Studies of the encapsulation and release of carbon dioxide from amorphous and crystalline alpha cyclodextrin powders and its application in food systems

Studies of the Encapsulation and Release of Carbon Dioxide from Amorphous and Crystalline Alpha-Cyclodextrin Powders and Its Application in Food Systems Minh Thao Ho M.Eng (Food Engineering and Bioprocess Technology) and B.Eng (Food Technology) A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2017 School of Agriculture and Food Sciences Abstract Carbon dioxide gas has been widely used in food production Nevertheless, the conventional ways to utilize CO2 gas have limitations in terms of safety, convenience, handling and storage To offer a safe and convenient approach to use CO2 gas, the production of food-grade CO2 powder in which CO2 release can be controlled was investigated Conventionally, such gas powder has been produced via molecular encapsulation, accomplished by compression of the gas into either a solution of alpha-cyclodextrin (-CD) or crystalline -CD in a solid state However, shortcomings (low yield or stability of the complex) of these techniques have prevented their actual application In this project, an innovative method to produce CO2--CD complex powder with high yield and stability was investigated using amorphous spray-dried α-CD powder followed by crystallization of the complex Due to a lack of understanding of amorphous α-CD powder properties and the complexities of conventional methods to quantify CO2 in solid systems, the project commenced with the characterization of α-CD powders and the development of a simple system to determine the amount of encapsulated CO2 The study of the structure of α-CD powders revealed that spray drying of α-CD solution resulted in a completely amorphous powder (Tg  83oC) The differences in molecular structure between crystalline and amorphous α-CDs were illustrated by the analytical results of SEM, X-ray, FTIR, DSC, TGA and 13C-NMR The study of moisture sorption showed that an amorphous α-CD powder adsorbed more water than its crystalline counterpart at the same aw but it crystallized as it was equilibrated at higher than 65% RH (>13.70g moisture/100 g of dry solids) A simple system to quantify the CO2 in the complex through measuring the amount of CO2 released from the complex into an air-tight chamber headspace by using an infra-red CO2 probe was designed and tested The concentrations measured using this new system and conventional acidbase titration were insignificantly different (p > 0.05) This was also validated by the gas chromatography method A study of solid encapsulation of crystalline (9.84% MC, w.b.) and amorphous (5.58% MC, w.b.) αCD powders at 0.4-1.6 MPa for 0-96 h showed that amorphous α-CD encapsulated a much larger quantity of CO2 than the crystalline form at low pressure and short time (p < 0.05) An increase in pressure and prolongation of the time increased encapsulation capacity (EC) of α-CD, especially for the crystalline form The highest EC of crystalline α-CD was 1.45 mol CO2/mol α-CD, which was markedly higher than that of amorphous α-CD (0.98 mol CO2/mol α-CD) Solid encapsulation did ii not affect the structure of amorphous α-CD, but slightly altered the structure of crystalline α-CD Peak representing the encapsulated CO2 in the complex was clearly observed on the FTIR (2334 cm-1) and NMR (125.3 ppm) spectra However, the complexes were not stable enough for actual application, especially those produced from amorphous α-CD To improve the stability of CO2 gas, crystallization of CO2-amorphous α-CD complex was developed To achieve this, initially water was added to the amorphous α-CD powder to increase its MC to around its crystallization induced level (13, 15 and 17% MC, w.b.), and complexation was undertaken under 0.4-1.6 MPa and compared with crystalline CD complexation The results showed that the EC of amorphous α-CD significantly increased up to 1.1-1.2 mol CO2/mol α-CD Under the same conditions, the EC of crystalline α-CD showed a considerable decline with an increase of initial MC The phase transformation of amorphous α-CD powder during complexation was clearly observed in the analytical results of SEM, FTIR, X-ray, NMR and DSC The crystals of the complex have a cage-type structure entrapping the CO2 molecules into isolated cavities However, a large amount of water on the complex surface (aw > 0.95) due to crystallization made it still low in stability Dehydration of the crystallised complex produced from amorphous -CD powder to improve its stability by desiccant adsorption using silica gel and CaCl2 desiccants, and release properties of the desiccated complex in air, water and oil media, were investigated CaCl2 reduced the complex aw faster, with less CO2 loss during dehydration, than using silica gel Dehydration dramatically improved the complex stability The release rate of CO2 markedly increased with an increase in RH, and was much faster in water than in oil However, almost none of the CO2 was released from the complex kept in airtight packaging during storage One potential application for controlling the mould and yeast growth in cottage cheese was investigated by direct mixing of the dehydrated CO2 powder (0.5-0.6 mol CO2/mol α-CD) into the product before packing The results showed a significant inhibition of the mould and yeast growth during storage of cottage cheese at temperatures of and 25oC This demonstrated the ease of use of CO2 powder in food products if CO2 gas is needed to extend the shelf-life of these products iii Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis I have clearly stated the contribution of others to my thesis as a whole, including statistical assistance, survey design, data analysis, significant technical procedures, professional editorial advice, and any other original research work used or reported in my thesis The content of my thesis is the result of work I have carried out since the commencement of my research higher degree candidature and does not include a substantial part of work that has been submitted to qualify for the award of any other degree or diploma in any university or other tertiary institution I have clearly stated which parts of my thesis, if any, have been submitted to qualify for another award I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the policy and procedures of The University of Queensland, the thesis be made available for research and study in accordance with the Copyright Act 1968 unless a period of embargo has been approved by the Dean of the Graduate School I acknowledge that copyright of all material contained in my thesis resides with the copyright holder(s) of that material Where appropriate I have obtained copyright permission from the copyright holder to reproduce material in this thesis iv Publications during candidature a Peer-reviewed papers: 1) HO, T M., HOWES, T & BHANDARI, B R 2014 Encapsulation of gases in powder solid matrices and their applications: A review Powder Technology, 259, 87-108 2) HO, T M., HOWES, T & BHANDARI, B R 2015 Characterization of crystalline and spraydried amorphous α-cyclodextrin powders Powder Technology, 284, 585-594 3) HO, T M., HOWES, T & BHANDARI, B R 2015 Encapsulation of CO2 into amorphous and crystalline α-cyclodextrin powders and the characterization of the complexes formed Food Chemistry, 187, 407-415 4) HO, T M., TRUONG, T., HOWES, T & BHANDARI, B R 2016 Method of measurement of CO2 adsorbed into -cyclodextrin by infra-red CO2 probe International Journal of Food Properties, 19(8), 1696-1707 5) HO, T M., HOWES, T & BHANDARI, B R 2016 Methods to extend the shelf-life of cottage cheese - A review International Journal of Dairy Technology, 69(3), 313-327 6) HO, T M., HOWES, T & BHANDARI, B R 2016 Encapsulation of CO2 into amorphous alpha-cyclodextrin powder at different moisture contents - Part 1: Encapsulation capacity and stability of inclusion complexes Food Chemistry, 203, 348-355 7) HO, T M., HOWES, T., JACK, K S & BHANDARI, B R 2016 Encapsulation of CO into amorphous alpha-cyclodextrin powder at different moisture contents - Part 2: Characterization of complex powders and determination of crystalline structure Food Chemistry, 206, 92-101 8) HO, T M., HOWES, T & BHANDARI, B R 2016 Dehydration of CO2--cyclodextrin complex powder by desiccant adsorption method and its release properties Journal of Microencapsulation, 33(8), 763-772 9) HO, T M., TRUONG, T & BHANDARI, B R 2017 Methods to characterize the structure of food powders - A review Bioscience, Biotechnology, and Biochemistry, 81(4), 651-671 v 10) SHRESTHA, M., HO, T M & BHANDARI, B R 2017 Encapsulation of tea tree oil by amorphous beta-cyclodextrin powder Food Chemistry, 221, 1474-1483 b Book chapters: 1) HO, T M., TRUONG, T & BHANDARI, B R 2017 Spray-Drying and Non-Equilibrium States/Glass Transition In BHANDARI, B R & YRJÖ R (Eds.), Non-Equilibrium States and Glass Transitions in Foods, Processing Effects and Product-Specific Implications Chapter 5, p 111-136 Duxford: Woodhead Publishing (Elsevier) c Conference abstracts and presentations: 1) HO, T M., HOWES, T & BHANDARI, B R 2015 Characterization of amorphous -CD powder and its CO2 encapsulation capacity In 12th International Congress on Engineering and Food (ICEF12); Québec, Canada, 14-18 June, 2015 (poster presentation) 2) HO, T M., HOWES, T & BHANDARI, B R 2016 Characterization of carbon dioxide containing powder produced from amorphous alpha-cyclodextrin powder In 2nd International Conference on Food and Environmental Sciences (ICFES 2016); Ho Chi Minh, Vietnam, 24-25 February, 2016 (oral presentation) 3) HO, T M., HOWES, T & BHANDARI, B R 2016 Carbon dioxide powder production - an innovative application to extend the shelf life of cottage cheese In 2nd Asia Australia Food Innovations Conference (AAFIC 2016); Perth, Australia, 17-18 March, 2016 (oral presentation) 4) BHANDARI, B R., HO, T M & HO, B.T 2016 Molecular inclusion of gases by amorphous structure of -cyclodextrins 13th International Symposium on the Properties of Water (ISOPOW XIII); Olympic Museum in Lausanne, Switzerland, 26-29 June, 2016 (oral presentation) 5) HO, T M., HOWES, T & BHANDARI, B R 2016 An innovative approach to produce foodgrade carbon dioxide containing powder from alpha-cyclodextrin powder In The 33rd Cyclodextrin Symposium; Kagawa, Japan, 8-9 September, 2016 (poster presentation) vi 6) BHANDARI, B R., HO, T M & SHRESTHA, M 2016 Production, properties and application of amorphous cyclodextrins In The 33rd Cyclodextrin Symposium; Kagawa, Japan, 8-9 September, 2016 (oral presentation) Publications included in this thesis 1) HO, T M., HOWES, T & BHANDARI, B R 2014 Encapsulation of gases in powder solid matrices and their applications: A review Powder Technology, 259, 87-108 Several parts of this publication was incorporated into Chapter Contributors Thao M Ho (Candidate) Tony Howes (thesis co-advisor) Bhesh R Bhandari (thesis principle advisor) Statement of contribution - Developed the outline of review (85%) - Wrote the paper (70%) - Edited the paper (10%) - Developed the outline of review (15%) - Edited the paper (20%) 2) HO, T M., HOWES, T & BHANDARI, B R 2015 Characterization of crystalline and spraydried amorphous α-cyclodextrin powders Powder Technology, 28, 585-594 This publication was incorporated as Chapter Contributors Statement of contribution - Designed experiments (70%) Thao M Ho (Candidate) - Carried out experiments (100%) - Analysed experimental data (80%) - Wrote the paper (70%) Tony Howes (thesis co-advisor) - Analysed experimental data (5%) - Edited the paper (5%) - Designed experiments (30%) Bhesh R Bhandari (thesis principle advisor) - Analysed experimental data (15%) - Edited the paper (25%) 3) HO, T M., TRUONG, T., HOWES, T & BHANDARI, B R 2016 Method of measurement of CO2 adsorbed into -cyclodextrin by infra-red CO2 probe International Journal of Food Properties, 19(8), 1696-1707 This publication was incorporated as Chapter vii Contributors Statement of contribution - Designed experiments (70%) Thao M Ho (Candidate) - Carried out experiments (95%) - Analysed experimental data (80%) - Wrote the paper (70%) Tuyen T Truong Tony Howes (thesis co-advisor) - Carried out experiments (5%) - Analysed experimental data (5%) - Edited the paper (5%) - Designed experiment (30%) Bhesh R Bhandari (thesis principle advisor) - Analysed experimental data (15%) - Edited the paper (25%) 4) HO, T M., HOWES, T & BHANDARI, B R 2015 Encapsulation of CO2 into amorphous and crystalline α-cyclodextrin powders and the characterization of the complexes formed Food Chemistry, 187, 407-415 This publication was incorporated as Chapter Contributors Statement of contribution - Designed experiments (70%) Thao M Ho (Candidate) - Carried out experiments (100%) - Analysed experimental data (80%) - Wrote the paper (70%) Tony Howes (thesis co-advisor) - Edited the paper (5%) - Designed experiment (30%) Bhesh R Bhandari (thesis principle advisor) - Analysed experimental data (20%) - Edited the paper (25%) 5) HO, T M., HOWES, T & BHANDARI, B R 2016 Encapsulation of CO2 into amorphous alpha-cyclodextrin powder at different moisture contents - Part 1: Encapsulation capacity and stability of inclusion complexes Food Chemistry, 203, 348-355 This publication was incorporated as Chapter viii Contributors Statement of contribution - Designed experiments (70%) - Carried out experiments (100%) Thao M Ho (Candidate) - Analysed experimental data (80%) - Wrote the paper (70%) Tony Howes (thesis co-advisor) - Edited the paper (5%) - Designed experiments (30%) Bhesh R Bhandari (thesis principle advisor) - Analysed experimental data (20%) - Edited the paper (25%) 6) HO, T M., HOWES, T., JACK, K.S & BHANDARI, B R 2016 Encapsulation of CO2 into amorphous alpha-cyclodextrin powder at different moisture contents - Part 2: Characterization of complex powders and determination of crystalline structure Food Chemistry, 206, 92-101 This publication was incorporated as Chapter Contributors Statement of contribution - Designed experiments (70%) - Carried out experiments (100%) Thao M Ho (Candidate) - Analysed experimental data (75%) - Wrote the paper (70%) Tony Howes (thesis co-advisor) - Edited the paper (5%) - Designed experiments (5%) Kevin S Jack - Analysed experimental data (5%) - Edited the paper (5%) - Designed experiments (25%) Bhesh R Bhandari (thesis principle advisor) - Analysed experimental data (20%) - Edited the paper (20%) 7) HO, T M., HOWES, T & BHANDARI, B R 2016 Methods to extend the shelf-life of cottage cheese - A review International Journal of Dairy Technology, 69(3), 313-327 Several parts of this publication was incorporated as Chapters and ix Contributors Thao M Ho (Candidate) Tony Howes (thesis co-advisor) Bhesh R Bhandari (thesis principle advisor) Statement of contribution - Developed the outline of review (85%) - Wrote the paper (75%) - Edited the paper (10%) - Developed the outline of review (15%) - Edited the paper (15%) 8) HO, T M., HOWES, T & BHANDARI, B R 2016 Dehydration of CO2--cyclodextrin complex powder by desiccant adsorption method and its release properties Journal of Microencapsulation, 33(8), 763-772 This publication was incorporated as Chapter Contributors Statement of contribution - Designed experiments (70%) Thao M Ho (Candidate) - Carried out experiments (100%) - Analysed experimental data (80%) - Wrote the paper (70%) Tony Howes (thesis co-advisor) - Edited the paper (5%) - Designed experiments (30%) Bhesh R Bhandari (thesis principle advisor) - Analysed experimental data (20%) - Edited the paper (25%) 9) HO, T M., TRUONG, T & BHANDARI, B R 2017 Methods to characterize the structure of food powders - A review Bioscience, Biotechnology, and Biochemistry 81 (4), 651-671 Several parts of this publication was incorporated into Chapter Contributors Thao M Ho (Candidate) Tuyen T Truong Bhesh R Bhandari (thesis principle advisor) Statement of contribution - Developed the outline of chapter (80%) - Wrote the paper (65%) - Developed the outline of review (5%) - Wrote and edited the paper (30%) - Developed the outline of review (15%) - Edited the paper (5%) x ... 2008) The type of the stacking of complex molecules during their crystallisation may also influence the encapsulation capacity of CD and stability of complex In this regard, an understanding of the. .. SIKORSKI, C T 1995 Use of cyclodextrins for encapsulation in the use and treatment of food products In: RISCH, S J & REINECCIUS, G A (eds.), Encapsulation and Controlled Release of Food Ingredients, vol... 3) HO, T M., HOWES, T & BHANDARI, B R 2015 Encapsulation of CO2 into amorphous and crystalline α -cyclodextrin powders and the characterization of the complexes formed Food Chemistry, 187, 407-415