Zihao Wei - Rutgers University - Postdoctoral researcher

Zihao Wei

Rutgers University

Postdoctoral researcher

New Brunswick, NJ | United States

Additional Specialties: nutraceutical delivery systems, emulsions, food chemistry, protein modification, polysaccharide modification

Zihao Wei - Rutgers University - Postdoctoral researcher

Zihao Wei

Publications

23Publications

62Reads

4Profile Views

Modulation of Formation, Physicochemical Properties, and Digestion of Ovotransferrin Nanofibrils with Covalent or Non-Covalent Bound Gallic Acid.

J Agric Food Chem 2019 Sep 22;67(35):9907-9915. Epub 2019 Aug 22.

Department of Food Science , Rutgers University , 65 Dudley Road , New Brunswick , New Jersey 08901 , United States.

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http://dx.doi.org/10.1021/acs.jafc.9b02630DOI Listing
September 2019
7 Reads
2.912 Impact Factor

Ovotransferrin nanofibril formation in the presence of glycerol or sorbitol

Food Chemistry

https://www.sciencedirect.com/science/article/pii/S0308814619315687


Abstract


Impact of glycerol and sorbitol on assembly of iron-bound ovotransferrin (OVT) into nanofibrils was investigated. Thioflavin T fluorescence result indicated that the presence of glycerol or sorbitol could reduce the rate of OVT fibrillation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that 60% sorbitol could retard hydrolysis of OVT completely for a period of time during thermal treatment, and decoupling hydrolysis from fibril self-assembly helped to identify the building blocks of OVT nanofibrils. OVT nanofibrils were composed of both intact OVT monomers and OVT-derived peptides. Influence of glycerol and sorbitol on morphology of OVT nanofibrils was studied using atomic force microscopy. The presence of glycerol or sorbitol shortened OVT nanofibrils, and the presence of 60% glycerol or sorbitol could increase thickness of OVT nanofibrils. Hopefully, this work may provide new insight about building blocks of protein nanofibrils and impact of polyols on protein fibrillation.

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September 2019

In vitro digestion and stability under environmental stresses of ovotransferrin nanofibrils

Food Hydrocolloids

https://www.sciencedirect.com/science/article/pii/S0268005X19313141


Abstract


The objectives of this study were to investigate in vitro digestion and stability under environmental stresses of ovotransferrin (OVT) nanofibrils. Gastrointestinal digestion of OVT nanofibrils was characterized by thioflavin T (ThT) fluorescence and atomic force microscopy (AFM). Most of OVT nanofibrils were disrupted during gastrointestinal digestion, and some OVT nanofibrils showed resistance to proteolytic digestion in vitro. Long-term storage stability of OVT nanofibrils over a wide pH range was studied at room temperature, and storage stability of β-lactoglobulin (BLG) nanofibrils as function of pH was also studied. AFM data showed that these protein nanofibrils were stable at pHs below isoelectric point, but they were unstable at pHs above isoelectric point. It was worthwhile to note that this was the first study that relationships between long-term storage stability and zeta potential of food protein nanofibrils were clarified, which could advance understandings about long-term preservation of food protein nanofibrils. Negligible decrease in ThT fluorescence revealed that OVT nanofibrils suffered little loss of fibrillar structures after frozen storage−lyophilization−rehydration. AFM data demonstrated that OVT nanofibrils were fractured into short and curly fibrils after high-speed shearing, and ThT fluorescence measurement showed that few fibrillar structures were destroyed during shear treatment, indicating that high-speed shearing was a reliable and cost-effective strategy to tailor OVT nanofibrils for specific needs. Hopefully, this study could provide new insight about in vitrodigestion and stability under environmental stresses of protein nanofibrils.

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September 2019

Formation of Nanocomplexes between Carboxymethyl Inulin and Bovine Serum Albumin via pH-Induced Electrostatic Interaction.

Molecules 2019 Aug 22;24(17). Epub 2019 Aug 22.

Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901, USA.

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http://dx.doi.org/10.3390/molecules24173056DOI Listing
August 2019
2.416 Impact Factor

Curcumin-loaded Pickering emulsion stabilized by insoluble complexes involving ovotransferrin-gallic acid conjugates and carboxymethyldextran.

Food Funct 2019 Aug 25;10(8):4911-4923. Epub 2019 Jul 25.

Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey 08901, USA.

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http://dx.doi.org/10.1039/c9fo01162eDOI Listing
August 2019
6 Reads
2.791 Impact Factor

A Novel Sweetpotato Transcription Factor Gene Enhances Drought Tolerance in Transgenic .

Front Plant Sci 2019 15;10:1025. Epub 2019 Aug 15.

Key Laboratory of Sweetpotato Biology and Biotechnology, Ministry of Agriculture/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, China.

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http://dx.doi.org/10.3389/fpls.2019.01025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6704235PMC
August 2019
3.637 Impact Factor

Edible Pickering emulsions stabilized by ovotransferrin–gum arabic particles

Food Hydrocolloids, 2019, Volume 89, Pages 590-601

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2018.11.037


Abstract


The objective of the present work was to fabricate ovotransferrin–gum arabic particles with desirable properties as Pickering stabilizers. Complexation of ovotransferrin (OVT) with gum arabic (GA) was investigated using turbidimetric titrations, and OVT–GA complexation proved to be an effective method to assemble hardcore food-grade nanoparticles. Preparation of OVT–GA particles was optimized by controlling biopolymer ratios and pH values, and uniform OVT–GA nanoparticles with mean particle size of 175.8 ± 1.3 nm and air-water contact angle of 82.6° were prepared at r = 3:1 and pH 3.2. Involvement of electrostatic interaction, hydrophobic interaction and hydrogen bonding in nanoparticle formation was verified through titrations in the presence of destabilizing agents. Interfacial tension measurements revealed that OVT–GA nanoparticles could effectively reduce interfacial tension. Afterwards, OVT–GA nanoparticles were employed to prepare surfactant-free Pickering emulsions. Visual observation indicated that Pickering emulsions stabilized by OVT–GA nanoparticles possessed superior emulsified phase volume fraction and storage stability. Confocal laser scanning microscopy results indicated that OVT–GA nanoparticles were located at the oil-water interface. Microstructures of emulsions were dependent on the concentrations of applied particles and oil fraction. Rheological measurements of Pickering emulsions demonstrated that increasing either particle concentration or oil fraction could lead to an increase of storage modulus and viscosity.

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August 2019

Impact Factor 5.839

7 Reads

Food-grade Pickering emulsions stabilized by ovotransferrin fibrils

Food Hydrocolloids, 2019, Volume 94, Pages 592-602

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2019.04.005


Abstract

The present work aimed to explore the feasibility of fabricating stable food-grade Pickering emulsions stabilized by ovotransferrin (OVT) fibrils. Raman imaging microscopy and confocal laser scanning microscopy confirmed that Pickering emulsion droplets stabilized by OVT fibrils were successfully prepared. Visual observation revealed that OVT fibril-stabilized Pickering emulsions at different fibril concentrations and oil fractions had high emulsified phase volume, and these Pickering emulsions had high stability index during 20-day storage at 20 °C. OVT fibrils could be employed to stabilize Pickering emulsions at broad ionic strengths (i.e., 0–1000 mM) and pHs (i.e., 2–7). Increasing either ionic strength or pH was helpful for the formation of emulsions with higher emulsified phase volume fraction, smaller emulsion droplets, and larger gel strength. In terms of thermal stability, OVT fibril-stabilized Pickering emulsions were stable during 10-day storage at 50 °C. The acquired knowledge in this study may provide new insight into fabrication of food-grade Pickering emulsions with excellent stability.


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August 2019

Impact Factor 5.839

6 Reads

Assembly of Protein-Polysaccharide Complexes for Delivery of Bioactive Ingredients: A Perspective Paper.

J Agric Food Chem 2019 Feb 25;67(5):1344-1352. Epub 2019 Jan 25.

Department of Food Science , Rutgers, The State University of New Jersey , 65 Dudley Road , New Brunswick , New Jersey 08901 , United States.

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http://dx.doi.org/10.1021/acs.jafc.8b06063DOI Listing
February 2019
12 Reads
2.912 Impact Factor

Optimization of water-soluble polysaccharides from stem lettuce by response surface methodology and study on its characterization and bioactivities.

Int J Biol Macromol 2017 Dec 22;105(Pt 1):912-923. Epub 2017 Jul 22.

Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901, USA.

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https://linkinghub.elsevier.com/retrieve/pii/S01418130173184
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http://dx.doi.org/10.1016/j.ijbiomac.2017.07.125DOI Listing
December 2017
7 Reads
2.858 Impact Factor

Evaluation of structural and functional properties of chitosan-chlorogenic acid complexes.

Int J Biol Macromol 2016 May 25;86:376-82. Epub 2016 Jan 25.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, People's Republic of China. Electronic address:

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http://dx.doi.org/10.1016/j.ijbiomac.2016.01.084DOI Listing
May 2016
14 Reads
2.858 Impact Factor

Physicochemical characterisation of β-carotene emulsion stabilised by covalent complexes of α-lactalbumin with (-)-epigallocatechin gallate or chlorogenic acid.

Food Chem 2015 Apr 22;173:564-8. Epub 2014 Oct 22.

Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, China. Electronic address:

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http://dx.doi.org/10.1016/j.foodchem.2014.10.070DOI Listing
April 2015
16 Reads
3.391 Impact Factor

Impact of covalent or non-covalent bound epigallocatechin-3-gallate (EGCG) on assembly, physicochemical characteristics and digestion of ovotransferrin fibrils

Food Hydrocolloids, 2020, Volume 98, 105314

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2019.105314


Abstract


The objectives of the present study were to investigate impact of covalent or non-covalent bound (−)-epigallocatechin-3-gallate (EGCG) on ovotransferrin (OVT) fibrils. Bound EGCG showed fibril-inhibitory activity in a concentration-dependent manner, and covalent bound EGCG inhibited OVT fibrillation more intensely than an equal amount of non-covalent bound EGCG. Bound EGCG resulted in larger fibril building blocks. Covalent bound EGCG shortened OVT fibrils significantly, and non-covalent bound EGCG induced smaller changes in length of OVT fibrils than covalent bound EGCG. A larger amount of covalent or non-covalent bound EGCG led to shorter OVT fibrils. Covalent bound EGCG did not change thickness of OVT fibrils, while newly emerged thicker fibrils were observed in the presence of non-covalent bound EGCG. Covalent bound EGCG shifted isoelectric point of OVT fibril to lower pHs than non-covalent bound EGCG. Bound EGCG decreased surface hydrophobicity, storage modulus and viscosity of OVT fibrils. OVT fibrils with bound EGCG possessed strong antioxidant capacity. The gastrointestinal digestion result demonstrated that covalent bound EGCG contributed to a higher increase in fibril digestibility than non-covalent bound EGCG.

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November 0001

Impact Factor 5.839

4 Reads

Assembly of iron-bound ovotransferrin amyloid fibrils

Food Hydrocolloids, 2019, Volume 89, Pages 579-589

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2018.11.028


Abstract


The impacts of pH, temperature, ionic strength and stirring speed on the assembly of ovotransferrin (OVT) into amyloid fibrils were analyzed by using thioflavin T fluorescence and atomic force microscopy. Optimum OVT nanofibrillation condition was achieved at pH 2, 90 °C, an ionic strength of 150 mM and a stirring speed of 300 rpm. Apart from rigid and long amyloid fibrils, flexible and short amyloid fibrils were also detected under the optimal condition. Morphological changes observed by atomic force microscopy as a function of time demonstrated that short OVT amyloid fibrils (with contour length below 800 nm) were generated upon heating for 1 h, and long OVT amyloid fibrils (with contour length above 800 nm) appeared after 6 h heating. In terms of structural characteristics, circular dichroism study revealed that internal structures of OVT amyloid fibrils could be stacked β-sheet. Analysis of fibril periodicity indicated that OVT amyloid fibrils might consist of 2 or 4 multi-stranded filaments. With the aid of ANS (1-anilino-8-naphthalensulfonate) fluorescence probe, it was found that OVT amyloid fibrils had lower surface hydrophobicity than untreated OVT. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed that OVT amyloid fibrils had no in vitro cytotoxicity, implying great application potential in food. This work will advance our understanding of amyloid fibrils derived from iron-bound proteins.

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November 0001

Impact Factor 5.839

4 Reads

Genipin-crosslinked ovotransferrin particle-stabilized Pickering emulsions as delivery vehicles for hesperidin

Food Hydrocolloids, 2019, Volume 94, Pages 561-573

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2019.04.008


Abstract


The present work aimed to fabricate genipin-crosslinked ovotransferrin (OVT) particle-stabilized Pickering emulsions as delivery vehicles for hesperidin. Nearly monodisperse ovotransferrin colloidal particles were prepared by employing genipin crosslinking, and reaction mechanism for the crosslinking of ovotransferrin with genipin was proposed. Genipin-crosslinked OVT particles were found to be efficient Pickering stabilizers at different oil fractions, and high internal phase Pickering emulsions (oil fraction φ = 0.75) with emulsified phase volume fraction of 100% could be solely stabilized by these particles. Visual observation and microscopic image indicated that genipin-crosslinked OVT particle-stabilized high internal phase Pickering emulsion (particle concentration c = 2.0 wt%, oil fraction φ = 0.75) was stable during one-month storage at room temperature. Optical microscopy and rheological measurements revealed that microstructures and rheological properties of genipin-crosslinked OVT particle-stabilized Pickering emulsions were dependent on both protein particle concentration and internal oil phase volume fraction. Genipin-crosslinked OVT particle-stabilized high internal phase Pickering emulsions were also stable at various pHs (2.0–4.0) and ionic strengths (0–200 mM). Optical microscopy showed that increase of pH or ionic strength resulted in a slight decrease in emulsion droplet sizes. In vitro digestion study showed that these OVT particles-stabilized high internal phase Pickering emulsions could improve both extent of lipolysis and hesperidin bioaccessibility significantly.

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November 0001

Impact Factor 5.839

4 Reads

Developing organogel-based Pickering emulsions with improved freeze-thaw stability and hesperidin bioaccessibility

Food Hydrocolloids, 2019, Volume 93, Pages 68-77

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2019.01.050



Abstract:


Soybean oil-based organogel was structured using monostearin, and the organogel had a gel-sol melting temperature of 44.0 °C. Loading amount of hesperidin in soybean oil-based organogels could be about twice as much as metastable solubility of hesperidin in soybean oil. Organogel-in-water Pickering emulsion was formed using the soybean oil-based organogel as the oil phase and ovotransferrin (OVT) fibrils as the emulsifier. Visual observation indicated that organogel-based Pickering emulsions stabilized by OVT fibrils (40 mg/mL) at oil fractions of 0.50–0.85 had excellent storage stability and could withstand three cycles of freeze-thaw treatments. Conventional oil-in-water Pickering emulsion was prepared as control to better understand impact of organogel incorporation on freeze-thaw stability, and conventional Pickering emulsion was formed using soybean oil as the oil phase and OVT fibrils as the emulsifier. Freeze-thaw stability of organogel-based Pickering emulsions was better than that of conventional Pickering emulsions (without organogel) stabilized by OVT fibrils. In vitro digestion study revealed that organogel-based Pickering emulsion could improve both the extent of lipolysis and hesperidin bioaccessibility when compared with organogel. This study demonstrates the feasibility of formulating novel food-grade organogel-based Pickering emulsions with high nutraceutical loading, excellent freeze-thaw stability and improved nutraceutical bioaccessibility.

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November 0001

Impact Factor 5.839

7 Reads

Ovotransferrin fibril–stabilized Pickering emulsions improve protection and bioaccessibility of curcumin

Food Research International, 2019, Volume 125, 108602

Food Research International

https://doi.org/10.1016/j.foodres.2019.108602



Abstract


The present study aimed to investigate protection and bioaccessibility of curcumin in ovotransferrin (OVT) fibril-stabilized Pickering emulsions. Curcumin protection of OVT fibril-stabilized emulsions against ultraviolet light exposure was studied. OVT fibril-stabilized Pickering emulsion at an ionic strength of 1000 mM provided the best curcumin protection. OVT fibril-stabilized Pickering emulsion at pH 6 provided better curcumin protection than those at pH 2 and 4. Afterwards, digestion of OVT fibril-stabilized curcumin emulsion was investigated in both TNO dynamic digestion model (TIM-1) and pH-stat static digestion model. In terms of TIM-1 result, curcumin bioaccessibility in OVT fibril-stabilized emulsion increased by 129% when compared with that in bulk oil. In pH-stat digestion model, curcumin bioaccessibility increased by 114% after formulated into OVT fibril-stabilized droplets, which was due to higher extent of lipolysis. Interestingly, both TIM-1 and pH-stat digestion models gave almost consistent measurements of improved percentage in curcumin bioaccessibility. Curcumin bioaccessibility of the emulsion in TIM-1 and pH-stat model was 15.3% and 33.8% respectively, indicating bioaccessibility overestimation in pH-stat model. The novel findings in this work could facilitate designing food-grade Pickerinng emulsion with excellent nutraceutical protection and enhanced nutraceutical bioaccessibility.

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November 0001
5 Reads

Investigation of ovotransferrin conformation and its complexation with sugar beet pectin

Food Hydrocolloids, 2019, Volume 87, Pages 448-458

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2018.08.036


Abstract


Small-angle X-ray scattering (SAXS) has been used to investigate the conformation of ovotransferrin (OVT) in solutions of different pH values. OVT was found to be a spherical molecule at native state in aqueous solutions. Radius of gyration (Rg) of OVT increased by 19.6% upon transition from native to molten globular state, and Rg increased by 9.7% as OVT further unfolded to an extended conformation. Besides, OVT showed concentration scaling behaviors at molten globule state. The information about size and shape was expected to facilitate the understanding of interactions between OVT and sugar beet pectin (SBP). Increasing OVT/SBP mixing ratios altered critical pH transition points in phase diagram, and the ratio of 5:1 was close to the saturated complexation ratio between OVT and SBP. Turbidities of OVT–SBP mixtures decreased significantly in the presence of sodium chloride, indicating the domination of electrostatic interaction in OVT–SBP complexation. Atomic force microscopy data illustrated the formation, association and dissociation processes of OVT–SBP complexes. Fluorescence spectroscopy results revealed that binding constant between OVT and SBP decreased with increasing temperature. The negative ΔH and positive ΔS further indicated the strong attractive interaction between OVT and SBP, which overcame the entropy contribution. Emulsions stabilized by OVT–SBP complexes had smaller droplet sizes and better physical stability than those stabilized by either pure OVT or SBP.

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November 0001

Impact Factor 5.839

4 Reads

Heteroprotein complex formation of ovotransferrin and lysozyme: Fabrication of food-grade particles to stabilize Pickering emulsions

Food Hydrocolloids, 2019, Volume 96, Pages 190-200

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2019.05.024


Abstract


The present work aimed to fabricate food-grade Pickering emulsions stabilized by heteroprotein complexes formed by ovotransferrin (OVT) and lysozyme (LYS) as lipid-based nutraceutical delivery vehicles. The heteroprotein complexation, as confirmed by turbidity titrations, was proved to be an effective means to prepare food-grade particles. Multiple parameters such as particle size, zeta potential and dispersion stability were characterized in screening for proper OVT–LYS particles as Pickering stabilizers. OVT–LYS particles with OVT/LYS ratio of 8:1 at pH 9.3 met all requirements of eligible Pickering stabilizers such as intermediate wettability. Titrations in the presence of sodium chloride demonstrated that primary driving force of OVT–LYS particle formation was electrostatic attraction. Afterwards, food-grade Pickering emulsions were fabricated using OVT–LYS particles. Visual observation indicated that Pickering emulsions stabilized by OVT–LYS particles at various particle concentrations and oil fractions were stable during one-month storage at room temperature, and OVT–LYS particles could stabilize high internal phase Pickering emulsions at oil fraction of 0.75. Rheological measurements revealed that viscosity and gel-like structures of Pickering emulsions were dependent on particle concentration and oil fraction. When compared with the extent of lipolysis (32.1%) in bulk oil, the extent of lipolysis (71.5%) in OVT–LYS particle-stabilized Pickering emulsion was increased by 39.4%. Curcumin bioaccessibility was increased from 16.1% to 38.3% after encapsulation of curcumin into OVT–LYS particle-stabilized Pickering emulsion. Such improved bioaccessibility demonstrated that OVT–LYS particle-stabilized Pickering emulsion was an effective delivery vehicle for curcumin.

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November 0001

Impact Factor 5.839

2 Reads

Modification of ovotransferrin by Maillard reaction: Consequences for structure, fibrillation and emulsifying property of fibrils

Food Hydrocolloids, 2019, Volume 97, 105186

Food Hydrocolloids

https://doi.org/10.1016/j.foodhyd.2019.105186


Abstract


The present study first glucosylated and lactosylated ovotransferrin to acquire ovotransferrin–glucose conjugate (OGC) and ovotransferrin–lactose conjugate (OLC), respectively. Thioflavin T fluorescence result indicated that glycation could suppress fibrillation of ovotransferrin, and glucosylation exerted stronger inhibitory influence on fibril formation than lactosylation. SDS-PAGE analysis indicated that the major building blocks of OVTC fibrils, OGC fibrils and OLC fibrils were peptides, and building blocks of OGC fibrils and OLC fibrils had slightly larger molecular weight than those of OVTC fibrils. Morphology of ovotransferrin fibrils with covalent bound saccharides was closely related to type of saccharides. Both rigid and flexible fibrils were observed in OVTC fibrils and OLC fibrils, and an absence of rigid fibrils was observed in OGC fibrils. Afterwards, emulsibility of all fibrils was tested. Covalent bound saccharides weakened emulsifying property of ovotransferrin fibrils. Droplet size and rheological properties of emulsions stabilized by ovotransferrin fibrils with covalent bound saccharides were dependent on nature of saccharides. For emulsions at fixed fibril concentration of 4 wt% and oil fraction of 0.65, droplet size followed the order: OGC fibrils-stabilized emulsions > OLC fibrils-stabilized emulsions > OVTC fibrils-stabilized emulsions. Among all emulsions, emulsions stabilized by OGC fibrils had the lowest viscosity and storage modulus.

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November -0001

Impact Factor 5.839

2 Reads

Physicochemical properties of β-carotene emulsions stabilized by chitosan–chlorogenic acid complexes

LWT - Food Science and Technology, 2016, Volume 71, Pages 295-301

LWT - Food Science and Technology

https://doi.org/10.1016/j.lwt.2016.04.007


Abstract


    The objectives of the present study were to first synthesize chitosan–chlorogenic acid (CA) covalent complex and finally evaluate the ability of chitosan–CA covalent complex and physical complex in stabilizing a model β-carotene emulsion. Chitosan–CA covalent complex was synthesized according to carbodiimide-mediated coupling method. Data of proton nuclear magnetic resonance (1H NMR) indicated that chitosan formed covalent complex with CA successfully. Afterward, the research was focused on testing chitosan–CA complexes in stabilizing β-carotene emulsions. Mean droplet size of emulsion coated by chitosan–CA covalent complex was 364.3 ± 0.8 nm, which was the smallest among all investigated emulsions. In comparison with emulsions stabilized by control chitosan and chitosan–CA physical complex, the emulsion coated by chitosan–CA covalent complex had higher viscosity. Besides, interfacial concentration fraction of CA in the emulsion coated by chitosan–CA covalent complex and the emulsion stabilized by chitosan–CA physical complex was (73.7 ± 4.3)% and (44.9 ± 2.4)%, respectively. The physicochemical stabilities of the emulsion stabilized by chitosan–CA covalent complex were the best among all emulsions.

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    November -0001

    Physicochemical properties of β-carotene bilayer emulsions coated by milk proteins and chitosan–EGCG conjugates

    Food Hydrocolloids, 2016, Volume 52, Pages 590-599

    Food Hydrocolloids

    https://doi.org/10.1016/j.foodhyd.2015.08.002


    Abstract


    The objectives of the present study were to investigate the influence of chitosan–(–)-epigallocatechin-3-gallate (EGCG) conjugates on physicochemical properties of β-carotene emulsions coated by α-lactalbumin (LA) or sodium caseinate (SC). Covalent modification of chitosan with EGCG was achieved by hydroxyl–free radical grafting. Then based on layer-by-layer electrostatic deposition, β-carotene bilayer emulsions stabilized with different milk proteins and chitosan–EGCG conjugates (CEC) were prepared. The physicochemical properties of primary and secondary emulsions were mainly characterized by droplet size and distribution, zeta-potential, rheological behavior, transmission profiles using LUMiSizer and degradation of β-carotene in the emulsions during the storage. Besides, the effects of environmental stresses (ionic strength, freeze–thaw and thermal treatments) on physical stability of primary and secondary emulsions were evaluated. Data of droplet size and zeta potential indicated that cationic CEC were adsorbed on the droplet surfaces. Steady-state flow measurements revealed that the viscosity of primary emulsions could be enhanced by the adsorption of CEC. In addition, physical stability of SC-coated emulsion was improved by the adsorption of CEC, while the layer-by-layer electrostatic deposition hardly improved the stability of LA-stabilized emulsion in the absence or presence of environmental stresses. In comparison with the primary emulsions, the bilayer emulsions significantly improved chemical stability of β-carotene against heat treatment and ultraviolet (UV) light exposure, and the least degradation of β-carotene occurred in SC–CEC coated emulsion. In general, SC–CEC coated emulsion exhibited the best physicochemical properties among all emulsions studied in this research.

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    November -0001

    Impact Factor 5.839

    Evaluation of structural and functional properties of protein–EGCG complexes and their ability of stabilizing a model β-carotene emulsion

    Food Hydrocolloids, 2015, Volume 45, Pages 337-350

    Food Hydrocolloids

    https://doi.org/10.1016/j.foodhyd.2014.12.008


    Abstract


    The objectives of the present study were to first covalently modify different bovine milk proteins (α-lactalbumin, β-lactoglobulin, lactoferrin and sodium caseinate) using (−)-epigallocatechin-3-gallate (EGCG), then compare structural and functional properties between covalent and non-covalent protein–EGCG complexes and finally test the complexes with greater antioxidant potential in stabilizing a model β-carotene emulsion. Covalent modification of milk proteins with EGCG was testified by a reduction of free amino groups and free sulfhydryl groups as well as matrix-assisted laser desorption/ionization time-of-flight mass spectra (MALDI-TOF-MS). Furthermore, the proposed schematic formation pathway showed that milk proteins formed covalent complexes with EGCG dimers. Then structural and functional properties of covalent and non-covalent protein–EGCG complexes were analyzed. Covalent protein–EGCG complexes had higher denaturation temperatures than non-covalent ones. Besides, covalent protein–EGCG complexes exhibited much stronger antioxidant activity than the same amount of non-covalent ones. A comparison of interfacial concentration fraction of protein and EGCG in emulsions revealed that covalent protein–EGCG complexes exhibited better interfacial adsorption behavior and greater antioxidant potential than non-covalent ones in emulsion systems. Thus, research was then focused on testing covalent protein–EGCG complexes in a model β-carotene emulsion. Covalent protein–EGCG complexes significantly enhanced chemical stability of β-carotene in emulsions against heat treatment and ultraviolet (UV) light exposure. Given both physical and chemical stability of emulsions, the overall ability of covalent protein–EGCG complexes in stabilizing a model β-carotene emulsion followed the order: sodium caseinate > β-lactoglobulin > lactoferrin > α-lactalbumin.



    View Article
    November -0001

    Impact Factor 5.839

    3 Reads

    Top co-authors

    Qingrong Huang
    Qingrong Huang

    Rutgers University

    4
    Yanxiang Gao
    Yanxiang Gao

    China Agricultural University

    2
    Peilei Zhu
    Peilei Zhu

    USA; Institute of Horticulture

    1
    Chenzhipeng Nie
    Chenzhipeng Nie

    Anhui Province Agricultural Products Processing Engineering Laboratory

    1
    Hongwei Zhang
    Hongwei Zhang

    Xijing Hospital of Digestive Diseases

    1
    Fang Yuan
    Fang Yuan

    Ningbo University

    1
    Mingchun Wang
    Mingchun Wang

    College of Food Science and Technology

    1
    Shuping Ma
    Shuping Ma

    Anhui Province Agricultural Products Processing Engineering Laboratory

    1
    Fuguo Liu
    Fuguo Liu

    Qi-Lu Hospital of Shandong University

    1
    Xiaoya Wang
    Xiaoya Wang

    University of Maryland

    1