아임계 수 및 초임계 이산화탄소로 처리된 진주담치 (Mytilus edulis) 추출물의 물리화학적 특성 및 생리활성 평가

정유린 부경대학교 대학원 2020 국내석사

Blue mussel (Mytilus edulis), which is a shellfish belonging to the mussel family, is one of the important edible bivalves attached to the coastal reef areas using a byssus of highly adhesive proteinaceous fiber bundles. M. edulis is native to Europe and the Mediterranean, but is currently farmed in coastal areas of Korea, and is mainly used as a minor ingredient for soup or boiled foods. Due to its high protein content, M. edulis are effective in preventing coronary heart disease (CHD) and hypertension disease, and the amino acid composition of the protein contains glutamic acid and glycine, including a high content of taurine, which regulates the liver’s function and causes of Alzheimer's disease. In addition, although the lipid content is relatively low, it is generally well known that it is effective for antioxidant capacity, arthritis, and inflammation by high content of astaxanthin and ω-3 fatty acids. For this reason, it is believed that M. edulis have high potential for commercial development of functional foods or dietary supplements. Recently, there is an increasing number in the feasibility studies of new emerging green technologies since the conventional extraction techniques use a high amount of toxic solvents which compromise the safety of extracts, requiring extra-purification steps for their removal to avoid health risks they may cause upon ingestion. Therefore, in this study, supercritical carbon dioxide (SC-CO2) and subcritical water hydrolysis (SWH) process, which are eco-friendly technologies, were applied to extract physiological active substances. Carbon dioxide (CO2), which is widely used as a supercritical fluid, has characteristics of relatively low critical temperature (31.10°C) and pressure (7.39 MPa) compared to other fluids, and is widely used for separation and purification of heat-sensitive natural materials. In addition, CO2 is colorless, non-toxic, and non-flammable, so there is no residual solvent after extraction and can be reused. Since the extract is easy to separate from the solvent, it has high selectivity with excellent sample recovery. The extraction conditions conducted for SC-CO2 varied for pressure (20, 30 MPa) and temperature (45, 55℃), while the flow rate was kept constant during the experiment (27 g/min). The extracted M. edulis oil analyzed the extraction yield, oil stability (acid value and peroxide value), fatty acid composition, antioxidant activity (DPPH and ABTS), color and TGA. The lipid-free residue extracted by supercritical carbon dioxide was hydrolyzed through a subcritical water hydrolysis process. Subcritical water is one of the chemical reactions generated due to changes in physical properties including dielectric constant depending on temperature or pressure. These properties result in a hydrolysis reaction capable of decomposing peptide bonds, ester bonds and glycosidic bonds without a catalyst. SWH was used for the purpose of enhancing the food functionality and improve yield as well as safety, economics and environmental friendliness. Applied temperatures ranged from 120 to 240°C with the pressure and reaction time fixed at 30 bar and 30 min, respectively. The obtained M. edulis hydrolysates measured hydrolysis efficiency, pH, color, antioxidant capacity (ABTS, DPPH and FRAP), total phenolic content (TPC), total flavonoid content (TFC), total protein, amino acid composition, taurine content and anti-hypertensive activity. As a results, the best extraction yield condition of M. edulis oil extracted by SC-CO2 indicated at 55℃/30 MPa, resulting in the highest yield of 6.02±0.79%. The best conditions of oil stability and antioxidant capacity of M. edulis oil was obtained at 55℃/30 MPa and 45℃/20 MPa, respectively. The oils were characterized for their fatty acid (FAs) composition using gas chromatography, while it was revealed that the major FAs were Palmitic acid, Palmitoleic acid, Electroosapentaenoic acid (EPA), and Docosahexaenoic acid (DHA). Astaxanthin content increased with increasing extraction pressure, it showed the highest content at 45℃/30 MPa with 9.88±0.33 mg ASX/g oil. In addition, the hydrolysis efficiency of M. edulis hydrolysates increased continuously with increasing temperature, showed the highest value of 90.65±0.11% at 240°C. DPPH, ABTS, FRAP, TFC also indicated maximum activity at 240°C with 12.79±0.01 mg TE/g dried sample, 9.52±0.02 mg TE/g dried sample, 4.68±0.08 mg TE/g dried sample, 15.66±0.06 mg QE/g dried sample, respectively, while TPC showed the higest content at 210°C with 7.18±0.20 mg GAE/g dried sample. The total protein content and anti-hypertensive activity reached the highest values at 180°C with 52.87±0.16 g BSA/100 g dried sample and 95.38±0.20%, respectively. From the obtained results, M. edulis extracts recovered using SC-CO2 and SWH is a effective techniques for producing physiological substances and will have important influence in food industry, and is considered to be highly utilized as basic data for use as a material that can be used in various fields.

국내 관광객이 지각한 한·일 관계갈등이 일본 방문의도에 미치는 영향 : 일본에 대한 부정적 감정의 조절효과

정유린 세종대학교 관광대학원 2020 국내석사

The number of domestic tourists visiting Japan has surged in the last five years, but in 2019, a full-fledged boycott of Japan began as political tensions between South Korea and Japan intensified. As this has further revealed negative feelings about Japan, the number of domestic tourists visiting Japan has decreased dramatically, and the tourism and aviation industries involved have also been hit hard. Therefore, this study examines how the perception of conflict between Korea and Japan affects the way domestic tourists are visiting Japan, and further examines how negative feelings about Japan play an effect. Since the prior research related to the intention of domestic tourists to visit Japan is very inadequate, we hope that this study will be provided as an academic and practical implication for the intention of visiting Japan based on negative feelings about Japan by domestic tourists, and at the same time, it will be used as a resource for the recovery of tourism in the tourism industry. In order to identify the purpose of this study, the survey was conducted from domestic tourists, and 300 copies of the questionnaire were distributed. Thus, the entire 300-part questionnaire was utilized in this study, it was used for empirical analysis SPSS 22.0 statistical program. In addition, factor analysis and reliability analysis, regulatory regression analysis was used as an analysis method. A summary of the results of the study is as follows: First, the perception of the conflict between South Korea and Japan had a significant negative effect on the intention of domestic tourists to visit Japan. This means that the more domestic tourists perceive the conflict between South Korea and Japan, the lower their intention to visit Japan. Second, negative feelings about Japan failed to play a role as a regulatory variable in the perception of the conflict between South Korea and Japan and its effect on the intention of domestic tourists to visit Japan. In other words, the negative sentiment toward Japan is that it serves as an independent variable that directly affects the intention of visiting Japan, not as a regulatory variable, in the influence of the perception of rok-Japan relations conflict to the intention of domestic tourists to visit Japan. Based on the above results, the implications of this study are as follows: First of all, we must find realistic alternatives because the rok-Japan relationship and the negative feelings toward Japan do not help much with the intention of visiting Japan. Measures should be made to prevent Japan's destruction of the white state designation to South Korea, which is the starting point of political conflict, and various media should not disparage Japan or provoke negative sentiment. Of course, political conflicts will not be resolved immediately, but officials in the tourism industry will have to create a variety of imagery and convey them to potential customers. The modern tourism industry is called the chimney-free golden industry, but at the same time it is at the crossroads of many times of uncertainty. Therefore, based on the results of this study, we believe that studies that suggest a broader range of implications will be needed. 최근 5년간 일본을 방문하는 국내 관광객 수는 매우 급증하였으나, 2019년 한국과 일본의 정치적 갈등이 심화되면서 본격적인 일본 불매 운동이 시작되었다. 이로 인한 일본에 대한 부정적 감정이 더욱 드러나면서 일본을 방문하는 국내 관광객의 수가 급격히 줄어들게 되었고, 이에 따라 관련된 관광업계 및 항공업계 역시 큰 타격을 받고 있는 것으로 나타났다. 따라서 본 연구는 국내 관광객을 대상으로 한·일 관계 갈등 지각이 일본 방문의도에 어떠한 영향을 미치는지 알아보고, 더 나아가 일본에 대한 부정적 감정이 어떠한 조절효과의 역할을 하는지 살펴보고자 한다. 한·일 관계 갈등 지각에 대한 국내 관광객의 일본 방문 의도와 관련 된 선행 연구가 매우 미흡하기에, 본 연구가 국내 관광객의 일본에 대한 부정적 감정에 따른 일본 방문 의도에 대한 학술적, 실무적 시사점으로 제공되길 바라며 동시에 관광 산업의 관광 회복을 위한 자료로도 활용되기를 바라는 바이다. 본 연구의 목적을 규명하고자 국내 관광객을 대상으로부터 2020년 1월 1일부터 1월 31일까지 설문 조사를 진행하였으며, 설문지 300부를 배포하였고 전체 300부의 설문 자료가 본 연구에 활용되었다. 실증 분석을 위해 SPSS 22.0 통계 프로그램을 이용하였다. 또한 요인분석과 신뢰도 분석, 조절회귀분석을 분석 방법으로 활용하였다. 이에 따른 연구 결과의 요약은 다음과 같다. 첫째, 한·일 관계 갈등 지각은 국내 관광객의 일본 방문 의도에 유의한 음(-)의 영향을 미쳤다. 이는 국내 관광객이 한·일 관계 갈등을 지각할수록 일본을 방문 할 의도가 낮아진다는 것을 의미한다. 둘째, 한·일 관계 갈등 지각과 국내 관광객의 일본 방문의도에 미치는 영향 관계에 있어서 일본에 대한 부정적 감정이 조절 변수로서 역할을 수행하지 못하였다. 즉 일본에 대한 부정적 감정은 한·일 관계 갈등 지각이 국내 관광객의 일본 방문 의도에 미치는 영향에 있어 조절 변수로서의 역할이 아닌 일본 방문 의도에 직접 영향을 미치는 독립 변수로서의 역할을 수행하고 있다는 것이다. 위 결과를 바탕으로 본 연구의 시사점은 다음과 같다. 우선 한·일 관계와 일본에 대한 부정적 감정은 일본을 방문하는 의도에 큰 도움이 되지 않기 때문에 현실적 대안을 강구해야 한다. 정치적 갈등의 시발점인 일본의 한국에 대한 백색 국가 지정 파기를 막기 위한 대책을 만들어야 하고, 다양한 매체들은 일본을 너무 폄하하거나 부정적 감정을 자극 시켜서는 안될 것이다. 물론 정치적 갈등 해소가 바로 이루어지지는 않겠지만, 관광산업에 종사하는 관계자들은 다양한 관광 동기 이미지를 만들어서 잠재 고객들에게 전달해야 할 것이다. 현대 관광 산업은 굴뚝 없는 황금 산업이라 불리지만 동시에 수많은 불확실성 시대의 기로에 놓여 있기도 하다. 따라서 본 연구 결과를 바탕으로 더욱 광범위한 시사점을 제시하는 연구들이 필요할 것이라 생각한다.