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under severe conditions caused depolymerization and deacetylation. Shahidi and Synowiecki (1991) reported a 2 hr extraction period for removal of all proteins present in the shells. These workers also observed that relatively high ratios of solid to alkali solution, 1:10 or above is usually used to obtain uniformity in reaction with proper agitation. Cho and No (1999) performed deproteinization by autoclaving under conditions of 15 psi/121 o C with 3% NaOH for 15min and a solid: solvent ratio of 1:10. Their results showed that deproteinization can effectively be achieved by autoclaving conditions because no significant differences in nitrogen content and bulk density as well as water and fat binding capacity were observed. Rout (2001) investigated the effects of process modification of crawfish chitin and chitosan production by reversing the first two steps (deproteinization or demineralization) or reducing the number of steps (deproteinization or decoloration or both) on fat and water binding capacities of chitin and chitosans; he reported that simplifying the process affected both water and fat binding capacities. Among crab and crawfish chitosans, the DMPA crawfish chitosan had the highest fat binding capacity. No et al. (2002) investigated the effects of elimination of deproteinization step or reduction of alkali treatment time on physicochemical and functional properties of chitosan products. Chitosan prepared without deproteinization had comparable nitrogen content, lower degree of deacetylation, solubility, water and fat binding capacity, and lower dye binding capacity, but higher molecular weight and viscosity than chitosans prepared with deproteinization treatment. 2.5.2 Demineralization Demineralization is conventionally accomplished by extraction with dilute hydrochloric acid at room temperature to dissolve calcium carbonate to calcium chloride. Among such 26
methods are those of Hackman (1954), Anderson et al. (1978), Bough et al. (1978), and No et al. (1989). But, reaction time varied with preparation methods from 30 min (No et al., 1989) to over 2 days (Hackman, 1954). However, Synowiecki et al. (1981) and Chen et al. (1994) accomplished demineralization with 22% HCl and 6N HCl, respectively, at room temperature. To avoid modifications such as depolymerization or deacetylation caused by harsh treatments, Austin et al. (1981) suggested the use of mild acids such as ethylenediaminetetra-acetic acid (EDTA) for decalcification. Prolonged demineralization time for up to 24 hr results in only a very slight drop in the ash content but can cause polymer degradation (Brzeski, 1982) or decreased viscosity (Moorjani et al., 1975). Also it is important that the amount of acid be stoichimetrically equal to or greater than all minerals present in the shells to ensure complete reaction (Johnson and Peniston, 1982; Shahidi and Synowiecki, 1991). 2.5.3 Decoloration When bleached chitin is desired, pigments can be removed with reagents. Hackman (1954) obtained a cream-colored lobster chitin by washing with ethanol and ether, and Blumbeg (1951) extracted pigments with cold sodium hypochloride solution, containing 0.5% available chlorine, and Kamasastri (1961) with absolute acetone. Anderson (1978), Brine (1981), and Brzeski (1982) also accomplished decoloration of chitin with chloroform, H2O2, and ethyl acetate, respectively. No et al. (1989) prepared a white colored crawfish chitin by acetone extraction, followed by bleaching with 0.315% sodium hypochlorite solution. However, Moorjani et al. (1975) recommends not to bleach the material at any stage because the bleaching process considerably reduces the viscosity of the final chitosan product. 27
Page 1 and 2: PHYSICOCHEMICAL AND FUNCTIONAL PROP
Page 3 and 4: TABLE OF CONTENTS ACKNOWLEDGEMENTS
Page 5 and 6: LIST OF TABLES 1. Applications of C
Page 7 and 8: ABSTRACT Chitosan is made from chit
Page 9 and 10: CHAPTER 1 INTRODUCTION Chitosan is
Page 11 and 12: Crawfish shell as well as crustacea
Page 13 and 14: 5. Investigate the effect of deacet
Page 15 and 16: With regards to their chemical stru
Page 17 and 18: acetic acid. The second advantage i
Page 19 and 20: lower viscosity chitosan obtained f
Page 21 and 22: not deacetylated sufficiently to be
Page 23 and 24: 2.2.8 Emulsification Even though ch
Page 25 and 26: 2.2.10 Formation of Film Chitosan h
Page 27 and 28: Fortunately, the sequence of demine
Page 29 and 30: of the demineralization process. El
Page 31 and 32: 2.4 Factors Affecting Production of
Page 33: (0.841-0.177 mm) had no effect on t
Page 37 and 38: degree of deacetylation, and molecu
Page 39 and 40: 2.6.3 In Medical In the study condu
Page 41 and 42: 2) DM (Demineralization) Depending
Page 43 and 44: analyze. The encapsulated sample wa
Page 45 and 46: and centrifuged at 10,000 rpm for 1
Page 47 and 48: with 0.03% Oil-Red-O biological sta
Page 49 and 50: CHAPTER 4 RESULTS AND DISCUSSION Re
Page 51 and 52: The shell was almost impossible to
Page 53 and 54: ut the values were slightly higher
Page 55 and 56: %DD values. Thus, accurate determin
Page 57 and 58: degradation of the chitosan structu
Page 59 and 60: treatment for deproteinization. In
Page 61 and 62: chitosan samples, we arbitrarily de
Page 63 and 64: Amongst the five types of oil used,
Page 65 and 66: - 0.5% chitosan solution only. Even
Page 67 and 68: showed 271 ml/g. All modified chito
Page 69 and 70: At 0.1% concentration of chitosan,
Page 71 and 72: CHAPTER 5 SUMMARY AND CONCLUSIONS T
Page 73 and 74: REFERENCES Alimuniar and Zainuddin.
Page 75 and 76: pigment concentration in oil extrac
Page 77 and 78: Jeon, Y.J., Shahidi, F., and Kim, S
Page 79 and 80: Utilization of Louisiana Crawfish P
Page 81 and 82: Ogawa, S., Decker, E., McClememts D
Page 83 and 84: Smith, J.P. Simpson, B.K. and Morri
Page 85 and 86:
APPENDIX A. DATA OF PHYSICOCHEMICAL
Page 87 and 88:
APPENDIX 5. Degree of Deacetylation
Page 89 and 90:
Bulk density (g/ml) APPENDIX 9. Bul
Page 91 and 92:
WBC (%) 1200.0 1000.0 800.0 600.0 4
Page 93 and 94:
APPENDIX 13. Emulsion Capacity Meas
Page 95 and 96:
APPENDIX 15. Emulsion Viscosity Mea
Page 97 and 98:
APPENDIX 18. DMPCA y = 33.471x + 9.
Page 99 and 100:
APPENDIX 21. Vanson 75 y = 21.926x
Page 101 and 102:
APPENDIX C. DATA OF DEGREE OF DEACE
Page 103 and 104:
APPENDIX 27. DPMCA(control) A1655 =
Page 105 and 106:
APPENDIX D. DATA OF AMOUNTS OF OIL
Page 107:
VITA The author was born in Taegu,
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