Effect of ultrasonic modification on the binding ability of pectin to anthocyanin.

BACKGROUND: Pectin was considered as a potential candidate to improve the thermal stability of anthocyanins, and the binding ability of pectin to anthocyanins was influenced by its structure. In this study, sunflower pectins, modified by ultrasound (40 kHz) for different periods of time, were prepared and used to bind with anthocyanins, extracted from purple sweet potato. RESULTS: Characterization and thermal stability of pectin-anthocyanin complexes were investigated. The ultrasonic modification of pectin resulted in many changes in pectin chemical structure, including degradation of neutral sugar side chains, breakage of methoxyl groups, and increased molecular flexibility. Extension of ultrasonic modification time led to greater changes in pectin chemical structure. Analysis of the binding ability, as determined by Fourier transform infrared spectroscopy and molecular dynamics simulations, revealed that the interaction between pectin and anthocyanins was driven by hydrogen bonding, electrostatic interaction, and hydrophobic interaction. Pectins with different ultrasonic modification times bound with anthocyanins to different extents, mainly resulting from an increase in the number of hydrogen bonds. According to high-performance liquid chromatographic analysis, during heating at 90 °C the stronger the binding ability of pectin and anthocyanin complex, the better was its thermal stability. CONCLUSION: Ultrasonic modification of pectin could effectively enhance its binding ability to anthocyanin. © 2023 Society of Chemical Industry.

Effects of sunflower pectin on thermal stability of purple sweet potato anthocyanins at different pH.

The present study aimed to examine the impact of sunflower pectin (SFP) on the thermal stability and antioxidant activity of purple sweet potato anthocyanins (PSPA) at varying pH levels. It was observed that the pH value significantly influenced the ability of pectin to protect anthocyanins from thermal degradation, which was found to be associated with the rate of binding between PSPA and SFP. The binding rate of PSPA-SFP was observed to be highest at pH 4.0, primarily due to the influence of electrostatic interaction and hydrogen bonding. Monoacylated anthocyanins exhibited a binding rate approximately 2-4 % higher than that of diacylated anthocyanins. The PSPA-SFP demonstrated its highest thermal stability at pH 4.0, with a corresponding half-life of 14.80 h at 100 °C. Molecular dynamics simulations indicated that pectin had a greater affinity for the flavylium cation and hemiketal form of anthocyanins. The antioxidant activity of anthocyanins in PSPA and PSPA-SFP increased with increasing pH, suggesting that anthocyanins at high pH had higher antioxidant activity than anthocyanins at low pH.

Effects of organic and inorganic nitrogen sources on the transcriptome of gellan gum biosynthesis by Sphingomonas paucimobilis.

AIM: Investigate the effects of different nitrogen sources on the metabolic characteristics of Sphingomonas paucimobilis during gellan gum (GG) production was helpful for developing optimized conditions that are widely applicable to all GG production processes. METHODS AND RESULTS: We compared the effects of organic nitrogen (ON) and inorganic nitrogen (IN) sources during GG production using transcriptome sequencing. Our results showed that compared with the IN source, the ON source effectively improved the cell number and GG production of S. paucimobilis during fermentation. There were significant differences in gene transcription levels between the ON and IN groups at different fermentation times. CONCLUSIONS: The transcriptional levels of multiple genes in the pathways from α-D-glucose-1P to glyceraldehyde-3P were reduced in the ON group, whereas those of multiple genes in the pathways from glyceraldehyde-3P to acetyl-CoA were significantly enhanced in the ON group after 12 h of fermentation. The transcription levels of multiple genes participating in the citrate cycle and upstream of fatty acid metabolism pathways were significantly enhanced in the ON group after 12 h of fermentation. Except for the transcripts per million (TPMs) of pgm and rfbA genes in ON, which were significantly higher than those in IN at 12 h after fermentation, the TPMs of the majority of genes in ON were significantly lower than those in IN. The transcription levels of genes participating in the transformation of N-acetyl-D-glucosamine (GlcNAc) to UDP-N-acetyl-alpha-D-glucosamine (UDP-GlcNAc) were enhanced in the ON group during the fermentation process.

Effects of different re-fermentation methods on the quality characteristics of kombucha beverages.

The effects of different re-fermentation methods on the quality characteristics of kombucha beverages were investigated. The quality characteristics of kombucha beverages included the basic physicochemical indicators (pH, total acidity, reducing sugar, total sugar, organic acids, total phenolic compound, total flavonoid compound), antioxidant activity, volatile flavor substance and sensory evaluation of the beverages. The results showed the re-fermentation methods including the mixed fermentation and the step-by-step fermentation significantly decreased total acidity and various organic acids (P < 0.05) than traditional kombucha with no re-fermentation. In addition, the contents of total phenol compounds and total flavonoid compounds for the step-by-step fermentation were 184.70 and 338.33 mg/L respectively, and were higher compared with mixed fermentation and traditional kombucha with no re-fermentation. The antioxidant activity in the step-by-step fermentation was much stronger than that of mixed fermentation and traditional kombucha with no re-fermentation. Moreover, there were 53 kinds of volatile flavor compounds produced in the step-by-step fermentation, 14 of them were unique with good sensory quality. In conclusion, the re-fermentation methods for traditional kombucha (the step-by-step fermentation and mixed fermentation) had more active ingredients and better sensory quality, and the step-by-step fermentation was better than mixed fermentation.

Recent advances of octenyl succinic anhydride modified polysaccharides as wall materials for nano-encapsulation of hydrophobic bioactive compounds.

Polysaccharides can be esterified with octenyl succinic anhydride (OSA) to form derivatives with amphiphilic properties. The general preparation methods of OSA-polysaccharides are described, especially the aqueous method. The new hydrophobic groups introduced result in OSA-polysaccharides showing higher interfacial properties, better emulsifying stability, higher viscosity, and lower digestibility. There have been advances in the development of OSA-polysaccharides-based nano-encapsulation systems for hydrophobic bioactive compounds in recent years. Nano-encapsulation systems are formed through nanoemulsions, nanocapsules, nanoparticles, micelles, vesicles, molecular inclusion complexes, and so on. This review aims to describe the preparation methods, the structure characterizations, and the physicochemical properties of OSA-polysaccharides as encapsulating agents. In addition, the focus is on the different nano-encapsulation systems based on OSA-polysaccharides as wall materials. Future perspectives will concern OSA-polysaccharides-based nano-encapsulation systems with optimized functional properties for providing higher bioavailability and targeted delivery of various hydrophobic bioactive compounds. © 2022 Society of Chemical Industry.

Effect of optimal-water boiling cooking on the volatile compounds in 26 Japonica rice varieties from China.

The aim of this study was to scientifically investigate the impact of optimal-water boiling cooking on the volatile profile of 26 japonica rice varieties. A modified direct solvent extraction combined with gas chromatography-mass spectrometry was applied to analyze the volatiles in raw and cooked samples. 2-Acetyl-1-pyrroline (2AP) was only detected in aromatic varieties and decreased after cooking (-81.94% - -43.97%). Great losses of esters and long-chain ketones were exhibited after cooking. Cooking accelerated lipid oxidation and degradation of phenolic acids, thus volatiles originate from lipid oxidation and several benzenoid compounds showed increase trends in majority of the samples. Increases of 3 saturated aldehydes including hexanal (48.01% - 306.02%), octanal and nonanal (67.03% - 544.15%) could be observed in all samples. Acetophenone, 2-methoxy-4-vinylphenol (11.95% - 297.61%) and vanillin (14.29% - 319.25%) were also enhanced upon cooking. Correlations existed in volatiles with common precursors or involved in same pathways. According to multivariate and univariate statistical analysis, 18 volatiles most greatly influenced by cooking were selected. This study will facilitate the aroma improvement of cooked rice in the future.

A comparative HS-SPME/GC-MS-based metabolomics approach for discriminating selected japonica rice varieties from different regions of China in raw and cooked form.

Japonica rice is widely planted in different regions of China. Rice of different geographical origins may have substantially different economic values. In this study, An untargeted metabolomics based approach using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME/GC-MS) was applied to distinguish 27 japonica rice varieties originated from South, Northern and Northeastern China in raw and cooked form, respectively. Orthogonal partial least-squares discriminant analysis (OPLS-DA) models exhibited good geographic discrimination. Sixteen and twenty-two volatiles were selected as the discriminant markers in raw and cooked rice, respectively. However, only hexanal, 3,5-octadien-2-one and 2-butyl-2-octenal were selected both in raw and cooked rice. Markers in raw rice mainly involved in terpenes, lipoxygenases, indole, and shikimate and benzoic acid pathways. Markers in cooked rice were mainly derived from lipid oxidation. The results provided a deeper understanding of volatiles variation of rice in China from different geographic origins.

Fabrication and characterization of octenyl succinic anhydride modified pullulan micelles for encapsulating curcumin.

BACKGROUND: Curcumin has become increasingly popular in functional foods and beverages field as a result of its high biological activity. Nevertheless, the application of curcumin is usually limited by its poor water solubility, low absorption, rapid metabolism and instability. Accordingly, the development of an appropriate wall material is crucial for its effective use. In the present study, curcumin-octenyl succinic anhydride modified pullulan (Cur-OSAP) micelles were successfully prepared by an anti-solvent co-precipitation method. RESULTS: Octenyl succinic anhydride modified pullulan (OSAP) micelles exhibited the highest encapsulation efficiency (57.31%) and loading capacity (5.73%) of curcumin when the mass ratio of OSAP to curcumin was 10:1 and the degree of substitution of OSAP was 0.0469, at which point Cur-OSAP micelles formed via hydrogen binding and hydrophobic interactions, as confirmed by Fourier transform infrared and fluorescence techniques. The transmission electron microscopy results showed that the Cur-OSAP micelles were roughly spherical in shape with diameters in the approximate range 30-60 nm. CONCLUSION: The encapsulation of OSAP greatly improved photostability and sustained release properties of curcumin in Cur-OSAP micelles. These findings suggest that OSAP can be used as a carrier to encapsulate and protect hydrophobic food ingredients. © 2021 Society of Chemical Industry.

Influence of diverse natural biopolymers on the physicochemical characteristics of borage seed oil-peppermint oil loaded W/O/W nanoemulsions entrapped with lycopene.

Borage seed oil (BSO), peppermint oil (PO) and lycopene (LC) have accomplished a lot of interest due to their therapeutic benefits in the food and pharmaceutical sectors. However, their employment in functional food products and dietary supplements is still precluded by their high susceptibility to oxidation. Thus, the encapsulation can be applied as a promising strategy to overcome these limits. In the present study, doubly layered water/oil/water (W/O/W) nanoemulsions were equipped using purity gum ultra (PGU), soy protein isolate (SPI), pectin (PC), whey protein isolate (WPI) and WPI-PC and SPI-PC complexes, and their physico-chemical properties were investigated. Our aim was to investigate the influence of natural biopolymers as stabilizers on the physicochemical properties of nanoemulsified BSO, PO and lycopene thru W/O/W emulsions. The droplet size of the fabricated emulsions coated with PGU, WPI, SPI, PC, WPI-PC, and SPI-PC was 156.2, 265.9, 254.7, 168.5, 559.5 and 656.1 nm, correspondingly. The encapsulation efficiency of the entrapped bioactives for powders embedded by PGU, WPI, SPI, PC, WPI-PC, and SPI-PC was 95.21%, 94.67%, 97.24%, 92.19%, 90.07% and 92.34%, respectively. In addition, peroxide and p-anisidine values were used to measure the antioxidant potential of the entrapped bioactive compounds during storage, which was compared to synthetic antioxidant and bare natural antioxidant. The collected findings revealed that oxidation occurred in oils encompassing entrapped bioactive compounds, but at a lower extent than for non-encapsulated bioactives. In summary, the findings obtained from current research prove that the nanoencapsulation of BSO surrounded by innermost aqueous stage of W/O/W improved its stability as well as allowed a controlled release of the entrapped bioactives. Thus, the obtained BSO-PO-based systems could be successfully used for further fortification of food-stuffs.

Spray dried nanoemulsions loaded with curcumin, resveratrol, and borage seed oil: The role of two different modified starches as encapsulating materials.

Recently, food industries are directing on the promotion of innovative food matrices fortified with bioactive compounds in order to enhance the consumer's health. Octenyl succinic anhydride modified starches (OSA-MS) such as Hi-cap100 (HCP) and purity gum 2000 (PUG) were used to fabricate emulsions co-entrapped with borage seed oil (BSO), resveratrol (RES) and curcumin (CUR), which were further spray dried to obtain powders. The fabricated microcapsules loaded with BSO, RES, and CUR displayed excellent dissolution performance, high encapsulation efficiency (≈93.05%) as well as semi-spherical shape, revealed via scanning electron microscopy (SEM). We also evaluated the impact of storage time (4 weeks) and temperature (40 °C) on the physicochemical characterization of OSA-MS coated microcapsules. Microcapsules coated with HCP exhibited greater oxidative stability, lower water activity and moisture contents rather than PUG coated microcapsules during storage because of its good film-forming properties. Addition of CUR enhanced the oxidative stability and retention of bioactive compounds. HCP microcapsules loaded with BSO + RES + CUR presented supreme retention of RES (70.32%), CUR 81.6% and γ-linolenic acid (≈ 96%). Our findings showed that CUR acted as an antioxidant agent; also, lower molecular weight OSA-MS as wall material could be used for the entrapment of bioactive compounds and promotion of innovative food products.

Emulsifying properties and structure characteristics of octenyl succinic anhydride-modified pullulans with different degree of substitution.

Pullulan was successfully esterified with octenyl succinic anhydride (OSA) in aqueous alkaline solutions. The degree of substitution (DS) was regulated from 0.0163, 0.0346 to 0.0469 by changing the OSA concentration (3.0%, 6.0% and 9.0%, respectively). Meanwhile, the weight-average molecular weight (Mw) of OSA-pullulans varied from 2.050 × 105, 2.113 × 105 to 2.124 × 105. The chemical structures of OSA-pullulans were characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H NMR), which indicated that OSA groups were successfully grafted into pullulan. The surface tension, interfacial tension and droplet size of the emulsions stabilized by OSA-pullulans significantly reduced with the increase of DS. Furthermore, the emulsion stability (ES) and viscosity dramatically increased with DS compared with those of emulsion stabilized by pullulan. These results indicated emulsifying properties of OSA-pullulans were improved by increasing DS. Additionally, OSA-pullulans had excellent emulsion stability when DS was higher than 0.0346.

Drug nanodelivery systems based on natural polysaccharides against different diseases.

Drug nanodelivery systems (DNDSs) are fascinated cargos to achieve outstanding therapeutic results of various drugs or natural bioactive compounds owing to their unique structures. The efficiency of several pharmaceutical drugs or natural bioactive ingredients is restricted because of their week bioavailability, poor bioaccessibility and pharmacokinetics after orally pathways. In order to handle such constraints, usage of native/natural polysaccharides (NPLS) in fabrication of DNDSs has gained more popularity in the arena of nanotechnology for controlled drug delivery to enhance safety, biocompatibility, better retention time, bioavailability, lower toxicity and enhanced permeability. The main commonly used NPLS in nanoencapsulation systems include chitosan, pectin, alginates, cellulose, starches, and gums recognized as potential materials for fabrication of cargos. Herein, this review is centered on different polysaccharide-based nanocarriers including nanoemulsions, nanohydrogels, nanoliposomes, nanoparticles and nanofibers, which have already served as encouraging candidates for entrapment of therapeutic drugs as well as for their sustained controlled release. Furthermore, the current article explicitly offers comprehensive details regarding application of NPLS-based nanocarriers encapsulating several drugs intended for the handling of numerous disorders, including diabetes, cancer, HIV, malaria, cardiovascular and respiratory as well as skin diseases.

Role of peppermint oil in improving the oxidative stability and antioxidant capacity of borage seed oil-loaded nanoemulsions fabricated by modified starch.

Borage seed oil (BSO) is one of the richest sources of γ-linolenic acid and linoleic acid, which are considered to retain plenty of health promoting benefits. However, its application in functional foods and dietary supplements remains limited owing to its superior vulnerability to oxidation. To solve this problem, ultrasound-assisted BSO-loaded nanoemulsions were prepared with modified starch incorporating different concentrations of peppermint oil (PO), as a natural antioxidant. The influence of different PO levels on the mean droplet size, rheology attributes, and oxidative stability of nanoemulsions stored at various temperatures (4, 25, and 40 °C) during 30 days storage was analyzed. In addition, DPPH and ABTS assays were used to determine the antioxidant activity and antioxidant capacity of BSO-loaded nanoemulsions, respectively. The optimized formulation (NE3; 5:5% v/v PO: BSO) exhibited a slight change in droplet size and oxidative stability at all temperatures during storage compared to other formulations. At a concentration of 328.08 µL/mL, formulation NE3 presented the minimum DPPH IC50 at 40 °C, which was lower than other formulations. The findings of this study revealed that the maximum retained antioxidant capacity (99.42 µg Trolox/mL) was related to NE3 comprising (5:5% v/v PO: BSO) stored at 40 °C for 30 days; which could be accredited to the role of PO as a natural antioxidant in order to improve the oxidative stability of nanoemulsion delivery system. Taken together, co-encapsulation of BSO and PO within nanoemulsions provides novel insights regarding the development of functional foods, dietary supplements and beverages.

The mechanism of improved gellan gum production by two-stage culture of Sphingomonas paucimobilis.

A two-stage culture (with controlled sucrose concentrations and temperatures) of Sphingomonas paucimobilis for gellan gum production has been previously investigated. Herein, the mechanism of a two-stage culture favoring gellan gum overproduction was revealed by analysing the cell-membrane permeability and the proteomics for gellan gum biosynthesis. The two-stage culture, resulted in 79.8% increased content of unsaturated fatty acids, and 3.95% increased ratio of unsaturated to saturated fatty acids in the cell membrane. Moreover, cell membrane permeability increased and thus further enhanced gellan gum biosynthesis. Proteomic analysis results indicated that 13 identified protein spots were involved in energy generation, glycogen biosynthesis, and glycolysis. These findings revealed that two-stage culture impellel carbon flux flow toward gellan gum biosynthesis.

Carotenoid-loaded nanocarriers: A comprehensive review.

Carotenoids retain plenty of health benefits and attracting much attention recently, but they have less resistance to processing stresses, easily oxidized and chemically unstable. Additionally, their application in food and pharmaceuticals are restricted due to some limitations such as poor bioavailability, less solubility and quick release. Nanoencapsulation techniques can be used to protect the carotenoids and to uphold their original characteristics during processing, storage and digestion, improve their physiochemical properties and enhance their health promoting effects. The importance of nanocarriers in foods and pharmaceuticals cannot be denied. This review comprehensively covers recent advances in nanoencapsulation of carotenoids with biopolymeric nanocarriers (polysaccharides and proteins), and lipid-based nanocarriers, their functionalities, aptness and innovative developments in preparation strategies. Furthermore, the present state of the art encapsulation of different carotenoids via biopolymeric and lipid-based nanocarriers have been enclosed and tabulated well. Nanoencapsulation has a vast range of applications for protection of carotenoids. Polysaccharides in combination with different proteins can offer a great avenue to achieve the desired formulation for encapsulation of carotenoids by using different nanoencapsulation strategies. In terms of lipid based nanocarriers, solid lipid nanoparticles and nanostructure lipid carriers are proving as the encouraging candidates for entrapment of carotenoids. Additionally, nanoliposomes and nanoemulsion are also promising and novel-vehicles for the protection of carotenoids against challenging aspects as well as offering an effectual controlled release on the targeted sites. In the future, further studies could be conducted for exploring the application of nanoencapsulated systems in food and gastrointestinal tract (GIT) for industrial applications.

Effect of nano-TiO2 on the physical, mechanical and optical properties of pullulan film.

In this study, effects of nano-TiO2 on the microstructural, physical, mechanical and optical properties of pullulan films were investigated. The results showed that the addition of nano-TiO2 improved the water vapor barrier properties of the film due to the tortuous path formed by nano-TiO2. When the concentration of nano-TiO2 was 0.04 g/100 mL, the tensile strength of the film showed a maximum value (15.99 MPa). The elongation at break of the film continued to decrease with the increase of nano-TiO2. The TEM analysis showed that higher concentration of nano-TiO2 would cause greater aggregation. Meanwhile, the results of FTIR and low-field NMR indicated that the miscibility between pullulan and nano-TiO2 was due to the formation of intermolecular hydrogen bonds during film formation. Furthermore, the addition of nano-TiO2 significantly improved the film barrier properties to ultraviolet light.

Effect of 2-deoxy-D-glucose on gellan gum biosynthesis by Sphingomonas paucimobilis.

2-Deoxy-D-glucose (2-DG) is a non-metabolizable glucose analogue and competitive inhibitor of glycolysis. Effect of 2-DG on gellan gum biosynthesis by Sphingomonas paucimobilis ATCC31461 were studied in this research. The concentration and the addition time of 2-DG significantly affected the biomass and gellan gum accumulation. The maximum gellan gum yield of 20.78 g/L was obtained with the addition of 50 µg/L of 2-DG at 24 h. The mechanism of 2-DG addition favoring to gellan production was revealed by determining the activities of key enzymes. Results indicated that 2-DG addition increased the activities of glucosyltransferase and inhibited UDP-glucose pyrophosphorylase activity. The result indicated that 2-DG inhibited glycolysis and changed metabolic driving force to activate gellan gum biosynthesis metabolism pathways.

Effects of konjac glucomannan and acetylated distarch phosphate on the gel properties of pork meat myofibrillar proteins.

The effects of konjac glucomannan (KGM) and acetylated distarch phosphate (ADSP) on properties of pork meat myofibrillar protein (MP) were investigated using rotary rheometer, colorimeter, texture analyzer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM). The addition of KGM and ADSP resulted in increase in both storage modulus (G') and water holding capacity. Whiteness of MP gels was not influenced by the addition of KGM or ADSP, but the texture of MP gels changed apparently with the incorporation of KGM or ADSP. The temperature sweep showed that the increase in G' was associated with the gelatinization of ADSP and its synergistic effect with KGM. The FTIR indicated that the addition of KGM and ADSP enhanced the hydrogen bond in the gel system. The addition of KGM and ADSP changed the microstructures of MP gels, indicating the possible interactions among KGM, ADSP and MP. The images of CLSM showed that starch granules filled in the gap in the protein network, meanwhile the KGM evenly dispersed in the protein network structure.

Effects of low molecular sugars on the retrogradation of tapioca starch gels during storage.

The effects of low molecular sugars (sucrose, glucose and trehalose) on the retrogradation of tapioca starch (TS) gels stored at 4°C for different periods were examined with different methods. Decrease in melting enthalpy (ΔHmelt) were obtained through differential scanning calorimetry analysis. Analysis of decrease in crystallization rate constant (k) and increase in semi-crystallization time (τ1/2) results obtained from retrogradation kinetics indicated that low molecular sugars could retard the retrogradation of TS gels and further revealed trehalose as the best inhibitor among the sugars used in this study. Fourier transform infrared (FTIR) analysis indicated that the intensity ratio of 1047 to 1022 cm-1 was increased with the addition of sugars in the order of trehalose > sucrose > glucose. Decrease in hardness parameters and increase in springiness parameters obtained from texture profile analysis (TPA) analysis also indicated that low molecular sugars could retard the retrogradation of TS gels. The results of FTIR and TPA showed a consistent sugar effect on starch retrogradation with those of DSC and retrogradation kinetics analysis.

Rapid, accurate, and simultaneous measurement of water and oil contents in the fried starchy system using low-field NMR.

Fried starchy food is rich in oil that may pose a risk to health. For controlling of the oil uptake, a rapid and accurate method for the determination of oil content in the fried starchy food is important. In this study, low-field nuclear magnetic resonance (LF-NMR) was applied to simultaneously determine water and oil contents in the model fried starchy system. The proton signals from oil and water were verified and distinguished by desiccation at 105°C. There was no superposition between oil and water signals in the fried starch, making it possible for quantitative analysis of water and oil in a single test. Compared with Soxhlet extraction, the LF-NMR analysis provided a more accurate result of oil content in the fried starchy system, confirming the practicability of the application of LF-NMR technology as a fast and accurate method for the quantification of water and oil in the fried starchy system.