26. Technology for processing of cotton seed.

27. Technology for processing of linseed

28. Technology for processing of castor

29. Soya bean products – process flow chart for soya bean milk, paneer, soya temp, soya tofu, soya protein concentrate and soya isolate

30. Technology for processing of groundnut and sunflower.

31. Technology for processing of rape seed and mustard.

32. Hydrogenation of oils; New technologies in oilseed processing; Utilization of oil seed meals for different food uses.

Flow diagram of vegetable oil processing

Flow diagram for oilseed extraction

Technology for processing of cotton seed.

Technology for processing of linseed

Technology for processing of castor

Technology for processing of groundnut

Technology for processing of sunflower

Process flow chart for soya bean milk

Process flow chart for soya bean Tofu

Process flow chart for soya protein isolate

Hydrogenation of oils; New technologies in oilseed processing; Utilization of oil seed meals for different food uses. �

Alkaline hydrolysis (saponification) of oil to make soaps.

• There are many methods for hydrolysis of triacylglycerol molecule.
• The most common method is alkaline hydrolysis.
• Heating (around 100°C) triacylglycerols with aqueous solution of sodium hydroxide results in glycerol and alkaline salt of fatty acid (i.e. soap) (Figure).
• This is called saponification, and used for production of soap.

Hydrogenation

• Number of double bonds in oils and fats affects physical property such as melting point, crystallinity.
• Generally, double bonds reduce the oil’s melting point.
• Therefore, oils rich in unsaturated fatty acids are liquid, while ones with small amount of unsaturated fatty acids are solid or semi-solid.
• Hydrogenation is a process to add hydrogen atoms into double bonds of unsaturated fatty acids.
• As the result of hydrogenation, liquid oil becomes solid or semi-solid.
• A typical example of hydrogenation is in the process of margarine and shortening production.
• Vegetable oil is hydrogenated with gaseous H2 in the presence of a metal catalyst (usually nickel catalyst).
• If the hydrogenation is completely performed, all the double bounds are converted to the saturated ones with the same carbon number.
• For example, complete hydrogenation of linoleic acid (18:2 !-6) generates stearic acid (18:0)

Hydrogenation

Hydrogenation

Hydrogenation accomplishes two things-:

• It increases the melting point of the oil or fat.
• Resistance to oxidation and flavor deterioration.

Hydrogenation process depends on several parameters:

• Pressure& Temperature,
• Type of catalyst,
• Speed of agitation etc.

Trans fatty acids or trans fat

• Vegetable oil is too soft for margarine or shortening because it is liquid.
• Saturated fat obtained by complete hydrogenation is too hard.
• Margarine requires something in the middle, i.e. not too hard but not too soft.
• Margarine and shortening makers “partially hydrogenate” their product.
• They only add hydrogen atoms until the oil is at the desired consistency.
• During the hydrogenation process, hydrogen atoms are inserted in no particular order.
• When they stop the incomplete hydrogenation process, unsaturated fatty acids are in varying stages of hydrogenation.
• Some molecules are mostly hydrogenated, while others are not.
• And the double bonds have often shifted to unnatural positions, resulting in the generation of trans fatty acids or trans fat, which is thought to increase risk of coronary heart disease.

Transesterification

• Transesterificaton includes chemical reactions where an ester is reacted with alcohol (alcoholysis), acid (acidolysis), or another ester (intereseterification or ester exchange), to generate a new ester.

Alcoholysis

• When methanol is used in alcoholysis, the reaction is called methanolysis, in which fatty acid methyl ester and glycerol are generated (Figure).
• Fatty acid methyl esters can be used as an alternative fuel for diesel engine (biodiesel). Biodiesel is a substitute or extender for traditional petroleum diesel.
• It can be used in conventional diesel engines, and the use of biodiesel is advantageous for reducing emission of CO2, CO, SO2 and particle materials.
• Biodiesel is now spreading world wide.
• For example, in France, all the diesel fuel marketed contains 5% of biodiesel.

Acidolysis

• An industrial application of acidolysis is production of long chain fatty acid vinylesters from vinylacetate (this is obtained by chemical reaction of ethylene and acetic acid) and fatty acids.
• Long chain fatty acid vinyl esters are industrial raw material for making plastics

Interesterification

• Interesterification of oil changes its molecular composition. Oils or fats are mixture of various triacylglycerol molecules having different fatty acids and positional distribution.
• Treating oils and fats with sodium methoxide as a catalyst at 80 °C causes intermolecule ester exchange, changing the molecular composition, while leaving the fatty acid composition unchanged.
• As a result, the oil changes its physical properties such as melting point and consistency.

Need of hydrogenation

• Hydrogenated fat is basically a substitute to butter fats.
• Hydrogenated oil helps to increase shelf life and save cost.
• High costs of butter fat and its poor storage stability were detrimental factors that led to the investigation of alternative sources of hard fats.
• This investigation led to the invention of catalyzed H2 addition across unsaturated sites of oils and fats and was quickly commercialized.
• Conversion of liquid oils to solid and semi-solid fats having wide spectrum of physical & chemical characteristics of products were thus obtained

Need of hydrogenation

• Hydrogenated fat is basically a substitute to butter fats.
• Hydrogenated oil helps to increase shelf life and save cost.
• High costs of butter fat and its poor storage stability were detrimental factors that led to the investigation of alternative sources of hard fats.
• This investigation led to the invention of catalyzed H2 addition across unsaturated sites of oils and fats and was quickly commercialized.
• Conversion of liquid oils to solid and semi-solid fats having wide spectrum of physical & chemical characteristics of products were thus obtained