Structured lipids from rice bran oil and stearic acid using immobilized lipase from Rhizomucor miehei

Rajni, Chopra and Yella Reddy, S. and Sambaiah, K. (2008) Structured lipids from rice bran oil and stearic acid using immobilized lipase from Rhizomucor miehei. European Journal of Lipid Science and Technology, 110. pp. 32-39.

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Abstract

The major objective of the present study was to prepare structured lipids rich in stearic acid from rice bran oil (RBO) using immobilized lipase (IM 60) from Rhizomucor miehei. The effects of incubation time and temperature, substrate molar ratio, and enzyme load on incorporation of stearic acid were studied. Acidolysis reactions were performed in hexane. Pancreatic lipase-catalyzed sn-2 positional analysis and tocopherol analyses were performed before and after enzymatic modification. The kinetics of the reaction was studied and maximum incorporation of stearic acid was observed at 6 h, at 37 7C, when the triacylglycerol and stearic acid molar ratio was maintained at 1 : 6 and the enzyme concentration was 10% of total substrates weight. Stearic acid in RBO after acidolysis was increased from 2.28 to 48.5%, with a simultaneous decrease in palmitic, oleic and linoleic acids. HPLC analysis of tocopherols and tocotrienols was carried out and their content in modified RBO was not significantly affected compared to that of native RBO. The oryzanol content of the modified RBO was reduced from 1.02 to 0.68%. Melting and crystallizing characteristics of the modified fat were studied using differential scanning calorimetry. The total solid fat content at 25 7C increased from 26.12 to 34.8% with an increase in stearic acid incorporation into RBO from 38 to 48%, but it was comparatively less than for cocoa butter and vanaspati. However, the modified RBO completely melted at 37 7C and was useful as plastic fat for various culinary purposes, bakery and confectionary applications. The results of the present study indicated that structured lipids prepared from RBO rich in stearic acid retained their beneficial nutraceuticals; in addition, they do not contain any trans fatty acids.

Item Type:	Article
Uncontrolled Keywords:	Structured lipids, Rice bran oil, Enzymatic acidolysis, Immobilized lipase, Stearic acid.
Subjects:	600 Technology > 08 Food technology > 19 Lipids-oils/fats
Divisions:	Dept. of Biochemistry Lipid Science and Traditional Foods
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	12 Aug 2008 09:11
Last Modified:	15 May 2012 11:27
URI:	http://ir.cftri.res.in/id/eprint/8689

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