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5. Mechanisms of RS III formation during cooling, freezing and drying 5.1 The mechanisms of RS III formation during cooling The rate of cooling of the gelatinized starch to the nucleating temperature should be as fast as possible and may be at least about 1°C per min on average, preferably at least about 3°C per min on average, most preferably at least about 4°C per min on average. By cooling to the nucleation temperature rapidly, the propagation of undesirable crystal forms, such as amylose-lipid complexes, is substantially reduced or eliminated. Also, rapid cooling generally promotes the generation of large numbers of small seed crystals, rather than fewer, larger crystals. After nucleation, the nucleated crystals of enzyme-resistant starch type III may be propagated or grown by raising the temperature of the gelatinized starch from the nucleation temperature to a crystal-propagating temperature (Eliasson and Kim, 1992). Propagation of the resistant starch type III crystals may be achieved at a temperature above the melting point of any of amylose-lipid complexes which may have been formed during nucleation. Thus, use of a crystal-propagating temperature above the melting point of the amylose-lipid complexes remelts the complexes, thereby making more amylose available to formation of resistant starch type III. However, the crystal-propagation temperature is maintained below the melting point of the desired crystals of enzyme-resistant starch type III to avoid melting or destroying them. The temperature is preferably raised from the nucleating temperature to the crystal-propagating temperature at a rapid rate to avoid any substantial propagation of undesirable crystals, such as amylose-lipid complexes (Yuan and Thompson, 1998). 5.2 The mechanisms of RS III formation during freeze-thawed process Freezing is a physical treatment widely applied for preservation, drying and lyophilisation of starchy food (Ahmed and Lelievre, 1978). It is also used for sample preparation in granule structural investigations by means of many physical 55
methods, for instance in scanning electron microscopy (SEM) or transmission electron microscopy (TEM) (Hayagava et al. 1998). It was also considered to cause some changes in the nutritional properties of starch (Guraya et al. 2001b). Freezing of starch solutions resulted in their cooperation and increasing retrogradation, while pregelatinised starch became less sensitive to retrogradation and stayed smooth after the process (Waigh et al. 1998) well as Donald et al. (2001) reported that some reversible structural disorder of starch granules occurred at subzero temperatures. Repeated freeze–thawing procedures slightly influenced the water solubility and the water holding capacity, but did not change the branching characteristics of starch granules (Szymonska et al. 2003). Retrogradation is enhanced when starch gels are subjected to freezing and thawing. Freezing of starch gel causes the phase separation upon ice crystal formation. Upon thawing, water can be expressed from the gel known as syneresis. Resistant starch type III is cooked cooled and retrogradation of starch, some of which is resistant to the enzymatic digestion in the human digestive system. In the previous studied retrogradation of starch gels (starch pastes) is often enhanced when they are subjected to freezing and thawing treatments. During freezing, the gel can separate into fractions by the formation of ice crystals, such that the starch is concentrated in a non-ice phase. When thawed, the ice crystals melt to form a mixture of water and gel. The freeze-thaw stability of starch gels has been evaluated by measuring the quantity of liquid that can be separated from a thawed gel after centrifugation (Hood and Scifried, 1974). Varavinit et al. (2002) investigated the freeze-thaw stabilities of three different rice flour gels (amylose rice flour with 28% amylose, Jasmine rice flour with 18% amylose and waxy rice flour with 5% amylose) by first freezing at -18°C for 22 h and subsequent thawing in a water bath at 30°C, 60°C and 90°C. The freeze-thaw stability was determined for five cycles. Starch gels thawed at higher temperature exhibited a lower syneresis value (percent of water separation) than those thawed at lower temperature. Amylose rice flour gels gave the highest syneresis value (especially in the first cycle). The jasmine rice flour gels gave a highest syneresis 56
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THESIS ENZYME-RESISTANT STARCH TYPE
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ACKNOWLEDGEMENTS I wish to express
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LIST OF TABLES Table Page 1 Classif
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LIST OF TABLES (Continued) Table Pa
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LIST OF FIGURES (Continued) Figure
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LIST OF FIGURES (Continued) Appendi
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LIST OF ABBREVIATIONS (Continued) R
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een used to produce a sample with l
Page 19 and 20: Overall objectives: OBJECTIVES 1. T
Page 21 and 22: However, it was discovered that a r
Page 23 and 24: Cassidy et al. (1994), in an intern
Page 25 and 26: fed both the 45 and 63g/100g rice s
Page 27 and 28: only about 3 g. The physiological b
Page 29 and 30: (Brown et al. 1995). This product,
Page 31 and 32: Figure 1 A detailed structure of th
Page 33 and 34: 2.3 Chemical composition of rice st
Page 35 and 36: helix with only the ring oxygen poi
Page 37 and 38: Figure 5 Idealized diagram of the c
Page 39 and 40: 2.5 Rice starch gelatinization Gela
Page 41 and 42: in excess water. The loss of birefr
Page 43 and 44: morphological changes occurring at
Page 45 and 46: amylose is the linear fraction of s
Page 47 and 48: units are known to inhibit retrogra
Page 49 and 50: (-1 to 43 o C) on concentrated star
Page 51 and 52: Figure 10 Schematic diagram showing
Page 53 and 54: ice due to the various cooking and
Page 55 and 56: Recently, there has been a flurry o
Page 57 and 58: 3.1 Processing condition on improve
Page 59 and 60: of RS overall, 60%, among the three
Page 61 and 62: chains but liberates longer chains
Page 63 and 64: 4.1 Amylolytic enzymes Three groups
Page 65 and 66: Structure and properties of β- amy
Page 67 and 68: Structure and properties: The pullu
Page 69: Action pattern: The amyloglucosidas
Page 73 and 74: 6. Low glycemic butter cake product
Page 75 and 76: Sugar increases cake volume by decr
Page 77 and 78: cereals, and baked potatoes. Low gl
Page 79 and 80: way to achieve a healthy food produ
Page 81 and 82: complexes. In the meantime, and inv
Page 83 and 84: would be only 2. In comparison, the
Page 85 and 86: ecause of an absolute decrease in t
Page 87 and 88: enhanced fat oxidation at the expen
Page 89 and 90: 1. Raw Materials MATERIALS AND METH
Page 91 and 92: Methods 1. Production of resistant
Page 93 and 94: 1.2.3 Degree of syneresis Degree of
Page 95 and 96: 1.2.9 Starch hydrolysis rate and es
Page 97 and 98: 1.3.3 Resistant starch content, sta
Page 99 and 100: 2.1.1 Cake sample preparation Cake
Page 101 and 102: Nevertheless, the former refers to
Page 103 and 104: 3. Experimental Design and Statisti
Page 105 and 106: essentially linear polymer of α-(1
Page 107 and 108: hydrolysis of the rice starch prehe
Page 109 and 110: a) b) Figure 15 Scanning electron m
Page 111 and 112: amylose content of starch had a har
Page 113 and 114: Degree of syneresis (%) 70.0 60.0 5
Page 115 and 116: 1.2.7 Physicochemical properties of
Page 117 and 118: 1.2.8 In vitro starch digestibility
Page 119 and 120: 1.2.9 Hydrolysis index and glycemic
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Table 16 Effect of preheated treatm
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1.2.10 Crystallinity of RS III 108
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Figure 22 X-ray diffraction pattern
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content. The high correlation facto
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1.3.2 β-amylolysis (%) 114 β-amyl
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1.3.4 In vitro starch digestibility
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118 Non significant differences (P
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1.4.2 Degree of hydrolysis 120 The
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2 An application of resistant starc
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sucrose or maltose are reducing suc
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126 The different effect of HFCS on
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2.1.2 Sensory evaluation of HFCS re
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and objective percent moisture gene
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132 In the dietetic cake mix of Cor
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3) In vitro starch digestibility 13
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Table 23 Percentage (dwb) of starch
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al. (2006) reported that when gluco
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140 volume, crust and crumb color o
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(P
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2.2.2 Sensory evaluation of RS III
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3) Flavor score 146 Flavor is the m
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2.2.3 Chemical composition of RS II
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Table 27 Mean values for chemical c
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Table 28 Percentage (dwb) of starch
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cake is lower in these samples than
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CONCLUSIONS AND RECOMMENDATIONS 156
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158 syneresis of retrograded starch
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LITERATURE CITED Abe, J.I., K. Naka
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Biliaderis, C.G. and J. Zawastowski
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Cheng, H.H. and M.H. Lai. 2000. Fer
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Elgun, A. Z. Ertugay, M. Certel, an
Page 183 and 184:
Fitt L.E. and E.M. Snyder. 1984. Ph
Page 185 and 186:
Grandfeldt, A., C. Eliasson and I.
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Hoseney, R.C. 1990. Principles of C
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Juliano, B.O. and M.S. Goddard. 198
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Lavin, M., E. Eshbaugh, J.-M. Hu, S
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Ludwig, D.S. and R.H. Eckel. 2002.
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Meilgaard, M., Civille, O.V., and C
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Nakazawa, F., S. Noguchi, J.Takahas
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Piyarat, N. 2003. The assessment of
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Schoch, T. J. 1969. Non-carbohydrat
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Srinivasa Rao, P. 1970. Studies on
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Towar, J., C. Melito, E. Herrera, A
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Yuan, R.C. and D.B. Thompson. 1998.
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Appendix A Chemical analysis proced
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2.2 Method determination 196 Total
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source and detach the extractor and
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5.3 Procedure for Preparation for S
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1) Standard curve procedure 202 Usi
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7. Reducing sugar determination by
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8. Resistant starch determination b
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8.2.3 Measurement of resistant star
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lank. starch. 210 3. Measure the ab
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Appendix B Physical analysis proced
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2. X Ray Diffraction Measurement 2.
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Appendix C Picture of some experime
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Heated debranched samples Cooled de
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Appendix Figure C4 Visuals appearan
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1. Introduction 222 There are sever
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Appendix E Experimental data 224
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Appendix Table E3 X-ray diffraction
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Appendix F List of publications 228
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NAME : Miss Jirapa Pongjanta BIRTH
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THESIS

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