitosan hydrochloride salt, CHS) as a preservative against lipid oxidation and microbial growth in seasoned-dried Pangasius hypophthalmus fillets during storage. All chitosans exhibited antioxidant activity in vitro (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, total reducing power ability and lipid peroxidation inhibition activity). The lipid oxidation in dried pangasius fillets that were seasoned by immersing in a solution containing 1.5% chitosan was suppressed during the 8-week storage; such effect was more effective than immersing in a solution containing 0.05% vitamin C. Likewise, LMWC and its derivatives were more effective in inhibiting microbial growth (lower total viable count and yeast/mould counts) than the control. These results clearly show that LMWC and its derivatives could be a potent antioxidant and antimicrobial preservative in seasoned-dried pangasius fillets during 8-week storage at 20 °C.     

Nanostructures and polymorphisms in protein stabilised lipid nanoparticles,as food bioactive carriers: contribution of particle size and adsorbed materials

Eight oil-in-water emulsions were prepared using melt high-pressure homogenisation (HPH) at 300 or 1200 Bar. The emulsions produced from lipid phase (20%) were composed by palm oil alone or in mixture with α-tocopherol at 4:1 weight ratio, and an aqueous phase containing whey proteins alone or in mixture with phospholipids. The resulting nanoemulsions (fat droplet size ranging from 200-500 nm) presented different stability against aggregation and coalescence, fat crystallinity and polymorphisms in relation to different degrees of α-tocopherol encapsulation and protection against chemical degradation. Protein stabilised emulsions were monomodal, while emulsions stabilised by proteins and lecithins were slightly bimodal. Application of an isothermal treatment (4 °C for 2 hours) to these emulsions showed crystallization peaks located at longer time values in smaller particle size emulsions, while in the presence of added α-tocopherol average particle size values were higher and crystallization was not observed in 2 hours storage. Study of fat polymorphisms performed after 12 hours storage at 4 °C revealed the formation of 2L structures with coexistence of α, β’ and β forms in all of the emulsions. Increasing HPH from 300 to 1200 Bar favoured development of β structure (4.5 A^-1) in α-tocopherol added emulsions, with the presence of one extra peak β structure evolved at 3.9 A^-1 only in emulsions containing lecithins. α-tocopherol addition decreased in 2L structures (by approx. 40-50%). The formation of lipid nanoparticles with decreasing size values (increasing HPH parameters) was accompanied by increased long-term stability against aggregation and coalescence, but increased vitamin degradation (up to 15 wt% for 1200 bar). Degradation of α-tocopherol after 2 months storage at 4 °C was lower for nanoparticles stabilised by whey proteins alone (21 and 33%, respectively) than for nanoparticles stabilised by whey proteins in mixture with phospholipids and presenting higher size values (44 and 52%, respectively), where β polymorphs were more evolved.     

Physical and chemical properties of encapsulated rosemary essential oil by spray drying using whey protein–inulin blends as carriers

The objective of this study was to evaluate the influence of whey protein isolate (WPI) and inulin blends on the properties of rosemary essential oil microencapsulated by spray drying. The following ratios (w/w) of WPI to inulin were evaluated: 1:1, 1:3 and 3:1. Increasing the WPI concentration increased the particle instantanisation times and decreased the moisture content. The samples did not differ significantly (P > 0.05) in hygroscopicity and porosity. The microcapsules produced at higher inulin concentration showed the highest bulk density and tapped density and were significantly different from other treatments. WPI/inulin blends of 1:1 and 3:1 proved to be effective carriers to entrap rosemary essential oil. The encapsulated oil composition in particles proved to be quite similar to pure oil, and no interaction between wall matrix and encapsulated oil was demonstrated. The analysis of particle size distribution revealed that the particle size varied from 11.5 to 11.9 μm and that all samples had an amorphous structure.