Preparation and characterization of zein-based phytosterol nanodispersions fabricated by ultrasonic assistant anti-solvent precipitation

The Effect of Whey Protein Isolate Hydrolysate on Digestive Properties of Phytosterol

Phytosterol (PS) is a steroid, and its bioavailability can be enhanced by interacting with protein in the C-24 hydroxyl group. The interaction between sterols and amino acid residues in proteins can be enhanced by enzymatic hydrolysis. Phytosterol and whey insulation hydrolysates (WPH1-4) fabricated by the Alcalase enzyme at different enzymatic hydrolysis times were selected as delivery systems to simulate sterol C-24 hydroxyl group interaction with protein. Increasing hydrolysis time can promote the production of β-Lg, which raises the ratio of β-turn in the secondary structure and promotes the formation of interaction between WPH and PS. The correlation coefficient between hydrogen bonds and encapsulation efficiency (EE) and bioaccessibility is 0.91 and 0.88 (P < 0.05), respectively, indicating that hydrogen bonds of two components significantly influenced the combination by concealing the hydrophobic amino acids and some residues, which improved PS EE and bioavailability by 3.03 and 2.84 times after PS was combined with the WPI hydrolysate. These findings are expected to enhance the absorption of PS and other macromolecules by protein enzymatic hydrolysis to broaden their applications for food.

Current and New Insights on Delivery Systems for Plant Sterols in Food

Plant sterols are minor bioactive components of food lipids, which are often used for the formulation of functional foods due to their cholesterol-lowering properties. However, they have low solubility and tend to crystallize, which may affect their biological effects, the sensory profile of the sterol-enriched food, and its consumer acceptability. Moreover, due to the unsaturated structure of sterols, they are susceptible to oxidation, so different encapsulation systems have been developed to improve their dispersibility/solubility, stability, delivery, and bioaccessibility. This chapter provides an overview of the main encapsulation systems currently used for plant sterols and their application in model and food systems, with a particular focus on their efficiency and impact on sterol bioaccessibility.

Preparation, structural and functional characterization of corn peptide-chelated calcium microcapsules using synchronous dual frequency ultrasound

The utilization of peptide-chelated calcium is low due to the influence of factors such as solubility, heat and digestive environmental conditions; therefore, it is crucial to protect, prolong and stabilize this nutrient in order to enhance its efficacy. This study was conducted to prepare corn peptide-chelated calcium microcapsules using β-cyclodextrin (β-CD) as the wall material through an improved ultrasonic-assisted method. The structure, solubility, thermal stability, and in vitro gastrointestinal digestion of these microcapsules were thoroughly investigated and analyzed. The microcapsules were prepared using the following recommended conditions: a chelate concentration of 5 mg/mL, a mass ratio of chelate to β-CD of 1:8 g/g, and a synchronous dual-frequency ultrasound (20/28 kHz) at a power of 75 W, a duty ratio of 20/5 s/s, and a time of 20 min. These specific parameters were carefully selected to ensure the optimal fabrication of the microcapsules. The results showed that the utilization of dual-frequency ultrasound resulted in a significant increase in both the encapsulation rate and yield, which were enhanced by 15.84 % and 15.68 %, respectively, reaching impressive values of 79.17 % and 90.60 %. Moreover, the results of the structure index analysis provided further confirmation that ultrasonic treatment had a significant impact on the structure of the microcapsules, leading to a noticeable reduction in particle size and transformation into nanoparticles. Furthermore, the microcapsules demonstrated excellent solubility within a wide pH range of 2 to 10, with solubility ranging from 93.54 % to 88.68 %. Additionally, these microcapsules exhibited remarkable thermal stability, retaining a minimum of 84.8 % of their stability when exposed to temperatures ranging from 40 to 80 °C. Moreover, during gastric and intestinal digestion, these microcapsules exhibited a high slow-release rate of 44.66 % and 51.6 %, indicating their ability to gradually release calcium contents. The inclusion of dual-frequency ultrasound in the preparation of high calcium microcapsules yielded promising outcomes. Overall, our work presents a novel method for synthesizing corn peptide-chelated calcium microcapsules with desirable properties such as good solubility, excellent thermal stability, and a significant slow-release effect. These microcapsules have the potential to serve as fortified high calcium supplements.

Complexes of glycated casein and carboxymethyl cellulose enhance stability and control release of anthocyanins

To improve the stability and sustained-release property of anthocyanins (ACNs), casein (CA) - dextran (DEX) glycated conjugates (UGCA) and carboxymethyl cellulose (CMC) were used to prepare ACNs-loaded binary and ternary complexes. The ACNs-loaded binary complexes (ACNs-UGCA) and ternary complexes (ACNs-UGCA-CMC) achieved by 8 min' ultrasonic treatment with 40 % amplitude. The binary and ternary complexes showed spherical structure and good dispersibility, with the average size of 121.2 nm and 132.4 nm respectively. The anthocyanins encapsulation efficiency of ACNs-UGCA-CMC increased almost 20 % than ACNs-UGCA. ACNs-UGCA-CMC had better colloidal stabilities than ACNs-UGCA, such as thermal stability and dilution stability. Simultaneously, both of the binary and ternary complexes significantly prevented anthocyanins from being degraded by heat treatment, ascorbic acid, sucrose and simulated gastrointestinal environment. The protective effect of ACNs-UGCA-CMC was more significant. Furthermore, ACNs-UGCA-CMC showed slower anthocyanins release in simulated releasing environment in vitro and a long retention time in vivo. Our current study provides a potential delivery for improving the stability and controlling release of anthocyanins.

Molecular Interaction of Pea Glutelin and Lipophilic Bioactive Compounds: Structure-Binding Relationship and Nano-/Microcomplexation

This study investigated the impact of ionic strength and lipophilicity of bioactive compounds on their interaction with the alkaline soluble pea glutelin fraction (ASF) using the fluorescence quenching technique. A Stern-Volmer quenching constant, KD, of 8.9 ± 0.10, 5.3 ± 0.06, 4.0 ± 0.01, 1.1 ± 0.00, 0.9 ± 0.02, and 0.1 ± 0.00 (×104 M-1) was observed for curcumin-ASF (CuASF), astaxanthin-ASF (AsASF), cholecalciferol-ASF (ChASF), β-carotene-ASF (βCaASF), coenzyme Q10-ASF (Q10ASF), and β-sitosterol-ASF (βSiASF) complexes, respectively. An increase in ionic strength did not significantly change KD, the effective quenching constant K, and the bimolecular quenching rate constant KQ. However, it changed the mode of interaction of the ASF with cholecalciferol, β-carotene, coenzyme Q10, and β-sitosterol from static to static-dynamic quenching. Transmission electron microscopy showed that the morphology formed with protein (spherical nanocomplexes, microaggregates, or fiber-like particles) differed among the compounds. The favorable binding of CuASF, AsASF, ChASF, and βCaASF complexes provides stable matrices for formulating protein-based delivery systems for lipophilic nutraceuticals.

Production, Characterization, Delivery, and Cholesterol-Lowering Mechanism of Phytosterols: A Review

Phytosterols are natural plant-based bioactive compounds that can lower blood cholesterol levels and help prevent cardiovascular diseases. Consequently, they are being utilized in functional foods, supplements, and pharmaceutical products designed to improve human health. This paper summarizes different approaches to isolate, purify, and characterize phytosterols. It also discusses the hypolipidemic mechanisms of phytosterols and their impact on cholesterol transportation. Phytosterols have a low water-solubility, poor chemical stability, and limited bioavailability, which limits their utilization and efficacy in functional foods. Strategies are therefore being developed to overcome these shortcomings. Colloidal delivery systems, such as emulsions, oleogels, liposomes, and nanoparticles, have been shown to be effective at improving the water-dispersibility, stability, and bioavailability of phytosterols. These delivery systems can be used to incorporate phytosterols into a broader range of cholesterol-lowering functional foods and beverages. We also discuses several issues that need to be addressed before these phytosterol delivery systems can find widespread commercial utilization.

Water-Dispersible Phytosterol Nanoparticles: Preparation, Characterization, and in vitro Digestion

For improving solubility and bioaccessibility of phytosterols (PS), phytosterol nanoparticles (PNPs) were prepared by emulsification–evaporation combined high-pressure homogenization method. The organic phase was formed with the dissolved PS and soybean lecithin (SL) in anhydrous ethanol, then mixed with soy protein isolate (SPI) solution, and homogenized into nanoparticles, followed by the evaporation of ethanol. The optimum fabrication conditions were determined as PS (1%, w/v): SL of 1:4, SPI content of 0.75% (w/v), and ethanol volume of 16 ml. PNPs were characterized to have average particle size 93.35 nm, polydispersity index (PDI) 0.179, zeta potential −29.3 mV, and encapsulation efficiency (EE) 97.3%. The impact of temperature, pH, and ionic strength on the stability of fabricated PNPs was determined. After 3-h in vitro digestion, the bioaccessibility of PS in nanoparticles reached 70.8%, significantly higher than the 18.2% of raw PS. Upon freeze-drying, the particle size of PNPs increased to 199.1 nm, resulting in a bimodal distribution. The solubility of PS in water could reach up to 2.122 mg/ml, ~155 times higher than that of raw PS. Therefore, this study contributes to the development of functional PS-food ingredients.

Pectin-zein based stigmasterol nanodispersions ameliorate dextran sulfate sodium-induced colitis in mice

Due to the insolubility of phytosterols in both water and oil, their application in the medicine and health and food industries is limited. In this study, zein and pectin were selected as wall materials of phytosterol nanoparticles to enhance the solubility and bioactivity of phytosterols. The colitis-inhibitory effects of zein-based stigmasterol nanodispersions (ZNs) and zein/pectin-based stigmasterol nanodispersions (ZPNs) were investigated in the sodium dextran sulfate (DSS)-induced colitis mouse model. The results showed that ZPNs' therapeutic effect was better than that of ZNs. According to electron microscopy observation, pectin adsorbed on the surface of zein appeared to form an elastic network structure, which increased the stability of stigmasterol nanodispersions. ZPNs not only relieved the adverse physiological symptoms of colitis in mice, but additionally prevented colonic length shortening and reduced fecal hemoglobin content. Immunohistochemical analysis showed that ZPNs could alleviate colitis by inhibiting the NF-κB signaling pathway involved in the expression of inflammatory factors TNF-α, IL-6, IL-1β, CSF-1 and coenzyme COX-2. This study suggests that supplement of nano-embedded stigmasterol based on zein and pectin has a positive therapeutic effect on alleviating colitis in mice. Such activities of nano-embedded stigmasterol in humans remain to be investigated.

Preparation and characterization of soybean protein isolate/pectin-based phytosterol nanodispersions and their stability in simulated digestion

In this study, stigmasterol was nanoencapsulated in soy protein isolate -pectin-based nanodispersions. Based on the particle size and zeta-potential, the optimal pectin/SPI ratio of stigmasterol nanodispersion was determined to be 1:10. At this ratio, nanodispersions was manufactured with an average particle size of 477 ± 33 nm, an encapsulation efficiency of 89.37%, and a loading amount of 17.87%. The physical properties and morphology of the nanodispersion were investigated. Fourier transform infrared spectroscopy and differential scanning calorimetry analysis revealed that stigmasterol was loaded in nanodispersions successfully. The pectin, which was used to stable nanodispersion, could restrict the release of stigmasterol in the simulated gastric fluid. This experiment indicated that the presence of pectin can improve the stability of the nanodispersion and can be used to achieve controlled release of bioactive compounds.

A review on chemical and physical modifications of phytosterols and their influence on bioavailability and safety

Phytosterols have been shown to lower cholesterol levels and to have antioxidant, anti-inflammatory and other biological activities. However, the high melting point and poor solubility limit their bioavailability and practical application. It is advantageous to modify phytosterols chemically and physically. This article reviews and discusses the chemical and physical modifications of phytosterols, as well as their effects on the bioavailability and possible toxicity in vivo. The current research on chemical modifications is mainly focused on esterification to increase the oil solubility and water solubility. For physical modifications (mainly microencapsulation), there are biopolymer-based, surfactant-based and lipid-based nanocarriers. Both chemical and physical modifications of phytosterols can effectively increase the absorption and bioavailability. The safety of modified phytosterols is also an important issue. Phytosterol esters are generally considered to be safe. However, phytosterol oxides, which may be produced during the synthesis of phytosterol esters, have shown toxicity in animal models. The toxicity of nanocarriers also needs further studies.

Formation, structural characterization, stability and in vitro bioaccessibility of 7,8-dihydroxyflavone loaded zein-/sophorolipid composite nanoparticles: effect of sophorolipid under two blending sequences

Anti-solvent co-precipitation (ASCP) is the most commonly used method of fabricating food-grade nanoparticles, while the impact of the blending sequence on the formation of nanoparticles lacks research. In this study, 7,8-dihydroxyflavone (7,8-DHF) loaded zein-/sophorolipid nanoparticles with two blending sequences (DHF-Z-S and DHF-Z/S) were successfully fabricated by the ASCP method and used to improve the storage stability and the in vitro bioaccessibility of 7,8-DHF. The results showed that blending sequences significantly affect the physicochemical properties of nanoparticles. DHF-Z-S nanoparticles had smaller particle size, lower polydispersity index and turbidity, and higher negative charge, entrapment efficiency and loading capacity compared to DHF-Z/S nanoparticles. Transmission electron microscopy and scanning electron microscopy revealed that DHF-Z-S and DHF-Z/S nanoparticles have core-shell spherical shape at the nanoscale and sophorolipid changed the surface morphology of zein nanoparticles. Fourier transform infrared spectroscopy and fluorescence spectrum analysis confirmed the presence of effective hydrogen bonding, electrostatic interactions and hydrophobic effects between 7,8-DHF, zein and sophorolipid and the presence of stronger hydrogen bonding and hydrophobic effects in DHF-Z-S nanoparticles. The encapsulated 7,8-DHF was in an amorphous state rather than a crystalline form as determined by X-ray diffraction analysis. Circular dichroism revealed that 7,8-DHF and sophorolipid were capable of changing the secondary structure of zein remarkably. More importantly, compared to DHF-Z/S nanoparticles, the DHF-Z-S nanoparticles possessed higher storage stability and in vitro bioaccessibility. Collectively, DHF-Z-S nanoparticles developed in this study might be a promising means of encapsulating, protecting and delivering hydrophobic nutraceuticals for applications in functional foods.

Effect of adjusting pH and chondroitin sulfate on the formation of curcumin-zein nanoparticles: Synthesis, characterization and morphology

This study is aiming to investigate the stabilizing effect of chondroitin sulfate (CS) on the preparation of curcumin nanoparticles (NPs). The results showed that adding CS before the anti-solvent process of zein (Z) at pH7 could fabricate most stable NPs (Cur/CS/Z-pH7) with particle size of 197 ± 5 nm and zeta-potential of -48.4 ± 1.9 mV. The pH had a significant effect on the fabrication of NPs. Cur/CS/Z-pH7 was more stable than Cur/CS/Z-pH3, while Cur/Z-CS-pH3 was more stable than the Cur/Z-CS-pH7. According to the results of XRD, FTIR, DSC and CD, CS can form irreversible macromolecular complexes with zein through non-electrostatic interactions during the anti-solvent process (Cur/CS/Z-pH7, Cur/CS/Z-pH3). However, CS was adsorbed on the surface of Zein NPs by electrostatic interaction (Cur/Z-CS-pH7, Cur/Z-CS-pH3), when CS was added after anti-solvent process of zein. These results illustrated that it is better to add CS before the anti-solvent process of zein at neutral pH.

Phytosterols extraction from hickory (Carya cathayensis Sarg.) husk with a green direct citric acid hydrolysis extraction method

This study investigated the direct citric acid hydrolysis extraction method to optimize phytosterols extraction from hickory husk. Single factor experiments followed by a three-level three-factor Box-Behnken experiments were performed. The optimal extraction parameters were determined as: pH of 2.0, liquid-to-solid ratio of 17.12: 1 mL/g, and temperature of 55.81 °C. Practical experiments were carried out in triplicate, and subsequently yielded phytosterols of 912.452 ± 17.452 μg/g DW, in good consistence with the predicted extraction yield of 902.874 μg/g DW. The conductivity of the extract was also found to play effective role under direct citric acid hydrolysis and recorded 36.30 ± 1.08 μs/cm at optimum extraction condition. β-Sitosterol stigmasterol, campsterol, ergosterol and lupeol were detected as main PSs and triterpenoids in hickory husk using UPLC-Triple-TOF/MS. Finally, the comparison between direct hydrolysis extraction and traditional solvent extraction showed that this new method was more effective and eco-friendlier to extract both free and conjugated phytosterols.

Fabrication and characterization of zein/lactoferrin composite nanoparticles for encapsulating 7,8-dihydroxyflavone: Enhancement of stability, water solubility and bioaccessibility

7,8-dihydroxyflavone (7,8-DHF), a tyrosine kinase B (TrkB) receptor agonist, can mimick physiological actions of brain-derived neurotrophic factor (BDNF) to attenuate neurogenic disease. However, its use as a functional food, is limited by its low-water solubility, chemical instability, and poor bioavailability. The purpose of this work is to fabricate stable 7,8-DHF loaded zein/lactoferrin (LF) composite nanoparticles (zein/LF-DHF) to overcome these challenges. Results showed that mean particle size of zein/LF nanoparticles was about 74 nm with low polydispersity index (<0.200) and turbidity (<0.300) values. Zein/LF nanoparticles had good stability against pH (3.0-9.0), ionic strengths (0-500 mM NaCl at neutral pH) and long-term storage. Zein/LF nanoparticles showed spherical structures formed by hydrogen bonding and hydrophobic interactions, however, LF changed surface morphology of zein nanoparticles as observed by scanning electron microscope. X-ray diffraction indicated 7,8-DHF was presented in an amorphous state inside zein/LF nanoparticles. Most importantly, zein/LF-DHF had good redispersibility, and increased the encapsulation efficiency, chemical stability, water solubility and bioaccessibility of 7,8-DHF. Collectively, zein/LF nanoparticles are promising delivery systems for 7,8-DHF in functional foods.