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2.7 Rice starch digestibility Starch that is resistant to digestion is thought to offer humans some protection from the development of various chronic diseases (Topping and Clifton, 2001). There have been several reports that have linked amylose content to rice starch digestibility (Goddard et al. 1984 and Noda et al. 2003). However, it has been found that similar hydrolysis of raw starch by amylase occurred with waxy and non waxy rice cultivars. Perez et al. (1991) reported that rice cultivars with similar amylose content varied in starch digestibility, the difference being associated with other properties, such as GT, cooking time, amylograph consistency, and volume expansion upon cooking. Therefore, amylose content alone is not a predictor of starch digestion rate (Perez et al. 1991). Zhang et al. (1996) showed that japonica waxy rice flour with different X-ray diffraction patterns differed in starch digestion, the percent digestion of group II flour was higher than group I flour, either with glucoamylase or with alpha-amylase. The authors suggested that the starch in group II had a looser structure arrangement, at the molecular level, than did those in group I. These allowed the enzymes to penetrate rapidly into the starch granules in group II. Perhaps, then, amylopectin may play a role in conferring the rate of rice starch digestion. Processing techniques are also reported to impact the rate of rice starch digestion. Parboiling reportedly decreases rice starch rate of digestion (Tetens et al. 1997). Rashmi and Urooj (2003) found that the steaming of rice created more resistant starch than boiling or pressure cooking. Storage under refrigeration also has been reported to slow the rate rice starch digestion (Frei et al. 2003). Kim et al. (2006) studied the effects of amylose content, autoclaving, parboiling, extrusion, and postcooking treatments on resistant starch (RS) content of different rice cultivars. They found that the extent of RS formation was significantly influenced by the amylose content of rice, volume of water used for cooking and cooling after cooking. The higher-amylose rice variety had more resistant starch than the loweramylose variety. The amounts of RS were between 0.1 to 0.26g/ 100g DM for raw rice and 0.13 to 0.14g/100g DM for extruded rice. The resistant starch formation in 37
ice due to the various cooking and cooling combinations under test ranged from 0.6 g to 5.1 g/100 g DM. Decreasing the rice : water ratio (1:2) and cooling (24 hr at 4 o C) after cooking significantly increased the RS content. Extrusion decreased the RS content in the high RS rice only (0.42 – 0.16 g/100 g). 2.8 Glycemic index of rice starch The glycemic index (GI) is a physiological concept used to classify carbohydrate containing foods. It is closely tied in with the term ‘glycaemic response’. Both refer to the ability of a particular food to elevate postprandial blood glucose concentrations. GI is measured as the incremental area under the blood glucose curve after consumption of 50 g of available carbohydrate from a test food, divided by the area under the curve after eating a similar amount of available carbohydrate in a control food (generally white bread or glucose) (Ludwig and Eckel, 2002). Foods with high GI value release glucose rapidly into the blood stream (elicit a rapid glycaemic response), while foods with a low GI value release glucose more slowly into the bloodstream and result in improved glycaemic and insulinaemic responses. Waxy and low-amylose rice had higher glycaemic indices than intermediate- and high-amylose rice (Goddard and Marcus, 1984; Juliano and Goddard, 1986; Jiraratsatit et al. 1987; Tanchoco et al. 1990), (Table 4). Processing, such as parboiling and noodle-making, tends to reduce the glycaemic index of rice, particularly which of high- and intermediate-amylose rice (Panlasigui, 1989; Wolever et al. 1986). By contrast, Tsai et al. (1990) reported that waxy rice, rice gruel, steamed rice and rice noodles had similar glycaemic indices to that of white bread in NIDDM patients. Among high-amylose rice, the low-GT, hard-gel IR42 had a higher glycaemic index than the intermediate-GT, softer-gel IR36 and IR62 (Panlasigui, 1989). By contrast, Srinivasa Rao (1970) reported that the ingestion of hard-gel IR8 resulted in a lower peak plasma glucose level than ingestion of the softer-gel both have high amylose and low GT. 38
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 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: Figure 10 Schematic diagram showing
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
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
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essentially linear polymer of α-(1
Page 107 and 108:
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
Page 117 and 118:
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
Page 137 and 138:
2 An application of resistant starc
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sucrose or maltose are reducing suc
Page 141 and 142:
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
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.
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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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