Microencapsulation of omega-3 fatty acids from flaxseed oil in flaxseed protein and flaxseed gum based matrix
- Authors: Kaushik, Pratibha
- Date: 2016
- Type: Text , Thesis , PhD
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- Description: The overarching goal of this research was to develop microencapsulated flaxseed oil as a plant based source of omega-3 fatty acids. To accomplish this, flaxseed oil was microencapsulated in a novel matrix composed of flaxseed protein isolate (FPI) and flaxseed gum (FG) and converted into a powder by freeze drying and spray drying. The primary objectives were: a) To evaluate the physicochemical and functional properties of FPI and FG; b) to optimise the process of complex coacervation between FPI and FG to maximise the yield of complex coacervates; c) to characterise the flaxseed oil microcapsules obtained through complex coacervation followed by freeze drying or spray drying. FPI and FG were extracted from whole flaxseeds at optimised temperatures to obtain 90% purity. The physicochemical and functional properties of FPI were found superior to most of the commonly used proteins. Lower extraction temperatures (30, 50 °C) of FG yielded higher levels of neutral monosaccharides and lower levels of acidic monosaccharides. The functional properties of FG, such as EAI and WAC, were negatively affected by the rise in extraction temperature. Electrostatic complexation studies between these two biopolymers showed that the optimum FPI-to-FG ratio is 3:1 and the optimum pH is 3.1. The complex coacervates of FPI-FG were used to microencapsulate flaxseed oil at different core to wall ratios (1:2, 1:3 and 1:4), and converted to powder through spray drying and freeze drying. The spray dried solid microcapsules had higher oil microencapsulation efficiency, lower surface oil content and higher oxidation stability compared to the freeze dried microcapsules. The oxidation stability obtained from spray dried microcapsules at core-to-wall ratio of 1:4 was nearly double to that of the unencapsulated flaxseed oil. This study affirms the potential of a solely plant based encapsulating matrix that returns superior nutritional outcomes to other commonly used wall materials.
- Description: Doctor of Philosophy
Preparation, characterization and functional properties of flax seed protein isolate
- Authors: Kaushik, Pratibha , Dowling, Kim , McKnight, Stafford , Barrow, Colin , Wang, Bo , Adhikari, Benu
- Date: 2016
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 197, no. (2016/04/15/ 2016), p. 212-220
- Full Text: false
- Reviewed:
- Description:
Flaxseed protein isolate (FPI) was extracted from flaxseeds, and its amino acid composition and functional properties (solubility, thermal stability, emulsifying properties and electrostatic charge density, water holding and fat absorption capacities) were determined. The highest purity of FPI (90.6%) was achieved by extraction at 60°C. FPI had a low lysine to arginine ratio of 0.25, which is desired in heart-healthy foods and infant formulas. The denaturation temperature of FPI was 105°C. FPI had the highest emulsion activity index (375.51m2/g), highest emulsion stability index (179.5h) and zeta potential (−67.4mV) when compared to those of other commonly used proteins, such as sodium caseinate (SC), whey protein isolate (WPI), gelatin (Gel) and soy protein isolate (SPI). The average emulsion droplet size of emulsions stabilized by these proteins was in the order SC
Complex coacervation between flaxseed protein isolate and flaxseed gum
- Authors: Kaushik, Pratibha , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Food Research International Vol. 72, no. (2015), p. 91-97
- Full Text:
- Reviewed:
- Description:
Flaxseed protein isolate (FPI) and flaxseed gum (FG) were extracted, and the electrostatic complexation between these two biopolymers was studied as a function of pH and FPI-to-FG ratio using turbidimetric and electrophoretic mobility (zeta potential) tests. The zeta potential values of FPI, FG, and their mixtures at the FPI-to-FG ratios of 1:1, 3:1, 5:1, 10:1, 15:1 were measured over a pH range 8.0-1.5. The alteration of the secondary structure of FPI as a function of pH was studied using circular dichroism. The proportion of a-helical structure decreased, whereas both β-sheet structure and random coil structure increased with the lowering of pH from 8.0 to 3.0. The acidic pH affected the secondary structure of FPI and the unfolding of helix conformation facilitated the complexation of FPI with FG. The optimum FPI-to-FG ratio for complex coacervation was found to be 3:1. The critical pH values associated with the formation of soluble (pHc) and insoluble (pH
Φ1 ) complexes at the optimum FPI-to-FG ratio were found to be 6.0 and 4.5, respectively. The optimum pH (pHopt ) for the optimum complex coacervation was 3.1. The instability and dissolution of FPI-FG complex coacervates started (pHΦ2 ) at pH2.1. These findings contribute to the development of FPI-FG complex coacervates as delivery vehicles for unstable albeit valuable nutrients such as omega-3 fatty acids. © 2015.
Microencapsulation of omega-3 fatty acids : A review of microencapsulation and characterization methods
- Authors: Kaushik, Pratibha , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article , Review
- Relation: Journal of Functional Foods Vol. 19, no. Part B (2015), p. 868-881
- Full Text: false
- Reviewed:
- Description: To improve consumption of omega-3 fatty acids, foods can be enriched with omega-3 rich oils. Microencapsulation of omega-3 oils minimizes oxidative deterioration and allows their use in stable and easy-to-handle form. Microencapsulation of omega-3 fatty acids can be achieved by using a variety of methods, with the two most commonly used commercial processes being complex coacervation and spray dried emulsions. A variety of other methods are in development including spray chilling, extrusion coating and liposome entrapment. The key parameter in any of these processes is the selection of wall material. For spray dried emulsions and complex coacervates protein or polysaccharides are primarily used as shell material, although complex coacervation is currently commercially limited to gelatin. Here we review the need for microencapsulation of omega-3 oils, methods of microencapsulation and analysis, and the selection of shell material components. In particular, we discuss the method of complex coacervation, including its benefits and limitations. This review highlights the need for research on the fundamentals of interfacial and complexation behaviour of various proteins, gums and polyphenols to encapsulate and deliver omega-3 fatty acids, particularly with regard to broadening the range of shell materials that can be used in complex coacervation of omega-3 rich oils. © 2014 Published by Elsevier Ltd. All rights reserved.
Microencapsulation of flaxseed oil in flaxseed protein and flaxseed gum complex coacervates
- Authors: Kaushik, Pratibha , Dowling, Kim , McKnight, Stafford , Barrow, Colin , Adhikari, Benu
- Date: 2016
- Type: Text , Journal article
- Relation: Food Research International Vol. 86, no. (2016), p. 1-8
- Full Text: false
- Reviewed:
- Description: Flaxseed oil, a rich source of omega-3 fatty acids, was microencapsulated in a novel matrix formed by complex coacervation between flaxseed protein isolate (FPI) and flaxseed gum (FG). This matrix was crosslinking with glutaraldehyde. Liquid microcapsules with three core (oil)-to-wall ratios (1:2, 1:3 and 1:4) were prepared and spray-dried or freeze-dried to produce powders. The microencapsulation efficiency, surface oil, morphology and oxidative stability of these microcapsules were determined. The spray-dried solid microcapsules had higher oil microencapsulation efficiency, lower surface oil content, smoother surface morphology and higher oxidation stability than the freeze-dried microcapsules. The highest microencapsulation efficiency obtained in spray-dried microcapsules was 87% with a surface oil of 2.78% at core-to-wall ratio 1:4 and oil load 20%. The oxidation stability obtained from spray-dried microcapsules at core-to-wall ratio of 1:4 was nearly double that of the unencapsulated flaxseed oil. © 2016 Elsevier Ltd.