Recovery of Bioactive and Valued Materials from Squid (Todarodes pacificus) Viscera Using Sub- and Supercritical Fluids
- Alternative Title
- 아임계 및 초임계 유체를 이용한 오징어 (Todarodes pacificus) 내장으로부터 유용성분 회수
- Abstract
- Squid is a popular food in many countries including Korea and Japan. Fish processing industries produce lot of squid viscera as a waste product. It contains lot of biomolecules that are useful to living beings. The disposal of these waste products is also a big problem for the fish processing industries. However, recovery of useful materials from squid viscera will be beneficial economically and environmentally. In this study, squid (Todarodes pacificus) viscera oil was extracted using an environmental friendly solvent, supercritical carbon dioxide (SC-CO2) and an organic solvent, hexane. The SC-CO2 extraction was carried out at the temperatures ranging from 35 to 45ºC and the pressures ranging from 15 to 25 MPa. The flow rate of CO2 (22 g/min) was constant at the entire extraction period of 2.5 hrs. The highest oil yield was found at higher extraction temperature and pressure. The extracted oil was analyzed by gas chromatography (GC) for fatty acid compositions. The oil obtained by SC-CO2 extraction contained high percentage of polyunsaturated fatty acids (PUFAs) especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The quality of squid viscera oil obtained by SC-CO2 extraction was compared with that of hexane extracted oil. The SC-CO2 extracted oil showed more stability than the oil obtained by hexane extraction. The amount of astaxanthin in squid viscera oil was determined by high performance liquid chromatography (HPLC) and compared at different extraction conditions. In SC-CO2 extraction, the highest yield of astaxanthin was found in squid viscera oil extracted at 25 MPa and 45ºC.
Marine lecithin was isolated and characterized from squid viscera residues deoiled by SC-CO2 extraction. The major phospholipids of squid viscera lecithin were quantified by HPLC. Phosphatidylcholine (PC- 80.54±0.68%) and phosphatidylethanolamine (PE- 13.18±0.24%) were the main phospholipids. Thin layer chromatography (TLC) was performed to purify the individual phospholipids. The fatty acid compositions of lecithin, PC and PE were analyzed by GC. A significant amount of EPA and DHA were present in both phospholipids of PC and PE. Emulsions of lecithin in water were prepared by a homogenizer. The oxidative stability of squid viscera lecithin was high in spite of its high concentration of long chain polyunsaturated fatty acids (LC-PUFAs).
Subcritical water hydrolysis was carried out to produce valued materials from squid viscera, the byproduct of fish processing industries. The reaction temperatures for hydrolysis of freeze dried raw and SC-CO2 extracted squid viscera were maintained from 180 to 280ºC for 5 min. The ratio of material to water for hydrolysis was 1:50. Most of the proteins from SC-CO2 extracted squid viscera were recovered at high temperature. The protein yield in raw squid viscera hydrolyzate decreased with the rise of temperature. The reducing sugar yield was higher at high temperature in subcritical water hydrolysis of both raw and SC-CO2 extracted squid viscera. The highest yield of amino acids in raw and SC-CO2 extracted squid viscera hydrolyzates were 233.25±3.25 and 533.78±4.13 mg/g at 180 and 280ºC, respectively. Most amino acids attained the highest yield at the reaction temperature range of 180-220ºC and 260-280ºC for raw and SC-CO2 extracted samples, respectively. The recovery of amino acids from SC-CO2 extracted squid viscera was about 1.5 times higher than that of raw squid viscera.
Finally, the applicability of SC-CO2 in enzyme purification system was checked. Three major classes of digestive enzymes of squid viscera were characterized following extraction of oil by SC-CO2 and hexane. The highest oil extracted residues of squid viscera (25 MPa and 45ºC) were used to characterize the digestive enzymes. The activities of protease, lipase and amylase were highest in hexane extracted squid viscera samples and lowest in SC-CO2 extracted samples. The crude extracts of SC-CO2 and hexane extracted squid viscera samples had almost same optimum pH and pH stability for each of the digestive enzymes. The optimum temperature of protease, lipase and amylase were found to be very similar in SC-CO2 and hexane extracted samples. However, the thermal stability for each digestive enzyme in SC-CO2 extracted squid viscera were slightly higher than that of hexane extracted squid viscera. Studies using SDS-PAGE showed no significant differences in protein patterns of the crude extracts of freeze dried raw and SC-CO2 and hexane extracted squid viscera, indicating that the proteins were not denatured.
- Issued Date
- 2011
- Awarded Date
- 2011. 2
- Type
- Dissertation
- Keyword
- Sub- and Supercritical Fluids
- Publisher
- Pukyong National University
- Affiliation
- Dept. of Food Science and Technology, Pukyong National University
- Department
- 대학원 식품공학과
- Advisor
- Byung-Soo Chun
- Table Of Contents
- Chapter 1: General introduction
1.1.Background 1
1.2.Squid 1
1.2.1.Todarodes pacificus 2
1.2.1.1.Habitat and biology of T. pacificus 3
1.3.Polyunsaturated fatty acids 7
1.3.1.Cardiovascular diseases 7
1.3.2.Cancers 7
1.3.3.Human immune and inflammatory responses 8
1.3.4.Psychiatric effects: Alzheimer’s and Schizophrenia 8
1.3.5.Infant brain and vision development 9
1.4.Supercritical fluids 10
1.4.1.History of supercritical fluids 10
1.4.2.Properties of supercritical fluids 11
1.4.3.Supercritical carbon dioxide (SC-CO2) 15
1.5.Outline of the thesis 17
1.6.References 18
Chapter 2: Supercritical carbon dioxide extraction of squid viscera oil
2.1.Introduction 25
2.2.Materials and methods 27
2.2.1.Materials 27
2.2.2.Sample preparation 27
2.2.3.SC-CO2 extraction 27
2.2.4.Soxhlet extraction by hexane 28
2.2.5.GC analysis for fatty acid compositions 28
2.2.6.Measurement of oil stability 31
2.2.6.1.Free fatty acid content of squid viscera oil 31
2.2.6.2.Peroxide value 31
2.2.7.HPLC analysis for the measurement of astaxanthin 33
2.2.8.Statistical analysis 33
2.3.Results and discussion 35
2.3.1.SC-CO2 extraction 35
2.3.2.Comparison of oil yield by SC-CO2 and hexane extraction 38
2.3.3.Fatty acid compositions 38
2.3.4.Oil stability 41
2.3.5.Extraction yield of astaxanthin 41
2.3.6.Solubility correlation of astaxanthin 45
2.4.Conclusions 45
2.5.References 49
Chapter 3: Isolation and characterization of lecithin from supercritical carbon dioxide extracted squid viscera
3.1.Introduction 53
3.2.Materials and methods 54
3.2.1.Materials 54
3.2.2.Isolation of lecithin 54
3.2.3.Characterization of squid viscera lecithin 55
3.2.3.1.Phospholipid content 55
3.2.3.2.Measurement of hexane insoluble matter, acid value and peroxide value 55
3.2.3.3.Free fatty acids 56
3.2.3.4.Major phospholipids quantification by HPLC 56
3.2.3.5.Thin layer chromatography (TLC) 56
3.2.3.6.Gas chromatography for fatty acid compositions 57
3.2.3.7.Oxidative stability 59
3.2.3.7.1.Thiocyanate method 59
3.2.3.7.2.TBA method 59
3.3.Results and discussion 60
3.3.1Characterization of squid viscera lecithin 60
3.3.2.Hexane insoluble matter, FFA content, acid value and peroxide value 60
3.3.3.Quantification of major phospholipids by HPLC 61
3.3.4.Fatty acid compositions of lecithin, PC and PE 61
3.3.5.Oxidative stability 65
3.4.Conclusions 65
3.5.References68
Chapter 4: Production of valued materials from squid viscera by subcritical water hydrolysis
4.1.Introduction 71
4.2.Materials and methods 72
4.2.1.Materials 72
4.2.2.Proximate composition 72
4.2.3.Subcritical water hydrolysis 72
4.2.4.Measurement of protein content of hydrolyzates 73
4.2.5.Measurement of reducing sugar content of hydrolyzates 73
4.2.6.Analysis of amino acids 73
4.3.Results and discussion 77
4.3.1.Compositions of freeze dried raw and SC-CO2 extracted squid viscera 77
4.3.2.Protein yield in hydrolyzates 77
4.3.3.Reducing sugar yields 78
4.3.4.Amino acid yields 81
4.4.Conclusions 82
4.5.References 86
Chapter 5: Digestive enzymes activities of squid viscera followed by supercritical carbon dioxide and organic solvent extraction
5.1.Introduction88
5.2.Materials and method 89
5.2.1.Materials 89
5.2.2.Digestive enzyme assay 90
5.2.2.1.Preparation of crude enzyme 90
5.2.2.2.Protease assay 90
5.2.2.3.Lipase assay 90
5.2.2.4.Amylase assay 91
5.2.3.Effect of pH and pH stability of protease, lipase and amylase 91
5.2.4.Effect of temperature and temperature stability of protease, lipase and amylase 91
5.2.5.Electrophoresis 92
5.3.Results and discussion 93
5.3.1.Digestive enzyme activities93
5.3.2.Optimum pH of protease, lipase and amylase 93
5.3.3.pH stability 94
5.3.4.Optimum temperature of protease, lipase and amylase 101
5.3.5.Temperature stability 101
5.3.6.Electrophoresis 102
5.4.Conclusions 102
5.5.References108
Summary 111
Abstract (In Korean) 112
Acknowledgements 114
- Degree
- Doctor
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