Intereseterification of oils
- 2. Introduction Interesterification refers to all those reactions that involve fatty acid esters reacting with other acids, alcohols or esters. Most cases it is used to describe ‘a rearrangement of the fatty acyl groups within and between different triglycerides’ This is generally done to modify the melting point, slow rancidification and create an oil more suitable for deep frying. This reaction normally requires very high temperatures, but, as has been noted, the use of catalysts allows for much milder conditions. Interesterification can be done by chemical or enzymatic methods
- 3. Mainly used catalysts Alkali (m)ethylates, Metals Sodium/potassium alloys. The actual mechanism of the interesterification reaction in triglycerides has been the subject of several research projects, publications and discussions within the realm of fats and oils chemistry
- 4. History The very first publication mentioning the synthesis of a triglyceride (by esterification of glycerol and butyric acid), by Pelouze from 1844 Afterwards it was discovered that if a small proportion of glycerol is used, the migration and interchange of the fatty acid radicals leads to the formation of triglycerides of new composition. After that it was found that no need of glycerol. Catalyst can be use. 80 years before the actual invention of interesterification in fats and oils occurs. The development of interesterification is rooted in the search for ‘cheaper butter’, for which the demand rose quickly after the First World War GermansGru¨n and Normann both filed patents on interesterification of fats and oils, in1920s
- 5. Real ester interchanges were established using alkali compounds. The research use of catalysts such as alkali compounds to do interchange. Eckey (1945), who introduced the use of sodium methoxide as catalyst, which permits much milder reaction conditions and which therefore established the classic chemical interesterification process. In the first decade of the 21st century, the enzymatic interesterification is introduced
- 6. Reaction mechanism Many discussion are conducted in last few decades how the reaction is propagated, or which molecular species really acts as the catalyst. There are various proposed catalytic reaction mechanisms for the interesterification reaction Carbonyl addition Claisen condensation Carbonyl addition suggest that reaction begins when the catalyst attacks the α hydrogen of an acyl group, forming an enolate ion, which then reacts with another ester to form a β- ketoester Another pathway is that the carbonyl group is directly attacked by the methoxide ion to form a diglyceride anion, which acts as the real catalyst and transfers acyl groups around the glyceride backbones
- 7. Source: Edible Oil Processing, Wolf Hamm, Richard J. Hamilton, Gijs Calliauw
- 8. Upon inactivation of the reaction an equivalent amount of soaps (or free fatty acids, FFA) is formed. The typical browning during interesterification is believed to be due to a complex formation involving the active catalyst. possibly associated with oxidation products.
- 9. Chemical Process chemical interesterification batch plant consists of an oil blending tank, a (static) oil–caustic soda mixer, an oil heat exchanger, the interesterification batch reactor, a catalyst dosing device, the products pumps and a vacuum unit The oil feed pump pumps the neutralised and bleached oil from blending tank into the interesterification batch reactor through an oil heater, where the oil is heated by means of low-pressure steam to about 100–110 ◦C. Initial amount of FFA in the oil exceeds 0.1%, the oil is first neutralised with caustic soda solution in an oil–caustic soda static mixer in order to eliminate the FFA as much as possible The oil is dried in the reactor at a pressure of about 80 mbara To increase drying oil is sprayed to an underpressurised reactor here the pressures is reduced to 10-5 mbara.
- 10. Only when the oil is sufficiently dried (<0.01%) is the catalyst introduced A standard randomisation reaction takes about 30–40 minutes Then post treatments are done to inactivate catalyst. The interesterified oil is pumped to the acid reactor/bleacher Citric acid that inactivates the catalyst and converts soaps back to FFA. After the acid reaction , the residual water that has been introduced in the oil together with the citric acid is evaporated under the low pressure applied in the acid reactor/bleacher the oil is sent to the interesterification post-treatment main filter, typically a leaf filter type Filtered oil is collected in the bleached oil tank and then pumped over a safety filter (typically back pulse) to the secondary safety bag filter and often to a final oil cooler.
- 11. VEGETABLE OILS | Oil Production and Processing W. Hamm, in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003
- 12. Process Parameters Oil quality The initial oil quality is important with respect to interesterification minor components or contaminants will also consume the catalyst to a considerable degree The presence of water can be a serious drawback for the pure reaction FFA will also deactivate the catalyst Peroxide value will lower the catalyst efficiency and thereby increase the cost of achieving full randomisation Source: Edible Oil Processing, Wolf Hamm, Richard J. Hamilton, Gijs Calliauw
- 13. Catalyst Active catalyst species needs to be an electron donor. In early days pure alkali metals such as sodium, potassium were used. And in small it was successful. for larger operations the most used catalysts for interesterification are the alkoxides, with sodium methoxide (or sodium methylate) are used Because of the high reaction rate at low temperature, and also allows clean after the reaction.
- 14. Source: Edible Oil Processing, Wolf Hamm, Richard J. Hamilton, Gijs Calliauw
- 15. Oil losses The oily material lost will largely consist of fatty acid methyl ester (FAME) and FFA or soaps depends on the addition of pH of water added to get inactivation. The minimal added water for the catalyst inactivation itself does not present a lot of problems. When the catalyst can be deactivated without addition of water, the small water- oil loss can be largely avoided, Adsorbents such as TrysilR can be used. Adding more solid material implies a higher oil loss through filtration. Apart from the inactivation-related oil loss, oil is lost by bleaching post treatment, The loss here is largely constituted by the presence of oil in the bleaching filter cakes, and not really by an inevitable chemical side reaction as in the deactivation step. Typical bleaching cake after blowing will still contain about 20–30% residual oil. It means bleaching earth used, about 0.3% loss of oil is there.
- 16. Enzymatic interesterification Enzymatic interesterification (EIE) involves the use of lipase to restructure TAGs, inducing the exchange of fatty acids among and between the TAGs Interesterification neither affects the degree of saturation nor causes isomerization of the fatty acid double bond Three types of reactions associated with interesterification acidolysis (fattyacid–TAG) glycerolysis (glycerol–TAG) transesterification (TAG–TAG)
- 17. The free water is the main reason to raise the FFA in the system it is very important to control water content in the system in order to reduce the contents of FFA and DAG in the final products Source: Edible Oil Processing, Wolf Hamm, Richard J. Hamilton, Gijs Calliauw
- 18. Immobilised enzymes are used, immobilisation increase the thermal stability and working life of the enzyme It will maintain enzyme activity through out the process. Source: Edible Oil Processing, Wolf Hamm, Richard J. Hamilton, Gijs Calliauw
- 19. High oleic sunflower oils + fully hydrogenated canola oil Adding immobilized Candida antarctica lipase (5%) Melted at 85ºC Placing flasks in an orbital shaker at 70ºC/24hrs/200rpm Vacuum filtration and storage at 4ºC
- 20. Source: Edible Oil Processing, Wolf Hamm, Richard J. Hamilton, Gijs Calliauw
- 21. Comparison between chemical & enzymatic interesterification Chemical interesterification Enzymatic interesterification Low processing cost (batch reactor) High processing cost (continuous plug-flow reactor, lipase) High processing loss (oil saponification) Minimum processing loss Low oxidative stability (tocopherol loss) No change in oxidative stability High levels of reaction by-products (MAG, DAG, glycerol) Low levels of reaction by-products Flavor reversion problem No flavor reversion Highly reproducible and easily controlled More complex operation and control
- 22. Industrial enzymatic interesterification plant (four packed-bed reactors) Typical batch reaction vessel for chemical interesterification T M
- 23. Measurement of interesterification Triacylglycerol Composition The change of TAG composition is one of the well-known parameters to monitor the interesterification degree Pt is peak ratio at reaction time of t, P∞ is the peak ratio at equilibrium, P0 is the peak ratio at the initial reaction time during the reaction
- 24. Solid Fat Content SFC0 is the initial SFC value SFC͚ is the SFC value when the reaction reaches equilibrium, k is the value related to reaction rate of the enzyme on the given blend τ is the reaction time
- 25. Application in food industry Fats and oils created by enzymatic interesterification provide several benefits to food manufacturers. These oils provide better health. Most often created through domestically sourced soybean oil, they provide a better risk management profile than globally produced palm oil. Lastly, producing enzymatic interesterified oil typically uses less processing and no harmful by- products creating a more sustainable, green process. Due to their physical characteristics, enzymatic interesterified fats have many food production applications, including cookies, crackers, biscuits, cakes and icings, dairy fat replacers, picrust, popcorn, flatbread and tortillas.
- 26. Conclusion Interesterification is the rearrangement of the fatty acyl groups within and between different triglycerides. These oils provide better health profiles than hydrogenated oil because they are trans fat free and lower in saturated fat. Enzymatic interesterified oil typically uses less processing and no harmful by- products creating a more sustainable, green process
- 27. References Source: Edible Oil Processing, Wolf Hamm, Richard J. Hamilton, Gijs Calliauw Lipid technology and its application by Frank D Gunstone, Fred B Padley. Interesterification of Edible Oils H .H. HUSTEDT, Chemical and Technical Director, Noblee & Thbrl GmbH, Hamburg-Harburg, West Germany Trends in Interesterification of Fats and Oils Alejandro G. Marangoni Saeed M. Ghazani
- 28. Thanks.