Physicochemical properties of pectin-Fe(III) gained by HG-type hawthorn with different esterification degree.

In this study, the complexation ability of HG-type hawthorn pectin with trivalent iron ions after de-esterification was investigated. The moderate esterification reaction could significantly increase the iron content in HG-type hawthorn pectin. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) experiments proved that -OH and -COOH in the pectin acted as a bridge connecting Fe3+ leading to the formation of ß-FeOOH structure, and the trivalent iron ions were successfully complexed into the HG-type hawthorn pectin. In addition, infrared and ultraviolet spectroscopic scans, particle size, and potentiometric measurements were carried out to demonstrate the complexation coordination mechanism of hawthorn pectin with Fe3+, and there were differences in the complexation effect of HG-type hawthorn pectin with different degrees of esterification. The gelling properties of HG-type hawthorn pectin were subsequently verified by in vitro gastrointestinal tract simulation experiments to aid the smooth passage of ferric ions through the gastric juices and reduce irritation. The success of the experiments demonstrated that HG-type hawthorn pectin is an excellent raw material for metal complexation, and the degree of esterification is one of the important factors affecting its complexation effect, which proves its potential application value as an iron supplement.

Construction of a pectin/sodium alginate composite hydrogel delivery system for improving the bioaccessibility of phycocyanin.

In this study, different concentrations of sodium alginate were compounded with pectin and phycocyanin to co-prepare composite hydrogel spheres (HP-PC-SA 0.2 %, 0.6 %, 1.0 %, 1.4 %) to evaluate the potential of the composite hydrogel spheres for the application as phycocyanin delivery carriers. The hydrogel spheres' physicochemical properties and bioaccessibility were assessed through scanning electron microscopy, textural analysis, drug-carrying properties evaluation, and in vitro and in vivo controlled release analysis in the gastrointestinal environment. Results indicated that higher sodium alginate concentrations led to smaller pore sizes and denser networks on the surface of hydrogel spheres. The textural properties of hydrogel spheres improved, and their water-holding capacity increased from 93.01 % to 97.97 %. The HP-PC-SA (1.0 %) formulation achieved the highest encapsulation rate and drug loading capacity, at 96.87 % and 6.22 %, respectively. Within the gastrointestinal tract, the composite hydrogel's structure significantly enhanced and protected the phycocyanin's digestibility, achieving a bioaccessibility of up to 88.03 %. In conclusion, our findings offer new insights into improving functionality and the effective use of phycocyanin via pectin-based hydrogel spheres.

Ultrasonic-microwave technique promotes the physicochemical structure of hydrogel and its release characterization of curcumin in vitro.

In this study, soybean protein isolate and hawthorn pectin were mixed to prepare binary hydrogels using ultrasound and microwave techniques. Moderate treatment can not only significantly improve the mechanical strength of the hydrogel, but also increase the tightness of the internal cross-linking. The strengthening of interactions (hydrogen bonds, hydrophobic interactions, and disulfide bonds) was the main reason for this trend. Especially, the ultrasonic-microwave (80 s) treatment hydrogel possessed excellent hardness (33.426 N), water-holding capacity (98.26%), elasticity (G' = 1205 Pa), and a more homogeneous and denser microstructure. In addition, the hydrogel minimized the extent of curcumin loss (21.23%) after 5 weeks of storage. In general, the ultrasonic-microwave technique could significantly promote the physicochemical structure and curcumin bioaccessibility of hydrogels, which showed excellent market prospects in the food industry.

Characterization, antioxidant activity and in vitro digestion of hawthorn pectin prepared by gradient ethanol precipitation.

Four modified hawthorn pectin fractions (MHPs), named MHP-30, MHP-50, MHP-70 and MHP-90, were obtained by ultrasonic-assisted pectin methyl esterase modification and gradient ethanol precipitation. The results indicated that all four MHPs were composed of galacturonic acid, galactose, xylose, arabinose, glucose and mannose in different proportions. With the increase of the ethanol concentration, the molecular weight, esterification degree and galacturonic acid content of MHPs all decreased, whereas the arabinose content and branching degree increased. The structural characterization from XRD, SEM, and FT-IR showed that four MHPs exhibited amorphous structure, similar functional groups, diverse surface morphologies. Besides, in vitro antioxidant assays confirmed that MHP-70 and MHP-90 exhibited stronger total antioxidant activities than MHP-30 and MHP-50. The results of simulated saliva-gastrointestinal digestion showed that the molecular weight of MHP-70 and MHP-90 remained stable, yielded small amounts of reducing sugars, and were resistant to digestion in the human upper digestive tract. Overall, MHP-70 and MHP-90 shown great potential as novel natural antioxidants, which are expected to be good carbon sources for the utilization of intestinal microorganisms.

Hawthorn pectin/soybean isolate protein hydrogel bead as a promising ferrous ion-embedded delivery system.

In this study, hydrogel beads [SPI/HP-Fe (II)] were prepared by cross-linking soybean isolate protein (SPI) and hawthorn pectin (HP) with ferrous ions as a backbone, and the effects of ultrasound and Fe2+ concentration on the mechanical properties and the degree of cross-linking of internal molecules were investigated. The results of textural properties and water-holding capacity showed that moderate ultrasonic power and Fe2+ concentration significantly improved the stability and water-holding capacity of the hydrogel beads and enhanced the intermolecular interactions in the system. Scanning electron microscopy (SEM) confirmed that the hydrogel beads with 60% ultrasonic power and 8% Fe2+ concentration had a denser network. X-ray photoelectron spectroscopy (XPS) and atomic absorption experiments demonstrated that ferrous ions were successfully loaded into the hydrogel beads with an encapsulation efficiency of 82.5%. In addition, in vitro, simulated digestion experiments were performed to understand how the encapsulated Fe2+ is released from the hydrogel beads, absorbed, and utilized in the gastrointestinal environment. The success of the experiments demonstrated that the hydrogel beads were able to withstand harsh environments, ensuring the bioactivity of Fe2+ and improving its bioavailability. In conclusion, a novel and efficient ferrous ion delivery system was developed using SPI and HP, demonstrating the potential application of SPI/HP-Fe (II) hydrogel beads as an iron supplement to overcome the inefficiency of intake of conventional iron supplements.

Effect of ultrasonic pretreatment on fermentation performance and quality of fermented hawthorn pulp by lactic acid bacteria.

In order to explore the effects of ultrasonic pretreatment on the fermentation performance and quality characteristics of fermented hawthorn pulp. Five types of fermented hawthorn pulp were obtained using 0 W for 5 min, 300 W for 5 min, 360 W for 5 min, 420 W for 5 min, 540 W for 5 min. The fermentation performance and quality of fermented hawthorn pulp were characterized. The results indicated Low power ultrasound (360 W) could improve the fermentation performance and quality of FHP, and high power ultrasound (540 W) could reduce the fermentation performance and quality. Under the ultrasonic condition of 360 W for 5 min; the cell membrane of lactic acid bacteria produced repairable damage and the morphology did not change significantly, the consumption of reducing sugar, total acid, soluble solids, amino nitrogen, conductivity, and sensory quality of the fermented hawthorn pulp reached the highest. The fermentation performance and quality of fermented hawthorn pulp were improved by the optimum ultrasonic treatment, which could be used as an effective and alternative method for producing FHP with good flavor, high bioactivity and good quality.

Physicochemical properties and Pb2+ adsorption capacity of freeze-dried hawthorn pectin fractions by gradient ethanol precipitation.

Three fractions of FHP20, FHP40 and FHP60 were obtained from freeze-dried hawthorn pectin by gradient ethanol precipitation (20-60 %), and their physicochemical properties and adsorption performance on Pb2+ were investigated. It was found that the content of galacturonic acid (GalA) and esterification of FHP fractions gradually reduced with the increase of ethanol concentration. FHP60 had the lowest molecular weight (60.69 × 103 Da), and the composition and proportion of monosaccharides were significantly different. The experimental results of Pb2+ adsorption showed that the adsorption process fitted well with the Langmuir monolayer adsorption and the pseudo-second-order models. Our findings suggested that pectin fractions with good homogeneity of molecular weight and chemical construction can be obtained by gradient ethanol precipitation, and hawthorn pectin could be developed as a potential adsorbent for Pb2+ removal.

Characterization of hawthorn pectin gained via different ethanol concentrations.

Pectin is identified as an effective delivery material due to its excellent gel-forming ability, low immunogenic properties, biocompatibility, and biodegradability. These excellent properties depend on the preparation method of pectin. In the study, four pectin fractions (named: CAHP30, CAHP40, CAHP50, and CAHP60, respectively) were obtained by different ethanol precipitations (30%, 40%, 50%, and 60%). Physicochemical properties, antioxidant activity, and emulsifying ability of HP were investigated and analyzed. Results showed that the surface structure of pectin was changed by ethanol fractional precipitation, and four fractions were low methoxy pectin. They had different monosaccharide compositions, but all rich in GalA. The Mw/Mn of CAHP30, CAHP40, CAHP50, and CAHP60 were 3.29, 2.57, 2.66, and 2.77, respectively. CAHP30 and CAHP60 had excellent emulsifying ability; moreover, CAHP60 was endowed with additional lipid antioxidant capacity and had the best thermal stability. E-CAHP40 exhibited a property between the entangled network structure. Overall, pectin with specific properties could be obtained by different ethanol concentrations.

Effect of different processing methods of hawthorn on the properties and emulsification performance of hawthorn pectin.

Five types of hawthorns were obtained using hot air drying (HH), vacuum freeze-drying (FH), Parched processing (PH), Charred processing (CH), and blackening (BH). Five types of pectins (HHP, FHP, PHP, CHP, BHP) were extracted and characterized based on a series of characterization methods. The results indicated that the esterification and molecular weight of BHP were the lowest, which were 30.92 % and 73.67 × 103 (g/mol), respectively. FHP had the highest apparent viscosity and molecular weight (464.42 × 103 g/mol). PHP and CHP differ in galacturonic acid, molecular weight, and monosaccharide composition depending on the time of processing. The emulsion of HHP had the best stability, and the emulsification properties of FHP, PHP, and CHP also showed better performance compared to BHP. In conclusion, our results showed that different processing methods of hawthorn affected the physicochemical properties of pectin, and pectin with specific properties could be obtained by choosing the appropriate processing method.

Encapsulation and sustained release of curcumin by hawthorn pectin and Tenebrio Molitor protein composite hydrogel.

In this study, the effects of pH value, mixing ratio and the Ca2+ concentration on the complex gelation of hawthorn pectin (HP) and Tenebrio Molitor protein (TMP) were investigated. The turbidity results showed that the composite gel had the maximum polymer concentration when the mixing ratio was 2:1 and the pH value was 3.35. The rheological measurement results showed that TMP/HP (15 mmol/L) hydrogel (THIH) had the highest storage modulus and loss modulus, indicating that the properties of the hydrogel at this Ca2+ concentration had been significantly improved. The results of scanning electron microscope and pore size also proved that the network structure prepared under this condition was compact and uniform, the pore size was small, which was beneficial to the entrapment of active components. Subsequently, in order to explore the storage stability and antioxidant activity of THIH-loaded curcumin in simulated gastrointestinal environment, in vitro simulated digestion experiment was carried out and satisfactory results were obtained. To sum up, THIH was a promising delivery system with broad application prospects, which was expected to provide a novel idea for the entrapment and delivery of active components.

Comparative study of HG-type low-ester hawthorn pectin as a promising material for the preparation of hydrogel.

Homogalacturonan (HG)-type pectin has been considered suitable for the formation of hydrogel, but it is unknown whether the less side chain will limit the properties of hydrogel. The current study successfully obtained low methoxyl HG-type hawthorn pectin (LMHP) from hawthorn by sequential hot water extraction and alkaline de-esterification. The proportion of HG domain, the proportion of rhamnogalacturonan-I (RG-I) domain, molecular weight, and particle size of LMHP were 81.13 %, 4.04 %, 348.43 kDa, and 1386.92 nm, respectively. Compared with commercial citrus pectin (CP), LMHP was more suitable for the preparation of hydrogel. The hydrogel with the densest network structure and relatively stable performance in digestion simulation environment can be obtained as the concentration of LMHP increases to 2.5 %, which is lower than the consumption of commercial citrus pectin. Overall, these findings highlight the potential of hawthorn pectin as a novel hydrogel raw material.

Synthesis, physicochemical characterization, antibacterial activity, and biocompatibility of quaternized hawthorn pectin.

Quaternized polysaccharides are considered as potential antimicrobial materials due to their antimicrobial activity, biodegradability, biocompatibility, and water solubility. In this work, hawthorn pectin (HP) was obtained by ultrasound­sodium citrate assisted extraction, quaternized hawthorn pectin (QHP) derivatives (namely: QHP-1, QHP-2, QHP-3, and QHP-4) with different degree of substitution were produced using (3-Chloro-2-hydroxypropyl) trimethylammonium chloride under alkaline conditions. The structure, properties, and morphology of HP and QHP were characterized by FTIR, XRD, 1H NMR, high-performance gel permeation chromatography (HPGPC), thermal analysis, and SEM. The results of FTIR and 1H NMR demonstrated that the quaternary ammonium modification was successful, and the degree of substitution (DS) of derivatives was calculated through elemental analysis. The determination of the minimum inhibitory concentrations and biofilm inhibition assay exhibited that QHP has a certain inhibitory effect on Escherichia coli and Staphylococcus aureus. Acceptable values of QHP were obtained in cytotoxicity assay on human keratinocytes.

Characterization of edible film fabricated with HG-type hawthorn pectin gained using different extraction methods.

In this study, four HG-type pectins were obtained using hydrochloric acid extraction (HA-HP), citric acid extraction (CA-HP), ultrasonic-assisted extraction (UA-HP), and microwave-assisted extraction (MA-HP). Four pectin films (HA-HPF, CA-HPF, UA-HPF, and MA-HPF) were prepared by a solution casting method, respectively. Compared to four pectins, the asymmetric COO - vibrational peak of UA-HPF, HA-HPF, and CA-HPF were blue-shifted (1604-1606 cm-1), while was red-shifted (1611 cm-1) in MA-HPF. The crystallinity was greater for HA-HPF and CA-HPF than UA-HPF and MA-HPF. Four pectin films all had relatively homogeneous surface morphology. CA-HPF had the best mechanical properties and oxygen barrier performance, HA-HPF had the best transparency. UA-HPF had the lowest hydrophilicity and water vapor permeability. MA-HPF had the best thermal stability. Our study shows that different physicochemical properties of HG-type pectins can influence the physicochemical properties of films. The difference of these properties gives the resulting film different possibilities for application.

Physicochemical properties and antioxidant activity of pectin from hawthorn wine pomace: A comparison of different extraction methods.

In the paper, to enhance the value and utilization rate of hawthorn wine pomace waste, four kinds of pectin were gained from hawthorn wine pomace by hydrochloric acid method (HA-HP), citric acid method (CA-HP), cellulase method (E-HP) and microwave-assisted chelating agent method (MH-HP). The physical and chemical properties of extracted hawthorn pectin were analyzed, however, different extraction methods lead to different characteristics of extracted pectin samples. We found that the extracted hawthorn pectin was all low-methoxy pectin, and the highest extraction yield of 72.89% with high ash (9.20%) was obtained by the MH-HP method, while the galacturonic acid (Gal A) content was up to 72.24% after dealing with the CA-HP method which was the highest among the four samples, besides, the quality of gel formed by E-HP method was the best. What's more, the four extracted samples all reveled degrees of antioxidant activity with dose-dependent in vitro antioxidant, and it was CA-HP method had the best antioxidant activity, making this the first comprehensive research describing the extracting pectin from hawthorn wine pomace. This research also provides a base for industrial production of high-value products from low-cost raw materials.

Effect of ultrasound on the properties and antioxidant activity of hawthorn pectin.

In this paper, the effects of ultrasonic on the degradation kinetics, structure properties, and antioxidant activity of hawthorn pectin were studied. According to our study, as ultrasonic time extended, the intrinsic viscosity for different hawthorn pectin concentrations decreased. The ultrasonic degradation of hawthorn pectin reaction conformed to the first-order kinetic equation. As the reaction rate constant (k) decreased, hawthorn pectin concentration increased. When ultrasonic time was 10 min, the Gal A increased by 10.62% and the DE decreased by 45.57% compared with control, additionally, the particle size, turbidity and gel properties of hawthorn pectin decreased. Hawthorn pectin molecular weight and its distribution all decreased after ultrasonic treatment. FTIR analysis indicated that ultrasonic treatment did not change pectin's primary structures, and SEM analysis showed that the surface characteristic of ultrasonic treatment pectin was different from native pectin. Moreover, in vitro antioxidant activity assays indicated that ultrasonic treatment significantly improved the antioxidant activity of pectin. It was concluded that ultrasonic treatment not only affected the properties of pectin, but also affected its antioxidant activity.

The Preparation of Cyclic Butylene Terephthalate Fibers with Novel Morphology Based on Melt Electrospinning.

Electrospinning of low molecular weight compounds is relatively under-investigated compared to that of polymers. In this paper, cyclic butylene terephthalate oligomers (CBT) were fabricated into a novel fiber structure without any carrier polymer or template via melt electrospinning technique. The electrospun CBT fibers were prepared at 190 °C and characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). SEM images of the CBT fibers showed that they had a mean diameter of 1.8-2.6 µm. In contrast to most electrospun fibers, the CBT electrospun fibers were discontinuous and exhibited a rod-like morphology with an average length of 6.8-7.1 µm. This kind of morphology is rare in products made by electrospinning or electrospraying. In addition, the fiber morphology was not significantly affected by varying the preparation parameters, such as by collection distance or electric voltage value. FTIR and DSC results showed that CBT structure was not changed in the preparation process, but the degree of polymerization of CBT may be changed because of transesterification reaction. Furthermore, the formation mechanism of the discontinuous fibers was also discussed in this work.

The effect of ultrasound on the properties and conformation of glucoamylase.

In this study, the effects of ultrasonic treatment on the enzyme activity of glucoamylase were investigated and the mechanism of the effect was explored by determining their conformational changes. The enzyme activity was increased by 21.07% over the control with ultrasound at 420W for 10min at 60°C, and Vmax and Km values of glucoamylase were also increased. After ultrasonic treatment at 420W, thermodynamic experiments of glucoamylase showed that Ea, ΔG, ΔH decreased but slight increase in ΔS was observed. In addition, after the treatment, the UV spectra showed that the number of tryptophan and tyrosine on glucoamylase surface increased, and the contents of α-helix and random coil increased by 17.8%, 12.41%, respectively, through the circular dichroism spectrum scanning. Besides, fluorescence spectra indicated that the absorption of tryptophan has a red shift. Furthermore, fourier transform infrared spectra suggested that the glucoamylase was significantly influenced by ultrasound. The results indicated that the activity of glucoamylase could be modified by ultrasonic treatment mainly in terms of the variation of their conformation.

Effect of ultrasound pretreatment on enzymolysis and physicochemical properties of corn starch.

In the paper, the effects of ultrasound on the enzymolysis properties of corn starch were investigated. The results showed that the rate of enzymolysis changed with the change of ultrasonic conditions. Ultrasound pretreatment starches reduced the time in liquefaction process, and resulted in significantly higher DE value in saccharification process. DE value was negatively correlated to PV, BV, SV, To, Tp, ΔHg, DO, DD, N-O'KI, RC, Mw and DP, respectively, and positively correlated to Mw/Mn. X-ray diffraction analysis showed that the relative crystallinity was reduced, and the starch exhibited an A-pattern. Scanning electron microscope indicated that the notch and groove appeared on the surfaces of starch granules. The polarized cross of starch becomes smaller or even disappear. It was concluded that enzymolysis efficiency of different ultrasound pretreatment to changes due to its effect not only on the physicochemical properties, but also on the structural characteristics of corn starch.

Optimization of ultrasound-assisted extraction (UAE) of flavonoids compounds (FC) from hawthorn seed (HS).

Hawthorn seed (HS), an important by-product of the Hawthorn industry, is rich in potentially health-promoting flavonoids compounds. In this paper, the ultrasound-assisted extraction (UAE) of FC from HS was investigated. Important variables and their levels were obtained using Plackett-Burman (PB) design and Box-Behnken (BB) design. A mathematical model was developed to show the effects of each variable and their combinatorial interactions on extraction yield of FC. A high coefficient of determination (R(2) = 91.26%) indicated good agreement between the experimental and predicted values of FC yield. The optimum levels of these significant parameters were determined using response surface methodology (RSM), which revealed these as follows: ultrasound temperature 65 °C, ultrasonic time 37 min, extraction temperature 91 °C, extraction time 1.5h, solid-liquid ratio of 1:18, and 72% ethanol. Under the optimum condition, the UAE rate of FC was up to 91.7%, and the yield of FC was 16.45 ± 0.02 mg/g (P<0.05) that was 1.32-fold the yield of conventional reflux extraction (CRE).

Effects of aqueous chlorine dioxide treatment on nutritional components and shelf-life of mulberry fruit (Morus alba L.).

Effects of aqueous chlorine dioxide (ClO(2)) treatment on nutritional components and shelf-life of mulberry fruit (Morus alba L.) were investigated. Mulberry fruit were immersed into 20, 60, and 80 mg/l ClO(2) solutions for 5, 10, and 15 min, respectively. Mulberries were then rinsed with potable tap water for 1 min and stored at -1°C for 14 d. ClO(2) treatment was effective in retention of flavonoid, ascorbic acid, reducing sugar, and titratable acid. ClO(2) concentration and treatment time were significant factors affecting ClO(2) treatment. The shelf-life of the samples treated by 60 mg/l ClO(2) for 15 min was extended to 14 d compared to 8 d for the control. No ClO(2), ClO(2)(-), or ClO(3)(-) residues were detected in samples treated by 60 mg/l ClO(2) for 15 min. These results indicated that ClO(2) treatment was a promising approach to preserve mulberry fruit with no significant risks of chemical residues.