Study on Isolation of Rice Bran Lipase and its Hydrolysis Reaction.

Raja Rajan, R. G. and Sowmya, Joy and Priya, P. B. and Gopala Krishna, A. G. (2011) Study on Isolation of Rice Bran Lipase and its Hydrolysis Reaction. Journal of Lipid Science and Technology, 43 (4). pp. 158-165.

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Abstract

Rice bran contains an endogenous lipase, which degrades the oil present in it to free fatty acids and glycerol. The purpose of the study was to find out the effect of individual parameters such as moisture content, temperature, incubation period, defatted rice bran/crude lipase extract and substrate concentration on the activity of lipase enzyme in vitro. Rice bran was defatted by using three different kinds of solvents by two methods, one at room temperature and another at 5-8°C using Soxhlet extraction method. The resultant defatted rice bran had moisture, 7.7-8.2%; residual fat, 2.2-3.2%; water solubles, 16.2-21.7%; water insolubles, 78.2-83.7%; and protein content, 8.2-9.0%. The LAU/g protein/h was slightly more in Soxhlet defatted bran (1270) than in the room temperature extracted bran (1032). Buffer (pH 7.0 with CaCl2 solution) was used for the extraction of crude lipase from defatted rice bran. The yield of dry extract from Soxhlet defatted rice bran was a little more (10 g/ 100g with 1578 LAU/g/h units) while it was slightly lesser for room temperature defatted bran (7.1g/100g with LAU of 525 units). The hydrolysis reaction of defatted rice bran and the crude enzyme extract increased with increase in moisture content, crude enzyme concentration and the incubation period and the reaction slowed down with increase in temperature and substrate concentration. This was probably due to inactivation of the enzyme at higher temperatures and decreased amount of the enzyme concentration respectively. The optimum conditions for carrying out the hydrolysis reaction for defatted bran and its crude enzyme extract were moisture content (0.5mL/2.0 mL), temperature (30°C), incubation period (72 h), lipase concentration (defatted bran, 0.5 g; crude enzyme extract 0.1 g) and substrate concentration (0.2 g). During the normal process of oil, extraction from rice bran the enzyme gets deactivated and hence its extraction from commercial deoiled bran is not possible. This study throws light on extraction and utilization of the enzyme using Soxhlet method of defatting.

Item Type:	Article
Uncontrolled Keywords:	Defatted rice bran, rice bran lipase, lipase active units (LAU), rice bran oil (RBO), linseed oil (LSO), olive oil (OO), hydrolysis reaction
Subjects:	600 Technology > 08 Food technology > 19 Lipids-oils/fats
Divisions:	Lipid Science and Traditional Foods
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	06 May 2014 05:57
Last Modified:	06 May 2014 05:57
URI:	http://ir.cftri.res.in/id/eprint/11547

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