Nanocomplexes derived from chitosan and whey protein isolate enhance the thermal stability and slow the release of anthocyanins in simulated digestion and prepared instant coffee

Nanolipsome Modified with Inulin and Pea Protein Isolate Improve the Thermal Stability and Slow the Release of Anthocyanin at Simulated In Vitro Digestion and Hot Cocoa Beverage

Anthocyanin (ACN) is a natural pigment with various biological activities, but their stability is compromised by external environmental factors, which limits their practical application in food processing. To enhance the stability of anthocyanin, double-layer-modified anthocyanin nanoliposomes (ACN-NLs) were prepared in this study using pea protein isolate (PPI) and inulin (IN) through layer-by-layer assembly in this study. The preparation conditions of unmodified, single-modified, and double-layer-modified nanoliposomes (ACN-NLs, PPI-ACN-NLs, and IN-PPI-ACN-NLs) were optimized via analysis of their average particle size, zeta potential, and encapsulation efficiency (EE). In addition, the structure of the nanoliposomes was characterized via transmission electron microscopy (TEM) and a Fourier transform infrared (FTIR) spectrometer. Furthermore, the thermal stability of nanoliposomes in hot cocoa and their release behavior during in vitro simulated digestion were evaluated. The results indicated that the optimal formulation for IN-PPI-ACN-NLs was 6% PPI and 2% IN. Under these conditions, the IN-PPI-ACN-NLs had a particle size of 270.2 ± 0.66 nm, a zeta potential of -15.76 ± 0.81 mV, and a high EE of 88.6 ± 0.71%. TEM analysis revealed that IN-PPI-ACN-NLs exhibited a spherical core-shell structure, while FTIR confirmed the interaction between ACNs and the encapsulating materials (PPI and IN). Compared with unmodified or monolayer-modified nanoliposomes, IN-PPI-ACN-NLs exhibited thermal stability in beverage systems and enhanced DPPH radical scavenging activity. During in vitro digestion, IN-PPI-ACN-NLs demonstrated a sustained-release effect and improved the digestive stability of ACN. These properties make it a promising functional additive for applications in the food and pharmaceutical industry.

Study on preparation of "ping-pong" ball shaped chitosan oligosaccharide - based hollow mesoporous carbon carrier for efficient anthocyanins loading

Carriers for efficient loading and delivery of compounds are urgently needed. A multifunctional nanoplatform of ordered hollow mesoporous carbon (HMC) was developed to load anthocyanins (AN) efficiently. The morphology, specific surface area, binding mode, and biocompatibility of HMC were verified. HMCs were uniformly spherical with well-defined cavities and mesoporous shells, similar to a "ping-pong" ball shape, and this shape of HMC provided a more spatial location for the load of the AN. And the best loading result of AN was 33.39% ± 3.00%. Coarse-grained molecular dynamics (CGMD) simulations showed that HMC and AN may bind by electrostatic interaction and hydrogen bonding, the binding process indicated that HMC contributed to the loading of AN, and the cytotoxicity results showed no significant toxicity of the complex. The homogeneous morphology and good biocompatibility of HMC offer new probabilities for the high effectiveness of oral delivery of active substances.

Improving stability and bioavailability of ACNs based on Gellan gum-whey protein isolate nanocomplexes

Blueberry anthocyanins (ACNs) have been widely applied in the food industry and medicine due to their numerous beneficial properties. However, the stability of ACNs is extremely poor. This study aimed to develop a delivery system for ACNs using nanocomplexes prepared from gellan gum (GG) and whey protein isolate (WPI) via Maillard reaction. The effects of the GG-WPI nanocomplexes on the stability, antioxidant capacity, and bioavailability of ACNs were investigated. FTIR, fluorescence spectroscopy, and UV-vis absorption spectroscopy revealed covalent bonding between the GG and WPI in the nanocomplexes. The nanocomplex demonstrated a good loading efficiency for ACNs (60.34 %), with a particle size of 368.42 nm. It also showed better stability and bioaccessibility than free ACNs, and their DPPH radical scavenging capacity reached a maximum of 63.11 %. Our research is significant for developing novel multifunctional foods and constructing high-performance food delivery systems.

Factors affecting the stability of anthocyanins and strategies for improving their stability: A review

Anthocyanins, as the most common and widely distributed flavonoid compounds, are widely present in fruits and vegetables. Anthocyanins show various biological activities including antioxidant, anticancer, anti-inflammatory, antibacterial, and immunomodulatory activities. Hence, anthocyanins are widely used in the fields of food and pharmaceuticals. However, anthocyanins are susceptible to environmental and processing factors due to their structural characteristics, which leads to poor storage and processing stability. Numerous studies have indicated that structural modification, co-pigmentation, and delivery systems could improve the stability and bioavailability of anthocyanins in the external environment. This article reviews the main factors affecting the stability of anthocyanins. Moreover, this review comprehensively introduces methods to improve the stability of anthocyanins. Finally, the current problems and future research advances of anthocyanins are also introduced. The findings can provide important references for deeper research on the stability, biological activities, and bioavailability of anthocyanins.

Microcapsule Preparation and Properties of Flavonoid Extract from Immature Citrus reticulata 'Chachiensis' Peel

Citrus reticulata 'Chachiensis' is a citrus cultivar in the Rutaceae family, and its peel is commonly utilized as a raw material for Guangchenpi. This study used flavonoid extract from the peel of immature Citrus reticulata 'Chachiensis' (CCE) as the raw material to investigate the encapsulation ability of different wall materials (plant-based proteins, including soybean protein isolation (SPI), pea protein (PP), and zein; carbohydrates, including maltodextrin (MD), Momordica charantia polysaccharide (MCP), and gum acacia (GA); and composite wall materials of both types) on CCE. The wall material with the highest encapsulation rate was selected for the preparation of CCE microcapsules. Furthermore, the physicochemical characteristics, antioxidant capacity, bioavailability, and storage stability of the CCE microcapsules were explored. The results indicated that among all wall materials, the composite wall material PPMD had the highest encapsulation rate, which was 84.44 ± 0.34%. After encapsulation, the microcapsules tended to have a yellow color and exhibited characteristics such as system stability, low moisture content, and low hygroscopicity. In vitro antioxidant assays revealed that the encapsulation of CCE significantly increased the scavenging rates of DPPH and ABTS free radicals. In vitro gastrointestinal digestion experiments indicated that the release rate of PPMD-CCE in intestinal fluid was significantly greater than that of free CCE, ultimately reaching 85.89 ± 1.53%. Storage experiments demonstrated that after 45 days under various temperature and light conditions, the retention rate of CCE in the microcapsules was significantly greater than that of free CCE. The above findings provide new possibilities for the application of PP and plant proteins and lay a foundation for the future industrial application of CCE.

Chitosan/Polyvinyl Alcohol-Based Biofilms Using Ternary Deep Eutectic Solvents towards Innovative Color-Stabilizing Systems for Anthocyanins

Anthocyanins are amazing plant-derived colorants with highly valuable properties; however, their chemical and color instability issues limit their wide application in different food industry-related products such as active and intelligent packaging. In a previous study, it was demonstrated that anthocyanins could be stabilized into green plasticizers namely deep eutectic solvents (DESs). In this work, the fabrication of edible films by integrating anthocyanins along with DESs into biocompatible chitosan (CHT)-based formulations enriched with polyvinyl alcohol (PVA) and PVA nanoparticles was investigated. CHT/PVA-DES films' physical properties were characterized by scanning electron microscopy, water vapor permeability, swelling index, moisture sorption isotherm, and thermogravimetry analysis. Innovative red-to-blue formulation films were achieved for CHT/PVA nanoparticles (for 5 min of sonication) at a molar ratio 1:1, and with 10% of ternary DES (TDES)-containing malvidin-3-glucoside (0.1%) where the physical properties of films were enhanced. After immersion in solutions at different pH values, films submitted to pHs 5-8 were revealed to be more color stable and resistant with time than at acidic pH values.

Development and evaluation of guar gum-coated nano-nutriosomes for cyanidin-3-O-glucoside encapsulation

Cyanidin-3-O-glucoside (C3G) is a type of water-soluble flavonoid compound that is abundantly found in fruits and vegetables. C3G possesses numerous biological activities, however, it is prone to breakdown under environmental conditions. To overcome these issues, we developed nano-nutriosome (NS) carriers created by vortex-mixing and probe-sonication techniques for C3G encapsulation in which the phospholipid and Nutriose® FB06 were chosen as carrier material, and guar gum (GG) as a coating material to formulate a unilamellar and multicompartment structure. This study aimed to develop and evaluate C3G-loaded nano-nutriosomes coated by GG (GG-C3G-NS) for improving physicochemical stability, antioxidant activity, cellular uptake, and controlled release properties. The C3G-NS and GG-C3G-NS are nanosized (143.47 to 154.13 nm), with high encapsulation efficiency (>93.31 %). The NS carriers successfully encapsulated C3G which was confirmed by transmission electron microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy. C3G showed more stability in storage, thermal, pH, ionic, and oxidative conditions. Furthermore, the NS exhibited a better-controlled release of C3G in different food stimulant conditions and in vitro release study. Additionally, NS systems enhanced cellular uptake and showed no cytotoxicity. Overall, GG-NS could be a promising nanocarrier for improving the stability, controlled release, and antioxidant activity of bioactive compounds.

Unveiling the impact of high-pressure processing on anthocyanin-protein/polysaccharide interactions: A comprehensive review

Anthocyanins, natural plant pigments responsible for the vibrant hues in fruits, vegetables, and flowers, boast antioxidant properties with potential human health benefits. However, their susceptibility to degradation under conditions such as heat, light, and pH fluctuations necessitates strategies to safeguard their stability. Recent investigations have focused on exploring the interactions between anthocyanins and biomacromolecules, specifically proteins and polysaccharides, with the aim of enhancing their resilience. Notably, proteins like soy protein isolate and whey protein, alongside polysaccharides such as pectin, starch, and chitosan, have exhibited promising affinities with anthocyanins, thereby enhancing their stability and functional attributes. High-pressure processing (HPP), emerging as a non-thermal technology, has garnered attention for its potential to modulate these interactions. The application of high pressure can impact the structural features and stability of anthocyanin-protein/polysaccharide complexes, thereby altering their functionalities. However, caution must be exercised, as excessively high pressures may yield adverse effects. Consequently, while HPP holds promise in upholding anthocyanin stability, further exploration is warranted to elucidate its efficacy across diverse anthocyanin variants, macromolecular partners, pressure regimes, and their effects within real food matrices.

Valorization of cashew nut testa phenolics through nano-complexes stabilized with whey protein isolate and β-cyclodextrin: Characterization, anti-oxidant activity, stability and in vitro release

Cashew nut testa (CNT) is an underutilized cashew by-product rich in polyphenols. The applications of CNT are limited due to its astringency, less solubility, and instability of polyphenols during the processing. Nanoencapsulation was used to overcome these limitations. β-cyclodextrin alone and in combination with whey protein isolate (WPI) was used for nano-complex preparation. The WPI/CD-CNT nano-complex powder showed higher encapsulation efficiency (86.9%) and yield (70.5-80%) compared to CD-CNT powder. Both the spray-dried powders showed improved thermal stability, higher solubility (97%), less moisture content, and increased DPPH and ABTS radical scavenging activities indicating potential food and agricultural applications. In addition, the nano-complex powders showed a controlled release of core bio-actives under gastric and intestinal pH compared to the non-encapsulated CNT phenolic extract. Degradation kinetics studies of the CNT extract after thermal and light treatments were also discussed. Both the nano-complexes showed high stability under light and thermal treatment. The results suggest that valorization of CNT can be done through nano-complex preparation and WPI and β-CD are efficient carrier materials for the encapsulation of polyphenols with potential applications in food and agriculture.

Co-encapsulation of curcumin and anthocyanins in bovine serum album-fucoidan nanocomplex with a two-step pH-driven method

BACKGROUND

Curcumin (CUR) and anthocyanins (ACN) are recommended due to their bioactivities. However, their nutritional values and health benefits are limited by their low oral bioavailability. The incorporation of bioactive substances into polysaccharide-protein composite nanoparticles is an effective way to enhance their bioavailability. Accordingly, this study explored the fabrication of bovine serum albumin (BSA)-fucoidan (FUC) hybrid nanoparticles using a two-step pH-driven method for the delivery of CUR and ACN.

RESULTS

Under a 1:1 weight ratio of BSA to FUC, the point of zero charge moved from pH ⁓ 4.7 for BSA to around 2.5 for FUC-coated BSA, and the formation of BSA-FUC nanocomplex was pH-dependent by showing the maximum CUR emission wavelength shifting from 546 nm (CUR-loaded BSA-FUC at pH 4.7) and 544 nm (CUR/ACN-loaded BSA-FUC nanoparticles at pH 4.7) to 540 nm (CUR-loaded BSA-FUC at pH 6.0) and 539 nm (CUR/ACN-loaded BSA-FUC nanoparticles at pH 6.0). Elevated concentrations of NaCl from 0 to 2.5 mol L-1 caused particle size increase from about 250 to about 800 nm, but showing no effect on the encapsulation efficiency of CUR. The CUR and ACN entrapped, respectively, in the inner and outer regions of the BSA-FUC nanocomplex were released at different rates. After incubation for 10 h, more than 80% of ACN was released, while less than 25% of CUR diffused into the receiving medium, which fitted well to Logistic and Weibull models.

CONCLUSION

In summary, the BSA-FUC nanocomposites produced by a two-step pH-driven method could be used for the co-delivery of hydrophilic and hydrophobic nutraceuticals. © 2023 Society of Chemical Industry.

Fabrication of nanocomplexes for anthocyanins delivery by ovalbumin and differently dense sulphate half-ester polysaccharides nanocarriers: Enhanced stability, bio-accessibility, and antioxidant properties

This study aimed to fabricate novel nanocomplexes for delivery of anthocyanins (ACN) utilizing ovalbumin (OVA) and sulphated-polysaccharides with varying linear charge density (κ-,ι-, λ-carrageenan and dextran sulfate: κC < ιC < λC < DS). Influence of OVA-sulphated-polysaccharides on ACN stability, antioxidant capacity, and bioaccessibility was investigated. Fabricated nanoparticlecosmeticsed superior encapsulation efficiency (94.11-96.2%) and loaded capacity (9.05-9.54%) for ACN. OVA-DS displayed the smallest particle size and turbidity, while OVA-κC-ACN exhibited the largest ones. ζ-Potential of nanoparticles raised with increasing ester-sulfate level in sulphated-polysaccharides. FT-IR, Raman and OVA conformational alterations revealed existence of intermolecular-interactions between ACN and OVA-polysaccharides. DSC and TGA showed considerable thermo-stability of self-assembled (ACN-loaded) OVA-polysaccharides. Spheroid-nanoparticles size increased after ACN-loading in SEM and CLSM. Composite nanocomplexes enhanced ACN stability and antioxidant properties under accelerated degradation conditions and simulated digestion, particularly, OVA-DS-ACN and OVA-λC-ACN. We provide a choice for reinforcing stability of hydrophilic nutraceuticals and improving its applications.

Investigation on the interaction mechanisms for stability of preheated whey protein isolate with anthocyanins from blueberry

Proteins and anthocyanins coexist in complex food systems. This research mainly studied the steady-state protective design and mechanism of the preheated protein against anthocyanins. Multispectral and molecular dynamics are utilized to illustrate the interaction mechanism between preheated whey protein isolate (pre-WPI) and anthocyanins. The pre-WPI could effectively protect the stability of anthocyanins, and the effect was better than that of the natural whey protein isolate (NW). Among them, NW after preheating treatment at 55 °C showed better protection against anthocyanin stability. Fluorescence studies indicated that pre-WPI there existed a solid binding affinity and static quenching for malvidin-3-galactoside (M3G). Multispectral data showed a significant variation in the secondary structure of pre-WPI. Furthermore, molecular dynamics simulation selects AMBER18 as the protein force field, and the results showed that hydrogen bonding participated as an applied force. Compared with NW, pre-WPI could better wrap anthocyanins and avoid damage to the external environment due to tightening of the pockets. Protein protects anthocyanins from degradation, and this protective effect is influenced by the preheating temperature of protein and the structure of protein. On the basis of the above results, it is possible to pinpoint the interaction mechanism between preheated proteins and anthocyanins.

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.

Fermentation improves flavors, bioactive substances, and antioxidant capacity of Bian-Que Triple-Bean Soup by lactic acid bacteria

The ancient traditional Chinese drink Bian-Que Triple-Bean Soup made by fermentation (FTBS) of Lactococcus lactis subsp. lactis YM313 and Lacticaseibacillus casei YQ336 is a potential functional drink. The effect of fermentation on the flavor and biological activity of FTBS was evaluated by analyzing its chemical composition. Five volatile flavors were detected in modified FTBS. Fermentation decreased the proportion of nonanal (beany flavor substances) but significantly increased the total flavone contents, phenol contents and many bioactive small molecule substances in FTBS. The changes of these substances led to the significant improvement of FTBS sensory evaluation, antioxidant activity and prebiotic potential. This research provides a theoretical basis for the application of Lactic acid bacteria (LAB) in the fermentation of edible plant-based foods and transformation from traditional food to industrial production.

Stability of Purple Corn Anthocyanin Encapsulated by Maltodextrin, and Its Combinations with Gum Arabic and Whey Protein Isolate

Purple corn anthocyanins are important natural colourants with cheap prices and rich bioactivities. However, their stability is limited. Microencapsulation is an effective way to improve anthocyanin stability and the influence of the type of wall material on the stability of encapsulated anthocyanin is very important. In this study, maltodextrin (MD) and its combination with whey protein isolate (WPI) or gum arabic (GA) were utilised as wall materials to obtain encapsulated purple corn anthocyanins (PCAs) (MD-PCA, MD-WPI-PCA, MD-GA-PCA) using spray drying. The effect of the amount of the wall material was determined by encapsulation efficiency, anthocyanin content, and colour. On this basis, the effects of the types of wall materials on the physicochemical characteristics, storage, and digestion stabilities of encapsulated PCA, as well as their stabilities in chewing tablets, were investigated. The highest encapsulation efficiency, suitable colour, and anthocyanin content were obtained with the mass ratios 1:1 PCA to MD, 2:3 PCA to MD-GA, and 1:1 PCA to MD-WPI. Microencapsulation increased PCA storage and digestion stabilities. All three types of PCA microcapsules had low water content and hygroscopicity and good water solubility. MD-PCA had the strongest stability when stored at 25 °C; MD-GA-PCA-when stored at 40 °C, or in the presence of 5000 Lux light illumination; MD-WPI-PCA-when stored in 75% relative humidity or during gastric-intestinal digestion, but its resistance to 40 °C temperature and light illumination was lower than those for the two others. When used in chewing tablets, MD encapsulation was most stable in the presence of Ca²⁺, V_C, or Fe²⁺ and improved PCA digestion stability. In conclusion, MD is a good choice for PCA encapsulation in regular conditions. MD-GA and MD-WPI can be used when considering high storage temperature (or light illumination) and high humidity (or for high digestion stability), respectively. The results of this study provide a reference for the storage and application of PCA.

Soy protein isolate-polyguluronate nanoparticles loaded with resveratrol for effective treatment of colitis

Polyguluronate (PG) is an acidic homopolymer of α-(1,4)-l-guluronate separated from alginate. In this study, PG was first grafted with soy protein isolate (SPI) through the Maillard reaction to obtain a new glycoprotein (SPI-PG). Then, this novel glycoprotein was used to prepare nanoparticles to encapsulate the resveratrol (RES). Our results showed that SPI-PG-RES had better pH stability, storage stability and ionic stability than SPI-RES. In vitro digestion experiments showed that the RES bioavailability of SPI-PG-RES was much higher than that of free RES and SPI-RES. Furthermore, the in vitro antioxidant capacity of SPI-PG-RES was much stronger than that of free RES and SPI-RES. In addition, SPI-PG-RES was more effective in preventing the symptoms of DSS-induced colitis than RES and SPI-RES. These results suggested that the protein nanoparticles prepared using SPI-PG were a stable and effective hydrophobic polyphenol carrier and could be applied to food-grade components in functional foods and nutritional supplements.

Anthocyanins: Modified New Technologies and Challenges

Anthocyanins are bioactive compounds belonging to the flavonoid class which are commonly applied in foods due to their attractive color and health-promoting benefits. However, the instability of anthocyanins leads to their easy degradation, reduction in bioactivity, and color fading in food processing, which limits their application and causes economic losses. Therefore, the objective of this review is to provide a systematic evaluation of the published research on modified methods of anthocyanin use. Modification technology of anthocyanins mainly includes chemical modification (chemical acylation, enzymatic acylation, and formation of pyran anthocyanidin), co-pigmentation, and physical modification (microencapsulation and preparation of pickering emulsion). Modification technology of anthocyanins can not only increase bioavailability and stability of anthocyanin but also can improve effects of anthocyanin on disease prevention and treatment. We also propose potential challenges and perspectives for diversification of anthocyanin-rich products for food application. Overall, integrated strategies are warranted for improving anthocyanin stabilization and promoting their further application in the food industry, medicine, and other fields.

Utilization of ultrasound and glycation to improve functional properties and encapsulated efficiency of proteins in anthocyanins

The purpose of this study is to explore the optimal conditions for the preparation of bovine serum albumin (BSA)/casein (CA)-dextran (DEX) conjugates by ultrasonic pretreatment combined with glycation (U-G treatment). When BSA and CA were treated with ultrasound (40% amplitude, 10 min), the grafting degree increased 10.57% and 6.05%, respectively. Structural analysis revealed that ultrasonic pretreatment changed the secondary structure, further affected functional properties of proteins. After U-G treatment, the solubility and thermal stability of BSA and CA was significantly increased, and the foaming and emulsifying capacity of proteins were also changed. Moreover, ultrasonic pretreatment and glycation exhibited a greater impact on BSA characterized with highly helical structure. Complexes fabricated by U-G-BSA/CA and carboxymethyl cellulose (CMC) exhibited protection on anthocyanins (ACNs), delaying the thermal degradation of ACNs. In conclusion, the protein conjugates treated by ultrasonic pretreatment combined with glycation have excellent functionality and are potential carrier materials.

Effects of encapsulation methods on bioaccessibility of anthocyanins: a systematic review and meta-analysis

Anthocyanins have multiple health benefits. However, they are prone to degradation during gastrointestinal digestion, impeding their utilization. Various encapsulation systems have been proposed to improve their bioaccessibility and bioavailability. This review aims to provide a systematic evaluation and meta-analysis of published studies examining the effect of microencapsulation on the bioaccessibility of anthocyanins. A comprehensive and systematic literature search of three databases (Scopus, PubMed, and Web of Science) was conducted. Studies were selected according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria and were reviewed independently by two investigators. Overall, 34 articles were included in the systematic review and 24 were included in the meta-analysis. The fold changes in bioaccessibility between encapsulated and non-encapsulated anthocyanins from eligible studies were calculated. The median and 95% confidence intervals (CI) of the fold changes for spray-drying (median 1.23, 95% CI 0.91-1.92), freeze-drying (median 1.19, 95% CI 0.61-1.28), simple coacervation (median 1.80, 95% CI 1.41-3.20), and complex coacervation (median 1.61, 95% CI 0.21-25.00) were calculated. Simple coacervation showed a promising protection against degradation during in vitro digestion. However, when a large number of anthocyanins cannot be released from the microparticles during digestion, encapsulation impedes the bioaccessibility of anthocyanins.

Improved Stabilization and In Vitro Digestibility of Mulberry Anthocyanins by Double Emulsion with Pea Protein Isolate and Xanthan Gum

There is significant evidence that double emulsion has great potential for successfully encapsulating anthocyanins. However, few research studies are currently using a protein-polysaccharide mixture as a stable emulsifier for double emulsion. This study aimed to improve the stability and in vitro digestibility of mulberry anthocyanins (MAs) by employing a double emulsion composed of pea protein isolate (PPI) and xanthan gum (XG). The influence of various XG concentrations (0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%) and different temperatures (5 °C, 25 °C, 45 °C, 65 °C) on the physical stability and the thermal degradation of MAs from double emulsions were investigated. In addition, the physicochemical properties of double emulsions and the release performance of MAs during in vitro simulated digestion were evaluated. It was determined that the double emulsion possessed the most stable physical characteristics with the 1% XG addition. The PPI-1% XG double emulsion, when compared to the PPI-only double emulsion, expressed higher thermal stability with a retention rate of 83.19 ± 0.67% and a half-life of 78.07 ± 4.72 days. Furthermore, the results of in vitro simulated digestion demonstrated that the MAs in the PPI-1% XG double emulsion were well-protected at oral and gastric with ample release found in the intestine, which was dissimilar to findings for the PPI-only double emulsion. Ultimately, it was concluded that the double emulsion constructed by the protein-polysaccharide system is a quality alternative for improving stability and absorption with applicability to a variety of food and beverage systems.

Improving the thermal stability of natural bioactive ingredients via encapsulation technology

Bioactive compounds (bioactives) such as phenolic acids, coumarins, flavonoids, lignans and carotenoids have a marked improvement effect on human health by acting on body tissues or cells. Nowadays, with increasing levels of knowledge, consumers prefer foods that can provide bioactives beside the necessary nutrients (e.g., vitamins, essential fatty acids and minerals). However, an important barrier for incorporating bioactives into foods is their low thermal stability. Nevertheless, thermal processing is widely used by the food industries to achieve food safety and desired texture. The aim of this work is to give an overview of encapsulation technology to improve thermal stability of bioactives incorporated into different food products. Almost all thermal analysis and non-thermal methods in the literature suggest that incorporation of bioactives into different walls can effectively improve the thermal stability of bioactives. The level of such thermal enhancement depends on the strength of the bioactive interaction and wall molecules. Furthermore, contradictory results have been reported in relation to the effect of encapsulation technique using the same wall on thermal stability of bioactives. To date, the potential to increase the thermal resistance of various bioactives by gums, carbohydrates, and proteins have been extensively studied. However, further studies on the comparison of walls and encapsulation methods to form thermally stable carriers seem to be needed. In this regard, the same nature of bioactives and the specific protocol in the report of study results should be considered to compare the data and select the optimum conditions of encapsulation to achieve maximum thermal stability.

Storage stability and in vitro digestion of apigenin encapsulated in Pickering emulsions stabilized by whey protein isolate–chitosan complexes

Few studies have investigated the encapsulation of apigenin in solid particle-stabilized emulsions. In this work, Pickering emulsions containing apigenin and stabilized by whey protein isolate-chitosan (WPI-CS) complexes were created to enhance the bioavailability of apigenin. Different lipids including medium-chain triglycerides (MCTs), ethyl oleate (EO), and corn oil (CO) were selected to fabricate lipid-based delivery systems. The microstructure of the Pickering emulsions, as revealed by optical and cryo-scanning electron microscopies, showed that the oil droplets were dispersed evenly and trapped by a three-dimensional network formed by the WPI-CS complexes, which was further confirmed by rheology properties. After 30 days of storage, Pickering emulsions with MCTs achieved the highest apigenin retention rate, exhibiting 95.05 ± 1.45% retention when stored under 4°C. In vitro gastrointestinal tract experiments indicated that the lipid types of the emulsions also affected the lipid digestion and release rate of apigenin. Pickering emulsions with MCTs achieved a higher bioaccessibility compared to that of the other two emulsions (p < 0.01). These results indicate that the delivery system of Pickering emulsions with MCTs stabilized by WPI-CS complexes offers good storage stability and improved bioaccessibility of apigenin.

Beneficial effects of high pressure processing on the interaction between RG-I pectin and cyanidin-3-glucoside

In the present study, the effects of high-pressure processing (HPP) on the binding capacity, structural properties, antioxidant capacity and stability of rhamngalacturonan I (RG-I) pectin and cyanidin-3-glucoside (C3G) were investigated. HPP was found to have a positive effect on the binding between the two molecules, and the binding rate was increased by 32.8% after treatment (500 MPa/15 min). The increase in the binding rate is mainly due to the influence of high pressure on noncovalent effects such as hydrogen bonding and hydrophobicity. The results indicate that high pressure can be used to maintain the antioxidant capacity of C3G and improve the stability of C3G. The C3G retention rate is increased by 34.0% and 38.3% after heat treatment and simulated digestion, respectively. The results indicate that HPP improved stability of the C3G-RG-I pectin complex through interaction between C3G and RG-I pectin.

Advancement of Protein- and Polysaccharide-Based Biopolymers for Anthocyanin Encapsulation

Although evidence shows that anthocyanins present promising health benefits, their poor stability still limits their applications in the food industry. Increasing the stability of anthocyanins is necessary to promote their absorption and metabolism and improve their health benefits. Numerous encapsulation approaches have been developed for the targeted release of anthocyanins to retain their bioactivities and ameliorate their unsatisfactory stability. Generally, choosing suitable edible encapsulation materials based on biopolymers is important in achieving the expected goals. This paper presented an ambitious task of summarizing the current understanding and challenges of biopolymer-based anthocyanin encapsulation in detail. The food-grade edible microencapsulation materials, especially for proteins and polysaccharides, should be employed to improve the stability of anthocyanins for effective application in the food industry. The influence factors involved in anthocyanin stability were systematically reviewed and highlighted. Food-grade proteins, especially whey protein, caseinate, gelatin, and soy protein, are attractive in the food industry for encapsulation owing to the improvement of stability and their health benefits. Polysaccharides, such as starch, pectin, chitosan, cellulose, mucilages, and their derivatives, are used as encapsulation materials because of their satisfactory biocompatibility and biodegradability. Moreover, the challenges and perspectives for the application of anthocyanins in food products were presented based on current knowledge. The proposed perspective can provide new insights into the amelioration of anthocyanin bioavailability by edible biopolymer encapsulation.

Enhanced stability of stilbene-glycoside-loaded nanoparticles coated with carboxymethyl chitosan and chitosan hydrochloride

Stilbene-glycoside (THSG) is a promising dietary supplement with remarkable biological properties, however, its poor stability and low oral bioavailability hinder its application as an ingredient in functional foods. Herein, stilbene-glycoside-loaded nanoparticles (THSG-NPs) coated with carboxymethyl chitosan (CMC) and chitosan hydrochloride (CHC) using a complex coacervation method were successfully prepared for enhancing the stability of THSG. The optimized preparation parameters were 2.5 mg/mL CMC, 1.0 mg/mL CHC, 1.5 mg/mL THSG and preparation temperature of 25 °C, under which the experimentally designed particles averaged 381.9 nm with encapsulation efficiency (EE) of 68.6%. Solid-state characterization was assessed by Fourier transform infrared spectroscope and Differential scanning calorimetry. THSG-NPs showed significant protective effects against heat and solar radiation and exhibited remarkable pH-dependent and controlled release. This work demonstrated that enhanced stability and delayed release of THSG could be achieved using THSG-NPs, which could contribute to its potential application in the functional foods industry.

The interactions between anthocyanin and whey protein: A review

Anthocyanins (ACN) are natural pigments that produce bright red, blue, and purple colors in plants and can be used to color food products. However, ACN sensitivity to different factors limits their applications in the food industry. Whey protein (WP), a functional nutritional additive, has been shown to interact with ACN and improve the color, stability, antioxidant capacity, bioavailability, and other functional properties of the ACN-WP complex. The WP's secondary structure is expected to unfold due to heat treatment, which may increase its binding affinity with ACN. Different ACN structures will also have different binding affinity with WP and their interaction mechanism may also be different. Circular dichroism (CD) spectroscopy and Fourier transform infrared (FTIR) spectroscopy show that the WP secondary structure changes after binding with ACN. Fluorescence spectroscopy shows that the WP maximum fluorescence emission wavelength shifts, and the fluorescence intensity decreases after interaction with ACN. Moreover, thermodynamic analysis suggests that the ACN-WP binding forces are mainly hydrophobic interactions, although there is also evidence of electrostatic interactions and hydrogen bonding between ACN and WP. In this review, we summarize the information available on ACN-WP interactions under different conditions and discuss the impact of different ACN chemical structures and of WP conformation changes on the affinity between ACN and WP. This summary helps improve our understanding of WP protection of ACN against color degradation, thus providing new tools to improve ACN color stability and expanding the applications of ACN and WP in the food and pharmacy industries.

Nanoencapsulation in low-molecular-weight chitosan improves in vivo antioxidant potential of black carrot anthocyanin

BACKGROUND

Anthocyanins are flavonoids that are potential antioxidant, anti-inflammatory, anti-obesity, and anti-carcinogenic nutraceutical ingredients. However, low chemical stability and low bioavailability limit the use of anthocyanins in food. Nanoencapsulation using biopolymers is a recent successful strategy for stabilization of anthocyanins. This study reports the development, characterization, and antioxidant activity of black carrot anthocyanin-loaded chitosan nanoparticles (ACNPs).

RESULTS

The ionic gelation technique yielded the ACNPs. The mean hydrodynamic diameter d and polydispersity index PDI of chitosan nanoparticles and ACNPs were found to be d = 455 nm and PDI = 0.542 respectively for chitosan nanoparticles and d = 274 nm and PDI = 0.376 respectively for ACNPs. The size distribution was bimodal. The surface topography revealed that the ACNPs are spherical and display a coacervate structure. Fourier transform infrared analysis revealed physicochemical interactions of anthocyanins with chitosan. The loading process could achieve an encapsulation efficiency of 70%. The flow behavior index η of encapsulated ACNPs samples revealed Newtonian and shear thickening characteristics. There was a marginal reduction in the in vitro antioxidant potential of anthocyanins after nanoencapsulation, as evidenced from 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays. Interestingly, the in vivo antioxidant potential of anthocyanins improved following nanoencapsulation, as observed in the serum antioxidant assays.

CONCLUSION

The optimized nanoencapsulation process resulted in spherical nanoparticles with appreciable encapsulation efficiency. The nanoencapsulation process improved the in vivo antioxidant activity of anthocyanins, indicating enhanced stability and bioavailability. The promising antioxidant activity of the ACNPs suggests a potential for utilization as a nutraceutical supplement. © 2021 Society of Chemical Industry.

Complexation of rice glutelin fibrils with cyanidin-3-O-glucoside at acidic condition: Thermal stability, binding mechanism and structural characterization

The complexation of rice glutelin fibrils (RGFs) with cyanidin-3-O-glucoside (C3G) at acidic condition was investigated. The RGFs at pH 3.5 had a greatest protective effect on the thermal stability of C3G. The binding of C3G for RGFs was exothermic and driven by hydrophobic and electrostatic interactions. The RGFs exhibited a stronger binding interaction with C3G than rice glutelin (RG), resulting from the exposure of hydrophobic groups and positive charges on the fibrils surface, and thus RGFs exhibited better protective effect on C3G. The interaction with C3G resulted in the rearrangement of polypeptide chain, thereby reducing the β-sheet content. The larger aggregates were observed in RG/RGFs-C3G complexes due to protein-polyphenols aggregation. It was noteworthy that the pre-formed RGFs were restructured into entangled aggregates due to the interaction. This study proposed a novel protein fibril to protect anthocyanins, expanding the application of anthocyanins as stable and functional ingredients in acidic food systems.

Assembled milk protein nano-architectures as potential nanovehicles for nutraceuticals

Nanoencapsulation of hydrophobic nutraceuticals with food ingredients has become one of topical research subjects in food science and pharmaceutical fields. To fabricate food protein-based nano-architectures as nanovehicles is one of effective strategies or approaches to improve water solubility, stability, bioavailability and bioactivities of poorly soluble or hydrophobic nutraceuticals. Milk proteins or their components exhibit a great potential to assemble or co-assemble with other components into a variety of nano-architectures (e.g., nano-micelles, nanocomplexes, nanogels, or nanoparticles) as potential nanovehicles for encapsulation and delivery of nutraceuticals. This article provides a comprehensive review about the state-of-art knowledge in utilizing milk proteins to assemble or co-assemble into a variety of nano-architectures as promising encapsulation and delivery nano-systems for hydrophobic nutraceuticals. First, a brief summary about composition, structure and physicochemical properties of milk proteins, especially caseins (or casein micelles) and whey proteins, is presented. Then, the disassembly and reassembly behavior of caseins or whey proteins into nano-architectures is critically reviewed. For caseins, casein micelles can be dissociated and further re-associated into novel micelles, through pH- or high hydrostatic pressure-mediated disassembly and reassembly strategy, or can be directly formed from caseinates through a reassembly process. In contrast, the assembly of whey protein into nano-architectures usually needs a structural unfolding and subsequent aggregation process, which can be induced by heating, enzymatic hydrolysis, high hydrostatic pressure and ethanol treatments. Third, the co-assembly of milk proteins with other components into nano-architectures is also summarized. Last, the potential and effectiveness of assembled milk protein nano-architectures, including reassembled casein micelles, thermally induced whey protein nano-aggregates, α-lactalbumin nanotubes or nanospheres, co-assembled milk protein-polysaccharide nanocomplexes or nanoparticles, as nanovehicles for nutraceuticals (especially those hydrophobic) are comprehensively reviewed. Due to the fact that milk proteins are an important part of diets for human nutrition and health, the review is of crucial importance not only for the development of novel milk protein-based functional foods enriched with hydrophobic nutraceuticals, but also for providing the newest knowledge in the utilization of food protein assembly behavior in the nanoencapsulation of nutraceuticals.

A review of the interaction between anthocyanins and proteins

Anthocyanins have good physiological functions, but they are unstable. The interaction between anthocyanins and proteins can improve the stability, nutritional and functional properties of the complex. This paper reviews the structural changes of complex of anthocyanins interacting with proteins from different sources. By circular dichroism (CD) spectroscopy, it was found that the contents of α-helix (from 15.90%-42.40% to 17.60%-52.80%) or β-sheet (from 29.00%-50.00% to 29.40%-57.00%) of the anthocyanins-proteins complex increased. Fourier transform infrared spectroscopy showed that the regions of amide I (from 1627.87-1641.41 cm^-1 to 1643.34-1651.02 cm^-1) and amide II (from 1537.00-1540.25 cm^-1 to 1539.00-1543.75 cm^-1) of anthocyanins-proteins complex were shifted. Fluorescence spectroscopy showed that the fluorescence intensity of the complex decreased from 150-5100 to 40-3900 a.u. The thermodynamic analysis showed that there were hydrophobic interactions, electrostatic and hydrogen bonding interactions between anthocyanins and proteins. The kinetic analysis showed that the half-life and activation energy of the complex increased. The stability, antioxidant, digestion, absorption, and emulsification of the complex were improved. This provides a reference for the study and application of anthocyanins and proteins interactions.