Source: RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY submitted to
IMPROVING ANTIOXIDANT ACTIVITIES OF NUTRACEUTICALS THROUGH ENGINEERING EMULSIONS WITH CONTROLLED INTERFACIAL DISTRIBUTIONS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
REVISED
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1009551
Grant No.
(N/A)
Project No.
NJ10161
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jun 30, 2016
Project End Date
Mar 31, 2021
Grant Year
(N/A)
Project Director
Huang, QI, .
Recipient Organization
RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY
3 RUTGERS PLZA
NEW BRUNSWICK,NJ 08901-8559
Performing Department
Food Science
Non Technical Summary
Encapsulation and controlled-release of active functional food ingredients such as nutraceuticals are important applications in food and nutrition. Encapsulation techniques have been commonly used to improve the stability of food flavors against degradationand to enhance the oral bioavailability of bioactive food ingredients.Emulsions are one of the most commonly used encapsulation platforms.Establishing reliable criteria for selecting the most efficient antioxidant (AO) for minimizing peroxidation in emulsified foods remains a major unsolved problem in food emulsions and dispersionsand one of general importance in nutrition and health.A number of methods are available for determining AO distributions between the aqueous, and oil regions of emulsions, but these methods do not provide estimates of the fraction of AO in the interfacial region between the oil droplets and water,which is a problem because the interfacial region is believed to be the primary location of the AOs in emulsions.Most methods for determining AO distributions are based on separation, e.g., by centrifugation or ultrafiltration, followed by HPLC analysis of AO concentrations in each phase. However, this approach does not provide estimates of interfacial concentrations.Our approach combines the use of AOs, interfacial engineering and nano- or micro-encapsulation technology, which is of great interest to food, beverage, infant nutrition, and dietary supplement industries, giving added value by extending shelf-life, preventing peroxidation, improving handling characteristics, and enabling controlled release in vivo, etc. The chemical kinetic approach provides quantitative estimates AO partition constants and distributions between water and interfacial and oil and interfacial regions, and an estimate of the second order rate constant in the interfacial region. The results open up the possibility of developing new approaches to obtaining a deeper understanding of mechanism(s) of lipid peroxidation in opaque emulsions and developing guidelines for selecting the most efficient AOs for a particular application. Here we propose to apply the method to a small part of the larger problems.
Animal Health Component
0%
Research Effort Categories
Basic
50%
Applied
40%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
50118991000100%
Knowledge Area
501 - New and Improved Food Processing Technologies;

Subject Of Investigation
1899 - Oilseed and oil crops, general/other;

Field Of Science
1000 - Biochemistry and biophysics;
Goals / Objectives
Our long term goalisto develop an emulsion-based liquid formulation that has significantly improved stability for LC-PUFAs against peroxidation. Currently, there is an increasing demand of using natural AOs to replace synthetic ones due to the safety concerns. Based on previous literature reports, two polyphenols from Rosemary extracts, carnosol and carnosic acid, will be used as the natural AOs stabilize LC-PUFAs. To test our hypotheses, we propose to develop two types of emulsions with very different interfacial properties using the proper combination of different food-grade oils, emulsifiers/stabilizers and AOs: (1) conventional emulsions using small molecular weight surfactants, such as lecithin, Span and Tween series and antioxidants such as carnosol and theaflavins; and (2) Pickering emulsions which use food protein colloidal particles as stabilizers. We will pursue our long-term goal by investigating the following six specific objectives over the three-year duration of this project:Objective 1: To formulate conventional nano- to micro- oil-in-water (O/W) emulsions containing AOs and LC-PUFAs through a combination of high-speed and high-pressure homogenization processes. LC-PUFAs will be incorporated into oils such as medium chain triacylglycerol (MCT) or sunflower oils, and mixed with emulsifiers of the lecithin, Tween and Span series;Objective 2: To characterize the physical properties of these emulsions by dynamic light scattering, rheology, zeta potential measurements, and pulsed field gradient spin echo-nuclear magnetic resonance (PFGSE-NMR);Objective 3: To rationally design prolamin protein-based nanoparticles with tunable sizes and hydrophobicities. Prolamin proteins (i.e., zein and karifin) will be self-assembled into colloidal particles by liquid-liquid dispersion method. Particle size and surface hydrophobicity will be tuned through the adjustment of polarity and ionic strength of solvent and stock concentration;Objective 4: To rationally design Pickering emulsions containing AOs and LC-PUFAs with controlled sizes, shell thickness and permeability. The dimension of microcapsules will be controlled by adjusting the oil to water phase ratio and particle concentrations;Objective 5: To determine the distributions of AOs between the oil, aqueous and droplet surface of the emulsions using an established kinetic method based on the pseudophase model for emulsion formulations. Values of the partition constants for the AOs between the oil and emulsifier/protein nanoparticles surface and aqueous and emulsifier/protein nanoparticles surface regions will be obtained from the changes in the rate of reaction of the AO with 16-ArN2+. The results will provide information on the relationships between the distributions of AOs and their AO efficiencies; andObjective 6: To evaluate the improved shelf-life of LC-PUFAs using gas chromatography. The effects of AO distribution, emulsion sizes, emulsifiers and oils used, emulsion type (conventional emulsion versus Pickering emulsion) on the time-dependent total LC-PUFAs contents and off-flavor production will be investigated, and the optimum conditions for LC-PUFAs emulsion preparation will be identified.
Project Methods
Research procedure for completing the objectivesPart 1: To determine the optimal relationships between AO efficiency and emulsion structure. The chemical kinetic method and model will be applied and adapted to various food emulsion models of variable sizes from nano- to micro- oil-in-water (O/W) containing AOs and LC-PUFAs through a combination of high-speed and high-pressure homogenization processes. LC-PUFAs will be incorporated into oils such as medium chain triacylglycerol (MCT) or sunflower oils, and mixed with small molecular weight emulsifiers such as lecithin, Tween and Span series or surface-active polymers such as modified starch and β-lactoglobulin. To characterize the physical properties of these emulsions by dynamic light scattering, rheology, zeta potential measurements, and pulsed field gradient spin echo-nuclear magnetic resonance (PFGSE-NMR). Sub-research methods will include:Selection of AOsPreparation of Emulsions Containing LC-PUFAs and Antioxidants for Kinetic and Structural Studies.Part 2. To rationally design Pickering emulsions prepared from prolamin protein-based nanoparticles with tunable sizes and hydrophobicities. Prolamin proteins (i.e., zein and karifin) will be self-assembled into colloidal particles by liquid-liquid dispersion method. Particle size and surface hydrophobicity will be tuned through the adjustment of polarity and ionic strength of solvent and stock concentration; To use the chemical kinetic method to determine the distributions of AOs between the oil, interfacial, and aqueous regions of both surfactant based and Pickering and prolamin emulsions. Distribution constants of the AOs in the oil, interfacial and aqueous regions will be computed from the partition constants and used to characterize the efficiency of the AO.Sub-research methods will include:Fabrication of nanoparticles based on self-assembly of prolamin proteinsRational design of size and hydrophobicity tunable prolamin nanoparticlesAntioxidant Studies, Structural and Reactivity EffectsPart3: To identify the optimal conditions for prolonged shelf-life of LC-PUFAs emulsions, the effects of AO distribution, emulsion sizes, emulsifiers and oils used, and emulsion type (conventional emulsion versus Pickering emulsion) on the time-dependent total LC-PUFAs contents and off-flavor production will be investigated. These results will be correlated with the AO distributions in the emulsions obtained by the chemical kinetic method.Sub-research methods will include:Shelf-Life Studies

Progress 10/01/16 to 09/30/17

Outputs
Target Audience: The target audiences include researchers from universities, governmental and industrial laboratories. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One graduate student received Ph.D. degree as a result of this project. How have the results been disseminated to communities of interest? Our research has been disseminated through publications, conferences, and invited presentations. For example, I was invited to present our research results in multiple national and international conferences, such as ACS annual meeting. What do you plan to do during the next reporting period to accomplish the goals?We will be working on Objectives 4 & 5.

Impacts
What was accomplished under these goals? The concept of stabilizing at least one interface of a double emulsion with a layer of colloidal particles, or Pickering double emulsion, has been realized only in very few cases. Unique properties of Pickering double emulsions, such as interfacial structure, instability mechanism and digestion profile after oral intake have scarcely been investigated. During the past year, a water-in-oil-in-water (W/O/W) Pickering double emulsion utilizing kafirin nanoparticles as outer layer stabilizer (KDE) was formulated. The effects of formulation parameters, including lipophilic emulsifier content, volume ratio of inner water phase (W1) to oil phase (O), volume ratio of W1/O to external water phase (W2) and kafirin particle concentration, on the formation of KDE were systematically investigated. The cross-section structure and the attachment of protein particles at the external interface were revealed via cryo- scanning electron microscopy (cryo-SEM). Its structural instability during storage was then studied by monitoring the leakage of encapsulated dye and structural evolution via confocal laser scanning mi- croscopy. Finally, the digestion profiles in simulated gastric and intestinal fluids were assessed by microscopic analysis and in vitro lipolysis. Results suggest that osmotic pressure gradients-driven swelling is the major challenge for long-term stability of KDE during storage and processing. Under simulated gastric digestion process, KDE underwent structural collapse and its lipid digestion profile in simulated intestinal fluids followed similar trend as the kafirin particles-stabilized single Pickering emulsion.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Xiao, J.; Lu, X. X.; Huang, Q. R. (2017) Double emulsion derived from kafirin nanoparticles stabilized Pickering emulsion: Fabrication, microstructure, stability and in vitro digestion profile. Food Hydrocolloids, 62, 230-238.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Xiao, J.; Shi, C.; Li, Y. Q.; Huang, Q. R. (2017) Pickering emulsions immobilized within hydrogel matrix with enhanced resistance against harsh processing conditions and sequential digestion. Food Hydrocolloids, 62, 35-42.


Progress 06/30/16 to 09/30/16

Outputs
Target Audience:The target audiences include researchers from universities, governmental and industrial laboratories. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This research project involved two Ph.D. students with backgrounds ranging from food physical chemistry to food biochemistry under the guidance of the PD. The combination of the topics in food delivery systems and food nutrition, as well as the challenging nature of the project has the potential to make significant contribution to the functional foods, dietary supplement, pharmaceutical, and personal care industries. How have the results been disseminated to communities of interest?Our research has been disseminated through publications, conferences, and invited presentations.For example, I was invited to present our research results in multiple national and international conferences, such as ACS and International Society of Nutraceuticals and Functional Foods annual meeting. What do you plan to do during the next reporting period to accomplish the goals?Objective 1: To formulate conventional nano- to micro- oil-in-water (O/W) emulsions containing AOs and LC-PUFAs through a combination of high-speed and high-pressure homogenization processes. LC-PUFAs will be incorporated into oils such as medium chain triacylglycerol (MCT) or sunflower oils, and mixed with emulsifiers of the lecithin, Tween and Span series;

Impacts
What was accomplished under these goals? We worked on the objective #3: Kafirin, the prolamin protein from sorghum, was fabricated into spherical nanoparticles and then introduced as a fully natural interfacial stabilizer for Pickering emulsions. Kafirin nanoparticles produced via anti-solvent precipitation method exhibited water over oil wetting preference. The resultant oil-in-water emulsions exhibited resistance against coalescence with internal oil phase fraction ranging from 58.8% to 78.6%. Emulsion droplet size distribution and rheological properties of emulsions stabilized by kafirin particles were influenced by the applied particle concentration, oil fraction and ionic strength in aqueous phase. Basic trends included: increasing particle concentration in aqueous phase led to increase in emulsified phase volume, decrease in oil droplet sizes and increase in storage moduli for the viscoelastic responses; As oil phase fraction increased, the emulsified phase volume fraction and droplet size increased, and the rheological properties shifted from fluid dominant to elastic dominant. The addition of salt in aqueous phase promoted the migration process and lifted the stiffness of gel-like emulsions. Cryoscanning electron microscopy (cryo-SEM) and optical microscopy under fluorescence field evidenced the attachment of kafirin particles on oil-water interface. Overall, kafirin nanoparticles offer promising prospects in fulfilling the demands of "surfactant-free" emulsions with tunable characteristics.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Xiao, J.; Wang, X. A.; Gonzalez, A. J. P.; and Huang, Q. R. (2016) Kafirin nanoparticles-stabilized Pickering emulsions: Microstructure and rheological behavior. Food Hydrocolloids, 54, 30-39.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Xiao, J.; Li, Y. Q.; and Huang, Q. R. (2016) Recent advances on food-grade particles stabilized Pickering emulsions: fabrication, characterization and research trends. Trends in Food Science & Technology, accepted, doi:10.1016/j.tifs.2016.05.010.