Rice Bran

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  • Topic: Fatty acid, Linoleic acid, Fat
  • Pages : 8 (3038 words )
  • Download(s) : 81
  • Published : October 16, 2012
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An Assignment on Rice Bran Oil Technology

Oil: Oils are esters of glycerol and fatty acid. In other words, oils are tri-glycerol ester of fatty acid. Hence ester of glycerol is known as glycerides and fatty acids both are saturated and unsaturated. Oils are liquid at ordinary temperature. Example: Rice bran oil, Coconut oil, Soybean oil, palm oil. Etc. Fats: Fats are same as oil, i.e. Fats are esters of glycerol and fatty acid, except that fat is solid at ordinary temperature. The melting point above 20°C. Example: Butter, Tallow, Lard etc. Waxes: Waxes are esters of long chain fatty acid. Usually contain 24-28 carbon atoms with long chain primary alcohol containing 16-36 carbon atoms or with alcohol of the steroid group. Waxes are non crystalline. Example: Bees wax, Carnauba wax, opal wax. Etc. Properties of oil: 1. At room temperature oils liquid. 2. Oils contains large proportion of unsaturated fatty acid. 3. Oils are insoluble in water but readily soluble in Hexane, ether, benzene, Carbon tetra chloride, etc. 4. Oils are easily hydrogenated like alkenes. 5. Oils react with Iodine, chlorine in aqueous alcoholic solution to form iodo-chloro derivatives. Terms related Definitions: Iodine value: Iodine value may be defined as the number of gm of Iodine that will add across the Carboncarbon double bond in hundred (100) gm of the fats or oils. Or simply the amount of iodine (in gm) absorbed by 100gm of fat. Significance: Iodine value is a measure of the extent of un saturation in fats or oils. The greater the number of double bond more iodine is required to break this bonds.ie. Iodine value is more. For example Oleic acid has one (C=C) double bond and it iodine value is 85whereas Linoleic acid contain two (C=C) double bond has iodine value is 181. Iodine value of Rica bran oil is 99-108. If Iodine value is below 90 then it is called non drying oil, If iodine value is above 90 and below 140 then it is called semi drying oil and if iodine value is above 140 then it is called drying oil. According to data Rice bran oil is a semi drying oil.

Acid Value: In chemistry, acid value (or "neutralization number" or "acid number" or "acidity") is the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of Oil or fat. The acid number is a measure of the amount of carboxylic acid groups in a Oil or fat, such as a fatty acid, or in a mixture of compounds. In a typical procedure, a known amount of sample dissolved in organic solvent is titrated with a solution of potassium hydroxide with known concentration and with phenolphthalein as a color indicator. The acid number is used to quantify the amount of acid present, for example in a sample of biodiesel. It is the quantity of base, expressed in milligrams of potassium hydroxide, that is required to neutralize the acidic constituents in 1 g of sample.

Acid value indicates the proportion of free fatty acid in the oil or fat. The normal Acid value for most samples lies within 0.5. The acid number is used to quantify the amount of acid present, for example in a sample of biodiesel. It is the quantity of base, expressed in milligrams of potassium hydroxide that is required to neutralize the acidic constituents in 1 g of sample. Classification of oil: Depending on sources, Oils are classified as – a) Animal fats and oil: These are obtained from animal sources. Example: Cod-liver oil, butter. b) Vegetable fats and oil: These are obtained from vegetable sources. Example: Rice bran oil, Coconut oil, Soybean oil, palm oil. etc. Depending upon the nature of carbon chain and iodine value vegetable oils are classified asa) Non drying oil: These oils contain least proportion of unsaturated acid containing two or three double bond. Non drying oil don’t absorb oxygen from air and don’t dry up to form a hard skin. Range of Iodine value is below 90-95. Example: Olive oil (85), Castor oil (85), Coconut oil (8.2-9.6), Palm oil (52). b) Semi drying oil: These oils...
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