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2.6.1 Factors affecting rice starch retrogradation The rate of rice starch retrogradation depends on a number of variables, including the structures and ratio of amylose and amylopectin, storage temperature, starch concentration, botanical sources of the starch and the presence and concentration of other ingredients, such as surfactants and salts. The retrogradation kinetics of starch has received wide attention though the underlying mechanism of retrogradation has not been concluded. Lai et al. (2000) reported the retrogradation kinetics of pure amylopectin from 13 rice cultivars. Generally, the amylopectin systems showed two stages of retrogradation behavior during early (< 7 days) and late (>7 days) storage. Correlation analysis suggested that the kinetics of early stage retrogradation were more correlated than the late stage retrogradation with the number-average molecular weight and chain lengths of the amylopectin molecules. The proportion of short, long and extra long chain fractions appeared to have greater effects on the enthalpy changes and late stage kinetics than the other structural factors. 1) Structures and ratio of amylose and amylopectin Tako and Hizukuri (2000) proposed some mechanisms for rice starch retrogradations which are based on the formation of hydrogen bonding at various levels. It is assumed that intramolecular hydrogen bonding may take place between OH-6 and the adjacent hemiacetal oxygen atom of the D-glucosyl residues. Intermolecular hydrogen bonding my take place between OH-2 of the amylopectin and an adjacent OH-6 of the amylose. Another intermolecular hydrogen bond may form between OH-2 of a D-glucose residue of the former molecule and OH-6 of a Dglucose residue of short side chain (A and B1) of the latter molecule. After saturation of intermolecular hydrogen bonding between amylose and amylopectin molecules, an intermolecular association may also take between amylopectin molecules through hydrogen bonding. The mechanism of retrogradation is complicated because retrogradation rate may vary from one cultivar to another due to differences in the proportion and interaction of amylopectin and amylose, chain length distribution, and molecular size of branched molecules (Hizukuri, 1986). The 1,4–linked α-D-glucan 29
amylose is the linear fraction of starch. Commercial samples of amylose usually occur in retrograded, water insoluble form, which can be solubillized by pressure cooking at 150-160 o C. On cooling, amylose solutions of 2% or higher concentrations, prepared in this way, rapidly gel, while at concentrations lower than 2% precipitation occurs (Schoch, 1964). Amylose is also soluble in dilute alkali, and rapid neutralization of concentrations greater than 2% results in gel formation. Both the gelation of amylose from concentrated solutions and precipitation from dilute solution can be termed retrogradation. The gels and precipitates formed result from the inherent tendency of amylose molecules to undergo conformational ordering and to tendency of amylose molecules to undergo conformation ordering and to subsequently align or aggregate (Gidley and Bulpin, 1989). The rate of retrogradation increases with increasing amylose concentration and with decreasing temperature and is greatest at pH 5-7. In addition, the retrogradation rate has a sharp maximum at amylose degree of polymerization (DP) of 80, shorter and longer molecules being much more soluble (Ring et al. 1987 and Jacobson et al. 1997). Goodfellow and Wilson (1990) studied the retrogradation of amylose using Fourier Transform Infrared (FT-IR). They found that helix formation must occur before the creation of crystallites; therefore double helix must form at the short or early on in the gelation process. Thus in summary, a same time as phase separation, to create a gel network, with subsequent aggregation of these helices producing crystallinity would be consistent with the experimental data (Figure 9). The IR results for amylopectin suggest an initial fast change followed by a much slow change. Previous IR work by Wilson et al. (1987) in which the spectra for amylopectin from 6 to 340 hour were obtained suggest that FT-IR and G´ monitor the same process-namely the crystallization of the amylopectin side chains followed by a slow aggregation of these helices to produce crystallinity (Figure 9) . 30
Page 1: THESIS ENZYME-RESISTANT STARCH TYPE
Page 5 and 6: ACKNOWLEDGEMENTS I wish to express
Page 7 and 8: LIST OF TABLES Table Page 1 Classif
Page 9 and 10: LIST OF TABLES (Continued) Table Pa
Page 11 and 12: LIST OF FIGURES (Continued) Figure
Page 13 and 14: LIST OF FIGURES (Continued) Appendi
Page 15 and 16: LIST OF ABBREVIATIONS (Continued) R
Page 17 and 18: 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: morphological changes occurring at
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 and 70: Action pattern: The amyloglucosidas
Page 71 and 72: methods, for instance in scanning e
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
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2.1.1 Cake sample preparation Cake
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Nevertheless, the former refers to
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3. Experimental Design and Statisti
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essentially linear polymer of α-(1
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hydrolysis of the rice starch prehe
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a) b) Figure 15 Scanning electron m
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amylose content of starch had a har
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Degree of syneresis (%) 70.0 60.0 5
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1.2.7 Physicochemical properties of
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1.2.8 In vitro starch digestibility
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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
Page 163 and 164:
2.2.3 Chemical composition of RS II
Page 165 and 166:
Table 27 Mean values for chemical c
Page 167 and 168:
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
Page 181 and 182:
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.
Page 187 and 188:
Hoseney, R.C. 1990. Principles of C
Page 189 and 190:
Juliano, B.O. and M.S. Goddard. 198
Page 191 and 192:
Lavin, M., E. Eshbaugh, J.-M. Hu, S
Page 193 and 194:
Ludwig, D.S. and R.H. Eckel. 2002.
Page 195 and 196:
Meilgaard, M., Civille, O.V., and C
Page 197 and 198:
Nakazawa, F., S. Noguchi, J.Takahas
Page 199 and 200:
Piyarat, N. 2003. The assessment of
Page 201 and 202:
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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