Characterization of the Supermolecular Structure of Polydatin/6‐O‐α‐Maltosyl‐β‐cyclodextrin Inclusion Complex

Polydatin is the main bioactive ingredient in many medicinal plants, such as Hu‐zhang (Polygonum cuspidatum), with many bioactivities. However, its poor aqueous solubility restricts its application in functional food. In this work, 6‐O‐α‐Maltosyl‐β‐cyclodextrin (Malt‐β‐CD), a new kind of β‐CD derivative was used to enhance the aqueous solubility and stability of polydatin by forming the inclusion complex. The phase solubility study showed that polydatin and Malt‐β‐CD could form the complex with the stoichiometric ratio of 1:1. The supermolecular structure of the polydatin/Malt‐β‐CD complex was characterized by ultraviolet–visible spectroscopy (UV), Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffractometry (XRD), thermogravimetric/differential scanning calorimetry (TG/DSC), and proton nuclear magnetic resonance (¹H‐NMR) spectroscopy. The changes of the characteristic spectral and thermal properties of polydatin suggested that polydatin could entrap inside the cavity of Malt‐β‐CD. Furthermore, to reasonably understand the complexation mode, the supermolecular structure of polydatin/Malt‐β‐CD inclusion complex was postulated by a molecular docking method based on Autodock 4.2.3. It was clearly observed that the ring B of polydatin oriented toward the narrow rim of Malt‐β‐CD with ring A and glucosyl group practically exposed to the wide rim by hydrogen bonding, which was in a good agreement with the spectral data.     

Inclusion complex of peony (Paeonia suffruticosa Andr.) seed oil with β‐cyclodextrin: preparation,characterisation and bioavailability enhancement

In this study, β‐cyclodextrin (β‐CD) was used to form an inclusion complex with peony seed oil (PSO), in order to improve its stability, transport convenience and bioavailability. Single‐factor optimisation method was applied to determine the optimum inclusion conditions. The inclusion complexes were prepared by saturated solution method and characterised by GC‐MS, SEM, FT‐IR, XRD, DSC and ¹H NMR analyses. All results suggested that PSO was successfully entered into the β‐CD cavity. What is more, inclusion rate of PSO reached 68.72 ± 2.14%, resulting in a product of 25.97% PSO content, and the unsaturated fatty acids, similar to PSO, accounted for 90.05% of all fat acids in complex. The linolenic acid in inclusion complex exhibited 64.84% higher bioavailability than that in PSO. The inclusion complex possessed of better stability for storage and transportation. Overall, the fabricated complex improved the feature of PSO and thus could be used for novel applications.     

Characteristics of Modified β‐Cyclodextrin Bound to Cellulose Powder

Monochlorotriazinyl‐β‐cyclodextrin (MCT‐β‐CD) was covalently bonded to cellulose powder. The amount of MCT‐β‐CD bonded to cellulose could be determined by infrared spectroscopy. The coupling reaction was characterized as a physical adsorption of the MCT‐β‐CD on the cellulose powder followed by an apparently zero order chemical reaction. The reaction rate constant was found to be k = 6.43 · 10^‐4 ± 0.11 · 10^‐4 g g^‐1 s^‐1. The immobilized cyclodextrin was able to include and release d‐limonene as a model flavor compound. The maximum molar inclusion ratio was 0.85, which is the same inclusion ratio as for d‐limonene in native β‐cyclodextrin. The release rates of dlimonene included in the fixed MCT‐β‐CD were monitored at various relative humidities and 50 °C. The release kinetics could be modeled using the Avrami equation. These results demonstrate that flavors as well as other hydrophobic compounds can be included and released from MCT‐β‐CD immobilized on cellulose.     

Extraction of Epigallocatechin Gallate and Epicatechin Gallate from Tea Leaves Using β‐Cyclodextrin

Use of organic solvents to extract phenolic compounds from plants may result in environmental pollution and cause health problems in persons. Replacing organic extraction solvents by green extracting agents without affecting the extraction yield is one of the most pressing problems to be solved. The aim of this study is to evaluate the capacity of β‐cyclodextrin (β‐CD) to recover phenolic compounds from tea leaves. The extract obtained using the ethanol/water mixture presented the highest total phenolic content, followed by those obtained using β‐CD solution and water. HPLC analysis of the extracts showed that the addition of β‐CD to the extracting agent had a selective effect on the extraction of epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). The extraction yield of EGCG and ECG using 15 g/L β‐CD were higher than that obtained using water and 50% ethanol. Molecular docking results indicated that the molecules of EGCG and ECG were more inclined to interact with β‐CD than epigallocatechin, epicatechin, and gallocatechin. The impact of β‐CD concentration, temperature, and time on EGCG and ECG extraction from tea leaves was investigated and the maximum amount of EGCG (118.7 mg/g) and ECG (54.6 mg/g) were achieved when extracted with 25 g/L aqueous β‐CD solution at 60 °C for 60 min. The present study indicates that aqueous β‐CD can be used as an alternative to organic solvents to recover EGCG and ECG from tea leaves.     

Screening of β‐Glucosidase and β‐Xylosidase Activities in Four Non‐Saccharomyces Yeast Isolates

The finding of new isolates of non‐Saccharomyces yeasts, showing beneficial enzymes (such as β‐glucosidase and β‐xylosidase), can contribute to the production of quality wines. In a selection and characterization program, we have studied 114 isolates of non‐Saccharomyces yeasts. Four isolates were selected because of their both high β‐glucosidase and β‐xylosidase activities. The ribosomal D1/D2 regions were sequenced to identify them as Pichia membranifaciens Pm7, Hanseniaspora vineae Hv3, H. uvarum Hu8, and Wickerhamomyces anomalus Wa1. The induction process was optimized to be carried on YNB‐medium supplemented with 4% xylan, inoculated with 106 cfu/mL and incubated 48 h at 28 °C without agitation. Most of the strains had a pH optimum of 5.0 to 6.0 for both the β‐glucosidase and β‐xylosidase activities. The effect of sugars was different for each isolate and activity. Each isolate showed a characteristic set of inhibition, enhancement or null effect for β‐glucosidase and β‐xylosidase. The volatile compounds liberated from wine incubated with each of the 4 yeasts were also studied, showing an overall terpene increase (1.1 to 1.3‐folds) when wines were treated with non‐Saccharomyces isolates. In detail, terpineol, 4‐vinyl‐phenol and 2‐methoxy‐4‐vinylphenol increased after the addition of Hanseniaspora isolates. Wines treated with Hanseniaspora, Wickerhamomyces, or Pichia produced more 2‐phenyl ethanol than those inoculated with other yeasts.     

Structural characterisation of β‐cyclodextrin crosslinked by adipic acid

This study was conducted to investigate the structural characterisation of β‐cyclodextrin (β‐CD) crosslinked by adipic acid. β‐CD was treated with different concentrations (0%, 5%, 10% and 15%, w/v) of adipic acid. Different instruments, such as scanning electron microsope (SEM), Fourier‐transform infrared (FT‐IR) spectroscopy and ¹H and ¹³C nuclear magnetic resonance (NMR) spectra were used to find out chemical structure in the crosslinked β‐CD. SEM analysis suggested that crosslinking β‐CD with 15% adipic acid changed the original morphology and considerably increased the particle size of the raw material. FT‐IR spectroscopy data showed that an intensive absorption band at 1706 cm^?1 was present in the β‐CD samples treated with 10% and 15% adipic acid, indicating a crosslinking between hydroxyl groups of β‐CD and carboxyl groups of adipic acid. NMR spectra revealed that the ester linkages between hydroxyl groups of β‐CD and carboxyl groups of adipic acid were formed after crosslinking of β‐CD with adipic acid.     

Antimicrobial Effects of Nisin,Essential Oil,and γ‐Irradiation Treatments against High Load of Salmonella typhimurium on Mini‐carrots

This study aimed at using essential oil (EO) alone or combined EO with nisin and γ‐irradiation to control Salmonella Typhimurium during the refrigerated storage of mini‐carrots. Peeled mini‐carrots were inoculated with S. Typhimurium at a final concentration of approximately 7 log CFU/g. Inoculated samples were coated by 5 different coating solutions: (i) nisin solution at final concentration of 10³ IU/mL; (ii) mountain savory EO solution at 0.35%; (iii) carvacrol solution at 0.35%; (iv) mountain savory EO at 0.35% plus nisin solution of 10³ IU/mL; or (v) carvacrol at 0.35% plus nisin solution of 10³ IU/mL. Coated mini‐carrots were then irradiated at 0.5 or 1.0 kGy and compared to an unirradiated control sample. Samples were kept at 4 °C and microbial analyses were conducted at days 1, 3, 6, and 9. The results showed that mini‐carrots coated by carvacrol plus nisin solution or mountain savory EO plus nisin solution in combination with irradiation at 1.0 kGy completely eliminated S. Typhimurium to under the detection limit during the storage. Thus, the combined treatments using carvacrol plus nisin or mountain savory EO plus nisin coating solution and irradiation at 1.0 kGy could be used as an effective method for controlling S. Typhimurium in mini‐carrots.     

Purification and physicochemical characterization of ovine β‐lactoglobulin and α‐lactalbumin

Ovine whey proteins were fractionated and studied by using different analytical techniques. Anion‐exchange chromatography and reversed‐phase high‐performance liquid chromatography (HPLC) showed the presence of two fractions of β‐lactoglobulin but only one of α‐lactalbumin. Gel permeation and sodium dodecyl sulfate (SDS)‐polyacrylamide gel electrophoresis allowed the calculation of the apparent molecular mass of each component, while HPLC coupled to electrospray ionisation‐mass spectrometry (ESI‐MS) technique, giving the exact molecular masses, demonstrated the presence of two variants A and B of ovine β‐lactoglobulin. Amino acid compositions of the two variants of β‐lactoglobulin differed only in their His and Tyr contents. Circular dichroism spectroscopy profiles showed pH conformation changes of each component. The thermograms of the different whey protein components showed a higher heat resistance of β‐lactoglobulin A compared to β‐lactoglobulin B at pH 2, and indicated high instability of ovine α‐lactalbumin at this pH.     

Functional Properties and Retrogradation of Heat‐Moisture Treated Wheat and Potato Starches in the Presence of Hydroxypropyl β‐cyclodextrin

Some functional and retrogradation properties of native and heat‐moisture treated potato and wheat starches were examined in the presence of hydroxypropyl β‐cyclodextrin (HPβ‐CD). HPβ‐CD increased swelling factor, amylose leaching, and solubility of both native and heat‐moisture treated wheat starches but it had less impact on corresponding potato starches. Gelatinization enthalpy of native wheat starch was decreased in the presence of HPβ‐CD but was increased in potato starch with increasing concentration. Reduction of amylose‐lipid complex endotherm in both native and heat‐moisture treated wheat starch was observed in the presence of HPβ‐CD. Heat‐moisture treatment did not change the transition parameters of amylose‐lipid complex showing its resistance to hydrothermal treatment. HPβ‐CD greatly decreased the pasting temperature of wheat starch. Cold paste viscosity of both native and heat‐moisture treated wheat starch was increased by HPβ‐CD to a greater extent than corresponding potato starch. Amylopectin retrogradation of all the starches was unaffected in the presence of HPβ‐CD but heat‐moisture treatment slightly decreased retrogradation of potato starch. These results suggest that HPβ‐CD can disrupt the amylose‐lipid complex within the starch granule in both native and heat‐moisture treated wheat starch but has no influence on amylopectin retrogradation. However, greatly increased wheat starch setback with HPβ‐CD indicates its greater effect on wheat starch amylose retrogradation.     

The role of pulsed electric fields treatment in enhancing the stability of amino acid – sugar complexes:‐ interactions between L‐Phenylalanine and β‐Cyclodextrin

In this work, the effect of pulsed electric fields (PEF) treatment on the interactions between amino acids (using L‐Phenylalanine: L‐Phe) and sugar (using β‐Cyclodextrin: β‐CD) complex was analysed by fluorescence spectroscopy, Raman spectroscopy and simultaneous thermal analyzer. Moreover, the molecular dynamics of β‐CD–L‐Phe inclusion complex treated by PEF was calculated by molecular modelling. The results indicated that β‐CD–L‐Phe complexes are formed by a molar ratio of 1:1, and the stability constant of such complexes increased from 147 to 614 M^?1 by PEF treatment. Thermal characterisations of β‐CD–L‐Phe complexes indicated that the PEF treatment could increase the yield of complexes. The PEF treatment resulted in an increase in the reaction enthalpy of β‐CD–L‐Phe inclusion complexes by DSC curve. These results show that PEF treatment has the potential to promote the chemical processing, especially the small organic molecules participate in inclusion or cross‐linking reaction.     

Characteristics of immobilised β‐glucosidase and its effect on bound volatile compounds in orange juice

In this study, bound volatile compounds were isolated and extracted with Amberlite XAD‐2 resin and then hydrolysed by free or immobilised β‐glucosidase. The released bound volatiles were analysed by GC‐MS. In addition, the optimisation of immobilisation method on sodium alginate and the characteristics of immobilised β‐glucosidase were studied. The results showed that crosslinking‐entrapment was the best method. The optimal conditions of this method were as follows: sodium alginate concentration 3.5%, glutaraldehyde concentration 1%, crosslinking time 3 h, immobilisation time 2 h and CaCl₂ concentration 3%. The optimum temperature for β‐glucosidase (65 °C) was decreased by 10 °C after immobilisation, while the optimum pH values for free and immobilised β‐glucosidase were both at pH 5.0. The K_m values of free and immobilised β‐glucosidase were 14.89 and 0.59 m , respectively. In total, thirteen and six bound volatile compounds were detected in orange juice hydrolysed by free and immobilised β‐glucosidase, including benzenic compounds, terpenic compounds, hydroxy esters, C₁₃‐norisoprenoids and alcohols.     

Hypolipidemic Activity of Peony Seed Oil Rich in α‐Linolenic,is Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid β‐Oxidation

Peony seed oil (PSO) is a new resource food rich in α‐Linolenic Acid(ALA) (38.66%). The objective of this study was to assess the modulatory effect of PSO on lipid metabolism. Lard oil, safflower oil (SFO), and PSO were fed to wistar rats with 1% cholesterol in the diet for 60 d. Serum and liver lipids showed significant decrease in total cholesterol (TC), triglyceride (TG), and low density lipoprotein‐cholesterol (LDL‐C) levels in PSO fed rats compared to lard oil and SFO fed rats. ALA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), contents were significantly increased, whereas linoleic acid (LA), arachidonic acid (AA) levels decreased in serum and liver of PSO fed rats. Feeding PSO increased ALA level and decreased n‐6 to n‐3 polyunsaturated fatty acid (PUFA) ratio. The hypolipidemic result of PSO indicated that PSO participated in the regulation of plasma lipid concentration and cholesterol metabolism in liver. The decreased expression of sterol regulatory element‐binding proteins 1C (SREBP‐1c), acetyl‐CoA carboxylase (ACC), and fatty acid synthase (FAS)‐reduced lipid synthesis; Activation of peroxisome proliferator–activator receptor (PPARα) accompanied by increase of uncoupling protein2 (UP2) and acyl‐CoA oxidase (AOX) stimulated lipid metabolism and exerted an antiobesity effect via increasing energy expenditure for prevention of obesity.