제주산 마유의 추출과 불포화지방산 및 포화지방산 분리

Abstract

Horse oil has been recently interested in the cosmetic and food industry. However, there is not enough scientific evaluation of horse oil properties. And the fatty acid composition of horse oil is quite different with other animal fats derived from pork, beef, chicken, so it affects horse oil quality by lipid oxidation and rheological properties under a certain temperature. Therefore, this study was conducted to investigate the properties of horse oil extracted by hot water extraction and saturated and unsaturated fatty acid of extracted horse oil was separated by low-temperature crystallization. First, hot water extraction which is safest among various extraction methods for further application on food or cosmetic products was selected to extract horse oil. Horse oil was extracted with various amount of green tea leaves (0, 1, 5, 10%) and then it was observed the change of horse oil properties especially lipid oxidation according to different storage temperature (5, 25, 60°C) for 35 days. Green tea leaves addition did not show significant effect than expected except TBA value. Storage temperature was more influential factor in horse oil quality. At 60°C, lipid oxidation of horse oil was easily generated namely, pH, acid value, and peroxide value showed the highest lipid peroxidation. TBA value showed that a higher concentration of green tea leaves was effective to inhibit lipid peroxidation by delaying malondialdehyde generation. In iodine value results, it was about 55 to 75 at all samples which is higher than pork fat or beef fat. The fatty acid composition of horse oil was about 41% saturated fatty acid and 54% unsaturated fatty acid, but the fatty acid composition was not significantly different according to treatments. As iodine value and fatty acid composition results shows, horse oil contained more unsaturated fatty acid compared with other animal fats. As a result of calculating the shelf life of the peroxide value as a quality index, the shelf life of about 6 months was calculated. Secondly, the saturated and unsaturated fatty acid of extracted horse oil (control) was separated by low-temperature crystallization, and then cooling curve, cloud point, iodine value, thermal property by DSC was evaluated. Solid phase and liquid phase were separated during low-temperature crystallization processing. Before separation, the cloud point of horse oil was near 25.6°C (54.3 min) and after separation, could point of the liquid phase and solid phase was observed at around 7.6°C (289.7 min) and 29.4°C (36.5 min), respectively. Iodine value was highest at liquid phase horse oil as expected (p<0.05). In cooling thermogram, crystallization temperature was observed at -2.11°C in liquid phase horse oil, -0.11°C and 14.59°C in whole horse oil), 2.55°C and 21.95°C in solid phase horse oil. In heating thermogram, melting temperature was measured at 2.74°C in liquid phase horse oil, -1.62°C and 21.8°C in whole horse oil), 1.01°C and 39.54°C in solid phase horse oil. After separation of saturation fatty acid, crystallization of horse oil occurred lower temperature and melting temperature of horse oil was higher. In this study, horse oil properties were observed that storage temperature was more effective factor to change lipid peroxidation of horse oil than addition of natural antioxidative material or storage time. And horse oil was certainly higher iodine value than other animal fat. Namely, lipid peroxidation of horse oil would be easily generated. To separate fatty acid of horse oil low-temperature crystallization method was quite easy and effective. In a further study, it needs to observe more specific properties like oxidative stability, phase change, morphological structure. And liquid phase or solid phase of horse oil should be applied to food or cosmetic production processing.

본 연구에서는 마유의 이취를 줄이고 저장성을 향상시키기 위해 녹차잎을 첨 가하여 마유를 추출하고 녹차잎 0, 1, 5, 10% (w/w)의 농도, 저장온도(5°C, 25°C, 60°C), 35일의 저장기간에 따른 마유의 pH, 산가, 과산화물가, TBA, 요오드화가 와 지방산조성을 측정 및 분석하여 이화학적 특성을 관찰하고 결정화분리법을 이용하여 마유의 불포화지방산과 포화지방산을 분리 하고자 15°C에서 결정화분 리를 하여 고체상과 액체상을 분리하여 냉각곡선, 운점(Cloud point), 요오드화가, 시차주사열량분석(DSC)에 의한 열분석을 측정 및 분석하여 결정화 분리 전과 후 의 마유의 특성변화를 관찰하였다. 이화학 특성에서 pH의 경우 대조구와 실험구 모두 60°C에서 저장시 급격히 감소하는 경향을 보였으며, 산가에서는 10% 실험구를 35일간 60°C에서 저장시 약 0.21의 값으로 가장 높은 값을 나타내었고 5°C와 25°C의 대조구와 실험구는 모두 0.05이하의 안정적인 값을 나타내었다. 과산화물가의 경우 녹차의 클로로필 로 인해 녹차잎 첨가 농도가 증가할수록 과산화물가가 증가하는 경향을 보였다. TBA에서는 5°C와 25°C 저장 시 큰 변화를 보이지 않았으며, 60°C 저장 시 10% 실험구를 제외한 모든 대조구와 실험구가 증가하다 감소하는 경향을 보였으며, 대조구에서 가장 높은 값을 나타내었다. 요오드가에서는 대조구와 실험구 모두 60 전후의 값들을 보였으며 증가하거나 감소하는 경향을 보이진 않았다. 지방산 조성에서는 35일 저장 후 대부분 포화지방산의 조성비가 감소하는 경향을 보였 으며, 불포화지방산의 경우 감소하거나 증가하는 경향을 보였으나 큰 폭으로 감 소 및 증가하는 변화는 보이지 않았다. 유통기한산출프로그램을 이용하여 본 연 구의 과산화물가 결과값을 품질 지표로 산출한 결과 약 6개월의 유통기한이 산 출되었다. 결정화분리 전과 후의 마유의 특성변화에서는, 냉각곡선의 경우 결정화 분리 전과 후에 상관없이 유사한 냉각곡선을 나타내었다. 운점에서는 분리 전의 마유 를 기준으로 분리 후 액체상의 경우 운점이 낮아지고, 고체상의 경우 높아지는 것을 확인할 수 있었다. 요오드가에서는 결정화 분리 후의 액체상이 가장 높은 값을 나타내었다. 시차주사열량법(DSC)에 의한 열분석에서는 결정화 분리 전의 마유를 기준으로 분리 후 액체상은 낮은 온도의 발열 및 흡열 피크가 나타났고 고체상의 경우 높은 온도의 발열 및 흡열 피크가 나타났는데, 이는 고체상의 결 정구조에 액체상의 지방산이 가두어져 생긴 피크로 사료된다.