| Trans fatty acids (TFA) were unsaturated fatty acid isomers, which mainly present in ruminant animal fats, refined and hydrogenated oils. They have been applied in all kinds of food and used as function solid fats. While the relationship between trans-fatty acids and human health has been caused high attaches by social in recent years, How to reduce and restrict the production of trans-fatty acids have become an international hotspot and focus issue. The molecular rearrangement technique was a method to improve grease properties by changing the structure of triglycerides, As it couldn’t change the fatty acid composition of fats and would maintain the nutritional value of the natural fatty acids, which could provided a theoretical basis for the preparation of low trans fatty acid products, it will have broader prospects on future oil development and application areas.Objective11、 To reduce the reaction conditions and improve product yield by optimizing rearrangement reaction conditions and improving the traditional post-processing method;2、 To investigate the effect of molecular rearrangement on the properties of blends oil, especially to verify the molecular rearrangement wouldn’t cause the formation of trans fatty acids;3、 To preparation a variety of esterification butter which melting point range30℃to38℃, have high-linoleic acids but low cost and low-trans fatty acids with molecular rearrangement reaction, it would improve the nutritional value of the product and expand the range of application.Methods1、 The effect of reaction temperature, reaction time and amount of catalyst on the depression rate of melting point were investigated detected by using the palm stearin and soybean oil blends, sodium ethoxide as a catalyst. Then the optimal conditions of the molecular rearrangement reaction were optimized by the Box-Benknken response surface Design according to the change of melting point. 2、 The products after the reaction were treated with different volume fractions of ethanol solution range0to50%, respectively. The aqueous solution of ethanol optimum volume fraction of the post-processing were selected by comparing the yield and the amount of solution used in different treatments, and their properties before and after the reaction:3、 The low-price palm stearin and rich-polyunsaturated fatty acids soybean oil were blended at a ratio rang1:9to9:1, the qualitative change of different combinations of raw oil before reaction and the same proportion of blends oils before and after reaction were compared, the proportion of raw materials were selected ultimately according to the melting point determination which range of30-38℃after reaction.4、 According to the coconut oil have rich middle/short chain saturated fatty acids which have beneficial effect on the human health, It would mix with Palm stearinand soybean oil and coconut oil mixed at proportion of5:4:1,4:4:2,3:4:4, respectively, then analysed their properties change before and after reaction.5、The fatty acid composition, iodine value, triglyceride composition, solid fat content and melting curve were analysed by Chromatography-Mass spectrometry (GC-MS), ABB oil analyzer, High performance liquid chromatography (HPLC)-evaporative light scattering detector, nuclear magnetic resonance analyzer and Differential calorimeter scanner respectively.Results(1) The optimization conditions were achieve by response surface, when there were0.45%catalyst, at79.1℃for15.6min, The melting point would drop of23.45%.(2) When the product was treated with ethanol elution which volume fraction was50%, It would have the highest yield but the least amount of solution, at the same time, using these aqueous solution of ethanol elution could reduce the environment pollution as ethanol can be recycled at last, It don’t change the nature of the oil especially there were not trans fatty acids production.(3) When the proportion of palm stearin and soybean oil were6:4to3:7, the melting points of esterification reaction were range30℃to38℃, the content of linoleic acid were25%-40%; (4) When the proportion of the palm stearin, soybean oil and coconut oil were5:4:1,4:4:2,3:4:4, the melting point of esterification butter in30℃～38℃， the linoleic acid content was25%, oleic acid content was about20%～20%, linolenic acid was2%, the medium/short carbon chain saturated fatty acid content was6%～20%;(5) The nature of the mixed oil would change when the ratio of oils were different; After transesterification reaction, the melting point, triglyceride composition, solid fat content, DSC melting curve changed significantly, but the acid composition of and iodine value were same before and after reaction, there did not cause fatty acid structure and saturation changes, in other words, it wouldn’t produce trans fatty acids.ConclusionsMolecular rearrangement was an important means in oil modification, The results showed that when using molecular rearrangement to prepare esterification butter, the triglyceride composition, solid fat content, DSC melting curve had obvious changed, but the fatty acid composition was constant, importantly the fatty acids isomerization didn’t occur, there was not trans fatty acids in esterification butter. Therefore, molecular rearrangement would have more important development direction in oil processing and functional oils preparation. |
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