아임계 가수분해를 통한 방사무늬김(Pyropia yezoensis) 가수분해물과 분무건조 분말의 특성

Abstract

Laver (Pyropia yezoensis) is a marine plant belonging to the genus of red algae and is widely distributed in the Pacific coast of Korea and Japan. As a representative of seaweeds, it exports more than US $ 500 million annually (as of 2017), and is a representative marine product that has become the leading player in the export of Korean seafood. The proximate composition of laver contains 1% of lipid, 45% for carbohydrate content and 35% protein content. It is generally reported that red algae’s protein contents are more than 2 times brown algae, in addition to overpouring, it may be possible to use it as a source of vegetable protein for the development of balanced foods. The amino acid composition of the protein contains a high content of alanine and glutamic acid, a large amount of taurine that regulates liver function and causes Alzheimer's disease. It is a food with strong physiological activity with various pigment ingredients. However, the laver products currently distributed in Korea are limited to dry laver and seasoning laver products, so new researches are needed. It is essential that the physiologically active substance contained in laver is low in molecular weight because it has a large molecular weight in order to be used as a health functional food ingested through oral or cosmetic absorbed through skin. However, the conventional chemical methods and hydrolysis methods using enzymes may be problematic in terms of recovery rate, environmental pollution, and economical problems. Therefore, development of high value-added products derived from laver with high quality and safety through application of new separation process is needed. Therefore, in this study, hydrolysis method using subcritical water was applied to extract these substances. The high-temperature high-pressure water, which is the critical point of water between 374℃ and 220 bar and the boiling point of 100℃ and 1 bar, is called subcritical water. These properties lead to hydrolysis reactions that can degrade peptide bonds, ester bonds and glycosidic bonds without catalysts. The subcritical hydrolysis technique was used for the purpose of enhancing the functionality of the food and improving the yield as well as safety, economical efficiency and environmental friendliness. Thus, subcritical hydrolysis was carried out in this study. The hydrolysate obtained by each extraction method was analyzed by hydrolysis yield, pH, color, antibacterial activity, antioxidant ability (ABTS, DPPH), total phenol content (TPC), total flavonoid content (TFC), total sugar, amino acids composition, and taurine content were measured. In the case of lipid-forming fatty acids, 48-54% of unsaturated fatty acids and 38-42% of saturated fatty acids were found depending on the extraction solvent, and the content of EPA as omega-3 fatty acid was about 39-42%. The yield of laver hydrolysate increased continuously with increasing temperature, and the highest yield of 78% was obtained at 180℃. The DPPH, ABTS, TPC and TFC results were highest at 210℃ (180℃) except for TFC and were 16.63 mg Trolox/g dried mass, 19.45 mg Trolox/g dried mass, 14.29 mg Gallic acid/g dried mass and 8.01 mg Quercethin/g dried mass. Although there have been many studies on the quality and physiological activity of laver containing various functions, there have been almost no studies on the characteristics of the extract according to the drying process. A study on improvement of the manufacturing process and quality improvement of the dry powder is necessary. The fine pulverization technology is artificially wrapping a useful ingredient and can be applied to medicines, industrial materials, fragrances, and foods. In the field of food, it is possible to improve the prevention of oxidation and preservation of food materials by stabilizing ingredients, materials, masking unnecessary smell, solidifying liquid foods, controlling release rate of food materials, and improvement of physical properties. There have been reported about 10 methods of pulverizing or finely pulverizing liquid foods including hot-air drying, vacuum drying, spray drying and freeze drying, but spray drying using a spray dryer is the most common and economically advantageous for industrialization. In this study, as a basic study on the powderization of laver hydrolysate, we investigated the possibility of the fine powder coating material of the carrier which is suitable for each characteristic of gelatin, whey protein, starch (potato) and dextrin widely used in food. Powder was prepared according to each carrier using spray drying method which is easy to industrialize and its characteristics were investigated. The spray drying yield, color, moisture content and water activity, PSA, FT-IR and TGA etc. were performed to characterize each powder. As a result, the spray dried powder should be selected in consideration of the purpose and direction of the final product to be used.