Starch Pickering Emulsions Process and Encapsulation Stability Marefati, Ali PDF
Preview Starch Pickering Emulsions Process and Encapsulation Stability Marefati, Ali
Starch Pickering Emulsions Process and Encapsulation Stability Marefati, Ali 2018 Document Version: Publisher's PDF, also known as Version of record Link to publication Citation for published version (APA): Marefati, A. (2018). Starch Pickering Emulsions: Process and Encapsulation Stability. [Doctoral Thesis (compilation), Lund University]. Department of Food Technology, Lund University. Total number of authors: 1 General rights Unless other specific re-use rights are stated the following general rights apply: Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Read more about Creative commons licenses: https://creativecommons.org/licenses/ Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. LUND UNIVERSITY PO Box 117 221 00 Lund +46 46-222 00 00 Starch Pickering Emulsions Process and Encapsulation Stability DEPARTMENT OF FOOD TECHNOLOGY, ENGINEERING & NUTRITION | LUND UNIVERSITY ALI MAREFATI Starch Pickering Emulsions Process and Encapsulation Stability Ali Marefati DOCTORAL DISSERTATION by due permission of the Faculty of Engineering, Lund University, Sweden. To be defended on Friday the 23rd March 2018, at 13:00, in Lecture Hall B at the Centre for Chemistry and Chemical Engineering. Faculty opponent Professor Karin Schroën Wageningen University, The Netherlands i Organization: Document name: LUND UNIVERSITY Doctoral Dissertation Department of Food Technology, Date of issue: February the 27th, 2018 Engineering and Nutrition P.O. Box 124, SE-22100 Lund, Sweden Author: Ali Marefati Sponsoring organization: Swedish Research Council Title and subtitle: Starch Pickering Emulsions: Process and Encapsulation Stability Abstract The emulsion stabilization functionality of surfactants and biopolymers can be replaced by solid particles adsorbed at the interface, where they create a category of emulsions known as Pickering emulsions. Recently, health and environmental concerns have led to new market demand for natural, biodegradable and renewable sources of ingredients. Starch granules meet these ingredient requirements and are also good candidates for stabilization of Pickering type emulsions due to their properties such as neutral color, taste, odor and being non-allergic. Starch granules are generally hydrophilic and in order to improve their emulsifying capacity they are modified with hydrophobic groups. The most widely used chemical modification is esterification with acid anhydride, such as octenyl succinic anhydride (OSA). Emulsions stabilized by OSA modified starch have shown to have high stability. Moreover, the application of a heat treatment can induce a partial gelatinization of the starch at the oil-water interface, which leads to changes in interfacial properties of the starch granule stabilized emulsions. This thesis focuses on the development and application of starch Pickering emulsions and has been carried out along three main lines of investigation where each line has its own section in the thesis. In the first section, the preparation and properties of oil-in-water emulsions stabilized by starch granules with small sizes, including quinoa, rice and amaranth, were investigated. In the second section, the process and encapsulation stabilities of the emulsions were evaluated in the context of simple oil-in-water and double water-in-oil-in-water emulsions, with or without heat treatment. In the third section, the physical and encapsulation stabilities of the emulsions during in vitro digestion were evaluated. Quinoa starch granules showed to have higher emulsifying efficiency both in the initial state and after accelerated stability testing. Moreover, the heat induced gelatinized layer showed to not only contribute to initial general stability, but also increased the process and encapsulation stabilities of the emulsions. Modified starch granules appeared to protect the emulsions against destabilization mechanisms during processing (i.e. freezing and freeze-drying). It was possible to create powders from starch stabilized Pickering emulsions with high oil content (up to 80%). Furthermore, emulsions stabilized by starch granules showed high stability for encapsulation of bioactive compounds during in vitro digestion. The results of this work can be used for the development of lipid-based encapsulated systems, in both liquid and powder forms for the delivery of bioactive compounds in food, pharmaceutical and cosmetic applications. Key words: Starch granules, Pickering emulsions, Encapsulation, Freeze-thaw stability, Freeze- drying, In vitro digestion, in vitro intestinal lipolysis Classification system and/or index terms (if any) Supplementary bibliographical information Language: English ISSN and key title ISBN (print): 978-91-7422-575-4 ISBN (digital): 978-91-7422-576-1 Recipient’s notes Number of pages:101 Price Security classification I, the undersigned, being the copyright owner of the abstract of the above-mentioned dissertation, hereby grant to all reference sources permission to publish and disseminate the abstract of the above-mentioned dissertation. Signature Date: February the 14th, 2018 ii Starch Pickering Emulsions Process and Encapsulation Stability Ali Marefati iii Cover photo by Hisyalina Saari Back cover by Stephen Hall Copyright Ali Marefati Faculty of Engineering, Lund University Department of Food Technology, Engineering and Nutrition ISBN (print) 978-91-7422-575-4 ISSN (digital) 978-91-7422-576-1 Printed in Sweden by Media-Tryck, Lund University Lund 2018 iv Two roads diverged in a wood, and I– I took the one less traveled by, And that has made all the difference. Robert Frost (1874-1963) v Contents Abstract .................................................................................................................... 1 Popular science summary ......................................................................................... 3 List of publications ................................................................................................... 6 Additional publication not included in this thesis .................................................... 7 Author’s contribution to the publications ................................................................. 8 Contribution to conferences and workshops ............................................................ 9 Aim and objectives ................................................................................................. 11 Introduction ............................................................................................................ 12 Overview of design of the thesis work ......................................................... 13 Background ............................................................................................................ 14 Emulsions ..................................................................................................... 14 Multiple emulsions ....................................................................................... 15 Instability mechanisms ................................................................................. 16 Emulsion characteristics ............................................................................... 18 Pickering Emulsions ..................................................................................... 21 Starch............................................................................................................ 25 Size, shape and morphology of starch granules .................................. 25 Small granular starches ........................................................................ 25 Structure of starch granules ................................................................. 27 Bioavailability/digestibility ................................................................. 29 Gelatinization ...................................................................................... 29 Retrogradation ..................................................................................... 31 Modified starch ............................................................................................ 32 Starch as emulsion stabilizer ........................................................................ 33 Molecular starch .................................................................................. 33 Starch particles .................................................................................... 33 Functionality and application of Pickering emulsions ................................. 34 Process stability ................................................................................... 34 Encapsulation ...................................................................................... 35 vi Lipolysis inhibition .............................................................................. 37 General Methods .................................................................................................... 39 Isolation, modification and characterization of starch granules ................... 39 Isolation of starch ................................................................................ 39 OSA modification ................................................................................ 40 Characterization of starch granules ..................................................... 41 Emulsification and characterization of emulsions ........................................ 42 Emulsification ..................................................................................... 42 Accelerated stability test ...................................................................... 43 Application of heat treatment .............................................................. 43 Emulsions droplet size characterization .............................................. 44 Assessment of functional properties of starch Pickering emulsions ............ 45 Process stability ................................................................................... 45 Encapsulation stability ......................................................................... 46 Physiological stability ......................................................................... 47 Summary of the main results .................................................................................. 51 Section I (papers I and II) ............................................................................. 51 Section II (papers III and IV) ....................................................................... 58 Section III (papers V and VI) ....................................................................... 64 Conclusions ............................................................................................................ 74 Section I (papers I and II) ............................................................................. 74 Section II (papers III and IV) ....................................................................... 75 Section II (papers V and VI) ........................................................................ 75 Future perspectives ................................................................................................. 77 Acknowledgements ................................................................................................ 79 References .............................................................................................................. 81 vii
Description:The list of books you might like
