软质棕榈油
软质棕榈油是棕榈油的液体分提物。棕榈油最常见的三大粗分提物为硬质棕榈油 (palm stearin)、棕榈油中间分提物 (palm mid-fraction) 及软质棕榈油 (palm olein)[1],相较于棕榈油,软质棕榈油的饱和脂肪较少,由38.3%棕榈酸、42.1%油酸以及10.6%亚麻油酸所组成,在室温下呈现澄清透明[2],但在低温下仍会结晶[3]。经研究软质棕榈油的澄清度会受到甘油三酯组成、碘价以及二酸甘油酯 (diacylglycerol) 含量影响,碘价越高越澄清[2]。为符合消费者对烹调用油的使用习惯与澄清透明状态的偏好,而将软质棕榈油再进一步分提可得到碘价更高,饱和脂肪更少的超级软质棕榈油,相较于软质棕榈油在10℃下约有37%的固脂率,超级软质棕榈油则仅有17%固脂率,碘价通常介于63-65之间,在低温下冷冻稳定性更佳。
在烹调与油炸上的应用
为使食用油的品质稳定,最常见的方法即为调整脂肪酸组成。前人研究发现,将不同油脂调合可以提升营养价值及扩大产品的应用范围,如油炸使用[4],常见以多元不饱和程度高的油脂与含有较饱和或富含高含量单元不饱和的油脂进行搭配调合。由于软质棕榈油氧化安定性佳,相较于其他植物油脂如葵花油、大豆油[5]、花生油,其酸败速率明显较慢[6],常被用于与其他油种混合以改善其他植物油的油炸品质与稳定性,例如大豆油[7]、葵花油[4]与橄榄油[4]等,因此在油炸及烹调用量上有遽增的趋势[8][9],软质棕榈油亦为马来西亚最主要的家庭煎炸用油[10]。
营养研究
由于棕榈油有高含量属饱和脂肪酸的棕榈酸,所以软质棕榈油常被拿来跟其他的油脂比较其对心血管疾病与血脂的影响。有众多研究结果指出,与其他油脂相比,软质棕榈油不会特别造成血脂及脂蛋白组成的变化,甚至或许具有降低血脂浓度的作用,因此软质棕榈油不会提高罹患心血管疾病的风险。例如与橄榄油相较,软质棕榈油可降低血浆甘油三酯浓度,且在心血管疾病的风险指标物方面,如血浆HDL、胰岛素以及葡萄糖浓度上与橄榄油皆无显著差异[11],而也有人体研究比较摄取软质棕榈油、椰子油及初榨橄榄油三者对于心血管疾病和发炎反应上的影响,结果三者间发炎相关的细胞激素及发炎指标浓度变化也无显著差异[12]。
参考来源
- ^ 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.
- ^ 2.0 2.1 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.
- ^ Effect of Diglycerides on the Crystallisation of Palm Oleins (页面存档备份,存于互联网档案馆) Wai-Lin Siew, andWee-Lam Ng Journal of the Science of Food and Agriculture 71(4): 496-500
- ^ 4.0 4.1 4.2 Effect of Saturated/Unsaturated Fatty Acid Ratio on Physicochemical Properties of Palm Olein–Olive Oil Blend (页面存档备份,存于互联网档案馆) 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.
- ^ [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.
- ^ Frying performance of palm oil liquid fractions (页面存档备份,存于互联网档案馆) U. Bracco, A. Dieffenbache and L. Kolarovic. 1981.Journal of the American Oil Chemists’Society. 58(1): 6-12.
- ^ Quality changes of RBD palm olein, soybean oil and their blends during deep-fat frying (页面存档备份,存于互联网档案馆) Y. B. Che Man, J. L. Liu, B. Jamilah and R. Abdul Rahman. 1999. Journal of Food Lipids. 6(3): 181-193.
- ^ 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 (页面存档备份,存于互联网档案馆) Reza Farhoosh, Reza Esmaeilzadeh Kenari and Hashem Poorazrang. 2009.Journal of the American Oil Chemists’Society. 86(1): 71-76
- ^ 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.
- ^ Tine Tholstrup, Julie Hjerpsted and Marianne Raff. 2011.Palm olein increases plasma cholesterol moderately compared with olive oil in healthy individuals. (页面存档备份,存于互联网档案馆)The American Journal of Clinical Nutrition. 94(6): 1426-1432.
- ^ 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. (页面存档备份,存于互联网档案馆) The American Journal of Clinical Nutrition. 94(6): 1451-1457.