Release of yerba mate antioxidants from corn starch–alginate capsules as affected by structure

Effect of incorporating modified pinhão starch in alginate-based hydrogel beads for encapsulation of bioactive compounds by hydrodynamic electrospray ionization jetting

Known for its antioxidant properties, Araucaria angustifolia bracts extract was encapsulated using hydrodynamic electrospray ionization jetting within calcium alginate cross-linked hydrogel beads with varying contents of modified pinhão starch. The rheological properties of the dispersions and analysis of the physicochemical and digestive properties of encapsulated beads were studied. The results demonstrated that dispersions containing starch exhibited higher viscosity and reduced compliance values, indicating samples with stronger, more compact, and stable structures that are less susceptible to deformation. This was confirmed by the beads rupture strength test. The ATR-FTIR analysis suggest that no new chemical bonds were formed, with encapsulation being responsible only for physical interactions between the functional groups of the polymers used and the active groups of the compounds present in the extract. The thermal stability of starch-containing beads was higher. Total tannins were higher in beads containing starch, with 53.61 %, 56.83 %, and 66.99 % encapsulation yield for samples with 2 %, 4 %, and 6 % starch, respectively, and the remaining antioxidant activity ranged from 96.04 % to 81.08 %. In vitro gastrointestinal digestion simulation indicated that the highest releases occurred in the intestinal phase, ranging from 60.72 % to 63.50 % for the release of total phenolic compounds.

Sequential starch modification by branching enzyme and 4-α-glucanotransferase improves retention of curcumin in starch-alginate beads

A new super-branched amylopectin with longer exterior chains was produced from normal maize starch by modification with branching enzyme followed by 4-α-glucanotransferase, and applied for co-entrapment of a curcumin-loaded emulsion in alginate beads. The network structure of the gel beads was obtained with Ca2+-cross-linked alginate and a modest load of retrograded starch. The dual enzyme modified starch contained more and longer α-1,6-linked branch chains than single enzyme modified and unmodified starches and showed superior resistance to digestive enzymes. Alginate beads with or without starch were of similar size (1.69-1.74 mm), but curcumin retention was improved 1.4-2.8-fold in the presence of different starches. Thus, subjecting the curcumin-loaded beads to in vitro simulated gastrointestinal digestion resulted in retention of 70, 43 and 22 % of the curcumin entrapped in the presence of modified, unmodified, or no starch, respectively. Molecular docking provided support for curcumin interacting with starch via hydrogen bonding, hydrophobic contacts and π-π stacking. The study highlights the potential of utilizing low concentration of dual-enzyme modified starch with alginate to create a versatile vehicle for controlled release and targeted delivery of bioactive compounds.

Encapsulation of pomegranate polyphenols by ionic gelation: Strategies for improved retention and controlled release

This study aimed at producing pectin hydrogel beads by ionic gelation proce to carry pomegranate extract (PE) evaluating approaches to increase its retention and protect the polyphenols from environmental conditions that interfere in the stability and color of these compounds, such as the pH of the medium. Several strategies were tested to reduce the mass transfer and consequently increase its retention. The insertion of a filler (gelatinized starch), the employment of different concentrations from the external environment, the adsorption using blank pectin-starch beads, and the electrostatic coating using chitosan were performed. The release of entrapped compounds over time was employed to evaluate the release pattern of PE in water media. Diffusion coefficients calculated from these experiments were then used to estimate the PE release behavior. The encapsulation efficiency (EE) was significantly improved (42 % to 101 %) when equalizing the concentration of the external medium with that from the beads formulation. Furthermore, the increase in the PE concentration was proportional to the rise in the mechanical strength (MS) of the beads which indicates a modification of internal structure due to the presence of polyphenols. The adsorption was efficient in entrapping the active compound, and despite the high PE content observed for all beads (average value of 2960.26 mg of gallic acid equivalent/100 g sample), they had the lowest diffusion coefficient from the release in water media. Finally, the coating was able to reduce the release rate in most of the tests (DAB uncoated = 0.5 DAB coated), however, during the electrostatic deposition a loss of about 32 % of the phenolic compounds in the chitosan solution was observed which led to a reduced EE. Despite the obtention of retarded release, coating studies need to be improved. Some adjustments in the execution of this technique are necessary so that the losses are reduced and the process becomes viable for the use of beads in food.

Yerba Mate (Ilex paraguariensis) Processing and Extraction: Retention of Bioactive Compounds

Ilex paraguariensis is a native tree from South America known for the presence of bioactive compounds, and its processed leaves are consumed as hot and cold infusions. After harvest (step 1), the leaves are subjected to flame blanching to inactive the enzymes (step 2), followed by drying and milling (step 3). The impacts of I. paraguariensis processing on leaf composition were investigated by extracting the major compounds (chlorogenic and isochlorogenic acids (3-CQA, 4-CQA, 5-CQA, 3,4-DQA, 3,5-DQA and 4,5-DQA), p-coumaric acid, caffeine and rutin) using different ratios of ethanol and water as extraction solvent (EW 25:75, 50:50, and 75:25 (w/w)). The solvent ratio of EW 50:50 was more effective in extracting the chlorogenic acids isomers, with retention of chlorogenic acids of 3463, 9485, and 9516 µg mL- 1 for steps 1, 2, and 3, respectively. Rutin and p-coumaric acid exhibited similar behavior with the increment of processing steps; however, p-coumaric acid was only detected in steps 2 and 3 for the solvent ratios EW 50:50 and 25:50. The caffeine extraction from I. paraguariensis varied from 936 to 1170 µg mL- 1 for all processing steps, with emphasis on its concentration extracted in step 1. The evolution of processing steps led to a higher retention of phenolic compounds from I. paraguariensis, which was not observed when using different solvent ratios, and the solvent ratio EW 50:50 was more effective for the extraction of chlorogenic acids. The successful extraction of chlorogenic acids from I. paraguariensis in this study proved to be a promising alternative for the use of yerba mate beyond the cuia cup.

Polyphenol Release and Antioxidant Activity of the Encapsulated Antioxidant Crude Extract from Cold Brew Spent Coffee Grounds under Simulated Food Processes and an In Vitro Static Gastrointestinal Model

An ionic gelation technique based on an alginate-calcium-based encapsulation process was prepared as the delivery matrix for antioxidant crude extracts from cold brew spent coffee grounds (350 mg/mL). All the encapsulated samples were treated with different simulated food processes, namely pH 3, pH 7, low-temperature long-time (LTLT) pasteurization, and high-temperature short-time (HTST) pasteurization, to evaluate the stability of the encapsulated matrices. The results showed that alginate (2%, w/v)/maltodextrin (2%, w/v) (CM), and alginate (2%, w/v)/inulin (5%, w/v) (CI) could enhance encapsulation efficiency (89.76 and 85.78%, respectively) and provide lower swelling behavior after being treated using the simulated food processes. Both CM and CI could control the release of antioxidants during the gastric phase (2.28-3.98 and 2.52-4.00%, respectively) and gradual release in the intestinal phase (6.80-11.78 and 4.16-12.72%, respectively) compared to pure alginate (CA). In addition, pasteurization treatment at pH 7.0 produced the highest accumulated release of total phenolic content (TPC) and antioxidant activity (DPPH) after digestion in the in vitro gastrointestinal system compared to the other simulated food processes. The thermal process resulted in a greater release of compounds from the encapsulated matrix during the gastric phase. On the other hand, the treatment with pH 3.0 resulted in the lowest accumulated release of TPC and DPPH (5.08 and 5.12%, respectively), which indicated phytochemical protection.

Evaluation of alginate-biopolymers (protein, hydrocolloid, starch) composite microgels prepared by the spray aerosol technique as a carrier for green tea polyphenols

Effects of low methoxyl pectin, milk protein concentrate (MPC), and waxy starch on the encapsulation of green tea-polyphenols in alginate gels produced using spray aerosol technique were evaluated. MPC and waxy starch treated first by cold-renneted induced gelation method and gelatinization method, respectively. DSC thermal analysis and FTIR spectroscopy were used to prove the presence of polyphenols in gel matrixes. The encapsulation efficiency (%EE) and the polyphenols release were investigated using Folin-Ciocalteu assay. The results showed that the addition of biopolymers into alginate gels increased the encapsulation efficiency (%EE) but reduced the release percentage of polyphenol in water and simulated gastric fluid (SGF). Among the three biopolymers, cold-renneted MPC gave the best protection for polyphenols encapsulated in alginate microgels. It increased %EE from 63% to 68% in fresh gels, reduced the release percentage in water from 72% to 62% and reduced the release percentage in SGF from 76% to 67%.

Technological and Sensory Aspects of Macaroni with Free or Encapsulated Azolla Fern Powder

Azolla might be considered an alternative and promising dietary ingredient for antioxidants. There have not been any reports on the incorporation of free Azolla fern powder (FAP) or its microcapsules in foods, especially fresh pasta, yet. Microencapsulation was used to mask the undesirable taste and odour of Azolla, as well as to preserve its antioxidant potential. The current study concentrated on two major goals. The first goal was to use alginate as a wall material for FAP encapsulation, as well as to characterise the FAP microcapsule for its encapsulation efficiency, solubility, and thermal stability. The second goal was to assess the impact of integrating FAP or its microcapsules into fresh macaroni on its colour parameters, cooking quality, texture properties, and sensory characteristics. The microspheres had a high encapsulation efficiency (88.19%) and a low water solubility (85.23 g/kg), making them suitable for use in foods that require cooking in water. When compared to free Azolla powder, encapsulation reduced the antioxidant activity loss rate by 67.73%. All the cooking and textural properties of fresh macaroni were not significantly affected, except for water absorption and weight gain, but the overall acceptability index (85.13%) was not affected by microcapsule incorporation.

Protection and Controlled Gastrointestinal Release of Bromelain by Encapsulating in Pectin-Resistant Starch Based Hydrogel Beads

Hybrid pectin and resistant starch–based hydrogel beads loaded with bromelain using the extrusion gelation method were prepared and evaluated to enhance the activity of bromelain during gastrointestinal passage and thermal processing. The solutions of pectin–resistant starch with bromelain were dropped into the gelation bath containing calcium chloride (0.2 M) solution to develop various types of hydrogel beads. The physicochemical characteristics of the synthesized hydrogel beads were evaluated. The ratio (4.5:1.5 w/w) of pectin and resistant starch concentration significantly (p < 0.05) enhanced the encapsulation efficiency (80.53%). The presence of resistant starch resulted in increased entrapment of bromelain, improved swelling properties with sustained release behavior, and improved gastric stability than pectin hydrogels alone. The swelling of hydrogel beads was higher at pH 7.4 than pH 1.2. Optimized batch of hybrid pectin/resistant starch exhibited a spherical shape. Optical and scanning electron microscopy showed a more packed and spherical shape from the pectin/resistant starch hydrogel bead network. Fourier transformation infrared spectroscopy was also used to confirm the presence of bromelain in the hydrogel beads. The encapsulated bromelain in the pectin/hi-maize starch beads produced at a pectin/hi-maize ratio of 4.5:1.5 (percent w/w; formulation P4) obtained the highest relative bromelain activity in all heat treatments including at 95°C, whereas the highest activity of free bromelain was found only at 30°C. Bromelain encapsulated in hydrogels released at a faster rate at simulated intestinal fluid (SIF, pH 7.4) than at simulated gastrointestinal fluid (SGF, pH 1.2).

Alginate-based microparticles structured with different biopolymers and enriched with a phenolic-rich olive leaves extract: A physico-chemical characterization

Encapsulation of olive leaves extracts (OLE), rich of healthy components like Oleuropein, Hydroxytyrosol and Verbascoside, represents a new challenge to improve stability and nutritional value of food as well as a way to recover value added compounds from by-products, contributing to a more sustainable food system. In this context, OLE-loaded microbeads of Na alginate alone or in combination with Pectin, Na Caseinate or Whey protein isolates, were produced by emulsification internal ionotropic gelation. Encapsulation efficiency of the main phenolic compounds (Oleuropein, Hydroxytyrosol, Verbascoside) was carried out along with microparticles morphological characterization by scanning electron microscopy (SEM), thermal properties by differential scanning calorimetry (DSC) and color. Encapsulation efficiency resulted higher for Alginate/Pectin, whilst Alginate/Caseinate was the less performing system, probably due to the lower interaction with polyphenols. SEM revealed collapsed structures and continuous smooth surfaces for Alginate and Alginate/Pectin microbeads while more regular structures and porous surfaces were observed for Alginate/Caseinate and Alginate/Whey proteins. Higher hue angle and lower chroma values were observed for all the beads with respect to the pure extract, indicating a reduction of the yellow/brown color. DSC highlighted higher thermal stability for the microbeads in comparison to the original ingredients, showing also new thermal transitions related to bonds formation between polymers and OLE.

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Verbascoside showed higher encapsulation efficiency compared to Oleuropein.

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Alginate/Pectin was the most efficient system for encapsulation purposes.

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Microstructural traits were linked to the encapsulation efficiency.

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Thermal analysis revealed increased thermal stability of encapsulated polyphenols.

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Encapsulation allowed a mitigation of the color properties of the olive leaf extract.

Mechanical properties of starch-filled alginate gel particles

The aim of this work was to investigate the mechanical behaviour of alginate-based composite particles. Alginate gel beads with entrapped starch were used as the replicates of storage cells of plant tissue. Beads were formulated using different ratios of both ingredients and were produced using two methods, resulting in particles in the macro- and micro-scale size range. Compression tests revealed an effect of bead size on mechanical properties and a dominant role of the alginate on the material properties. Starch was successfully encapsulated as native granules in the beads and once encompassed, it suffered restricted swelling, up to 45 % of its original size, after undergoing heating. Force versus displacement data were fitted to both an empirical and the Hertz model and Young's modulus was found to increase only with heated starch inclusions. Microscopy was deemed crucial for the interpretation of mechanical measurements.

Microencapsulation of probiotic Lactobacillus brevis ST-69 producing GABA using alginate supplemented with nanocrystalline starch

Microencapsulation technology can be used to improve the probiotic viability under stress condition in the human gastrointestinal tract and during storage. The purpose of this study was to evaluate the protective effect of encapsulation materials on the survival of GABA-producing probiotics using alginate containing cassava starch nanocrystals under simulated gastrointestinal conditions and shelf storage. Lactobacillus brevis ST-69, GABA-producing probiotic strain, was isolated from kimchi and encapsulated using emulsion technique. The GABA activity, encapsulation efficiency, morphology, probiotic viability were evaluated. The encapsulation efficiency using emulsion technique was 89.72%. Probiotic encapsulated in alginate-nanocrystalline starch gel capsules showed high survival rate at 94.97% of probiotic cells under simulated gastrointestinal conditions and during long-life storage at 4 °C compared to free cells. Results showed that for improving the viability of probiotics against gastrointestinal and storage conditions, complex materials with nanocrystalline starch might be a better encapsulating matrix for the preparation of gel capsules.

Development of functional pasta with microencapsulated Spirulina: technological and sensorial effects

BACKGROUND

Spirulina microalgae have been added to food; however, there have been few reports on the methods used to protect the antioxidant potential against process conditions, and the effects on the sensory characteristics of products need to be better described. The aim of this study was to evaluate the influence on the technological properties, sensory profile, and acceptability of the pasta with free or microencapsulated Spirulina biomass added. Pasta formulations included: free Spirulina (FSP), microencapsulated Spirulina (MSP), and empty microspheres (EMP), which were compared with the control pasta (CP).

RESULTS

The microencapsulation protected the antioxidant potential of Spirulina in 37.8% of the pasta cooking conditions. The microspheres presented low solubility in water (86 g.kg^-1 ) and high encapsulation efficiency (87.6%), this being appropriate for addition to products that need cooking in water. The technological properties of pasta (water absorption, weight gain, firmness, and adhesiveness) were affected, but the overall acceptability index (85.13%) was not influenced by the addition of microspheres, despite changes observed in the sensory profile obtained by the CATA (check-all-that-apply).

CONCLUSIONS

Spirulina could be added to pasta even without microencapsulation but the microencapsulation in alginate allows for the protection of the antioxidant potential of the biomass, representing a potential alternative for the bakery industry. © 2019 Society of Chemical Industry.

L. inermis-loaded nanofibrous scaffolds for wound dressing applications

Since ancient times, some herbal medicines have been extensively used for burn and wound treatments, showing preference to the common synthetic medications by virtue of having less side effects and faster healing rate. In this study, hybrid nanofibrous scaffolds of poly-l-lactic-acid (PLLA) and gelatin incorporated L. inermis were fabricated via electrospinning technique. Morphology and characteristics of the scaffolds were studied by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR), respectively. The release profile of the L. inermis from the nanofibers was also assessed in vitro. Moreover, the structural stability of the released L. inermis from the nanofibers was evaluated using high-performance liquid chromatography (HPLC). The nanofibers showed a gradual release of L. inermis up to two days while the intact structure was preserved. Furthermore, antibacterial assay demonstrated that L. inermis-loaded nanofibrous scaffolds could effectively kill E. coli and S. aureus within 2 h. Finally, biocompatibility of the nanofibers was proven on 3T3 fibroblasts. Therefore, the L. inermis loaded PLLA-Gelatin nanofibers showed a potential application as a wound dressing in order to control wound infections.

Engineering pectin-based hollow nanocapsules for delivery of anticancer drug

Multifunctional capsules have great applications in biomedical fields. In this study, novel polysaccharide-based nanocapsules were prepared via a layer-by-layer technique using silica as the templates. The shell was constructed based on the electrostatic interactions between pectin and chitosan. The pectin-chitosan nanocapsules ((Pec/Cs)₃Pec) could keep good colloidal stability within 96h in PBS solution and 48h in BSA solution. Meanwhile, the nanocapsules exhibited a high drug loading and pH-sensitive release property for doxorubicin hydrochloride. Moreover, (Pec/Cs)₃Pec nanocapsules had no cytotoxicity to both human hepatocellular carcinoma cells (HepG2 cells) and mouse fibroblast cells (L929 cells). More importantly, (Pec/Cs)₃Pec nanocapsules could be more easily uptaken by HepG2 cells when compared with L929 cells. In vitro anticancer activity tests indicated the carriers could effectively kill HepG2 cells. Overall, (Pec/Cs)₃Pec nanocapsules have great potential as a novel anticancer drug carrier as a result of their pH-sensitivity, good colloidal stability and anticancer activity.

Thyme Oil Encapsulated in Halloysite Nanotubes for Antimicrobial Packaging System

An antimicrobial capsule releasing thyme oil was developed using modified halloysite nanotubes (HNTs). In order to increase the pore volume, HNTs were treated with 5.0 mol/L NaOH solution, which resulted in the encapsulation of more thyme oil molecules inside the HNTs. The morphology of the raw HNTs and NaOH-treated HNTs (N-HNTs) was characterized using transmission electron microscopy and nitrogen adsorption-desorption analysis. The loading capacity increased from 180.7 ± 12.7 to 256.4 ± 16.7 mg thyme oil/g HNT after the NaOH treatment. The aerial release characteristics of thyme oil from both the HNT capsules were investigated in a closed-package atmosphere system at 4, 25, and 40 °C. The antimicrobial activity of the capsule against Escherichia coli O157:H7 was determined using the vapor phase assay. Moreover, the antimicrobial effects of the capsule against E. coli O157:H7, total mesophilic aerobic bacteria (MAB), and molds and yeasts (MY) on the surfaces of cherry tomatoes were investigated at 4 and 25 °C for 5 d. When the cherry tomatoes were exposed to the thyme oil-loaded N-HNT capsule, the number of E. coli O157:H7, MAB, and MY significantly reduced during storage.

Effects of Accelerated Storage on the Quality of Kenaf Seed Oil in Chitosan-Coated High Methoxyl Pectin-Alginate Microcapsules

The objective of this research was to study the oxidative stability and antioxidant properties of microencapsulated kenaf (Hibiscus cannabinus L.) seed oil (MKSO) produced by co-extrusion technology upon accelerated storage. The combination of sodium alginate, high methoxyl pectin, and chitosan were used as shell materials. The oxidative stability of the kenaf seed oil was determined by iodine value, peroxide value, p-Anisidine value, total oxidation (TOTOX), thiobarbituric acid reactive substances assay, and free fatty acid content. Total phenolic content, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical-scavenging assay and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay were used to examine the antioxidant properties of oils. Oxidative stability tests showed that bulk kenaf seed oil (BKSO) was oxidized significantly higher (P < 0.05) than MKSO. The total increment of TOTOX value of BKSO was 165.93% significantly higher (P < 0.05) than MKSO. Co-extrusion technology has shown to be able to protect kenaf seed oil against lipid oxidation and delay the degradation of natural antioxidants that present in oil during storage.

Improved Water Barrier Properties of Calcium Alginate Capsules Modified by Silicone Oil

Calcium alginate films generally offer poor diffusion resistance to water. In this study, we present a technique for encapsulating aqueous drops in a modified calcium alginate membrane made from an emulsion of silicone oil and aqueous alginate solution and explore its effect on the loss of water from the capsule cores. The capsule membrane storage modulus increases as the initial concentration of oil in the emulsion is increased. The water barrier properties of the fabricated capsules were determined by observing the mass loss of capsules in a controlled environment. It was found that capsules made with emulsions containing 50 wt% silicone oil were robust while taking at least twice the time to dry completely as compared to capsules made from only an aqueous alginate solution. The size of the oil droplets in the emulsion also has an effect on the water barrier properties of the fabricated capsules. This study demonstrates a facile method of producing aqueous core alginate capsules with a modified membrane that improves the diffusion resistance to water and can have a wide range of applications.

Preparation and characterization of alginate and alginate-resistant starch microparticles containing nisin

Delivery systems with sustained release of nisin have been proposed to improve stability and long-term effectiveness of this bacteriocin in foods. In this study, nisin was encapsulated in alginate (Alg) and alginate-resistant starch (Alg-RS) microparticles and its release was investigated. Studies found that the nisin concentration has significant influence on encapsulation efficiency (EE), loading capacity (LC) and size of both microparticles. Furthermore, encapsulation efficiency and loading capacity values were more increased by the addition of resistant starch to the alginate formulation. The highest encapsulation efficiency was obtained with Alg-RS microparticles prepared using initial nisin to alginate weight ratio of 25% w/w (59.77 ± 2.26%). Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results confirmed the presence of nisin in the microparticles. The in vitro nisin release from these microparticles followed a controlled-release pattern consistent with a Fickian diffusion mechanism. The release rate from Alg-RS microparticles was less than that from the Alg microparticles.