Self-assembled dipeptide confined in covalent organic polymers for fluorescence sensing of tryptamine in fermented meat products.

Diphenylalanine(FF)-Zn self-assembly (FS) confined in covalent organic polymers (FS@COPs) with efficient fluorescence was synthesized for fluorescence sensing of biogenic amines, which was one of the most important indicators for monitoring food freshness. FS@COPs combined excellent biodegradability of self-assembled dipeptide with chemical stability, porosity and targeted site recognition of COPs. With an optimal excitation wavelength of 360 nm and an optimal emission wavelength of 450 nm, FS@COPs could be used as fluorescence probes to rapidly visualize and highly sensitive determination of tryptamine (Try) within 15 min, and the linear range was from 40 to 900 µg L-1 with a detection limit of 63.08 µg kg-1. Importantly, the FS@COPs showed a high fluorescence quantum yield of 11.28%, and good stability, solubility, and selectivity, which could successfully achieve the rapid, accurate and highly sensitive identification of Try. Furthermore, we revealed the mechanism of FS@COPs for fluorescence sensing of targets. The FS@COPs system was applied to the fluorescence sensing of Try in real samples and showed satisfactory accuracy of 93.02%-105.25%.

Molecularly imprinted thermosensitive probe based on fluorescent advanced glycation end products to detect α-dicarbonyl compounds and inhibit pyrraline formation.

A thermal-sensitive molecularly imprinted optosensing probe based on fluorescent advanced glycation end products (AGEs) was prepared by one-pot hydrothermal synthesis. Carbon dots (CDs) derived from fluorescent AGEs were used as the luminous centers, while molecularly imprinted polymers (MIPs) were wrapped outside of the CDs to form specific target recognition sites to highly selectively adsorb the intermediate product of AGEs of 3-deoxyglucosone (3-DG). Thermosensitive N-isopropylacrylamide (NIPAM) was combined with acrylamide (AM) as co-functional monomers, and ethylene glycol dimethacrylate (EGDMA) was chosen as a cross-linker for targeting identification and detection of 3-DG. Under optimal conditions, the fluorescence of MIPs could be gradually quenched with the adsorption of 3-DG on the surface of MIPs in the linear range of 1-160 µg/L, and the detection limit was 0.31 µg/L. The spiked recoveries of MIPs ranged from 82.97 to 109.94% in two milk samples, and the relative standard deviations were all less than 1.8%. In addition, the inhibition rate for non-fluorescent AGEs of pyrraline (PRL) was 23% by adsorbing 3-DG in the simulated milk system of casein and D-glucose, indicating that temperature-responsive MIPs not only could detect the dicarbonyl compound 3-DG quickly and sensitively, but also had an excellent inhibitory effect on AGEs.

Red emissive N-doped carbon dots encapsulated within molecularly imprinted polymers for optosensing of pyrraline in fatty foods.

A novel and facile method was proposed for preparation of red emissive N-doped carbon dots encapsulated within molecularly imprinted polymers (RNCDs@MIPs) using a one-pot room-temperature reverse microemulsion polymerization. RNCDs used citric acid and urea as carbon and nitrogen sources by one-step solvothermal synthesis with the optimum emission of 620 nm. Unique optical properties of RNCDs coupled with high selective MIPs make the RNCDs@MIPs conjugate capable to adsorb specific targets of pyrraline (PRL), such a binding event was then transduced to quench fluorescence response signal of the RNCDs. RNCDs@MIPs for PRL showed linearity from 0.1 to 40 µg/L, with a detection limit of 65 ng/L. The RNCDs@MIPs exhibited a good reproducibility of 4.67% obtained from four times of rebinding for PRL. The optosensing probe was successfully applied to the detection of PRL in fatty foods with the spiked recovery of 85.93-106.96%.

Molecularly imprinted bulk and solgel optosensing based on biomass carbon dots derived from watermelon peel for detection of ethyl carbamate in alcoholic beverages.

Biomass carbon dots synthesized by biological waste conform to the trend of ecological environmental protection and the requirements of green chemistry, which show great application potential in practice. In the study, we used watermelon peels as the raw materials to synthesize a novel blue biomass carbon dots (CDs) by a hydrothermal process with high fluorescence quantum yield of 22.8%. Through bulk polymerization and solgel method, two kinds of core-shell nanospheres were developed as fluorescent probes to recognize and detect ethyl carbamate (EC) rapidly without complex samples pretreatment. The obtained CDs@MIPs integrated the high-performance optical characteristics of CDs with excellent selectivity and adsorption of MIPs, which showed ideal linear relationships in the EC concentration range 1-120 µg L-1 and low LOD of 0.57 µg L-1 and 0.94 µg L-1, respectively. Both CDs@MIPs have a short equilibration time which was around 20 min, and the imprinting factors (IF) are 4.04 and 2.62. The recoveries of the six spiked samples were satisfying, and the RSD precisions were lower than 5.57%. Gas chromatography-mass spectrometry was seen as a parallel analysis to validate the correctness of the results, which indicated the practicability and reliability of the developed method. This proposal strategy of optical sensors provided an effective channel for trace EC recognition, with numerous advantages, involving eco-friendly, low cost, high sensitivity, separation effect, and good selectivity.

Recent advances in molecularly imprinted polymers (MIPs) for visual recognition and inhibition of α-dicarbonyl compound-mediated Maillard reaction products.

α-Dicarbonyl compounds (α-DCs) are important intermediates and precursors of harmful Maillard reaction products (e.g., acrylamide and late glycosylation end-products), and they exist widely in thermoprocessed sugar- or fat-rich foods. α-DCs and their end-products are prone to accumulation in the human body and lead to the development of various chronic diseases. Therefore, detection of α-DCs and their associated hazards in food samples is crucial. This paper reviews the preparation of molecularly imprinted polymers (MIPs) enabling visual intelligent responses and the strategies for recognition and capture of α-DCs and their associated hazards, and provides a comprehensive summary of the development of visual MIPs, including integration strategies and applications with real food samples. The visual signal responses as well as the mechanisms for hazard recognition and capture are highlighted. Current challenges and prospects for visual MIPs with advanced applications in food, agricultural and environmental samples are also discussed. This review will open new horizons regarding visual MIPs for recognition and inhibition of hazards in food safety.

Photostimulus-Responsive Peptide Dot-Centered Covalent Organic Polymers: Effective Pesticide Sensing via Enhancing Accessibility.

Pesticide detection and monitoring are necessary for human health as the overapplication has serious consequences for environmental pollution. Herein, a proper modulation strategy was implemented to construct the photostimulus-responsive peptide-dot-centered covalent organic polymer (P-PCOP) nanoarchitecture for selective sensing of pesticides. The as-constructed P-PCOP was prepared at room temperature by using amino-containing peptide dots as a building block instead of common organic molecules, and the merits of P-PCOP enable it to reduce the steric hindrance of recognition, enhance the interfacial contact of the target, and facilitate the accessibility of sites, which promises to improve the sensitivity. The P-PCOF exhibited a low detection limit of 0.38 µg L-1 to cartap over the range of 1-80 µg L-1 (R2 = 0.9845), and the recoveries percentage in real samples was estimated to be 93.39-105.82%. More importantly, the DFT calculation confirmed the selective recognition ability of P-PCOP on chemical pesticides. In conjunction with a smartphone-integrated portable reading device, on-site chemical sensing is achieved. The proper modulation strategy of fixing a functional guest on the COP system contributes to the advanced structure-chemical properties that are conducive to their applications in chemical sensing.

A Ratiometric Molecularly Imprinted Sensor for Visual Detection and Removal of α-Dicarbonyl Compounds Based on Biomass Carbon Dot-Embedded Fluorescent Covalent Organic Frameworks.

α-Dicarbonyl compounds (α-DCs) are important intermediate products during the thermal processing of foods and are closely related to the development of chronic diseases in the human body. However, there remains a significant gap in the availability of rapid detection methods for α-DCs. So, the ratiometric molecularly imprinted polymers (RCDs@GCOFs@MIPs) based on red-emitting biomass carbon dots (RCDs) and green-emitting fluorescent covalent organic frameworks (GCOFs) were constructed for the detection and removal of α-DCs in food processing. The ratiometric fluorescent sensors exhibited satisfactory detection and had good spiking recoveries in milk samples. And the excellent inhibition of pyrraline (PRL) by ratiometric fluorescent sensors was verified by simulating the milk pasteurization process. In addition, rapid onsite detection of α-DCs was achieved by recognizing the RGB value of the ratiometric fluorescence sensors via the smartphone. The ratiometric fluorescence sensors presented a new strategy for detecting and removing hazardous substances in food processing.

Fast detection of tryptamine in meat products with azide-functionalized covalent organic frameworks confined in molecularly imprinted polymers.

Tryptamine is a biogenic amine that affects organoleptic quality through the generation of off-odours in foods. Herein, imine-based covalent organic frameworks (COFs) were synthesized via Schiff base reactions and postmodified with click chemistry to generate azide-functionalized COFs with tunable azide units on the walls. The combination of molecular imprinting with COFs enabled the specific recognition of the targets. The resulting optosensing system (azide-functionalized COFs@MIPs) was used as a sample-to-answer analyser for detecting tryptamine (detection time within 10 min). A linear relationship was observed for the fluorescence response to tryptamine concentrations in the range of 3-120 µg L-1, with a limit of detection of 1.74 µg L-1. The recoveries for spiked samples were satisfactory, with relative standard deviations <9.90%. The optosensing system is a potential tool for the quantitative detection of tryptamine in meat products because of its lower cost, shorter processing time, and simpler processing steps compared to conventional chromatographic techniques.

Conjugated molecularly imprinted polymers based on covalent organic frameworks: Fluorescent sensing platform for specific capture of urea and elimination of ethyl carbamate.

This study described the preparation of an azide covalent organic framework-embedded molecularly imprinted polymers (COFs(azide)@MIPs) platform for urea adsorption and indirect ethyl carbamate (EC) removal from Chinese yellow rice wine (Huangjiu). By modifying the pore surface of COFs using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, COFs(azide) with a high fluorescence quantum yield and particular recognition ability were inventively produced. In order to selectively trap urea, the COFs(azide) were encased in an imprinted shell layer via imprinting technology. With a detection limit (LOD) of 0.016 µg L-1 (R2 = 0.9874), the COFs(azides)@MIPs demonstrated a good linear relationship with urea in the linear range of 0-5 µg L-1. Using real Huangjiu samples, the spiking recovery trials showed the viability of this sensing platform with recoveries ranging from 88.44 % to 109.26 % and an RSD of less than 3.40 %. The Huangjiu processing model system achieved 38.93 % EC reduction by COFs(azides)@MIPs. This research will open up new avenues for the treatment of health problems associated with fermented alcoholic beverages, particularly Huangjiu, while also capturing and removing hazards coming from food.

Preparation and characterization of Baijiu Jiuzao cellulose nanofibers-kafirin composite bio-film with excellent physical properties.

Jiuzao is the main solid by-products of Baijiu industry, which contain a high amount of underutilized cellulose and proteins. In recent years, cellulose nanofibers mixed with proteins to prepare biodegradable bio-based film materials have received widespread attention. In this study, we propose a novel method to simultaneously extract kafirin and cellulose from strong-flavor type of Jiuzao, and modify cellulose to prepare cellulose nanofibers by the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxide) oxidation-pressure homogenization technique, and finally mix kafirin with cellulose nanofibers to prepare a new biodegradable bio-based composite film. Based on the analysis of one-way and response surface experiments, the highest purity of cellulose was 82.04 %. During cellulose oxidation, when NaClO was added at 25 mmol/g, cellulose nanofibers have a particle size of 80-120 nm, a crystallinity of 65.8°. Finally, kafirin and cellulose nanofibers were mixed to prepare films. The results showed that when cellulose nanofibers were added at 1 %, the film surface was smooth, the light transmittance was 60.8 %, and the tensile strength was 9.17 MPa at maximum, which was 104 % higher than pure protein film. The contact angle was 34.3°. This paper provides new ideas and theoretical basis for preparing biodegradable bio-based composite film materials, and improves the added value of Jiuzao.

A Smartphone-Integrated Ratiometric Fluorescence Sensor for the Ultrasensitive and Selective Detection of 5-Heneicosylresorcinol in Whole Wheat Foods.

Precise on-site monitoring of alkylresorcinols, a vital biomarker, is crucial for verifying whole wheat foods and accurately quantifying the whole wheat content in various consumer and industrial products. Herein, for the first time, we introduce a novel ratiometric fluorescence sensor (CDs@ZIF-8/CdTe@MIP) for ultrasensitive and selective detection of alkylresorcinols. 5-Heneicosylresorcinol (C21:0 AR), the primary alkylresorcinol homologue in whole wheat grains, was selected as the target analyte. This analyte was specifically and selectively recognized by the incorporation of a molecularly imprinted polymer (MIP) layer. Within this nanoreactor, blue-emitting carbon dots embedded in zeolitic imidazolate framework-8 (CDs@ZIF-8) and orange-emitting CdTe quantum dots served as the self-calibration signal and response signal, respectively. Exploiting a photoinduced electron transfer effect between CdTe and C21:0 AR, the established fluorescence sensor exhibited remarkable sensing performance, offering wide linear responses in 0.005-1 µg·mL-1 and 1-80 µg·mL-1 concentration ranges, and achieving a low detection limit of 1.14 ng·mL-1. The proposed assay effectively detected C21:0 AR in real samples, including 8 whole wheat foods and 19 whole wheat grains, demonstrating good recoveries and relative standard deviation. Furthermore, an intelligent sensing platform was established by integrating CDs@ZIF-8/CdTe@MIP with a smartphone-assisted device, thus validating the feasibility of visual and on-site monitoring of C21:0 AR. Because of its rapid response, portability, cost-effectiveness, superior sensitivity, and high selectivity, the proposed sensor serves as a reliable method for the analysis of C21:0 AR, thus having substantial potential for on-site monitoring of whole wheat foods.

A selectivity-enhanced fluorescence imprinted sensor based on yellow-emission peptide nanodots for sensitive and visual smart detection of λ-cyhalothrin.

The development of precise and efficient detection technologies to recognize λ-cyhalothrin (LC) in agricultural products has attracted attention worldwide due to its widespread use and notable toxic effects on humans. Herein, a novel fluorescence biomimetic nanosensor was elaborately designed based on Zn(II)-doped cyclo-ditryptophan (c-WW)-type peptide nanodots and incorporating molecularly imprinted polymer (c-WW/Zn-PNs@MIP) for LC assays. C-WW/Zn-PNs obtained by self-assembly with aromatic cyclic dipeptides as basic building blocks and coordination with Zn(II) have low-toxicity, photostability, and bright yellow fluorescence emission, as a sensitive signal transducer. High-affinity imprinting sites further endow c-WW/Zn-PNs@MIP with superior selectivity and reusability. Based on prominent merits, c-WW/Zn-PNs@MIP demonstrated a good linear range (1-360 µg/L) with a low limit of detection (LOD) (0.93 µg/L), fast kinetics in target capture (10 min), and strong practicability in the capture of LC from real samples (spiked recovery of 81.0-107.7%). Additionally, to attain onsite profiling of LC, a visual platform was developed by integrating c-WW/Zn-PNs@MIP with a smartphone-assisted optical device. This smart evaluation system can capture concentration-dependent fluorescent images and accurately digitize them, enabling quantitative analysis of LC. This study developed a fluorescent c-WW/Zn-PNs@MIP-based smart evaluation system as a novel platform for LC monitoring applications, which not only has enormous economic value but also great environmental health significance.

Peptide-Based Molecularly Imprinted Polymer: A Visual and Digital Platform for Specific Recognition and Detection of Ethyl Carbamate.

A visual and digital platform was constructed by peptide-based molecularly imprinted polymers (PMIPs) for specific recognition and detection of ethyl carbamate (EC). Here, the optosensing core was creatively constructed by the covalent assembly of dipeptides (H-Phe-Phe-OH) and genipin biomolecules for high fluorescence quantum yield and dual-signal response capability. MIPs were wrapped in the shell of the optosensing core for selectivity of EC from actual samples of alcoholic beverages. The genipin-FF nanoparticles (GFPNs)@PMIPs exhibited dual-band red-blue fluorescence image with a low detection limit of 0.817 and 1.65 µg L-1, respectively, in the optimal linear range of 2-240 µg L-1. The accuracy of this method was verified by the spiked recovery experiment, and a good recovery from 83.97 to 106.75% of the proposed optosensing method was obtained. In addition, a smartphone application was coupled with GFPNs@PMIPs to realize online real-time detection of EC. With the addition of EC, the color change of G and B values was negligible compared with the R value. This work also provides a potential method for on-site visual detection of analytes.

A highly efficient molecularly imprinted fluorescence sensor for assessing whole wheat grains by the rapid and sensitive detection of alkylresorcinols.

To differentiate whole wheat foods from refined wheat foods is still challenging grain industry and confusing consumers. Alkylresorcinols (ARs), as biomarkers of whole wheat grains, can serve for assessing the authenticity of whole wheat foods. Herein, a highly efficient fluorescence sensing platform (CDs@MIP) for rapid and sensitive analysis of ARs was explored, using carbon dots (CDs) as fluorophores and 5-heneicosylresorcinol (C21:0 AR) as template molecules embedded in a molecularly imprinted polymer (MIP) coating. Benefiting from the specific cavities in the probe and a photo-induced electron transfer effect, the fluorescence intensity of CDs@MIP was significantly quenched in the presence of C21:0 AR, exhibiting a superior binding efficiency and selectivity. As a result, the fabricated optical sensor delivered a wide linear range of C21:0 AR from 0.015 to 60 µg mL-1 with an ultralow detection limit of 4 ng mL-1. It was noteworthy that the sensor was successfully applied for the rapid detection of C21:0 AR in commercial whole-wheat foods as well as visualization analysis on the test paper, comprehensively validating the practicality and efficacy of CDs@MIP based fluorescence assay. The study provides a rapid and sensitive detection method of C21:0 AR, paving a new way for guiding grain industry to effectively qualify the authenticity and to quantify the content of whole wheat in wheat-based foods.

Sonochemistry: An emerging approach to fabricate biopolymer cross-linked emulsions for the delivery of bioactive compounds.

Sonochemistry shows remarkable potential in the synthesis or modification of new micro/nanomaterials, particularly the cross-linked emulsions for drug delivery. However, the trend of utilizing sonochemical emulsions for delivery of food-derived bioactive compounds has been just started. The extension of sonochemistry as a tool for engineering bioactive delivery systems will make the approach more universal and greatly increase its applications in the food industry. This review summarizes different types of biopolymeric cross-linked emulsions (CLEs) synthesized via sonochemical approach, including CLEs, surface-modified CLEs, cross-linked high internal phase emulsions, and some novel systems templated on CLEs. Special emphasis is directed toward the cross-linking mechanisms of biopolymers at the oil-water interfaces under acoustic cavitation and the physicochemical principles underlying sonochemical fabrication. We also highlight the advantages and challenges associated with the delivery performance of each system for bioactive compounds. The potential in delivering bioactives using sonochemical emulsions has not been fully reached. There are still a number of issues that need to be overcome, including low cross-linking degree of biopolymers, degradation of bioactives in sonochemical process, and unclear biological fate of encapsulated bioactive compounds. This review may guide future trends in exploring efficient sonochemical strategies and multifunctional delivery systems for food applications.

Revelation for the Influence Mechanism of Long-Chain Fatty Acid Ethyl Esters on the Baijiu Quality by Multicomponent Chemometrics Combined with Modern Flavor Sensomics.

Long-chain fatty acid ethyl ester (LCFAEEs) is colorless and has a weak wax and cream aroma. It can be used as an intermediate for the synthesis of emulsifiers, and stabilizers and be applied in the production of flavor essence. It is also an important trace component in Baijiu and is attributed to making a contribution to the quality of Baijiu, but its distribution in Baijiu has not been clear, and its influence mechanisms on Baijiu quality have not been systematically studied. Therefore, the distribution of LCFAEEs for Baijiu in different years (2014, 2015, 2018, and 2022), different grades (premium, excellent, and level 1; note: here Baijiu grade classification was based on Chinese standard (GB/T 10781) and enterprise classification standard), and different sun exposure times (0, 6, 12, 20, 30, and 50 days) was uncovered. Thus, in this study, the effect of LCFAEEs on the quality of Baijiu was comprehensively and objectively proven by combining modern flavor sensomics and multicomponent chemometrics. The results showed that with the increase in Baijiu storage time, the concentration of LCFAEEs increased significantly in Baijiu (4.38-196.95 mg/L, p < 0.05). The concentration of LCFAEEs in level 1 Baijiu was significantly higher than that in excellent and premium Baijiu (the concentration ranges of ET, EP, EO, E9, E912, and E91215 were: 0.27-2.31 mg/L, 0.75-47.41 mg/L, 0.93-1.80 mg/L, 0.98-12.87 mg/L, 1.01-27.08 mg/L, and 1.00-1.75 mg/L, respectively, p < 0.05). With the increase in sun exposure time, the concentration of LCFAEEs in the Baijiu first increased significantly and then decreased significantly (4.38-5.95 mg/L, p < 0.05). As the flavor sensomics showed, the concentrations of LCFAEEs in Baijiu bodies were significantly correlated with the Baijiu taste sense (inlet taste, aroma sensation in the mouth), as well as with the evaluation after drinking (maintaining taste) (p < 0.05, r > 0.7). Based on the above, LCFAEEs are critical factors for Baijiu flavor thus, it is essential to explore a suitable concentration of LCFAEEs in Baijiu to make Baijiu's quality more ideal.

Fabrication of a fluorescence probe via molecularly imprinted polymers on carbazole-based covalent organic frameworks for optosensing of ethyl carbamate in fermented alcoholic beverages.

Ethyl carbamate (EC), which is a group 2A carcinogen, is a byproduct formed in the alcohol fermentation process that can accumulate with heating, transportation, and storage. In this study, molecularly imprinted polymers (MIPs) on carbazole-based covalent organic frameworks (COFs) were prepared as a fluorescence probe for the optosensing of EC in fermented alcoholic beverages. The excellent optical properties of carbazole-based COFs coupled with the good adsorption and selectivity of MIPs provided fast and efficient recognition of EC. MIPs on carbazole-based COFs exhibited advantages of high efficiency, a good separation effect, fluorescence dependence, and reproducibility. A good linear relationship was obtained over the concentration range of 1-200 µg L-1, with a low limit of detection (LOD) of 0.607 µg L-1. The RSD precision and five-cycle reproducibility were lower than 4.91% and 6.38%, respectively, and the recoveries were 85.30%-109.49%. This optosensor was applied to quantify EC contents in several fermented alcoholic beverages, all of which were less than LOD. The results of the optosensors based on MIPs on carbazole-based COFs were then validated using standard gas chromatography-mass spectrometry (GC-MS), which gave results consistent with the proposed method.

Synthesis, characterization, and methylene blue adsorption of multiple-responsive hydrogels loaded with Huangshui polysaccharides, polyvinyl alcohol, and sodium carboxyl methyl cellulose.

Huangshui (HS), a typical by-product of traditional Chinese Baijiu, has attracted more and more attention since its rich resources of polysaccharides. However, there's little information on hydrogels preparation by Huangshui polysaccharides (HSPs). A series of novel HSP-loaded hydrogels were synthesized using crude HSP (cHSP), polyvinyl alcohol (PVA), sodium carboxyl methyl cellulose (CMC), and in situ incorporation of Fe3O4 for methylene blue (MB) adsorption for the first time. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and texture tests indicated the paramagnetic hydrogels with porous structure were formed via physical crosslinking, and cHSP had no effect on hydrogel texture. Notably, cHSP enhanced the swelling capacity and MB adsorption ability of the hydrogels, and the corresponding maximum value was 38.67 g/g and 71.07 mg/g, respectively, when the additive amount of cHSP to the hydrogels was 2 % at 25°Ð¡. In addition, the swelling kinetics of hydrogels followed the Schott's second-order kinetics model, while MB adsorption fitted well with the Freundlich isotherm and pseudo-second-order model. Furthermore, intraparticle and film diffusion-controlled MB adsorption process. Significantly, cHSP amount could counteract the negative influence of high temperature on MB adsorption, and the prepared hydrogels could be reusable, demonstrating cHSP effectively promoted the properties of hydrogels and had potential application in MB removal. The adsorption mechanism of MB onto the hydrogels involved ion-exchange, hydrogen bonding, electrostatic interaction, and chemical reaction according to the above results together with the analysis by X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray (EDX) characterizations, thermodynamic, etc.

Advanced CaCO3-derived delivery systems for bioactive compounds.

Calcium carbonate (CaCO3) has long been used as a delivery system owing to its wide availability, biocompatibility, and degradability. However, it often suffers from many challenges toward rapid dissolution at stomach acid environment, low retention ability, and lack of sustained release. Many of these issues can be addressed by modifying the CaCO3 particles or integrating them with other encapsulation systems, generating advanced CaCO3-derived systems. This review article presents a recent progress (2015-2022) in the utilization of CaCO3 particles in the exploration of various advanced delivery systems, including polymer-doped CaCO3, surface-coated CaCO3, CaCO3-stabilized Pickering emulsions, CaCO3-in-hydrogels, and liposomal CaCO3. Some emerging systems templated on CaCO3 sacrificial cores, such as hollow capsules, matrix-type capsules, and core-shell capsules, are also reviewed. A brief description of each system is given, and then their formation, structure, and properties are described. Particular emphasis is given to the applications and challenges of these advanced systems for the protection and controlled delivery of bioactive compounds in the biological, pharmaceutical, and functional food fields.

Biopolymer-liposome hybrid systems for controlled delivery of bioactive compounds: Recent advances.

Conventional liposomes still face many challenges associated with the poor physical and chemical stability, considerable loss of encapsulated cargo, lack of stimulus responsiveness, and rapid elimination from blood circulation. Integration of versatile functional biopolymers has emerged as an attractive strategy to overcome the limitation of usage of liposomes. This review comprehensively summarizes the most recent studies (2015-2020) and their challenges aiming at the exploration of biopolymer-liposome hybrid systems, including surface-modified liposomes, biopolymer-incorporated liposomes, guest-in-cyclodextrin-in-liposome, liposome-in-hydrogel, liposome-in-film, and liposome-in-nanofiber. The physicochemical principles and key technical information underlying the combined strategies for the fabrication of polymeric liposomes, the advantages and limitations of each of the systems, and the stabilization mechanisms are discussed through various case studies. Special emphasis is directed toward the synergistic efficiencies of biopolymers and phospholipid bilayers on encapsulation, protection, and controlled delivery of bioactives (e.g., vitamins, carotenoids, phenolics, peptides, and other health-related compounds) for the biomedical, pharmaceutical, cosmetic, and functional food applications. The major challenges, opportunities, and possible further developments for future studies are also highlighted.