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Investigations on Nutraceutical, Physical and Textural Qualities of Differently Processed Biotransformed Rice

Venkatrao, N. (2008) Investigations on Nutraceutical, Physical and Textural Qualities of Differently Processed Biotransformed Rice. [Student Project Report]

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Abstract

This Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page.

Item Type: Student Project Report
Additional Information: Whole grain consumption is reported to have number of health beneficial effects and whole grain rice / brown rice is rich in number of biofunctional components like oryzanol, tocotrienols, tocopherols, B-vitamins, minerals and dietary fibre. In spite of that it has limited use due to poor cooking quality, higher chewiness and low consumer appeal. Biotransformation of brown rice by biotechnological methods like enzymatic treatment, fermentation or natural germination of rice is reported to enhance its quality and bioactive potential. Germination is a natural method to transform the biological molecules in their structural, functional and nutritional properties. In order to develop biotransformed rice forms, rough rice (paddy) of two varieties IR 64 (white / non-pigmented rice) and Jyothi (red/ pigmented rice) were subjected to controlled germination, steam treatment, milling and polishing. This resulted different rice forms like biotransformed brown rice, biotransformed steamed brown rice, biotransformed semi polished rice, biotransformed steamed semi polished rice, biotransformed steamed highly polished rice and respective raw rice forms as control. Further its quality characteristics like physical, nutraceutical and textural quality were studied. As a result of germination of paddy shoots and rootlets appeared by 30 hr and an increase in length in rootlet more than 15mm was observed by 72 hr. Milling yield of brown rice on dehusking was low in biotransformed rice and steam treatment resulted in reduction in broken rice. Colour value assessment showed slight increase in lightness and not much change in yellowness in both varieties, and a decrease in redness in IR 64 on biotransformation. On steaming lightness decreased in both, redness increased in IR 64, both redness and yellowness decreased in Jyothi. Decrease in Jyothi may be due to the loss in pigments in Jyothi. Yellowness decreased in IR 64 on polishing, but in Jyothi biotransformed steamed an increase was observed due to process induced changes in endosperm. On biotransformation, reduction in L/B ratio of IR 64 rice is decreasing due to reduction in length and in Jyothi it increased due to reduction in breadth. Polishing resulted in length, breadth and L/B ratio in al forms of rice. Thousand kernel weight decreased in IR 64 on biotransformation and normalized grain weight decreased in both varieties due to biomass loss on biotransformation. On polishing it decreased in biotransformed forms but remained same in steamed forms. This may be due to decrease in length due to breakage in former and intactness in later. Even though moisture content was substantially high during germination, after processing its level came down to <11% which will permit the safe storage of it. Content of oryzanol, one of the major nutraceutical in rice, was 29.5 mg% in IR 64 brown rice and 23.0mg% in Jyothi rice and did not change much on biotransformation. But on steamed rice it was slightly high. Semi polishing resulted in 45-50% loss in oryzanol in both varieties and higher polishing resulted in loss up to 80%. In spite of different processing steps in biotransformed steamed rice the content of oryzanol is stable and comparable to raw rice forms. Total antioxidant activity, an index of all bioactive components, of Jyothi was higher than that of IR 64 and biotransformation as well as steaming resulted in its decrease due to different steps of processing. Semi polishing resulted in 50-60% reduction of it in all forms of rice. HPLC analysis of vitamin E fractions showed the presence of delta, gamma & alpha tocotrienols and tocopherols in both IR 64 and Jyothi brown rice varieties. Gamma tocotrienol was found to be the major fraction followed by gamma tocopherol and alpha tocopherol. Total vitamin E content was 40.2ug/g and 55.4ug/g respectively in IR64 and Jyothi. Studies on biotransformed brown rice form of IR 64 showed that composition of vitamin E was not altered in it as a result of biotransformation. However, gamma tocopherol decreased and alpha tocopherol increased on germination. Steam processing of biotransformed rice resulted in 23% decrease in total vitamin E content with 49% loss in total tocopherol and only 17% loss in tocotreinols. In Jyothi variety also composition of vitamin E was not altered in biotransfrmed brown rice. Tocotrienols which form the 70% of vitamin E content was not affected. But total vitamin E content decreased (21%) due to significant decrease in gamma and alpha tocopherol. Steam processing of biotransformed rice did not affect the content of total vitamin E, even though a 22% reduction in alpha tocopherol was observed. Thus the advantages of steam processing as well as reduced loss of major component, tocotrienols, makes this process a suitable method to obtain nutraceutical rich rice form from both the varieties. Semi polishing results in 40 % loss of vitamin E in IR 64 and 30% loss in Jyothi. In spite of the loss 60-70 % is retained, and nutritionally semi polishing is superior to high polishing which result in excessive loss of available nutrients. Since semi polished forms of germinated steamed rice was of acceptable quality as table rice, sensory analysis was carried out in them and compared with conventionally used highly polished rice. In both varieties sweetness was high, colour, grain intactness, fluffiness and elongation were in acceptable range. Stickiness, a negative attribute, was also absent. Thus it may be concluded that by biotransformation, controlled steaming and polishing it is possible to obtain rice having the benefit of nutraceuticals and acceptable physical and textural quality.
Uncontrolled Keywords: Rice brown rice Biotransformation Nutritional aspects Phytonutrients
Subjects: 600 Technology > 08 Food technology > 21 Cereals > 01 Rice
600 Technology > 08 Food technology > 16 Nutritive value
Divisions: Grain Science and Technology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 24 Oct 2008 12:00
Last Modified: 28 Dec 2011 10:05
URI: http://ir.cftri.com/id/eprint/8773

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