A STUDY ON ULTRASOUND ASSISTED AQUEOUS EXTRACTION OF RICE BRAN OIL

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dc.contributor.advisorSmith, D.D.
dc.contributor.authorMOUNIKA, E
dc.date.accessioned2018-12-29T05:12:58Z
dc.date.available2018-12-29T05:12:58Z
dc.date.issued2018
dc.descriptionD5555en_US
dc.description.abstractRice (Oryza sativa) is a major cereal crop cultivated globally. Rice bran is cuticle between paddy husk and the rice grain. Rice bran is a by-product of rice milling industry. It contains 12-22% oil, 11-17% protein, 6-14% fibre, 10-15% moisture and 8- 17% ash. Rice bran offers various health benefits due to its content of antioxidants, vitamin E, B complex vitamins and essential fatty acids. It also serves as a natural source of phytosterols which provide blood sugar control and cholesterol metabolism. Commercial rice bran oil is extracted using organic solvents such as hexane. n-hexane has been used as the solvent for rice bran oil extraction due to the high oil extractability and easy availability. This process, however, has some problems with respect to the oil quality. To improve the oil quality, aqueous enzymatic extraction was used and to improve the yield, combination of ultrasound and aqueous enzymatic extraction of rice bran oil was investigated. Mechanism of ultrasound extraction is attributed to mechanical and cavitation efficacies which can result in disruption of cell wall and enhanced mass transfer across cell membrane. Firstly, moisture content of rice bran was determined. Rice bran was stabilized at 110 °C for 20 min in hot air oven. Rice bran oil was extracted for 6 h using soxhlet apparatus. The oil yield from conventional (hexane) extraction was set as 100% oil recovery for comparison. For aqueous enzymatic extraction, enzymes such as cellulase of 90 U, 144 U, 270 U, 360 U; amylase of 72 U, 180 U, 216 U, 135 U and protease of 45 U, 90 U, 135 U, 180 U individually were added to 50 g of rice bran and mixture was incubated at 37 °C. Incubated rice bran was mixed with water at the ratio of 1:6 (w/v) and pH of the slurry was adjusted to 7.0 with 0.1 N NaOH. Sample was centrifuged at 8000 rpm for 20 min to separate supernatant. Supernatant was evaporated for getting oil and the oil obtained was dried in hot air oven at 100 °C for 30 min to eliminate the traces of water. Experiment was performed in triplicates. Then, extraction with combination of enzymes for incubation periods of 1 h, 2 h, 3 h and 4 h was performed. The optimized combination was used for ultrasound treatment. Ultrasound treatment time of 15, 30, 45 and 60 min with on and off timings of 60 s on 5 s off, 60 s on 10 s off, 60 s on 15 s off and 60 s on 20 s off were conducted. Oil recovery with ultrasound assisted aqueous enzymatic extraction was observed and quality parameters like free fatty acid, peroxide value, color and viscosity of rice bran oil were examined. Moisture content of the fresh rice bran was found to be 11.80% (w.b.). Conventional method of extraction gave 8.0 g of oil per 50 g of rice bran. Among the four concentrations of three enzymes, 270 U of cellulase gave highest oil recovery (35.22%). From the combination of enzymes cellulase, amylase and protease (270 U+216 U+135 U) gave highest recovery of 62.68%, because of appropriate combination of enzymes and then this combination used for different incubation times. For 4 h of incubation, the highest oil recovery (76.48%) was obtained with (270 U+216 U+135 U) combination of enzymes. This combination was used for ultrasound treatment. Ultrasound treatment period of 30 min with 60 s on and 5 s off timings gave highest recovery of 88.15%. Ultrasound assisted aqueous enzymatic extraction of oil has a substantially lower content of free fatty acid (1.496 mg KOH/g) than that of conventionally (hexane) extracted oil (2.692 mg KOH/g). The peroxide value of the oil obtained from ultrasound assisted aqueous enzymatic extraction of rice bran oil was little higher (1.567 meq/ kg of oil) than the peroxide value of conventionally (hexane) extracted oil (1.220 meq/kg of oil). Ultrasound-assisted aqueous-extracted oil had a lower content of colouring substances (15Y+2R) than hexane extracted oil (20Y+2.8R) and viscosity of ultrasound assisted aqueous enzymatic extraction of rice bran oil (39.03 cP) was almost similar to that of conventional (hexane) extraction of oil (39.20 cP). Keywords: Rice bran oil; Oil extraction; Aqueous extraction of oil; Ultrasound assisted extraction; Ultrasound assisted aqueous enzymatic extractionen_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810086658
dc.keywordsULTRASOUND, ASSISTED AQUEOUS, RICE BRAN OILen_US
dc.language.isoen_USen_US
dc.pages64en_US
dc.publisherAcharya N.G. Ranga Agricultural Universityen_US
dc.research.problemA STUDY ON ULTRASOUND ASSISTED AQUEOUS EXTRACTION OF RICE BRAN OILen_US
dc.subAgricultural Engineeringen_US
dc.subjectnullen_US
dc.themeA STUDY ON ULTRASOUND ASSISTED AQUEOUS EXTRACTION OF RICE BRAN OILen_US
dc.these.typeM.Techen_US
dc.titleA STUDY ON ULTRASOUND ASSISTED AQUEOUS EXTRACTION OF RICE BRAN OILen_US
dc.typeThesisen_US
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