physicochemical and functional properties of crawfish chitosan as ...

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Wet crawfish shell Washing and drying Grinding and sieving Deproteinization Washing Demineralization Washing Decoloration Washing and Drying Deacetylation Washing and Drying Chitosan Figure 4. Traditional Crawfish Chitosan Production Flow Scheme (Modified from No and Meyers, 1995) 18 3.5% NaOH (w/v) for 2 h at 65 o C, solid: solvent (1:10, w/v) 1 N HCl for 30 min at room temp., solid: solvent (1:15, w/v) Extract with Acetone and Bleaching with 0.315% NaOCl (w/v) for 5 min at room temp., solid: solvent (1:10, w/v) 50% NaOH for 30 min at 115 psi / 121 o C., solid:solvent (1:10, w/v)
Fortunately, the sequence of demineralization and deproteinization steps can be reversed. In fact many authors have followed the procedure of acidic decalcification after removal of protein (Muzzarelli, 1977). Though the process normally involves the use of dilute sodium hydroxide and dilute hydrochloric acid for deproteinization and demineralization, respectively, there have been reports indicating several variations of the characteristics of final chitosan products, but this also depends on the crustacean species from which chitin is isolated, and on the production sequence (Cho et al., 1998; No et al., 2000b; Wu and Bough, 1978). The demineralized and deproteinized chitin has a light pink color due to the presence of astaxanthin pigment. When bleached product is desired, this pigment can be eliminated during the decolorization (DC) step. The resulting chitin is insoluble in most organic solvents; however, its deacetylated derivative chitosan is soluble in weak acids. The subsequent conversion of chitin to chitosan is generally achieved by treatment with concentrated sodium hydroxide solution (40- 50%) at 100ºC or higher for 30 minutes to remove some or all of the acetyl groups from the polymer (No and Meyers, 1995). 2.3.1 Deproteinization Chitin occurs naturally in association with protein (Chitinoprotein). Some of this protein can be extracted by mild methods, but other portion is not readily extracted, suggesting strong covalent bonding to chitin (Attwood and Zola, 1967). With regards to chemical structure, protein is bound by covalent bonds to the chitin through aspartyl or histidyl residues, or both, thus forming stable complexes such as glycoproteins. Crustacean shell waste is usually ground and treated with dilute sodium hydroxide solution (1-10%) at elevated temperature (65-100ºC) to dissolve the proteins present. Reaction time usually ranges from 0.5 to 12 hr depending on preparation methods. Prolonged alkaline 19
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: 2.2.10 Formation of Film Chitosan h
Page 29 and 30: of the demineralization process. El
Page 31 and 32: 2.4 Factors Affecting Production of
Page 33 and 34: (0.841-0.177 mm) had no effect on t
Page 35 and 36: methods are those of Hackman (1954)
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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