Studies on Foaming of Mixed Edible Oil with Coconut Oil under Deep-fat Frying

Research Project

Project/Area Number	61580064
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	家政学
Research Institution	Nara Women's University
Principal Investigator	HASEGAWA Kiyozo Nara Women's University, Professor, 家政学部, 教授 (00027179)
Co-Investigator(Kenkyū-buntansha)	FUJINO Sachiyo Nara Women's University, Assistant Professor, 家政学部, 助手 (70110806) MATOBA Teruyoshi Nara Women's University, Associate Professor, 家政学部, 助教授 (10027196)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1987: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Edible fats and oils / Deep-fat frying / Mixed oil / Interesterified oil / Foaming under deep-fat frying / Triacylglycerol composition / 油脂の熱酸化安定性 / ヤシ油 / 分子種 / 脂肪酸組成
Research Abstract	1. Cococut and palm kernel oils belong to the lauric oil and are commercially important. The disadvantages of this type oil are that admixture of the oils with other frying oils, e.g., soybean oil, produces a characteristic foaming under deep fat frying. In the present study, the foaming activity of the mixed oil between lauric and nonlauric oils was investigated in detail. The foaming properties of the mixed oils decreased remarkably after random interesterification, when the intermediate carbon number triacylglycerols increased, while the fatty acid compositions of the oils were remained unchanged. Similar effects of interesterification were found in a model system of mixtures of monoacid triacylglycerols. It was discussed that the characteristic foaming arose from the disparity of triacylglycerol molecular size, but not from that of fatty acid composition. 2. The influence of interesterification on the thermal oxidation stability of mixed oils during continuous heating at high temperature was investigated, using soybean, palm and coconut oils whose fatty acid compositions differ each other. The extent of thermal deterioration in each oil increased in proportion to the degree of unsaturation, and nearly no difference between the mixed oils and their interesterified oils. However, the refractive index of the interesterified oil increased more rapid than the others. It was supposed that the rapid increase might be caused by increasing of triacylglycerol molecular species which were easily polymerized.