炒焙溫度對大果苦茶油性質及揮發性成分之影響

Abstract

眾多植物油中，苦茶油富含不飽和脂肪酸，並具有預防腫瘤、保護肝臟和心臟、減緩心血管疾病及調節免疫系統等功效，是熱門的健康食用油之一。生產苦茶油的前處理過程繁複，包括果實採收、乾燥、脫除果殼與種殼、炒焙或水蒸等，其中炒焙或水蒸等前處理可提高種子的出油量，然而，種子經過不同溫度炒焙後會影響所製苦茶油之性質。本研究探討大果油茶（Camellia oleifera Abel.）種子經80、100及120℃炒焙後對壓榨之苦茶油性質及生物活性之影響，包括顏色、脂肪酸組成、Squalene及α-Tocopherol含量、總酚類化合物含量、酸價、過氧化價、油脂穩定指數、揮發性成分及線蟲（Caenorhabditis elegans）抗熱休克與抗麻痺性。結果顯示，種子炒焙溫度從80℃升至120℃，苦茶油顏色由黃色轉變為黃棕色，脂肪酸組成並無明顯變化，Squalene、α-Tocopherol含量及總酚類化合物含量皆增加，酸價無明顯改變，過氧化價下降，油脂穩定指數上升，且脂肪酸組成、酸價及過氧化價皆符合CNS對壓榨苦茶油的規範。另外，隨著種子炒焙溫度由80℃提高至100及120℃，苦茶油的主要揮發性成分由醛類化合物變為具有烘焙風味的呋喃衍生物及吡嗪衍生物，明顯的改變苦茶油的揮發性成分及其風味。生物活性試驗中，餵食苦茶油之線蟲比未食用者有較好的抗熱休克及抗麻痺性，然而，經餵食炒焙溫度80、100及120℃之相同濃度苦茶油的線蟲抗熱休克及抗麻痺性並無顯著差異。由本研究結果得知，將油茶種子的炒焙溫度由80℃提高至120℃，不影響苦茶油的脂肪酸組成及酸價，且可以降低其過氧化價、提高Squalene、α-Tocopherol及總酚類化合物含量與氧化穩定性，亦有開發為提高熱耐受性或預防阿茲海默症等健康食品的潛力。

Among many vegetable oils, camellia seed oil is rich in unsaturated fatty acids, and has the effects of preventing tumors, protecting the liver and heart, slowing down cardiovascular diseases and regulating the immune system. It is one of the popular healthy edible oils. The pretreatment process for producing camellia seed oil is complicated, including fruit harvesting, drying, removal of shells, roasting or steaming, etc., wherein pretreatment such as roasting or steaming can increase the oil yield. However, the seed roasting at different temperatures will affect the properties of camellia seed oil. This study was to investigate the effects of roasting seeds of Camellia oleifera at 80, 100 and 120 °C on the properties and biological activities of camellia seed oil, including color, fatty acid composition, squalene and α-tocopherol content, total phenolic content, acid value, peroxide value, oil stability index, volatile organic compound and Caenorhabditis elegans resistance to heat shock and anti-paralysis. The results showed that the seed roasting temperature increased from 80 °C to 120 °C, the color of camellia seed oil changed from yellow to yellowish brown, the fatty acid composition did not change significantly, the content of squalene, α-tocopherol and total phenolic content increased, the acid value did not change significantly, the peroxide value decreased, the oil stability index increased. Besides, the fatty acid composition, acid value and peroxide value were all in line with specifications of CNS for pressing camellia seed oil. In addition, as the seed roasting temperature is increased from 80 °C to 100 and 120 °C, the main volatile organic compounds of camellia seed oil changed from aldehyde to furan derivative and pyrazine derivative with roasting flavor, indicating that the roasting temperature will obviously change the volatile organic compounds and flavor of camellia seed oil. In the bioactivity test, the C. elegans that consumed camellia seed oil had better heat shock resistance and paralysis resistance than those who did not. However, there was no significant difference in heat shock resistance and paralysis resistance of C. elegans consumed the roasting temperatures of 80, 100 and 120 ℃ but the same concentration of camellia seed oil. In summary, the roasting temperature of Camellia oleifera seeds is increased from 80 °C to 120 °C, which does not affect the fatty acid composition and acid value of camellia seed oil, and can lower its peroxide value, increase squalene, α-tocopherol, total phenolic content and oxidative stability, and have the potential to develop into healthy food for improving heat tolerance or preventing Alzheimer's disease.