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• Black rice anthocyanins were encapsulated by spray-drying and ionic gelation. • Spray-dried microcapsules had better retention and release of anthocyanins. • Simulated digestion revealed the release characteristics of 13 wall materials used. • Whey protein isolate preserved in vitro intestinal anthocyanin stability and bioactivity. Anthocyanin-rich extracts derived from the bran of a select Thai black rice cultivar, Leum Pua, were encapsulated by spray drying. In this microencapsulation method, twelve wall materials comprising maltodextrin (M), gum arabic (G), whey protein isolate (W), and their combinations were employed. For comparison, an ionic gelation method was employed using alginate-whey protein isolate (AL-W) as a wall material. Thirteen microcapsules were analysed by scanning electron microscopy, and their encapsulation efficiencies were almost 100%, except for that of the W (83%). M (88%) and its combination with W exhibited the best anthocyanin retention, while pure W contained the highest amount of total phenolic compounds and antioxidant activity. An in vitro digestion study using simulated gastrointestinal fluids revealed the highest released total phenolic content and antioxidant activity of the intestinal fluids when the microcapsule was spray-dried with pure W. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Encapsulation of stevia crude extract within two alginate blends by ionic gelation has been assessed. • High encapsulation efficiency of polyphenols was achieved for all stevia-loaded beads. • Size of beads decreased as encapsulation efficiency increased for both the blends. • Metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. • Crosslinking conditions impacted on phenolic profile providing a selective uptake. Abstract We formulated and characterised two alginate blends for the encapsulation of stevia extract (SE) via ionic gelation through an extrusion technique. Calcium chloride in SE and calcium chloride solutions were assessed as crosslinkers to overcome phenolic losses by diffusion and increase encapsulation efficiency (EE). Regardless of the blend, all stevia-loaded beads exhibited high EE (62.7–101.0%). The size of the beads decreased as EE increased. Fourier transform infrared analysis showed increased hydrogen bonding between SE and alginates, confirming the successful incorporation of SE within the matrix. Untargeted metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. Flavonoids (catechin and luteolin equivalents) were predominant in SE whereas tyrosols and 5-pentadecylresorcinol equivalents were predominant in all bead formulations. Three-common discriminant compounds were exclusive to each blend and were inversely affected by the crosslinking conditions. Both alginate blends have been shown to be feasible as carrier systems of stevia extracts independent of crosslinking conditions. [ABSTRACT FROM AUTHOR]

Flaxseed oil is a major source of omega-3 polyunsaturated fatty acids (PUFAs), as it contains nearly 50% of alpha-linolenic acid. For this reason it is highly susceptible to auto-oxidation. The aim of the work was to increase the stability of flaxseed oil by a microencapsulation process based on ionic gelation through vibrating-nozzle extrusion technology, using pectin as shell material. Two different drying systems, passive air drying (AD) and fluid bed (FB), were compared. The results show that the encapsulation efficiency is very high (up to 98%). Besides being approximately 20-fold faster, FB gives beads showing on average higher payload (76% vs 68%) and lower peroxide value (9.64 vs 21.33) than the AD. An accelerated test carried out on FB-dried beads shows that the oxidative stability of encapsulated oil is 13-fold higher than bulk oil (PV FB: 20 vs PV oil: 260), demonstrating the protecting effect of microencapsulation. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effect of Prosopis alba exudate gum (G) as encapsulating matrix component on water-solid interactions, physical state, oxidative damage and appearance properties of alginate-chitosan encapsulates containing fish oil. With this purpose, water sorption isotherms were obtained at 25 °C. G increased the hygroscopicity of encapsulates, showing a higher monolayer water content (7.87 ± 0.47% db.) than control (1.07 ± 0.04% db.). G introduction reduced the plasticizing effect of water, increasing the a w range (a w  < 0.45) at which samples were in amorphous state and providing the highest protection against lipid oxidation. Appearance properties (chromatic and optical) were affected by hydration and were better maintained in samples containing G at a w  > 0.52. These results allow considering Prosopis alba exudate gum, as a novel excipient to protect fish oil encapsulated in low moisture polyelectrolyte systems, with the added benefits of employing an undervalued natural resource. [ABSTRACT FROM AUTHOR]

Hibiscus extract (HE) has a strong antioxidant activity and high anthocyanin content; it can be used as a natural pigment, also adding potential health benefits. The objective of this work was the microencapsulation of HE anthocyanin by ionic gelation (IG) using two techniques: dripping-extrusion and atomization, both by means of a double emulsion (HE/rapseed oil/pectin) and a cross-linked solution (CaCl 2 ). Particles (77–83% moisture content) were conditioned in acidified solution at 5, 15 and 25 °C, absence of light, and evaluated for anthocyanins and color for 50-days. The median diameter (D 50 ) of the particles ranged from 78 to 1100 μm and encapsulation efficiency ranged from 67.9 to 93.9%. The encapsulation caused higher temperature stability compared with the free extract. The half-life (t 1/2 ) values of the particles ranged from 7 (25 °C) to 180 days (5 °C) for anthocyanins and from 25 (25 °C) to 462 days (5 °C) for Chroma value. The IG increased the stability of HE anthocyanin. Both the dripping-extrusion and the atomization have shown to be feasible techniques. [ABSTRACT FROM AUTHOR]

Essential oils are a good antimicrobial and antioxidant agent alternative in human or animal feed. However, their direct use has several disadvantages such as volatilization or oxidation. The development of essential oil microspheres may help to avoid these problems. The objective of the present research was to microencapsulate thyme essential oil by generating emulsions with different dispersion degrees. The emulsions were encapsulated in calcium-alginate microspheres by ionic gelation. The microspheres were evaluated regarding size, shape, encapsulation efficiency, loading capacity and antimicrobial properties. The results indicate that encapsulation efficiency and loading capacity are dependent on concentration and degree of dispersion. The best encapsulation conditions were obtained at 2% v/v of thyme essential oil with a high dispersion degree (18,000 rpm/5 min), which was achieved with an efficiency of 85%. Finally, the microspheres obtained showed significant antimicrobial effect, especially in gram-positive bacteria. [ABSTRACT FROM AUTHOR]

The aim of the present work was to employ an exudate gum obtained from a South American wild tree ( Prosopis alba ), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate–chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate–chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate–chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect. [ABSTRACT FROM AUTHOR]

• Chitosan solution was directly used for polyphenol extraction from by-products. • Chitosan as solvent facilitates the follow-up encapsulation process. • Active loaded particles attained 52% of encapsulation efficiency. • Active coatings have a potential for extending the shelf life of guavas. Aiming the simplification of the production of chitosan nanoparticles as an encapsulating material, the primary approach of this study was to investigate the extraction of active compounds from acerola-pulp by-products directly in chitosan solution by using tip sonication. The results have shown that chitosan solution can be used as a good solvent, mainly for total phenolic compounds (TPC) extraction (1792.7 mg/100 g of dry by-product). The extract was submitted to ionic gelation process using, as counter-ion, the sodium tripolyphosphate to form loaded nanoparticles with TPC. The suspension was applied as protective coatings on the guavas. The nanoengineered coatings provided an effective barrier that delayed the maturation and maintained the green pigmentation for longer periods along with good firmness. To the best of our knowledge, this was the first study that uses chitosan solution as extraction solvent of TPC from food byproducts in order to facilitate the encapsulation process. [ABSTRACT FROM AUTHOR]