Anthocyanins from jussara (Euterpe edulis Martius) extract carried by calcium alginate beads pre-prepared using ionic gelation

New approaches for modulation of alginate-chitosan delivery properties

Alginate is a biopolymer widely used on delivery systems when bioactive protection at acidic pH is required, while chitosan can enhance mucoadhesion and controlled release at alkaline pHs. In this work, alginate ionotropic gelation and electrostatic complexation to chitosan were evaluated concomitantly or in a two-step approach to improve the delivery properties of systems in different pHs. The effect of pH on alginate gelation and chitosan interactions were also evaluated. Alginate microspheres were prepared by ionotropic gelation in CaCl2 at different pH values (2.5 and 6.0) by extrusion. Complexation with chitosan was carried out during alginate ionotropic gelation (one-step approach) or after alginate gel formation (two-step approach). Alginate microparticles without chitosan showed larger pores and lower mechanical strength. Extruded microspheres at pH 6.0 were more stable to pH and showed smaller pores than the formed at pH 2.5. One-step production retained a large amount of bioactive at pH 7.0 and resulted in lower release at the pH of intestinal digestion. The two-step approach retained less amount of bioactive but confer more protection to the pH of the stomach phase and higher release in pH of the intestinal phase than one-step samples. These results indicate that the formation of alginate gels by ionotropic gelation followed by the complexation with chitosan (in two-step) is promising for the transport and delivery of bioactives into intestinal conditions, whereas the ionotropic gelation concomitantly to electrostatic complexation (one-step approach) is indicated to the delivery of bioactives into lower pH environments.

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.

Encapsulation of purple basil leaf extract by electrospraying in double emulsion (W/O/W) filled alginate-carrageenan beads to improve the bioaccessibility of anthocyanins

The purple basil leaf extract (PBLE) was encapsulated in double emulsion (W1/O/W2)-loaded beads (emulgel) by electrospraying. The influence of κ-carrageenan (κ-CG) and cross-linking agents (Ca2+/K+) on the properties of alginate (SA) beads were assessed. In emulgel beads, κ-CG inclusion resulted in larger sizes and more distorted shapes, wrinkles on the surface, and lower gel strength. The encapsulation efficiency of anthocyanins (ACNs) in emulgel beads ranged from 70.73 to 87.89 %, whereas it ranged from 13.50 to 20.67 % in emulsion-free (hydrogel) beads. Fourier transforms infrared (FTIR) revealed the crosslinking of SA and κ-CG with Ca2+ and K+, thermogravimetric analysis (TGA), derivative thermogravimetric (DTG), and differential scanning calorimetry (DSC) thermograms showed emulgel beads yielded higher thermal stability. The emulgel beads elevated the in vitro bioaccessibility of ACNs under simulated digestion. At the gastric phase, 86 % of ACNs in PBLE, and 46 % of loaded ACNs in hydrogel beads were released, whereas no release was occurred in emulgel beads. At the intestinal phase, after 150 min of digestion, no ACNs were detected in PBLE and hydrogel beads, whereas all emulgel beads continued to release ACNs until 300 min. The incorporation of double emulsions in hydrogel beads can be utilized in the development of functional foods.

Alginate microbeads incorporated with anthocyanins from purple corn (Zea mays L.) using electrostatic extrusion: Microencapsulation optimization, characterization, and stability studies

Microencapsulation of purple corn anthocyanins was carried out via an electrostatic extruder using alginate as a wall material. The influence of alginate concentration (1-2 %), extract concentration (20-30 %), and extrusion voltage (3-5 kV) on encapsulation efficiency and mean particle size was evaluated using response surface methodology. Optimal conditions were obtained to produce two different extract-loaded microbeads. Microbeads with the highest encapsulation efficiency (EE) and minimum particle size were achieved at 1 % alginate, 20 % extract, and 5 kV extrusion voltage (EEC3G = 70.26 %, EETPC = 91.59 %, particle size = 1.29 mm). In comparison, the microbeads with the efficient entrapment and maximum particle size were obtained at 1 % alginate, 26 % extract, and 3 kV (EEC3G = 81.15 %, EETPC = 91.01 %, particle size = 1.87 mm). Brunauer-Emmett-Teller (BET) surface area, pore size, and pore volume decreased after the inclusion of extract, with the lowest values reported for the smallest microbeads containing the extract. Scanning electron microscopy confirmed the results obtained by BET method and demonstrated fewer cracks and lower shrinkage of encapsulated samples. Fourier-transform infrared results proved the presence of anthocyanins and further possible interactions between phenolics and alginate. Stability studies revealed the color maintenance of anthocyanins-loaded microbeads during 4 weeks of storage at 4 °C and 8 °C. Moreover, the small and large particles showed a 7.6 and 3.4-fold reduction in degradation rate at 4 °C compared to their unencapsulated counterparts. Anthocyanins-loaded alginate microbeads retained over 80 % of cyanidin-3-glucoside at 4 °C and 8 °C, suggesting a promising potential of optimized microbeads for intelligent packaging applications.

Stability of yerba mate extract, evaluation of its microencapsulation by ionic gelation and fluidized bed drying

Studies show that yerba mate (Ilex paraguariensis) has high antioxidant capacity occasioned by its high contents of total phenolic compounds. Microencapsulation, specifically ionic gelation, since it does not use heating during process, is considered as an alternative for preserving and applying the extract. The purpose of this study was to evaluate general characteristics and stability of hydroalcoholic extract of yerba mate, conduct the extract microencapsulation by ionic gelation followed by microparticle fluidized bed drying. The extract was evaluated for color stability, total phenolic compounds, and antioxidant activity for nine weeks and at three temperatures (5, 15, and 25 °C). From the extract, a double emulsion (W/O/W), generation of microparticles (ionic gelation by dripping), and fluidized bed drying were conducted. The extract had 32912.55 mg GAE/100 g of phenolic compounds and 2379.49 μmol TE/g of antioxidant activity. The main compound observed was chlorogenic acid (5-CQA) with 0.35 ± 0.01 g/100 mL. In the stability study, the temperature was observed to influence in phenolic compounds reduction, as well as in total color difference of the extract. Double emulsion has shown to be stable and appropriate for use. The values of microparticles total phenolic compounds and antioxidant activity were 423.18 ± 8.60 mg GAE/100 g and 21.17 ± 0.24 μmol TE/g, respectively. After drying, the moisture of microparticles was reduced from 79.2% to 19%. The extract had high total phenolic compound content and high antioxidant activity. Storage at the lowest temperature (5 °C) assured better preservation of extract total phenolic compounds. The dried microparticles showed content of total phenolic compounds and antioxidant activity with potential for commercialization and future application in food matrices.

Binary Alginate-Whey Protein Hydrogels for Antioxidant Encapsulation

Encapsulation of antioxidants in hydrogels, i.e., three-dimensional networks that retain a significant fraction of water, is a strategy to increase their stability and bioaccessibility. In fact, low oxygen diffusivity in the viscous gelled phase decreases the rate of oxidation. Moreover, some hydrocolloids such as alginate and whey proteins provide a pH-dependent dissolution mechanism, allowing the retention of encapsulated compounds in the gastric environment and their release in the intestine, where they can be absorbed. This paper reviews the information on alginate-whey protein interactions and on the strategies to use binary mixtures of these polymers for antioxidant encapsulation. Results showed that alginate and whey proteins strongly interact, forming hydrogels that can be modulated by alginate molecular mass, mannuronic acid: guluronic acid ratio, pH, Ca²⁺ or transglutaminase addition. Hydrogels of alginate and whey proteins, in the forms of beads, microparticles, microcapsules, and nanocapsules, generally provide better encapsulation efficiency and release properties for antioxidants with respect to the hydrogel of alginate alone. The main challenges for future studies are to extend knowledge on the interactions among three components, namely alginate, whey proteins, and the encapsulated bioactive compounds, and to investigate the stability of these structures under food processing conditions. This knowledge will represent the rationale basis for the development of structures that can be tailored to specific food applications.

Microencapsulation of anthocyanins as natural dye extracted from fruits - A systematic review

Anthocyanins are naturally colored compounds that can be extracted from plants, especially fruits. Their molecules are unstable under normal processing conditions; thus, they must be protected using modern technologies, such as microencapsulation. For this reason, many industries are searching for information from review studies to find the conditions that improve these natural pigments' stability. This systematic review aimed to elucidate different aspects of anthocyanins, such as main extraction and microencapsulation methods, gaps in analytical techniques, and industrial optimization measurements. Initially, 179 scientific articles were retrieved, of which seven clusters were found with 10-36 cross-linked references. Sixteen articles containing 15 different botanical specimens were included in the review, most focusing on the whole fruit, pulp, or subproducts. The extraction and microencapsulation technique resulting in the highest anthocyanin content was sonication with ethanol, temperature below 40 °C, and maximum time of 30 min, followed by microencapsulation by spray drying with maltodextrin or gum Arabic. Color apps and simulation programs may help verify natural dyes' composition, characteristics, and behavior.

Encapsulation of Lactobacillus plantarum ELB90 by electrospraying in a double emulsion (W1/O/W2) loaded alginate beads to improve the gastrointestinal survival and thermal stability

BACKGROUND

In the present study, the Lactobacillus plantarum ELB90 was encapsulated in double emulsion (W1/O/W2) loaded alginate beads (emulbeads) by electrospraying and compared with emulsion-free control beads. The viability of encapsulated and free cells was assessed by exposing them to thermal processing (65 °C for 30 min and 72 °C for 3 min) and simulated gastrointestinal conditions. The beads were characterized by optical, scanning electron, fluorescence, and confocal laser scanning microscopy, as well as Fourier transform infrared and gel strength analysis.

RESULTS

After the intestinal stage of digestion, the survival rate of free bacteria was 38% [3.70 log colony-forming units (CFU) g^-1 ], only increased to 43% and 53% for bare and chitosan-coated control beads, and it elevated the survival rate to 75% and 84% (8.70 log CFU g^-1 ) for bare and chitosan-coated emulbeads, respectively. The presence of inulin increased gastrointestinal viability only in uncoated emulbeads. The bacteria loaded in emulbeads retained greater viability (5.90-6.90 log CFU g^-1 ) against thermal treatment, compared to control beads (2.07-4.10 log CFU g^-1 ) and free bacteria (2.57-3.11 log CFU mL^-1 ). Encapsulation of L. plantarum ELB90 only in emulsion-free beads may not be appropriate for providing thermal stability. Inulin addition and chitosan-coating of the beads increased the size, and emulbeads presented smoother surfaces compared to emulsion-free beads.

CONCLUSION

The contribution of a double emulsion into the gel matrix of electrosprayed alginate beads exhibited enhanced protection for probiotic bacteria that could be useful for the development of functional foods. © 2023 Society of Chemical Industry.

Formulation and Biopharmaceutical Evaluation of Capsules Containing Freeze-Dried Cranberry Fruit Powder

Cranberry fruits are an important source of anthocyanins and anthocyanidins. The aim of the present study was to investigate the effect of excipients on the solubility of cranberry anthocyanins and their dissolution kinetics as well as on the disintegration time of the capsules. Selected excipients (sodium carboxymethyl cellulose, beta-cyclodextrin and chitosan) were found to affect the solubility and release kinetics of anthocyanins in freeze-dried cranberry powder. Capsule formulations N1-N9 had a disintegration time of less than 10 min, and capsule formulation N10 containing 0.200 g of freeze-dried cranberry powder, 0.100 g of Prosolv (combination of microcrystalline cellulose and colloidal silicon dioxide), and 0.100 g of chitosan had a capsule disintegration time of over 30 min. The total amount of anthocyanins released into the acceptor medium ranged from 1.26 ± 0.06 mg to 1.56 ± 0.03 mg. Capsule dissolution test data showed that the time to release into the acceptor medium was statistically significantly longer for the chitosan-containing capsule formulations compared to the control capsules (p < 0.05). Freeze-dried cranberry fruit powder is a potential source of anthocyanin-rich dietary supplements, and the choice of excipient chitosan could be a suitable solution in capsule formulations providing greater anthocyanin stability and modified release in the gastrointestinal tract.

Physicochemical Characterization and Evaluation of Gastrointestinal In Vitro Behavior of Alginate-Based Microbeads with Encapsulated Grape Pomace Extracts

Grape pomace is a byproduct of wineries and a rich source of phenolic compounds that can exert multiple pharmacological effects when consumed and enter the intestine where they can then be absorbed. Phenolic compounds are susceptible to degradation and interaction with other food constituents during digestion, and encapsulation may be a useful technique for protecting phenolic bioactivity and controlling its release. Therefore, the behavior of phenolic-rich grape pomace extracts encapsulated by the ionic gelation method, using a natural coating (sodium alginate, gum arabic, gelatin, and chitosan), was observed during simulated digestion in vitro. The best encapsulation efficiency (69.27%) was obtained with alginate hydrogels. The physicochemical properties of the microbeads were influenced by the coatings used. Scanning electron microscopy showed that drying had the least effect on the surface area of the chitosan-coated microbeads. A structural analysis showed that the structure of the extract changed from crystalline to amorphous after encapsulation. The phenolic compounds were released from the microbeads by Fickian diffusion, which is best described by the Korsmeyer-Peppas model among the four models tested. The obtained results can be used as a predictive tool for the preparation of microbeads containing natural bioactive compounds that could be useful for the development of food supplements.

Parameters affecting calcium-alginate bead characteristics: Viscosity of hydrocolloids and water solubility of core material

In this study, calcium-alginate beads were produced and characterized by ionic gelation technique using three different copolymers (gum arabic (GA), κ-carrageenan (CG), guar gum (GG)), and seven different phenolic compounds (tannic acid, chlorogenic acid, gallic acid, p-coumaric acid, caffeic acid, naringin, and hesperidin). The effect of the viscosity of copolymer and water solubility of the phenolic compound on the size, shape, swelling, encapsulation efficiency (EE), loading capacity (LC), and production yield (PY) of the beads were investigated. In addition, the impact of the core material concentration in the calcium chloride solution on the EE was determined. The bead sizes increased by 6.8, 11.4, and 35.3 %, respectively, with the use of GA, CG, and GG. The EE of the beads ranged from 28.36 to 89.30 % and increased with increasing copolymer viscosity and decreasing water solubility of the phenolic compound. When the core material concentration difference between the alginate and calcium chloride solutions was reduced to zero, the EE of the gallic acid bead increased from 32.95 % to 89.05 %. The results of this study show that copolymer viscosity, the water solubility of core material, and the core material concentration difference between alginate and calcium solutions should be considered in ionic gelation applications.

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.

Anthocyanin-Rich Jamun (Syzygium cumini L.) Pulp Transported on Protein-Coated Ionic Gelation Microparticles of Calcium Alginate: Production and Morphological Characteristics

Jamun (Syzygium cumini L.) is a fruit rich in anthocyanins, an important group of natural pigments, with color ranging from red to blue, soluble in water, highly antioxidant. Despite its great potential for use as a natural dye, its application is a challenge, due to the instability of these compounds in the environmental conditions of processing and storage commonly used by the food industry. Therefore, this study evaluated the microencapsulation of anthocyanin-rich jamun pulp by ionic gelation (IG) and its protein-coating by electrostatic interaction (PC). The effect of the ratio of sodium alginate solids and jamun pulp (1:0.40 to 1:2, w/w) and the concentration of gelatin coating solution (0% to 10%, w/w) on the morphology, water and total protein content and anthocyanins content in the microparticles were evaluated. Visually, the IG particles showed color tones ranging from reddish to purplish, which became less intense and opaque after being submitted to the gelatin coating process. Microscopic images demonstrated that microparticles formed had an irregular and heterogeneous shape with disorganized gel network formation is due to the presence of solid structures of jamun pulp, observed within the microparticles. The greater the concentration of gelatin in the coating solution, the greater the protein adsorption for the formation of the protective layer, ranging from 21.82 ± 0.72% (T1) to 55.87 ± 4.23% (T6). Protein adsorption on the GI resulted in a decrease in moisture content (ranging from 87.04 ± 0.22 to 97.06 ± 0.12%) and anthocyanins contents (ranging from 5.84 ± 0.62 to 0.78 ± 0.14%) in the PC microparticles.

Microwave-Vacuum Extraction Technique as a Green and Clean Label Technology: Kinetics, Efficiency Analysis, and Effect on Bioactive Compounds

Grape pomace is a rich source of bioactive compounds and dietary fiber. This study aims to valorize the grape pomace by microwave-vacuum-assisted drying and extraction, which is a novel, green, and clean label technology. The drying and extraction of bioactive compounds from the grape pomace was optimized using response surface methodology. Box-Behnken design was used for three process variables, i.e., time, power, and vacuum levels. The highest drying rate was observed (5.53 g/100 g min after 10 min of drying) at the combination of 80 W and 20 inHg. This combination significantly reduced the drying time (25%) and resulted in the highest yield (64.5%) of bioactive compounds. Equally, changes in moisture ratio behavior were rapid under these processing conditions. Furthermore, Midilli model (R2 = 0.999, RMSE = 0.002, SSE = 3.71 × 10−6) was the best to justify the fitness of experimental values with predicted values. In addition, the diffusion coefficient, activation energy, and extraction yield were increased with increase in power and pressure. The concentration of bioactive components was higher in dried pomace compared to the extract. The extraction was successfully achieved without the use of solvent and the characteristics of extracted phenolics remained unaltered. Based on these findings, the microwave-vacuum-assisted drying and extraction process can be claimed as a sustainable approach.

Encapsulation of Grape (Vitis vinifera L.) Pomace Polyphenols in Soybean Extract-Based Hydrogel Beads as Carriers of Polyphenols and pH-Monitoring Devices

In this work, novel bio-based hydrogel beads were fabricated by using soybean extract as raw waste material loaded with Lambrusco extract, an Italian grape cultivar. The phenolic profile and the total amount of anthocyanins from the Lambrusco extract were evaluated before encapsulating it in soybean extract-based hydrogels produced through an ionotropic gelation technique. The physical properties of the produced hydrogel beads were then studied in terms of their morphological and spectroscopic properties. Swelling degree was evaluated in media with different pH levels. The release kinetics of Lambrusco extract were then studied over time as a function of pH of the release medium, corroborating that the acidity/basicity could affect the release rate of encapsulated molecules, as well as their counter-diffusion. The pH-sensitive properties of wine extract were studied through UV-Vis spectroscopy while the colorimetric responses of loaded hydrogel beads were investigated in acidic and basic solutions. Finally, in the framework of circular economy and sustainability, the obtained data open routes to the design and fabrication of active materials as pH-indicator devices from food industry by-products.

Development of alginate/pectin microcapsules by a dual process combining emulsification and ultrasonic gelation for encapsulation and controlled release of anthocyanins from grapes (Vitis labrusca L.)

The aim of this study was to investigate the physicochemical, morphological, and gastrointestinal release properties of an anthocyanin-rich extract of grapes in alginate and pectin beads as carriers; the effects of ultrasonic gelation combined with emulsification were also investigated. In general, the alginate beads showed smaller size and more regular shape compared to pectin. The effect of emulsification combined with ionic gelation was more pronounced in the alginate beads and resulted in higher retention of anthocyanins, higher antioxidant capacity, and also allowed the best release profile during intestinal digestion. Thus, the simultaneous strategy could be an interesting delivery system and enhance the release of anthocyanins, providing an opportunity for the development of ingredients with different bioactive properties.

In Vitro Release of Anthocyanins from Microencapsulated Natal Plum (Carissa macrocarpa) Phenolic Extract in Alginate/Psyllium Mucilage Beads

Natal plum (Carissa macrocarpa) contains anthocyanins, cyanidin 3-O-β-sambubioside (Cy-3-Sa), and cyanidin 3-O-glucoside (Cy-3-G) that possess great bioactive properties. During in vitro gastrointestinal digestion, Cy-3-Sa and Cy-3-G are highly sensitive to pH changes and have low bioaccessibility rates of 7.9% and 22%, respectively. This study aimed to therefore use microencapsulation techniques to improve the bioaccessibility of Cy-3-Sa and Cy-3-G. The crude anthocyanin-rich extract was extracted from freeze-dried Natal plum fruit using ultrasonic-assisted ethanol extraction. The anthocyanin-rich extract was encapsulated using the ionic gelation method. Four distinct carrier agents, namely sodium alginate, pectin, xanthan gum and psyllium mucilage were used to form the wall materials. Encapsulation efficiency was highest for alginate/psyllium mucilage beads (93.67%), while alginate showed the least efficiency (86.80%). Scanning Electron Microscopy revealed a cracked and porous structure for the Natal plum extract and a continuous smooth structure for all the beads. Fourier transform infrared spectroscopy showed peaks at 3300 and 1610 cm⁻¹, confirming the presence of polyphenols and polysaccharides in all beads. Thermal stability was higher for the alginate/psyllium mucilage beads and the observed thermal transitions were due to the bonds formed between the polymers and the polyphenols. Alginate beads combined with xanthan gum, pectin, and psyllium mucilage showed a prolonged release of anthocyanins compared to alginate in vitro alone. The highest anthocyanin bioaccessibility was obtained from alginate/psyllium mucilage beads (85.42 ± 1.03%). The results showed the effectiveness of alginate/psyllium mucilage beads in improving stability and in vitro anthocyanin release.

Optimization of Encapsulation by Ionic Gelation Technique of Cryoconcentrated Solution: A Response Surface Methodology and Evaluation of Physicochemical Characteristics Study

The objective of this study was to evaluate the optimal conditions to encapsulate cryoconcentrate solutions via ionic gelation technique. Hydrogel beads were prepared using alginate (1%, 2% and 3% (w/w)) and cornstarch (0.5%, 1% and 2% (w/w)). Later, a sucrose/acid gallic solution was concentrated through block freeze concentration (BFC) at three cycles. Thus, each solution was a mixture with the respective combination of alginate/cornstarch. The final solution was added drop-wise on a CaCl₂ solution, allowing the formation of calcium alginate-cornstarch hydrogel beads filled with sucrose/acid gallic solution or cryoconcentrated solution. The results showed that alginate at 2% (w/w) and cornstarch at 2% (w/w) had the best efficiency to encapsulate any solution, with values close to 63.3%, 90.2%, 97.7%, and 75.1%, and particle sizes of approximately 3.09, 2.82, 2.73, and 2.64 mm, for initial solution, cycle 1, cycle 2, and cycle 3, respectively. Moreover, all the samples presented spherical shape. Therefore, the appropriate content of alginate and cornstarch allows for increasing the amount of model cryoconcentrated solution inside of the hydrogel beads. Furthermore, the physicochemical and morphological characteristics of hydrogel beads can be focused for future food and/or pharmaceutical applications, utilizing juice or extract concentrated by BFC as the solution encapsulated.

Influence of Fermentation Beetroot Juice Process on the Physico-Chemical Properties of Spray Dried Powder

Picking vegetables is, along with salting and drying, one of the oldest ways to preserve food in the world. This is the process of decomposition of simple sugars into lactic acid with the participation of lactic bacteria. The aim of the study was to obtain powders from fermented red beet juice with the highest possible amount of lactic acid bacteria (LAB) and active ingredients. For the analysis, juices were squeezed from the vegetables and two types of fermentation were used: a spontaneous fermentation and a dedicated one. After inoculation, samples were taken for analysis on a daily basis. Extract, pH, total acidity, pigments, and color were measured. In addition, microbiological tests were also carried out. The juices from the fifth day of fermentation was also spray dried, to obtain fermented beetroot powder. Juices from 3–5th day were characterized by a high content of LAB and betanin, had also a low pH, which proves that the lactic fermentation is working properly. The exception was the juice from spontaneous fermentation. According to the observations, the fermentation process did not run properly, and further analysis is needed. The powders were stable; however, results obtained from the pigment content and the LAB content are not satisfactory and require further analysis.

Electrosprayed chitosan-coated alginate-pectin beads as potential system for colon-targeted delivery of ellagic acid

BACKGROUND

Ellagic acid (EA), a potent dietary antioxidant, has limited bioavailability owing to its rapid absorption in the stomach and small intestine, and EA is transformed to more bioavailable compounds - urolithins - in the colon. An encapsulation system that sustains the release of EA in the gastrointestinal system and delivers more EA into the colon could improve the oral bioavailability of EA. Electrosprayed EA-loaded alginate-pectin beads were produced and coated with low- (LC) and high-molecular-weight chitosan (HC). The EA release from uncoated and coated beads under simulated gastrointestinal conditions was evaluated. The samples were characterized by particle size, gel strength, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analysis.

RESULTS

The encapsulation efficiency (EE%) of EA ranged from 49.53% to 69.85% for uncoated beads, which was elevated up to 86.50% by coating, and LC coating provided higher EE%. Pectin addition to alginate and chitosan coating reduced the gel strength and changed the size depending on the molecular weight of chitosan. SEM images of pectin-added beads showed fewer cracks but more wrinkles, and chitosan coating presented more aggregated surfaces. The ionic interaction of alginate-pectin-chitosan and the entrapment of EA were confirmed by FTIR. In the gastric medium, EA release was very low from uncoated beads (15.2-19.8%), and totally restricted by chitosan coating. In the intestinal stage, EA release from LC-coated alginate-pectin beads was only 18%, and it was between 55% and 65% for uncoated or HC-coated counterparts.

CONCLUSION

The LC-coated alginate-pectin beads could be further explored as a potential system for colon-targeted delivery of EA. © 2021 Society of Chemical Industry.

Microparticles coated with proteins in their natural state and in vitro gastrointestinal simulation

Abstract This study aimed to produce pectin and alginate microparticles by ionic gelation coated with different concentrations of bovine blood and egg white protein in their natural state. The coated microparticles were characterized, and their physical resistance and morphology were evaluated, as well as the released protein during in vitro gastrointestinal simulation. The highest protein adsorption (65.47%) was shown by pectin microparticles coated with bovine blood (10%), regardless of the protein type and concentration used. Likewise, higher amounts of adsorbed protein resulted as protein concentration increased, regardless of the type of microparticle. Nevertheless, the physical resistance of coated microparticles was affected more by the type of polysaccharide, being alginate microparticles more resistant. Adsorbed proteins on microparticles surface showed higher solubility values in vitro gastrointestinal simulation regardless of protein type. Bovine blood and egg white proteins in their natural state can be used as alternative coating materials for microparticles.

Physicochemical and release behaviour of phytochemical compounds based on black jamun pulp extracts-filled alginate hydrogel beads through vibration dripping extrusion

The phytochemical-rich extract obtained from black jamun pulp were encapsulated using vibrating dripping extrusion technique. The utilisation of alginate (AL) with four variations of core-shell material comprising gum Arabic (AL-GA), guar gum (AL-GG), pectin (AL-P) and xanthan gum (AL-X) was engaged to form calcium-alginate based lyophilised jamun extract encapsulated beads. It resulted that among four variations, lyophilised alginate with AL-GG based encapsulated jamun extract filled beads have better physicochemical characteristics and 95% encapsulation efficiency. The results revealed the morphological comparison of each variation. The release behaviour of AL-GG based beads has a higher release of total phenolics (TPC) and total anthocyanin content (TAC). The release kinetics model involving Ritger-Peppas and Higuchi model were applied for release TPC and TAC of all variations of beads. The Ritger-Peppas model was found best suitable in terms of average R² (0.965) and lowest χ² (0.0039). The release kinetics study showed that AL-GA based beads followed by AL-GG could also be the best suitable in release behaviour using simulated gastrointestinal fluids at 140-160 min. Overall, results shown the encapsulated Jamun beads have the best agro-industrial efficacy in form of phytochemical compounds based microparticles, holding decent antioxidant potential.

Physicochemical properties of heterogeneously acetylated glucomannan of A. oncophyllus and its performance for iron encapsulation

Abstract Well-known as a food additive, glucomannan has excellent biocompatibility and biodegradability properties. However, glucomannan is easily gelled, which limited its use in high concentration. To reduce the gel formation ability of glucomannan, acetylation was conducted. This work aims to study the effect of acetylation on physicochemical properties of glucomannan. Acetylation was performed in heterogeneous system which glucomannan was immersed in ethanol (96%) with various concentrations of glucomannan (5-25%) and acetic acid (5-99%). This modified glucomannan was subsequently used as an encapsulation matrix for producing iron beads. The results showed that higher concentration of acetic acid in acetylation impacted on higher solubility and viscosity of glucomannan. The transmittance intensity of Infrared (IR) spectra and morphology of glucomannan were changed due to the acetylation and encapsulation process. The highest viscosity of the matrix (484.33 cP) led to the highest Encapsulation Yield (EY) (53.3%). Gompertz’s model fitted to describe the release profile of iron in all samples (R2>0.92) that showed the burst phenomena in the initial release. This work found that acetylated glucomannan had higher solubility and has a potency to protect the iron taste during oral consumption as it releases slower in neutral pH solution.

The in-vitro digestion behaviors of micellar casein acting as wall materials in spray-dried microparticles: The relationships between colloidal calcium phosphate and the release of loaded blueberry anthocyanins

Micellar casein (MC) is a natural carrier for delivering various bioactive substances, and its gastrointestinal digestion behavior has an important impact on the loaded materials. Studies have shown that the digestion behavior of MC is dominated by colloidal calcium phosphate (CCP) in micelle structure. In this paper, The MCs with different CCP levels were used as the carriers to prepare spray-dried microparticles loaded with blueberry anthocyanins (ACNs), then the release of ACNs during digestion was investigated. The results found that the microparticles with less CCP showed the faster dissolution and quicker protein hydrolysis, which caused weaker curd ability. The coagulation was believed as the critical issue to influence the digestion and release behaviors. Therefore, lowering CCP resulted in significantly more ACNs released. This study demonstrated the possibility of using CCP levels to control MC digestion behaviors, which can further determine the release of loaded bioactive substances in casein-based delivery systems.

Microencapsulation of Anthocyanins—Critical Review of Techniques and Wall Materials

Anthocyanins are value-added food ingredients that have health-promoting impacts and biological functionalities. Nevertheless, there are technological barriers to their application in the food industry, mainly because of their poor stability and susceptibility to harsh environmental conditions, such as oxygen, temperature, pH, and light, which could profoundly influence the final food product′s physicochemical properties. Microencapsulation technology is extensively investigated to enhance stability, bioaccessibility, and impart controlled release properties. There are many varieties of microencapsulation methods and diverse types of wall materials. However, choosing a proper approach involves considering the processing parameters, equipment availability, and application purposes. The present review thoroughly scrutinizes anthocyanins′ chemical structure, principles, benefits, and drawbacks of different microencapsulation methods, including spray drying, freeze drying, electrospinning/electrospraying, inclusion complexes, emulsification, liposomal systems, ionic gelation, and coacervation. Furthermore, wall materials applied in different techniques plus parameters that affect the powders′ encapsulation efficiency and physicochemical properties are discussed. Future studies should focus on various processing parameters and the combination of different techniques and applications regarding microencapsulated anthocyanins in functional foods to assess their stability, efficiency, and commercialization potentials.

Microstructures of encapsulates and their relations with encapsulation efficiency and controlled release of bioactive constituents: A review

Vitamins, peptides, essential oils, and probiotics are examples of health beneficial constituents, which are nevertheless heat-sensitive and possess poor chemical stability. Various encapsulation methods have been applied to protect these constituents against thermal and chemical degradations. Encapsulates prepared by different methods and/or at different conditions exhibit different microstructures, which in turn differently influence the encapsulation efficiency as well as retention of encapsulated core materials. This review provides a summary of various microstructures resulted from the use of selected encapsulation methods or systems, namely, spray coating; co-extrusion; emulsion-, micelle-, and liposome-based; coacervation; and ionic gelation encapsulation, at different conditions. Subsequent effects of the different microstructures on encapsulation efficiency and retention of encapsulated core materials are mentioned and discussed. Encapsulates having compact microstructures resulted from the use of low-surface tension and low-viscosity encapsulants, high-stability encapsulation systems, lower loads of core materials to total solids of encapsulants and appropriate solidification conditions have proved to exhibit higher encapsulation efficiencies and better retention of encapsulated core materials. Encapsulates with hollow, dent, shrunken microstructures or thinner walls resulted from inappropriate solidification conditions and higher loads of core materials, on the other hand, possess lower encapsulation efficiencies and protection capabilities. Encapsulates having crack, blow-hole or porous microstructures resulted from the use of high-viscosity encapsulants and inappropriate solidification conditions exhibit the lowest encapsulation efficiencies and poorest protection capabilities. Compact microstructures and structures formed between ionic biopolymers could be used to regulate the release of encapsulated cores.

Development of alginate/inulin carrier systems containing non-conventional Amazonian berry extracts

Different carriers, such as the combination of sodium alginate and inulin, have been employed to protect foods against environmental effects. The goal of this work was to use the ionic gelation encapsulation process to produce microparticles containing Clidemia rubra extract, ranging the concentration of inulin from 1.5 to 3.5 g inulin.100 g^-1 of solution. Characteristic signals of sugars, organic acids and phenolic compounds were identified in the extract using the ¹H NMR technique. The carriers containing inulin presented significant difference in the moisture content when compared to the pure sodium alginate beads. The produced beads were found in the range of 0.81-1.06 mm. The addition of inulin to sodium alginate was significant for the encapsulation efficiency (EE) of the antioxidant compounds when compared to the beads formed only using pure sodium alginate. The microspheres presenting inulin and sodium alginate presented higher content of spherical particles. The addition of 2.5 g inulin.100 g^-1 of solution allowed its incorporation into the pores of the beads, favoring a possible chemical interaction between inulin and sodium alginate. This interaction resulted in a different crystal structure and better EE. Furthermore, beads containing inulin presented higher protection of the encapsulated bioactive compounds during the gastric phase.

Ultrasound assisted extraction of bioactive compounds from BRS Violet grape pomace followed by alginate-Ca2+ encapsulation

Objective of this study was to recover bioactive compounds from grape pomace, and to investigate the effect of thermosonication in the rate of aqueous extraction. The best extraction for phenolics and total anthocyanins, was at 55 °C, amplitude of 40% and 6 min of treatment. The ultrasound assisted extraction showed superior results when compared to conventional extraction, extraction averages were: 11% total phenolic compounds, 25% total anthocyanins. The extract obtained by ultrasound showed higher antioxidant capacity when compared to the one obtained by conventional extraction. The alginate-Ca²⁺ capsules were stable when stored in the presence or absence of light, with a reduced t1/2 (absence of light), indicating longer half-life in the absence of light. The use of thermosonication favored greater amounts of bioactive compounds in the grape pomace aqueous extract, and this encapsulated extract in alginate-Ca²⁺ shows good stability and less degradation in the light absence.

High-intensity ultrasound-assisted extraction of phenolic compounds from cowpea pods and its encapsulation in hydrogels

Currently and according to the growing worldwide interest in the revaluation of agricultural by-products, the use of legumes waste presents great potential to obtain bioactive compounds. In this context, an extract rich in phenolic compounds was obtained from Vigna unguiculata (cowpea) pods by optimizing the high-intensity ultrasound conditions (10 min and 36% of amplitude) using response surface methodology. Then, the extract was encapsulated in Ca(II)-alginate beads with the addition of arabic or guar gums or cowpea isolated proteins. A complete morphological study by image analysis and microstructural evaluation by SAXS has been carried out. Results showed that beads containing alginate and alginate-guar gum have the highest loading efficiency of total phenolic compounds (47 ± 5%) and antioxidant activity (44 ± 3%). However, the coupled effect of the cowpea extract and the isolated proteins (at it higher concentration) increased the antioxidant capacity of the beads due to the contribution of the phenolic compounds and the amino acids with anti-radical activity, reaching a value of 67 ± 3 % of inhibition of ABTS.+. Finally, the microstructural analyses revealed that cowpea pod extract increased the interconnectivity of the rods due to the presence of trivalent cations, conferring versatility, and larger coordination to the network. Also, it was observed that the addition of cowpea proteins produced more interconnected bigger and fewer compacts rods than beads containing only alginate, increasing 12 and 49 % the interconnection and the size, respectively, and decreasing 10 % their compactness. This research demonstrated the use of cowpea sub-products as a source of bioactive compounds that further modulate the microstructure of the hydrogel network, and the outstanding potential for being incorporated in techno-functional foods by using Ca(II)-alginate as a carrier.

Encapsulation and release behavior of curcumin based on nanoemulsions-filled alginate hydrogel beads

To provide the bilateral advantages of emulsions and hydrogels, a facile approach was used to fabricate nanoemulsions filled hydrogel beads through combining the method of self-emulsification and sodium alginate (SA) ionic gelation. The encapsulation and release behavior of curcumin (Cur) were further investigated. The results indicated that Cur packaged nanoemulsions were with the size of 24.26 ± 0.22 nm. The nanoemulsions filled SA hydrogel beads were spherical shell with the diameter of 0.46 ± 0.02 mm. For Cur, the EE and LC of emulsion filled SA hydrogel beads were 99.15 ± 0.85% and 7.25 ± 3.16 mg/g respectively. The release behavior could be regulated by external pH condition. The release behavior at pH 9.0 displayed a higher release rate than that at pH 7.0. Cur released behavior well followed the Hixcon-Crowell model which indicated that Cur was released in a diffusion-controlled model. Comparatively investigation of microstructure using field emission scanning electron microscope (FE-SEM) further investigates the corrosion behavior of SA gel beads during Cur release. The worth-while endeavor provided a practical combined technique of emulsions and ionic gelation to fabricate hybrid hydrogel beads that have potential in delivery system for hydrophobic composition.