軟質棕櫚油

軟質棕櫚油是棕櫚油的液體分提物。棕櫚油最常見的三大粗分提物為硬質棕櫚油 (palm stearin)、棕櫚油中間分提物 (palm mid-fraction) 及軟質棕櫚油 (palm olein) V. Gibon. 2006. Ch10 Fractionation of lipids for use in foods. Modifying lipids for use in food, 1st edition, 217-221. Cambridge, England: Woodhead Publishing Limited.，相較於棕櫚油，軟質棕櫚油的飽和脂肪較少，由38.3%棕櫚酸、42.1%油酸以及10.6%亞麻油酸所組成，在室溫下呈現澄清透明 Siew Wai Lin. 2011. Ch02 Palm oil. Vegetable oils in food technology: composition, properties and uses, 2nd edition, 33-37. Oxford, UK: Blackwell Publishing Ltd.，但在低溫下仍會結晶Effect of Diglycerides on the Crystallisation of Palm Oleins  Wai-Lin Siew, andWee-Lam Ng Journal of the Science of Food and Agriculture 71(4): 496-500。經研究軟質棕櫚油的澄清度會受到三酸甘油酯組成、碘價以及二酸甘油酯 (diacylglycerol) 含量影響，碘價越高越澄清。為符合消費者對烹調用油的使用習慣與澄清透明狀態的偏好，而將軟質棕櫚油再進一步分提可得到碘價更高，飽和脂肪更少的超級軟質棕櫚油，相較於軟質棕櫚油在10℃下約有37%的固脂率，超級軟質棕櫚油則僅有17%固脂率，碘價通常介於63-65之間，在低溫下冷凍穩定性更佳。

 在烹調與油炸上的應用 
為使食用油的品質穩定，最常見的方法即為調整脂肪酸組成。前人研究發現，將不同油脂調合可以提升營養價值及擴大產品的應用範圍，如油炸使用Effect of Saturated/Unsaturated Fatty Acid Ratio on Physicochemical Properties of Palm Olein–Olive Oil Blend  Mahsa Naghshineh, Abdul Azis Ariffin, Hasanah Mohd Ghazali, Hamed Mirhosseini, Abdulkarim S. Mohammad. 2010 Journal of the American Oil Chemists’ Society. 87(3): 255-262.，常見以多元不飽和程度高的油脂與含有較飽和或富含高含量單元不飽和的油脂進行搭配調合。由於軟質棕櫚油氧化安定性佳，相較於其他植物油脂如葵花油、大豆油[core.ac.uk/download/pdf/12221896.pdf Evaluation of potato crisps fried in market samples of palm olein, corn oil and soya oil. ] M. A. Augustin, L. K. Heng and Nor Aini Idris. 1988, Pertanika. 11(3): 393-398.、花生油，其酸敗速率明顯較慢Frying performance of palm oil liquid fractions  U. Bracco, A. Dieffenbache and L. Kolarovic. 1981.Journal of the American Oil Chemists’Society. 58(1): 6-12.，常被用於與其他油種混合以改善其他植物油的油炸品質與穩定性，例如大豆油Quality changes of RBD palm olein, soybean oil and their blends during deep-fat frying  Y. B. Che Man, J. L. Liu, B. Jamilah and R. Abdul Rahman. 1999. Journal of Food Lipids. 6(3): 181-193.、葵花油與橄欖油等，因此在油炸及烹調用量上有遽增的趨勢 Kun, T. Y. 1990. Improvements in the frying quality of vegetable oil by blending with palm olein. Palm oil development No. 15. PORIM, Bangi, Selangor, Malaysia.Frying Stability of Canola Oil Blended with Palm Olein, Olive, and Corn Oils   Reza Farhoosh, Reza Esmaeilzadeh Kenari and Hashem Poorazrang. 2009.Journal of the American Oil Chemists’Society. 86(1): 71-76，軟質棕櫚油亦為馬來西亞最主要的家庭煎炸用油Yusof Basiron. 2005. Ch 08 Fats and oils in bakery products. Bailey’s industrial oil and fat products, 6th edition, volume 02, 393. Canada: John Wiley & Sons, Inc.。

營養研究
由於棕櫚油有高含量屬飽和脂肪酸的棕櫚酸，所以軟質棕櫚油常被拿來跟其他的油脂比較其對心血管疾病與血脂的影響。有眾多研究結果指出，與其他油脂相比，軟質棕櫚油不會特別造成血脂及脂蛋白組成的變化，甚至或許具有降低血脂濃度的作用，因此軟質棕櫚油不會提高罹患心血管疾病的風險。例如與橄欖油相較，軟質棕櫚油可降低血漿三酸甘油酯濃度，且在心血管疾病的風險指標物方面，如血漿HDL、胰島素以及葡萄糖濃度上與橄欖油皆無顯著差異Tine Tholstrup, Julie Hjerpsted and Marianne Raff. 2011.Palm olein increases plasma cholesterol moderately compared with olive oil in healthy individuals. The American Journal of Clinical Nutrition. 94(6): 1426-1432.，而也有人體研究比較攝取軟質棕櫚油、椰子油及初榨橄欖油三者對於心血管疾病和發炎反應上的影響，結果三者間發炎相關的細胞激素及發炎指標濃度變化也無顯著差異Phooi Tee Voon, Tony Kock Wai Ng, Verna Kar Mun Lee, and Kalanithi Nesaretnam. 2011.Diets high in palmitic acid (16:0), lauric and myristic acids (12:0 + 14:0), or oleic acid (18:1) do not alter postprandial or fasting plasma homocysteine and inflammatory markers in healthy Malaysian adults.  The American Journal of Clinical Nutrition. 94(6): 1451-1457.。

 參考來源 

Category:食油
Category:植物性油脂