Simulated Digestive Conditions Research Articles

Starch-based encapsulation to enhance probiotic viability in simulated digestion conditions

This research aims to meet the demand for efficient delivery systems in the food, nutraceutical, and pharmaceutical industries. The study involved the synthesis of starch-based nanoparticles for potential application in the encapsulation of Lactobacillus rhamnosus. Various techniques such as zeta sizer, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to characterize the encapsulated probiotics in microbeads. The results showed 85.00 % encapsulation efficiency of beads. Microscopic analysis revealed that the probiotics accumulated within the wall material and formed small, smooth polygonal granules on the capsule surface. XRD analysis confirmed the presence of amorphous humps and some crystallinity of nanoparticles in the capsules. Moreover, encapsulation significantly improved probiotic viability under simulated gastrointestinal conditions. This study highlights the potential of starch-based nanoparticles to enhance the stability and viability of probiotics, demonstrating their potential applications across various industrial sectors. Further research should focus on investigating the long-term stability and functional efficacy of encapsulated probiotics in microbeads for real-world applications.

Gastrointestinal-inert prebiotic micro-composites improve the growth and community diversity of mucosal-associated bacteria.

The process of microencapsulation and the development of microparticle-based drug formulations have gained increased pharmaceutical interest, particularly for drug delivery and bacterial-encapsulation purposes for probiotic delivery. Existing studies have examined microcomposite (MC) responses to gastrointestinal (GI) conditions with the aim of controlling disintegration, and thus release, across the small and large bowel. However, the delivery of MCs which remain intact, without degrading, could act as bacterial growth scaffolds or materials providing a prebiotic support, conferring potentially beneficial GI health properties. This present study employs prilling as a method to produce a portfolio of MCs using a variety of biopolymers (alginate, chitosan, pectin and gellan gum) with a range of MC diameters and density compositions. Fluorescent probes are co-encapsulated within each MC to enable flow-cytometry directed release profile assessments following exposure to chemical simulated gastric and intestinal digestion conditions. We observe that MC size, gel-strength, density, and biopolymer material all influence response to gastric and intestinal conditions. Gellan gum (GG) MCs demonstrated complete resistance to disintegration throughout GI-simulation in the stomach and small intestine. Considering these MCs could reach the colon intact, we then examined how such MCs, doped with prebiotic growth supporting carboxymethyl cellulose (CMC) polymers, could impact microbial communities using a bioreactor model of the colonic microbiome. Following supplementation with GGCMC MCs, mucosal bacterial diversity (using 16 s rRNA sequencing and Shannon entropy and observed feature diversity metrics) and taxonomic composition changes were observed. Concentrations of short chain fatty acid (SCFA) metabolites were also found to be altered. This is the first study to comprehensivelyexamine how MC physicochemistry can be manipulated to tailor MCs to have the desired GI release performance and subsequently, how GI-resistant MCs could have influential microbial altering properties and be adopted in novel prebiotic strategies.

Encapsulation of Lactiplantibacillus plantarum probiotics through cross-linked chitosan and casein for improving their viability, antioxidant and detoxification

In the present study, encapsulation of Lactiplantibacillus plantarum (L.p) was performed using chitosan and casein through calcium phosphate intercrossing. Chitosan and casein both considered as non-toxic and biocompatible food derived components with intrinsic antioxidant properties. Layer by layer strategy was performed for deposition of modified cross-linked chitosan along with casein as the novel protective layers on the surface of probiotics. After confirmation of successful encapsulation, the viability and antioxidant activity of encapsulated L.p was evaluated. The results showed enhanced survival and antioxidant activity of encapsulated L.p compared to free bacteria in simulated digestive conditions. The survival of free and encapsulated L.p was respectively 1.38 ± 0.29 log cfu/ml and 6.99 ± 0.12 log cfu/ml in SGF and 8.54 ± 0.05 log cfu/ml and 7.25 ± 0.23 log cfu/ml in SIJ after 2 h of incubation. HPLC analysis was also used to investigate the detoxification activity of probiotics toward Aflatoxin M1 and obtained results showed encapsulated bacteria could significantly reduce aflatoxin M1 (68.44 ± 0.5 %) compared to free bacteria (43.76 ± 0.54 %). The results of this research suggest that the chitosan/casein mediated encapsulation of L.p with layer-by-layer technology is an effective method to improve the survival and antioxidant properties of probiotics with enhanced detoxification of AFM1.

Preparation and in vitro digestion of algal oil emulsion gel candy with high oxidation stability based on cold‐set gelation method

SummaryAlgal oil emulsion gel candies were prepared by a cold‐set gelation method, and the oxidative stability was analysed. Then, the release of algal oil and the microstructural changes of gel candies were investigated under in vitro simulated digestion conditions. The formula of gel candy was found to be 65% sucrose, 5% algal oil emulsion, 1.8% sodium alginate, 1.2% high methoxy pectin and 2% D‐glucono‐δ‐lactone. Cold‐set gel candies loaded with algal oil emulsion had good oxidative stability. Emulsion gel candies could maintain a relatively intact gel network structure in a gastric fluid environment, in which the DHA release rate was less than 5%, whereas the gel structure was loosened at 30 min of digestion in simulated intestinal fluid and destroyed at 60 min, with a release rate of about 75%. Altogether, these results lay a theoretical foundation for facilitating the development of novel DHA functional foods.

Bioactive Properties and In Vitro Digestive Release of Cannabidiol (CBD) from Tailored Composites Based on Carbon Materials.

The use of carriers to improve cannabidiol (CBD) bioavailability during digestion is at the forefront of research. The main objective of this research was to evaluate CBD bioactivity and develop CBD composites based on tailored carbon support to improve availability under digestive conditions. The antioxidant capacity of CBD was evaluated using spectrophotometric methods, and anti-proliferative assays were carried out using human colon carcinoma cells (SW480). Twenty-four composites of CBD + carbon supports were developed, and CBD desorption tests were carried out under simulated digestive conditions. The antioxidant capacity of CBD was comparable to and superior to Butylhydrox-ytoluene (BHT), a commercial antioxidant. CBD reflected an IC-50 of 10,000 mg/L against SW480 cancer cells. CBD in biological systems can increase the shelf life of lipid and protein foods by 7 and 470 days, respectively. Finally, acid carbons showed major CBD adsorption related to electrostatic interactions, but basic carbons showed better delivery properties related to electrostatic repulsion. A tailored composite was achieved with a CBD load of 27 mg/g with the capacity to deliver 1.1 mg, 21.8 mg, and 4 mg to the mouth, stomach, and duodenum during 18 h, respectively. This is a pioneering study since the carriers were intelligently developed to improve CBD release.

Dual-function starch aerogels: Nutraceutical carriers for iron and folic acid delivery

Iron and folic acid are especially important in pregnancy, where supplementation is often the only path to prevent anemia. Despite the available commercial solutions, the challenges of enhancing nutrient absorption and reducing side effects foster the search for novel approaches. In this work, freeze-dried starch aerogels were developed to act as nutraceutical carriers for co-delivery and tested under simulated digestion conditions. Iron and folic acid were loaded into starch gels, both separately and mixed. Iron presented a faster release than folic acid in intestinal conditions, reaching 75–80 % after 10 and 90 min, respectively. Molecular modeling suggests that folic acid interacts with amylose agglomerates in water by hydrogen bonds, probably delaying its release. Co-delivery of these nutraceuticals seems to not affect the release behavior. The Korsmeyer-Peppas kinetic model fits well to all release profiles. The proposed starch aerogel is a promising solution and further development can increase its competitiveness against conventional supplements.

Preparation, characterization and microencapsulation of walnut (Juglans regia L.) peptides-zinc chelate.

In this research, a novel kind of walnut (Juglans regia L.) peptides-zinc (Zn-WPs) chelate was obtained using the mass ratio of the walnut peptides (WPs) to ZnSO4.7H2O of 3.5:1 at pH 8.5 and 50°C for 84min, with the chelation rate of 84.5%. In comparison to walnut peptides (WPs), the contents of aspartic acid and glutamic acid in Zn-WPs chelate are approximately 27%, indicating that hydrophilic amino acids predominantly bind with walnut peptides. Following chelation with zinc ions, the ultraviolet-visible (UV) characteristic absorption peak shifted from 213nm to 210nm, while the average particle size of the chelate increased to 8.0±0.14µm, presenting a loose spherical structure under scanning electron microscopy. These findings suggest the formation of new substances. Fourier-transform infrared spectroscopy (FTIR) revealed carboxyl, amino, and peptide bonds as the chelation sites of WPs and zinc. The IC50 of walnut peptides-zinc (Zn-WPs) chelate is 2.91mg/mL, indicative of a favorable DPPH radical scavenging rate. Furthermore, Zn-WPs chelate microcapsules were produced via the spray drying method, achieving an encapsulation rate of 75.67±0.83% under optimal conditions. These microcapsules demonstrate robust stability across diverse environmental conditions. This study underscores the potential of Zn-WPs and its chelate microcapsules to enhance stability and bioactivity under varying circumstances. PRACTICAL APPLICATION: In this study, a new walnut peptide-zinc (Zn-WPs) chelate was prepared. The presence of zinc ions changes the structure and properties of walnut peptides and improves its stability. The production of Zn-WPs chelate microcapsules enables Zn-WPs to have strong in vitro stability under different pH and simulated gastrointestinal digestion conditions. These results provide novel insights for developing the walnut peptides as bioactive ingredients in functional foods.

Fabrication, characterization, and dihydromyricetin-loaded bioavailability of Pickering emulsions stabilized by Ampelopsis grossedentata polysaccharide -fish collagen peptide composite nanoparticles

A novel strategy was devised to synthesize robust nanocarriers by conjugating fish collagen peptides (FCP) with Ampelopsis grossedentata polysaccharide (AGP), culminating in the creation of FCP-AGP nanoparticles (FCAGPs) for advanced drug delivery systems. The innovative approach entailed the systematic investigation of particle size, zeta potential, and surface hydrophobicity alterations in FCAGPs upon varying AGP concentrations. The optimized FCAGP-4 nanoparticles, boasting a precisely engineered AGP content of 2.0 % (w/v) and an average particle diameter finely tuned to 353.2 ± 10.5 nm, demonstrated outstanding characteristics in dispersibility, stability, and emulsifying capacity. Furthermore, the water contact angle of FCAGP nanoparticles notably increased from 46.3 ± 2.8° to 70.2 ± 5.6°, indicating enhanced surface hydrophobicity. The mechanism by which FCAGP nanoparticles were attached to the surface of oil droplets to stabilize the emulsions was elucidated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Significantly, a modified sample pretreatment technique was employed to demonstrate clearly the emulsion phase interface on the SEM.Innovative FCAGP-stabilized Pickering emulsions achieved 65.39 % in DMY bioavailability, facilitating its slow-release and enhanced bioaccessibility during in vitro digestion. Pickering emulsions loaded DMY demonstrated improved stability and sustained release under simulated digestive conditions, bolstering its therapeutic efficacy. Our findings solidify the theoretical basis for green synthesis of propeptide-polysaccharide nanoparticles and introduce a novel strategy for targeted propeptide Pickering emulsions in drug delivery, highlighting the transformative potential of FCAGP nanoparticles in enhancing lipophilic drug bioavailability and pharmacological impact.

Enhancing therapeutic effects alginate microencapsulation of thyme and calendula oils using ionic gelation for controlled drug delivery

This study focuses on encapsulating and characterizing essential oils such as thyme and calendula oils, which are known for their therapeutic properties but are limited in pharmaceutical formulations due to their low water solubility and instability, with alginate microspheres. Alginate presents an excellent option for microencapsulation due to its biocompatibility and biological degradability. The ionic gelation (IG) technique, based on the ionic binding between alginate and divalent cations, allows the formation of hydrogel materials with high water content, mechanical strength, and biocompatibility. The microspheres were characterized using FT-IR, SEM, and swelling analyses. After determining the encapsulation efficiency and drug loading capacity, the microspheres were subjected to dissolution studies under simulated digestion conditions. It was observed that the swelling percentage of the microspheres in simulated gastric fluid (SGF) ranged from ∼15% to 100%, while in simulated intestinal fluid (SIF) it ranged from ∼150% to 325%. Thyme oil, with low viscosity, exhibited higher encapsulation efficiency than marigold oil. The highest encapsulation efficiency was observed in A-TO-2 microspheres, while the highest drug loading capacity was observed in A-TO-5 microspheres. During the examination of the dissolution profiles of the microspheres, dissolution rates ranging from 10.98% to 23.56% in SGF and from 52.44% to 63.20% in SIF were observed.

Isolation and Characterization of Antioxidant Peptides from Dairy Cow (Bos taurus) Placenta and Their Antioxidant Activities.

Our preliminary study identified dairy cow placenta extract (CPE) as a mixture of peptides with potent antioxidant activity both in vivo and in vitro. However, the specific antioxidant peptides (AOPs) responsible for this activity were not yet identified. In the current study, we employed virtual screening and chromatography techniques to isolate two peptides, ANNGKQWAEVF (CP1) and QPGLPGPAG (CP2), from CPE. These peptides were found to be less stable under extreme conditions such as high temperature, strong acid, strong alkali, and simulated digestive conditions. Nevertheless, under normal physiological conditions, both CP1 and CP2 exhibited significant antioxidant properties, including free-radical scavenging, metal chelating, and the inhibition of lipid peroxidation. They also up-regulated the activities of intracellular antioxidant enzymes in response to hydrogen-peroxide-induced oxidative stress, resulting in reduced MDA levels, a decreased expression of the Keap1 gene and protein, and increased levels of the Nrf2 and HO-1 genes and proteins. Furthermore, CP1 demonstrated superior antioxidant activity compared to CP2. These findings suggest that CP1 and CP2 hold potential for mitigating oxidative stress in vitro and highlight the efficacy of virtual screening as a method for isolating AOPs within CPE.

Lipolysis and Sterol Stability and Bioaccessibility of Wholemeal Rye Bread Enriched with Plant Sterols Subjected to Adult and Elderly Digestion Conditions.

This study evaluated the impact of different digestion conditions (adult and senior) on lipolysis and bioaccessibility of plant sterols (PS) and phytosterol oxidation products (POPs) in PS-enriched wholemeal rye bread. Under adult digestion conditions, the addition of gastric lipase (GL) reduced lipolysis products (by 6.1% for free fatty acids and 11.7% for monoacylglycerols) and the bioaccessibility of PS by 6.7%, compared to the control. In digestion with both GL and cholesterol esterase (CE), these reductions were 12.9, 20.1, and 11.3%, respectively. Both modifications (GL and GL + CE) increased the bioaccessibility of POPs by 4.5-4.0%. When simulating the elderly digestion, the modified gastric and intestinal phases did not alter PS bioaccessibility but decreased POPs bioaccessibility by 21.8% compared to control, along with reduced lipolysis. Incorporating GL and CE thus approached physiological conditions and influenced lipid digestion. Elderly simulated digestion conditions resulted in a positive outcome by maintaining PS bioaccessibility while reducing potentially harmful POPs.

The double-layer emulsions loaded with bitter melon (Momordica charantia L.) seed oil protect against dextran sulfate sodium-induced ulcerative colitis in mice

In this study, a whey protein isolate (WPI)-chitooligosaccharide (COS) stabilized bitter melon (Momordica charantia L.) seed oil emulsions (WC-BSOE) were prepared using the electrostatic layer-by-layer self-assembly technique, and their modulating effects on ulcerative colitis (UC) were investigated in dextran sulfate sodium (DSS)-induced UC mice model. The stability and releasing ability of WC-BSOE under simulated gastrointestinal digestion condition and their acute toxicity were also investigated. The results showed that WC-BSOE was stable to droplet aggregation in the simulated gastric and intestinal fluids and exhibited sustained release profile during gastrointestinal transit, evidenced by the measurement of particle size, polydispersity index, zeta-potential and released free fatty acids contents. Moreover, WC-BSOE had no toxic effects on BALB/c mice within the dose range of 40,000 mg/kg body weight (BW), and treatment with WC-BSOE at a dosage of 15 mg/kg BW effectively relieved DSS-induced UC symptoms in mice. Furthermore, WC-BSOE could improve the IL-4 and IgA contents in serum, as well as up-regulate the occludin and ZO-1 expressions and down-regulate MPO, MDA and ROS levels in colon tissues of colitis mice, and it also elevated the diversity and relative abundances of Firmicutes, Bacteroides, and Lactobacillus in the intestinal microbiota. These findings indicated that WC-BSOE exerted protective effects in UC through decreasing proinflammatory cytokines, increasing tight junction proteins, suppressing oxidative stress, and regulating intestinal microbiota. Collectively, this study suggested WC-BSOE might be developed as a promising dietary supplement for UC protection.

Anthocyanin-loaded milk-derived extracellular vesicles nano-delivery system: Stability, mucus layer penetration, and pro-oxidant effect on HepG2 cells

Anthocyanin (ACN) has attracted considerable attention due to its wide range of physiological effects. However, challenges such as poor stability and limited bioavailability have hindered its utilization in functional foods. To address these issues, this research utilized milk-derived extracellular vesicles (MEV) as carriers for encapsulating and binding ACN through various techniques, including ultrasonic, electroporation, saponin treatment, incubation, and freeze-thaw cycles. The objective of these approaches was to enhance the stability of ACN and improve its oral delivery. Notably, the ACN-loaded MEV (MEV-ACN) prepared through ultrasonic exhibited small particle sizes and good stability under processing, storage, and simulated digestion conditions. Cellular studies revealed that MEV-ACN exhibited pro-oxidant properties and induced oxidative stress, leading to cell apoptosis with greater efficacy compared to free ACN. These findings suggest that encapsulating ACN within MEV can significantly enhance its processing and oral stability, as well as strengthening its dietary defense capabilities in anti-tumor applications.

Exploring the binding process of lutein with hydroxypropyl-β-cyclodextrin: Multispectral and molecular simulation study

Lutein possesses various biological activities, including antioxidant and benefits for eye health, but its application is hindered by poor water solubility and chemical instability. The study utilized hydroxypropyl-β-cyclodextrin (HP-β-CD) in complexation with lutein to enhance stability. The preparation conditions of the inclusion complex (IC) were optimized using Box-Behnken design (BBD), and the IC binding mechanism was investigated and studied by multispectral and molecular docking techniques. The results indicated that the maximum encapsulation efficiency of 84.92% was obtained when shell-to-core ratio was 1:11 (g: g), stirring speed was 420 rpm, and time was 15 h. Moreover, the microstructure characterization and multispectral analysis indicate the formation of IC, with lutein exhibiting an amorphous structure. The results of molecular docking and molecular dynamics (MD) simulations further demonstrate that lutein and HP-β-CD are bound through electrostatic and hydrophobic interactions. IC exhibits higher stability compared to free lutein under varying temperatures and simulated digestive conditions, and enhance antioxidant activity. IC changes the original crystal form of lutein and improves water solubility, which may be more favorable for human absorption and utilization. Hence, encapsulating lutein with HP-β-CD may offer a promising strategy to enhance its applications in pharmaceuticals and food applications.

Effects of the dose of administration, co-antioxidants, food matrix, and digestion-related factors on the in vitro bioaccessibility of rosmarinic acid – A model study

This study aimed to determine the effect of the administration dose, combinations with co-antioxidants (vitamin C, caffeic acid, chlorogenic acid, catechin, rutin), and different food matrices (cooked and lyophilized hen eggs, chicken breast, soybean seeds, potatoes) on the potential bioaccessibility of rosmarinic acid (RA) in simulated digestion conditions, depending on the digestion stage (gastric and intestinal) and the contribution of physicochemical and biochemical digestion factors.The in vitro bioaccessibility of RA depended on the digestion stage and conditions. The physicochemical factors were mainly responsible for the bioaccessibility of RA applied alone. The higher RA doses improved its bioaccessibility, especially at the intestinal stage of digestion. Furthermore, the addition of vitamin C and protein-rich food matrices resulted in enhanced intestinal bioaccessibility of RA.In the future, the knowledge of factors influencing the bioaccessibility of RA can help enhance its favorable biological effects and therapeutic potential.

Effect of Mollusca shell extracts on inhibition of kimchi over-acidification

Mollusca species shell such as oyster shell (OS) and snail shell (SS), are discarded after taking the meat, and the discarded shell causes the environmental problems. Therefore, recycling shell waste could potentially eliminate the environmental problems. This study aimed to evaluate the potential of OS and SS as natural calcium resources. The minerals, calcium, magnesium, potassium, phosphorus and sodium were analyzed in OS and SS extracts. Among them, the calcium content was the highest: 36.87 (%) and 33.42 (%) in the OS and SS extracts, respectively. Further, the content of ionized bioavailable form of calcium in OS and SS was higher than that of CaCO3 under simulated gastrointestinal digestion conditions. Additionally, OS and SS were added to kimchi, and their inhibitory effect on kimchi acidification was evaluated by assessing pH, titratable acidity and microbial analysis. As the results indicated that the addition of OS and SS had little effect on inhibiting the growth of lactic acid bacteria. However, it was confirmed that calcium neutralizes the organic acids produced during fermentation. Overall, the results of this study provide preliminary information on the re-use of OS and SS extracts as ionized natural calcium supplements and fermentation retardants.

Preparation and characterization of iota carrageenan-cyclodextrin-curcumin fibers and the release nature of curcumin in simulated digestion conditions

Healthy foods, known as functional and medicinal foods, are gaining popularity as they contain reasonable amounts of bioactive compounds (BCs) that can boost immunity. However, the intrinsic water insolubility and instability of BCs limit the design and development of healthy foods. To this end, carriers are effective in overcoming these setbacks. Among the several carrier choices, herein, human-compatible hydrocolloid iota-carrageenan (IC), a food hydrocolloid with the ability to form thermos-reversible gels, is chosen due to its intrinsic non-toxic and inexpensive traits. The ordered network structures of iota-carrageenan have been created by complexing with α-, β-, and γ-cyclodextrin (CD); later, curcumin has been encapsulated. Curcumin release has been tested in aqueous, simulated gastrointestinal, and simulated intestinal conditions. The maximum curcumin release was obtained in the aqueous conditions, and the IC fibers containing 50 mM NaCl displayed the highest curcumin release of 1.55 mg/g, followed by IC50-0.1β-CD of 1.37 mg/g. On the other hand, in IC fibers with 100 mM NaCl, the best release obtained was from IC100-0.1γ-CD and IC100 of 0.84 and 0.83 mg/g, respectively, and the minimum release of 0.39 mg/g was from the IC100-0.5γ-CD fibers. In simulated gastric fluid (SGF) media (pH 1.2), the highest release detected was 0.26 mg/g from the fibers with 50 mM NaCl. However, in simulated intestinal fluid (SIF) conditions (pH 6.8), the maximum achieved release of 1.00 mg/g was from the IC50 fibers, followed by 0.93 mg/g from the IC50-0.1β-CD fibers. Overall, the IC-CD network thermally protects curcumin, and the type of CD impacts its sustained release nature. The outcome is important in designing value-added delivery systems of bioactive compounds required to develop novel functional foods and improve human health.

Adsorption/desorption of mercury (II) by artificially weathered microplastics: Kinetics, isotherms, and influencing factors

While both mercury (Hg) and microplastics (MPs) are well-studied global pollutants, comparatively little is known about the interactions between them and the mobilization of Hg from MPs into organisms. We examined the affinity of Hg(II) to artificially weathered MPs, including polyamide (w-PA), polyethylene (w-PE), polyethylene terephthalate (w-PET), polyester fibers (w-PEST), polyvinyl chloride (w-PVC), and polylactic acid (w-PLA), along with crumb rubber (CR) and PE collected from a wastewater treatment plant (WWTP-PE). WWTP-PE, CR, and w-PEST had particularly high Hg(II) affinities, which can be attributed to electrostatic interaction and pore filling. The adsorption followed a pseudo-second-order kinetic process and fitted the Freundlich model, suggesting multi-step (mass transfer and intraparticle diffusion) and heterogeneous adsorptions. Hydrochemical conditions (pH, dissolved organic matter (DOM), salinity and co-existent metal ions) all impacted Hg-MP behavior. Changes in Hg speciation and MP surface properties contributed to the different Hg(II) adsorption capacities for the MPs. Weathering of MPs generally increased the adsorption of Hg(II) onto MPs, but CR, PET and PEST did not follow this trend. Less than 3% of adsorbed Hg(II) was mobilized from the MPs in freshwater, but that increased up to 73% under simulated avian digestive conditions, suggesting increased bioavailability of Hg(II) from ingested MPs. Overall, weathered MPs adsorb and retain Hg(II) under environmentally relevant conditions but desorb much of it in simulated avian digestion fluid, suggesting that birds that ingest MPs may have increased Hg(II) exposure.

Effect of starch-based nanoparticles on the viability and stability of probiotics under adverse conditions

ABSTRACT Starch nanoparticles resist digestion in the upper intestine but not in the colon. They are proven to exert prebiotic effects on the human body. Starch-based nanoparticles have generated a great interest in the food and agriculture sector due to their biocompatibility, wide array of natural sources and ease of modification. In the current study, two starch sources (rice and water chestnut) were used to synthesize nanoparticles for the encapsulation of probiotic bacteria. Obtained nanoparticles were characterized for their morphological, molecular, and structural attributes using Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and zeta sizer. Furthermore, free and nano-encapsulated probiotics were subject to simulated gastrointestinal digestion conditions. The average size of rice and water chestnut starch-based nano-capsules ranged from 309 to 427 nm. The encapsulation efficiency was recorded for rice and water chestnut starch as 89% and 95%, respectively. SEM micrographs exhibited entrapment of probiotics in wall materials. The surface of the capsules showed tiny, smooth surface polygonal granules. XRD images showed loss of crystallinity structure following encapsulation. Higher probiotic viability was recorded under simulated gastrointestinal conditions for nano-encapsulated probiotics compared to free probiotics. Conclusively, water chestnut and rice-based starch nanoparticles showed overall the best results regarding the viability of probiotics under stressed conditions.

Characterization and stability investigation of rhein encapsulated microcapsules using different enteric biopolymers with pullulan and Jiuzao glutelin conjugates via Maillard reaction

The poor water solubility and rhein (RH) stability limit its application in the functional food industry. In the present study, the RH-loaded water-in-oil-in-water nano emulsion and microcapsules were prepared using the conjugates of pullulan-Jiuzao glutelin (JG) (m/m, 2:1, PJC-2) obtained by Maillard reaction and enteric-soluble materials (polymethlacrylic acid, hydroxypropyl methylcellulose phthalate, cellulose acetate phthalate, and D-mannitol). The effects of different formulations on the microstructure, physicochemical properties, and storage stability of microcapsules were analyzed. The results showed that microcapsules exhibited stability against different external environments. The encapsulation efficiency of RH in the four enteric-soluble-PJC-2 double-deck microcapsules (70.03 ± 3.24%-91.08 ± 4.78%) was significantly improved than PJC-2 ones (61.84 ± 0.47%). The antioxidant activity and stability of RH in the microcapsules were improved (ABTS, 49.7%-113.93%; DPPH, 40.85%-101.82%; FRA, 62.32%-126.42%; and FCA, 70.58%-147.20%) after in vitro simulated digestion and extreme environmental conditions compared to free RH. This work provides a microcapsule based on PJC-2 with enteric-soluble materials for insoluble functional ingredients to improve solubility, stability, and bioactivity in the food industry.