Crystallization Behavior of Diacylglycerol-Rich Oils Produced from Rapeseed Oil

• Published in: Journal of the American Oil Chemists' Society Vol. 89; no. 7; pp. 1231 - 1239
• Main Authors: Saitou, Katsuyoshi, Mitsui, Yuki, Shimizu, Masao, Kudo, Naoto, Katsuragi, Yoshihisa, Sato, Kiyotaka
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.07.2012; Springer; Springer Nature B.V
• Subjects: Agriculture; Biological and medical sciences; Biomaterials; Biotechnology; Calorimetry; Chemistry; Chemistry and Materials Science; Crystal structure; Crystallization; diacylglycerols; differential scanning calorimetry; Fat crystallization; Fat industries; Fats and oils; filtration; Food industries; Food Science; Fundamental and applied biological sciences. Psychology; gas chromatography; Industrial Chemistry/Chemical Engineering; Light microscopy; Lipid analysis; Lipid chemistry; Lipids; microscopy; oleic acid; Original Paper; Rape plants; Rapeseed oil; stearic acid; temperature; Vegetable oils; Lipid chemistry; Fats and oils; Lipid analysis; Fat crystallization; Crystallization; Diacylglycerol; Lipids; Vegetable oil; Oils and fats; Edible oil; Rapeseed oil; Oils and fats industry; Fat
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-012-2014-1

We examined the crystallization behavior of high-melting fractions in liquid oil containing high concentrations of diacylglycerols (DAG >80%) (hereafter referred to as DAG-rich oil). By differential scanning calorimetry and optical microscopy at moderate cooling rates, crystallization in the DAG-rich oil was detected at around 6 °C. It was found that the crystallization extent increased with decreasing temperatures of crystallization below 0 °C. A gas chromatographic analysis was performed on the crystallized fractions, which were separated by filtration at different periods of isothermal crystallization at 3 °C. The results indicated that at earlier crystallization periods, the concentrations of 1,3-disaturated DAG such as palmitic and stearic acid moieties (15 min) and 1,3-saturated–unsaturated mixed-acid DAG including oleic acid, palmitic, and stearic acid moieties (15 min–3 h) were predominant. However, the concentrations of 1,3-diunsaturated DAG including oleic acid moiety increased after a crystallization period of 6 h. To clarify the sequential crystallization process of DAG, we examined the binary mixing behavior of principal DAG components occurring in the rapeseed-based DAG-rich oil. It was evident that 1,3-disaturated DAG, 1,3-saturated–unsaturated mixed-acid DAG, and 1,3-diunsaturated DAG exhibited immiscible behavior. From these data, basic information on the precipitation processes in DAG-rich oils at chilled temperatures was obtained.