Complexing of chlorogenic acid with β-cyclodextrins: Inclusion effects, antioxidative properties and potential application in grape juice

Pickering emulsion stabilized by quercetin-β-cyclodextrin-diglyceride particles: Effect of diglyceride content on interfacial behavior and emulsifying property of complex particles

This research develops diacylglycerol (DAG) based Pickering emulsions with enhanced oxidative stability stabilized by self-assembled quercetin/DAG/β-cyclodextrin (β-CD) complexes (QDCCs) using a one-step agitation method. Influence of DAG content (5%, 15%, 40%, and 80%, w/w) on the self-assembly behavior, interfacial properties, and emulsifying ability of complex particles was investigated. SEM, XRD and ATR-FTIR studies confirmed the formation of ternary composite particles. QDCCs in 80% DAG oil had the highest quercetin encapsulation efficiency (6.09 ± 0.01%), highest DPPH radical scavenging rate and ferric reducing antioxidant property (FRAP). β-CD and quercetin adsorption rates in emulsion with 80% DAG oil were 88.4 ± 2.53% and 98.34 ± 0.15%, respectively. Pickering emulsions with 80% DAG had the smallest droplet size (8.90 ± 1.87 μm) and excellent oxidation stability. This research develops a novel approach to regulate the physicochemical stability of DAG-based emulsions by anchoring natural antioxidants at the oil-water interface through a one-pot self-assembly method.

Ultrasonic-Assisted Extraction of Phenolic Compounds from Lonicera similis Flowers at Three Harvest Periods: Comparison of Composition, Characterization, and Antioxidant Activity

Lonicera similis Hemsl. (L. similis) is a promising industrial crop with flowers rich in phenolic compounds. In this study, an ultrasound-assisted extraction (UAE) was designed to extract phenolic compounds from L. similis flowers (LSFs). A contrastive analysis on the phenolic compounds' yield and characterization and the antioxidant activity of the extracts at three harvest stages (PGS I, PGS II, and PGS III) are reported. The results indicate that the optimal conditions are a sonication intensity of 205.9 W, ethanol concentration of 46.4%, SLR of 1 g: 31.7 mL, and sonication time of 20.1 min. Under these optimized conditions, the TPC values at PGS I, PGS II, and PGS III were 117.22 ± 0.55, 112.73 ± 1.68, and 107.33 ± 1.39 mg GAE/g, respectively, whereas the extract of PGS I had the highest TFC (68.48 ± 2.01 mg RE/g). The HPLC analysis showed that chlorogenic acid, rutin, quercetin, isoquercitrin, and ferulic acid are the main components in the phenolic compounds from LSFs, and their contents are closely corrected with the harvest periods. LSF extracts exhibited a better antioxidant activity, and the activity at PGS I was significantly higher than those at PGS II and PGS III. The correlation analysis showed that kaempferol and ferulic acid, among the eight phenolic compounds, have a significant positive correlation with the antioxidant activity, while the remaining compounds have a negative correlation. Minor differences in extracts at the three harvest stages were found through SEM and FTIR. These findings may provide useful references for the optimal extraction method of phenolic compounds from LSFs at three different harvest periods, which will help to achieve a higher phytochemical yield at the optimal harvest stage (PGS I).

Effects of polyphenol and gelatin types on the physicochemical properties and emulsion stabilization of polyphenol-crosslinked gelatin conjugates

Herein, six types of polyphenol-crosslinked gelatin conjugates (PGCs) with ≥ two gelatin molecules were prepared using a covalent crosslinking method with two types of polyphenols (tannic acid and caffeic acid) and three types of gelatins (bovine bone gelatin, cold water fish skin gelatin, and porcine skin gelatin) for the emulsion stabilization. The structural and functional properties of the PGCs were dependent on both polyphenol and gelatin types. The storage stability of the conjugate-stabilized emulsions was dependent on the polyphenol crosslinking, NaCl addition, and heating pretreatment. In particular, NaCl addition promoted the liquid-gel transition of the emulsions: 0.2 mol/L > 0.1 mol/L > 0.0 mol/L. Moreover, NaCl addition also increased the creaming stability of the emulsions stabilized by PGCs except tannic acid-crosslinked bovine bone gelatin conjugate. All the results provided useful knowledge on the effects of molecular modification and physical processing on the properties of gelatins.

Unleashing the power of chlorogenic acid: exploring its potential in nutrition delivery and the food industry

In the contemporary era, heightened emphasis on health and safety has emerged as a paramount concern among individuals with food. The concepts of "natural" and "green" have progressively asserted dominance in the food consumption market. Consequently, through continuous exploration and development, an escalating array of natural bioactive ingredients is finding application in both nutrition delivery and the broader food industry. Chlorogenic acid (CGA), a polyphenolic compound widely distributed in various plants in nature, has garnered significant attention. Abundant research underscores CGA's robust biological activity, showcasing notable preventive and therapeutic efficacy across diverse diseases. This article commences with a comprehensive overview, summarizing the dietary sources and primary biological activities of CGA. These encompass antioxidant, anti-inflammatory, antibacterial, anti-cancer, and neuroprotective activities. Next, a comprehensive overview of the current research on nutrient delivery systems incorporating CGA is provided. This exploration encompasses nanoparticle, liposome, hydrogel, and emulsion delivery systems. Additionally, the article explores the latest applications of CGA in the food industry. Serving as a cutting-edge theoretical foundation, this paper contributes to the design and development of CGA in the realms of nutrition delivery and the food industry. Finally, the article presents informed speculations and considerations for the future development of CGA.

Coordinated encapsulation by β-cyclodextrin and chitosan derivatives improves the stability of anthocyanins

To improve the stability of anthocyanins (ACNs), ACNs were loaded into dual-encapsulated nanocomposite particles by self-assembly using β-cyclodextrin (β-CD) and two different water-soluble chitosan derivatives, namely, chitosan hydrochloride (CHC) and carboxymethyl chitosan (CMC). The ACN-loaded β-CD-CHC/CMC nanocomplexes with small diameters (333.86 nm) and had a desirable zeta potential (+45.97 mV). Transmission electron microscopy (TEM) showed that the ACN-loaded β-CD-CHC/CMC nanocomplexes had a spherical structure. Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (¹H NMR) and X-ray diffraction (XRD) confirmed that the ACNs in the dual nanocomplexes were encapsulated in the cavity of the β-CD and that the CHC/CMC covered the outer layer of β-CD through noncovalent hydrogen bonding. The ACNs from the dual-encapsulated nanocomplexes improved stability of ACNs under adverse environmental conditions or in a simulated gastrointestinal environment. Further, the nanocomplexes exhibited good storage stability and thermal stability over a wide pH range when added into simulated electrolyte drinks (pH = 3.5) and milk tea (pH = 6.8). This study provides a new option for the preparation of stable ACNs nanocomplexes and expands the applications for ACNs in functional foods.

Effect of fermentation on the antioxidant properties and phenolic compounds of Bambangan (Mangifera pajang) fruit

The study aimed to determine the antioxidant activities and phenolic compounds of Bambangan (Mangifera pajang), a type of wild fruit belongs to the family of Anacardiaceae during fermentation at room (28 °C) and elevated temperature (35 °C). The antioxidant capacity was estimated based on 2,2-diphenyl-1-picyrlhydrazyl (DPPH) scavenging activity, ferric-ion-reducing power (FRAP), 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation assay and oxygen-radical absorbing capacity (ORAC). A reversed phase high performance liquid chromatography (HPLC) was used to identify the phenolic compounds. Samples of bambangan fermented at 35 °C achieved the highest FRAP (141.42 mM Fe(II)/g extract) and ABTS values (5.00 mmol TE/g) within the first six days as compared to the samples fermented at room temperature (28 °C), which required 10 days to achieve the highest FRAP and ABTS values. No significant difference was found (p > 0.05) on the antioxidant activity of the samples that were kept at prolonged fermentation and storage. The total phenolic content (TPC) increased throughout the fermentation with the highest value of 44.69 ± 0.01 mg GAE/g. Gallic acid, chlorogenic acid, vanillin, ρ -coumaric acid and rutin are the major phenolic compounds identified in the fermented product. The results suggested that the antioxidant capacity of bambangan is affected by the fermentation temperature and the fermented product could be a source of antioxidants.

Simultaneously enhanced stability and biological activities of chlorogenic acid by covalent grafting with soluble oat β-glucan

Chlorogenic acid (CA) has a wide range of biological activities but the chemical structure is extremely unstable. In this study, CA was grafted onto a soluble oat β-glucan (OβGH) to improve the stability. Although the crystallinity and thermal stability of CA-OβGH conjugates reduced, the storage stability of CA significantly improved. The DPPH and ABTS scavenging ability of CA-OβGH IV (graft ratio 285.3 mg CA/g) were higher than 90 %, which is closed to activities of equivalent concentration of Vc (93.42 %) and CA (90.81 %). The antibacterial abilities of CA-OβGH conjugates are improved compared to the equivalent content of CA and potassium sorbate. Particularly, the inhibition rate of CA-OβGH for gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) are significantly higher than that of gram-negative bacteria (Escherichia coli). The results demonstrated that covalent grafted CA with soluble polysaccharide is an effective strategy to enhance its stability and biological activities.

Cyclodextrin-Based Delivery Systems and Hydroxycinnamic Acids: Interactions and Effects on Crucial Parameters Influencing Oral Bioavailability-A Review

Hydroxycinnamic acids (HCAs) are a subclass of phenolic acids presenting caffeic acid (CA), chlorogenic acid (CGA), coumaric acid (COA) isomers, ferulic acid (FA), and rosmarinic acid (RA) as the major representants, being broadly distributed into vegetal species and showing a range of biological potentials. Due to the low oral bioavailability of the HCAs, the development of delivery systems to promote better administration by the oral route is demanding. Among the systems, cyclodextrin (CD)-based delivery systems emerge as an important technology to solve this issue. Regarding these aspects, in this review, CD-based delivery systems containing HCAs are displayed, described, and discussed concerning the degree of interaction and their effects on crucial parameters that affect the oral bioavailability of HCAs.

Upscaling of Apple By-Product by Utilising Apple Seed Protein as a Novel Wall Material for Encapsulation of Chlorogenic Acid as Model Bioactive Compound

Encapsulation is a versatile technique used to protect sensitive bioactive compounds under gastrointestinal conditions. In this study, nanoencapsulation of chlorogenic acid into the apple seed protein matrix was performed using the green technique ultrasonication to protect it from harsh gastric conditions and increase its biological activity and bioavailability upon digestion. Both nano (Nano-Chl) and native capsules (NT-Chl) were characterised by particle size, charge, structure, and morphology. The encapsulation efficiency, release behaviour, antioxidant and antidiabetic properties were also evaluated. The experimental results show that the particle size of the NT-Chl and Nano-Chl was found in the range of 1.4 µm to 708 nm. The encapsulation efficiency was found to be 69% and 80% for NT-Chl and Nano-Chl, respectively. Furthermore, an in vitro digestion study revealed that Nano-Chl showed controlled-release behaviour under simulated intestinal conditions in comparison to NT-Chl. Moreover, Nano-Chl showed enhanced antioxidant and antidiabetic activity in comparison to NT-Chl after simulated digestion. It was concluded that the protein from apple seeds could be utilised as a functional ingredient itself or as a wall material for the encapsulation of sensitive bioactive compounds. Furthermore, these encapsulated particles can be fortified into different food formulations for the development of functional food.

Bioactive Compounds and Antioxidant Activity from Spent Coffee Grounds as a Powerful Approach for Its Valorization

Coffee is one of the world’s most popular beverages, and its consumption generates copious amounts of waste. The most relevant by-product of the coffee industry is the spent coffee grounds, with 6 million tons being produced worldwide per year. Although generally treated as waste, spent coffee grounds are a rich source of several bioactive compounds with applications in diverse industrial fields. The present work aimed at the analysis of spent coffee grounds from different geographical origins (Guatemala, Colombia, Brazil, Timor, and Ethiopia) for the identification of bioactive compounds with industrial interest. For this purpose, the identification and quantification of the bioactive compounds responsible for the antioxidant activity attributed to the spent coffee grounds were attempted using miniaturized solid-phase extraction (µ-SPEed), combined with ultrahigh-performance liquid chromatography with photodiode array detection (UHPLC-PDA). After validation of the µ-SPEed/UHPLC-PDA method, this allowed us to conclude that caffeine and 5-caffeoylquinic acid (5-CQA) are the most abundant bioactive compounds in all samples studied. The total phenolic content (TPC) and antioxidant activity are highest in Brazilian samples. The results obtained show that spent coffee grounds are a rich source of bioactive compounds, supporting its bioprospection based on the circular economy concept closing the loop of the coffee value chain, toward the valorization of coffee by-products.

Polycaprolactone/polyvinyl pyrrolidone nanofibers developed by solution blow spinning for encapsulation of chlorogenic acid

Study on the application of nanofibers in food active packaging has been a research hotspot in recent years. In this work, the solution blow spinning (SBS) was applied to rapidly fabricate the polycaprolactone (PCL), polyvinyl pyrrolidone (PVP), and PCL/PVP nanofibrous films to encapsulate chlorogenic acid (CGA). All the films showed uniform and smooth nanofibers, and the FTIR and XRD proved the success of mixed spinning of PCL and PVP. With the increase of PVP content, the thermal stability of the PCL/PVP nanofibrous films improved. The PCL/PVP (4:1) film possessed better mechanical properties than PCL and PVP films because of the stronger fiber-fiber interactions. The addition of PCL endowed the hydrophobic surfaces to the PCL/PVP films, and the PCL/PVP films had better water vapor barrier ability. The PCL/PVP (4:1) film exhibited the best long-term continuous release of CGA during 72 h. The PVP nanofibrous film exhibited no inhibition against S. aureus and E. coli due to the low encapsulation efficiency, but the PCL and PCL/PVP films exhibited good antimicrobial activity. The above results suggested that the nanofibrous films developed by SBS possessed the promising prospects in food packaging.

Application of starch-based nanoparticles and cyclodextrin for prebiotics delivery and controlled glucose release in the human gut: a review

Starches are a major constituent of staple foods and are the main source of energy in the human diet (55-70%). In the gastrointestinal tract, starches are hydrolyzed into glucose by α-amylase and α-glucosidase, which leads to a postprandial glucose elevation. High levels of blood glucose levels over sustained periods may promote type 2 diabetes mellitus (T2DM) and obesity. Increasing consumption of starchy foods with a lower glycemic index may therefore contribute to improved health. In this paper, the preparation and properties of several starch-based nanoparticles (SNPs) and cyclodextrins (CDs) derivatives are reviewed. In particular, we focus on the various mechanisms responsible for the ability of these edible nanomaterials to modulate glucose release and the gut microbiome in the gastrointestinal tract. The probiotic functions are achieved through encapsulation and protection of prebiotics or bioactive components in foods or the human gut. This review therefore provides valuable information that could be used to design functional foods for improving human health and wellbeing.

Antioxidant Activity, Polyphenolic Content, and FT-NIR Analysis of Different Aspilia africana Medicinal Plant Tissues

Aspilia africana has been used for generations to treat many diseases in Africa. Its biological activities, including antioxidant and anti-inflammatory potential, are attributed to a number of secondary metabolites, including alkaloids and polyphenolics. The antioxidant activities of A. africana callus (CA), juvenile in vitro leaf (IL) and root (IR), ex vitro root (SR) and leaf (SL), and wild leaf (WL) dried samples were assessed based on their diphenylpicrylhydrazyl (DPPH) free radical scavenging abilities. The total phenolic and flavonoid content of different plant samples was compared. Further, high-pressure liquid chromatography (HPLC) was used to quantitatively determine chlorogenic acid content in the A. africana plant samples. Fourier transform near-infrared (FT-NIR) analysis was also carried out to compare the antioxidant phytochemical content in the A. africana plant tissues. Among the samples, IR, with the highest total phenolic content (167.84 ± 1.057 mg GAE/g), total flavonoid content (135.06 ± 0.786 mg RUE/g), and chlorogenic acid (5.23 ± 0.298 mg/g) content, had the most potent antioxidant activity (IC₅₀ = 27.25 ± 5.028 μg/mL), followed by WL. The lowest polyphenolic content and antioxidant activity were observed in SR. The antioxidant activities of A. africana tissues were positively correlated with the total phenolic and flavonoid content in the samples. The differences in antioxidant activities of A. africana tissues could be attributed to the difference in their polyphenolic content. Our study reports, for the first time, the antioxidant activities of A. africana callus and roots (in vitro and ex vitro). The A. africana samples IR, CA, and WL could be valuable natural sources of antioxidants that could be further exploited for the development of useful pharmaceutical products.

Curcumin Extraction, Isolation, Quantification and Its Application in Functional Foods: A Review With a Focus on Immune Enhancement Activities and COVID-19

An entirely unknown species of coronavirus (COVID-19) outbreak occurred in December 2019. COVID-19 has already affected more than 180 million people causing ~3.91 million deaths globally till the end of June 2021. During this emergency, the food nutraceuticals can be a potential therapeutic candidate. Curcumin is the natural and safe bioactive compound of the turmeric (Curcuma longa L.) plant and is known to possess potent anti-microbial and immuno-modulatory properties. This review paper covers the various extraction and quantification techniques of curcumin and its usage to produce functional food. The potential of curcumin in boosting the immune system has also been explored. The review will help develop insight and new knowledge about curcumin's role as an immune-booster and therapeutic agent against COVID-19. The manuscript will also encourage and assist the scientists and researchers who have an association with drug development, pharmacology, functional foods, and nutraceuticals to develop curcumin-based formulations.

Integrated Green Process for the Extraction of Red Grape Pomace Antioxidant Polyphenols Using Ultrasound-Assisted Pretreatment and β-Cyclodextrin

Winemaking is a process that generates a large volume of solid waste biomass, which is currently under extensive investigation as a bioresource of precious polyphenolic compounds. These substances are retrieved from vinification side streams principally by deploying solid–liquid extraction methods. In this frame, the present investigation had as objective the development of an alternative, green extraction process for polyphenols, through integration of ultrasonication as a pretreatment stage, and subsequent extraction with aqueous β-cyclodextrin. Polyphenol recovery from red grape pomace (RGP) was shown to be significantly enhanced by ultrasonication pretreatment, and the use of β-cyclodextrin effectively boosted the aqueous extraction. Under optimized conditions, established by response surface methodology, the maximum yield in total polyphenols was 57.47 mg GAE g−1 dm, at 80 °C, requiring a barrier of 10.95 kJ mol−1. The extract produced was significantly enriched in catechin and quercetin, compared to the aqueous extract, exhibiting also increased antiradical activity. These findings highlighted the value of the process developed for targeted recovery of certain polyphenols and the preparation of task-specific extracts.

Study of the fluorescence and interaction between cyclodextrins and neochlorogenic acid, in comparison with chlorogenic acid

Neochlorogenic acid, a less-studied isomer of chlorogenic acid, has been seen to posses antioxidant, antifungal, anti-inflammatory and anticarcinogenic effects, which makes it an interesting candidate for incorporation in functional foods. However, its poor solubility in water and susceptibility to oxidation make such a task difficult. To overcome that, its encapsulation in cyclodextrins (CDs) is proposed. The fluorescence of neochlorogenic acid in different pH conditions was analyzed, and caffeic acid was proved to be the fluorescent moiety in the molecule. An encapsulation model whereby the ligand poses two potential complexation sites (caffeic and D-(-)-quinic moieties), showed that α-CD and HP-β-CD formed the best inclusion complexes with neochlorogenic acid, followed by M-β-CD, β-CD and γ-CD. Molecular docking with the two best CDs gave better scores for α-CD, despite HP-β-CD providing stabilization through H-bonds. The encapsulation of chlorogenic acid led to a similar CD order and scores, although constants were higher for α-CD, β-CD and M-β-CD, lower for HP-β-CD, and negligible for γ-CD. The protonation state affected these results leading to a different order of CD preference. The solubility and the susceptibility to oxidation of neochlorogenic acid improved after complexation with α-CD and HP-β-CD, while the antioxidant activity of both isomers was maintained.

Inclusion Complexes of Concentrated Orange Oils and β-Cyclodextrin: Physicochemical and Biological Characterizations

Concentrated orange oils (5x, 10x, 20x) are ingredients used in different industries as components of flavors and aromas due to their great organoleptic qualities. This research focuses on the search for alternative uses for their application through encapsulation in inclusion complexes with β-cyclodextrin (β-CD). Inclusion complexes of concentrated orange oils (COEO) and β-CD were developed by the co-precipitated method in ratios of 4:96, 12:88, and 16:84 (w/w, COEO: β-CD). The best powder recovery was in the ratio 16:84 for the three oils, with values between 82% and 84.8%. The 20x oil in relation 12:88 showed the highest entrapment efficiency (89.5%) with 102.3 mg/g of β-CD. The FT-IR analysis may suggest an interaction between the oil and the β-CD. The best antioxidant activity was observed in the ratio 12:88 for the three oils. The antifungal activity was determined for all the inclusion complexes, and the 10x fraction showed the highest inhibition at a concentration of 10 mg/mL in ratios 12:88 and 16:84. Antibacterial activity was determined by the minimum inhibitory concentration (MIC) and was found at a concentration of 1.25 mg/mL in ratios 12:88 and 16:84 for 5x and 20x oils.

Understanding structures and thermodynamics of β-cyclodextrin encapsulation of chlorogenic, caffeic and quinic acids: Implications for enriching antioxidant capacity and masking bitterness in coffee

Green coffee beans are rich in polyphenol chlorogenic acids (CGAs), which are decomposed to give caffeic acid (CFA) and quinic acid (QNA) upon roasting. CGA, CFA and QNA primarily confer the bitterness, astringency and acidity to the coffee brew. Aiming at the structural and thermodynamic insights into the β-cyclodextrin (β-CD) encapsulation of key compounds in coffee (CGA 1, CFA 2, and QNA 3), a systematic, comprehensive study using single-crystal X-ray diffraction and DFT calculation has been undertaken. Scrutinizing the X-ray-derived inclusion structures of 1-3 reveals that the CFA moiety plays a determinant role in complexation, in agreement with the DFT-derived relative thermodynamic stabilities. The guest molecules gain stability through OH⋯O hydrogen bonding with β-CD and are well shielded in the β-CD wall. The three stable β-CD inclusion complexes with coffee key compounds suggest the implications of CDs as encapsulating agents for improving bioactivities and masking bitter taste in foods.

Effects of α-, β- and maltosyl-β-cyclodextrins use on the glucoraphanin-sulforaphane system of broccoli juice

Cyclodextrins (CDs) are macromolecules with several industrial applications, being particularly used in the food industry as health-promoting compounds protection agents, as flavour stabilizers, or to eliminate undesired tastes and browning reactions, among others. This study shows the effects of α- (10, 30 and 40 mmol L^-1 ), β- (3, 6 and 10 mmol L^-1 ) and maltosyl-β-CDs (30, 60 and 90 mmol L^-1 ) use on the health-promoting glucoraphanin-sulforaphane system of a broccoli juice up to 24 h at 22 °C. Maltosyl-β-CD (90 mmol L^-1 ) highly retained glucoraphanin content after 24 h at 22 °C, showing better effectiveness than β-CD (10 mmol L^-1 ). Sulforaphane was efficiently encapsulated with β-CD at just 3 mmol L^-1 , and the sulforaphane formed was stable during 3 h at 22 °C. On the other hand, 40 mmol L^-1 α-CD retained a high glucoraphanin content in broccoli juice. In contrast, glucoraphanin levels in juice without CDs decreased by 71% after 24 h. Consequently, CDs addition may potentially preserve glucoraphanin in this broccoli juice during industrial processing with the possibility to be later transformed by endogenous myrosinase after ingestion to the health-promoting sulforaphane. © 2018 Society of Chemical Industry.

Inclusion complex of β-cyclodextrin with coffee chlorogenic acid: new insights from a combined crystallographic and theoretical study

This work reports the elusive structural evidence for the [4]pseudorotaxane of β-cyclodextrin (β-CD) with coffee chlorogenic acid (CGA), a conjugate of caffeic acid (CFA) and quinic acid (QNA). A single-crystal X-ray structure analysis of the inclusion complex β-cyclodextrin-chlorogenic acid-water (2/2/17), 2C₄₂H₇₀O₃₅·2C₁₆H₁₈O₉·17H₂O, reveals that CGA threads through β-CD and assembles via O-H...O hydrogen bonds and parallel-displaced π-π interactions in the twofold symmetry-related dimer yielding a [4]pseudorotaxane, which is crystallographically observed for the first time in CD inclusion complexes. The encapsulation of the aromatic ring and C=C-C(=O)O chain in the β-CD dimeric cavity indicates that the CFA moiety plays a determinant role in complexation. This is in agreement with the DFT-derived relative thermodynamic stabilities of the trimodal β-CD-CGA inclusion complexes, that is, β-CD complexed with different CGA components: C=C-C(=O)O chain > cyclohexane ring > aromatic ring. The complexation stability is further enhanced in the dimeric β-CD-CGA complex, with the CFA moiety totally enclosed in the β-CD dimeric cavity.

Construction of Crowning β-cyclodextrin with Temperature Response and Efficient Properties of Host-Guest Inclusion

Promoting a drug inclusion proportion in hydrophobic cavity of β-cyclodextrin using simple methods is a highly ambitious task. Herein, we report the crowning β-cyclodextrins formed by intramolecular hydrogen bonding interaction, which has greatly prolonged the cavity depth of β-cyclodextrin, and therefore further efficiently improved the inclusion proportion to complex drug molecule (vitamin E). Furthermore, the self-assembly behaviors, controllable release, and antioxidant properties of vitamin E embedded into the cavity of crowning β-cyclodextrins was investigated, and host-guest inclusions exhibited temperature-responsive controlled release, excellent antioxidant activity, and photostability.

Stabilizing and Modulating Color by Copigmentation: Insights from Theory and Experiment

Natural anthocyanin pigments/dyes and phenolic copigments/co-dyes form noncovalent complexes, which stabilize and modulate (in particular blue, violet, and red) colors in flowers, berries, and food products derived from them (including wines, jams, purees, and syrups). This noncovalent association and their electronic and optical implications constitute the copigmentation phenomenon. Over the past decade, experimental and theoretical studies have enabled a molecular understanding of copigmentation. This review revisits this phenomenon to provide a comprehensive description of the nature of binding (the dispersion and electrostatic components of π-π stacking, the hydrophobic effect, and possible hydrogen-bonding between pigment and copigment) and of spectral modifications occurring in copigmentation complexes, in which charge transfer plays an important role. Particular attention is paid to applications of copigmentation in food chemistry.

A pH-driven molecular shuttle based on rotaxane-bridged periodic mesoporous organosilicas with responsive release of guests

A pH-driven molecular shuttle was immobilized into the framework of the PMOs in which the β-CDs could shuttle mechanically.