Synthesis and Microencapsulation of Structured Lipids
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SYNTHESIS AND MICROENCAPSULATION OF STRUCTURED LIPIDS CONTAINING LONG-CHAIN POLYUNSATURATED FATTY ACIDS FOR POSSIBLE APPLICATION IN INFANT FORMULAS by SUPAKANA NAGACHINTA (Under the Direction of Casimir C. Akoh) ABSTRACT It has been well established that lower fat absorption in infants, fed with formula, is due to the difference between the regiospecificity of the palmitic acid in the vegetable oil blend versus that present in human milk fat (HMF). In HMF, most of the palmitic acids are esterified at the sn-2 position of the triacylglycerols (TAGs). However, in vegetable oil, they are predominantly present at the sn-1, 3 positions. Structured lipids (SLs), with fatty acid profiles and positional distributions similar to HMF, were developed via a single step enzymatic modification of either palm olein or tripalmitin. These SLs also were also enriched with long-chain polyunsaturated fatty acids (LCPUFAs), such as docosahexaenoic (DHA) and arachidonic (ARA), which are important for infant brain and cognitive development. SL from modified tripalmitin contained 17.69% total ARA, 10.75% total DHA, and 48.53% sn-2 palmitic acid. Response surface methodology was employed to study the effect of time, temperature, and substrate molar ratio on the incorporation of palmitic acid at the sn-2 position, and the total incorporation of LCPUFAs. Physicochemical properties of SLs were characterized for TAGs molecular species, melting and crystallization thermograms, and fatty acid positional distribution. SLs in powdered form were obtained by microencapsulation, using Maillard reaction products (MRPs) of heated protein- polysaccharide conjugates as encapsulants, followed by spray-drying. SL-encapsulated powders had high microencapsulation efficiency and oxidative stability. Infant formula prepared with microencapsulated SL in a dry-blending method, had a better oxidative stability and color quality than the formula prepared with non-microencapsulated SL in a wet-mixing/spray-drying method. INDEX WORDS: infant formula, structured lipid, lipase, enzymatic modification, microencapsulation, LCPUFAs SYNTHESIS AND MICROENCAPSULATION OF STRUCTURED LIPIDS CONTAINING LONG-CHAIN POLYUNSATURATED FATTY ACIDS FOR POSSIBLE APPLICATION IN INFANT FORMULAS by SUPAKANA NAGACHINTA B.Sc. Mahidol University International College, Thailand, 2004 M.Sc. The University of Georgia, USA, 2007 A Dissertation Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY ATHENS, GEORGIA 2013 © 2013 Supakana Nagachinta All Rights Reserved SYNTHESIS AND MICROENCAPSULATION OF STRUCTURED LIPIDS CONTAINING LONG-CHAIN POLYUNSATURATED FATTY ACIDS FOR POSSIBLE APPLICATION IN INFANT FORMULAS by SUPAKANA NAGACHINTA Major Professor: Casimir C. Akoh Committee: William L. Kerr Rakesh K. Singh Robert L. Shewfelt Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia May2013 DEDICATION To my wonderful parents and family. iv ACKNOWLEDGEMENTS I would like to thank Dr. Casimir C. Akoh for the opportunity to do my research in his group and for his support and guidance. I also would like to thank Dr. Joseph Frank and Dr. Jinru Chen for giving me opportunities to work with them prior to my transition into food chemistry area. I am grateful for the department funding, and would like to thank Dr. Rakesh K. Singh, Dr. Mark Harrison, and Karen Simmons. Thank you my wonderful lab group for your kind support. Special thanks to Garima Pande and Leslie Kleiner. I would like to thank Dr. Rakesh K. Singh, Dr. Robert Shewfelt, and Dr. William Kerr for their advice and for acting in my committee. Lastly, I would like to thank my parents and family for their endless love and encouragement. v TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ................................................................................................ v LIST OF TABLES ............................................................................................................. ix LIST OF FIGURES ............................................................................................................ xi CHAPTER 1 INTRODUCTION ............................................................................................. 1 REFERENCES……………………………………………………. ........... 4 2 LITERATURE REVIEW .................................................................................. 5 REFERENCES .......................................................................................... 24 3 ENRICHMENT OF PALM OLEIN WITH LONG-CHAIN POLYUNSATURATED FATTY ACIDS BY ENZYMATIC ACIDOLYSIS… ............................... ………………………………………..41 ABSTRACT .............................................................................................. 42 INTRODUCTION ..................................................................................... 43 MATERIALS AND METHODS .............................................................. 45 RESULTS AND DISCUSSION ................................................................ 51 ACKNOWLEDGMENTS ......................................................................... 57 REFERENCES .......................................................................................... 58 vi 4 PRODUCTION AND CHARACTERIZATION OF DHA AND GLA- ENRICHED STRUCTURED LIPID FROM PALM OLEIN FOR INFANT FORMULA USE ............................................................................................. 70 ABSTRACT .............................................................................................. 71 INTRODUCTION ..................................................................................... 72 MATERIALS AND METHODS .............................................................. 74 RESULTS AND DISCUSSION ................................................................ 80 CONCLUSION ......................................................................................... 85 ACKNOWLEDGEMENTS ...................................................................... 86 REFERENCES .......................................................................................... 86 5 SYNTHESIS OF STRUCTURED LIPID ENRICHED WITH OMEGA FATTY ACIDS AND SN-2 PALMITIC ACID BY ENZYMATIC ESTERIFICATION, AND ITS INCORPORATION IN POWDERED INFANT FORMULA ...................................................................................... 99 ABSTRACT ............................................................................................ 100 INTRODUCTION ................................................................................... 101 MATERIALS AND METHODS ............................................................ 103 RESULTS AND DISCUSSION .............................................................. 110 ACKNOWLEDGEMENTS .................................................................... 116 REFERENCES ........................................................................................ 117 6 SPRAY-DRIED STRUCTURED LIPID CONTAINING LONG-CHAIN POLYUNSATURATED FATTY ACIDS FOR USE IN INFANT FORMULAS……………………………………………………….……….134 vii ABSTRACT ............................................................................................ 135 INTRODUCTION ................................................................................... 136 MATERIALS AND METHODS ............................................................ 138 RESULTS AND DISCUSSION .............................................................. 142 CONCLUSION ....................................................................................... 147 ACKNOWLEDGEMENTS .................................................................... 147 REFERENCES ........................................................................................ 148 7 CONCLUSIONS ........................................................................................... 160 viii LIST OF TABLES Page Table 2.1: Major TAGs in natural fats and oils used for synthesis of SLs ........................ 37 Table 2.2: European union guidelines for the composition of infant milk formula .......... 38 Table 2.3: Recommended dietary intakes for total fat and fatty acid intake: infant (0-24 months) .................................................................................................................. 39 Table 2.4: Summary of key features of the spray-drying conditions used in the production of encapsulated vitamins, minerals, flavors, PUFA oils, and probiotic microorganisms ..................................................................................................... 40 Table 3.1: Central composition face design arrangement with levels of factors and the DHA+ARA incorporation (g/100g) ...................................................................... 63 Table 3.2: Predicted and observed values from RSM model verification ......................... 64 Table 3.3: Fatty acid composition of original oils, and structured lipid and their sn-2 positional fatty acid composition (g/100g) ............................................................ 65 Table 4.1: Percent incorporation of DHA, GLA, total DHA and GLA, and sn-2 palmitic acid in SL by acidolysis using RSM conditions .................................................... 91 Table 4.2: Predicted and observed values (%) from RSM model verification .................. 92 Table 4.3: Total and positional distribution of fatty acids (%) of substrates and produced SL 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