Preparation Of Tiger Nut Oil-based Margarine With Low Saturated By Interesterification

Margarine and other plastic fats have a large consumption market in China.However,their main ingredients are hydrogenated vegetable and animal oils or their mixtures,which contain a large amount of trans-fatty acids and high levels of saturated fatty acids and have a low nutritional value due to their single fatty acid composition.Regular intake of high-saturated fatty acid fats can lead to an increase in cholesterol,which increases the risk of coronary heart disease and harms human health.Tiger nut oil（TNO）is a high-oleic acid oil resource with a fatty acid composition similar to that of olive oil and hazelnut oil and does not contain cholesterol.Its nutritional value and quality are comparable to those of olive oil.However,this high-quality oil resource has not been reported in the field of plastic fats such as margarine.Based on this,this study used TNO and palm stearin（PS）as raw materials to prepare low-saturated tiger nut oil-based margarine.And then it was applied to the bakery experiment to further investigate its application and provide a theoretical reference for the application of TNO in the field of plastic fats such as margarine.The main research contents are as follows:Firstly,the alkaline-catalyzed interesterification reaction of TNO and PS was investigated for the preparation of tiger nut oil-based margarine base oil.The effects of different basic catalysts,feedstock material ratios,reaction temperatures,catalyst additions,and reaction times on this reaction were explored,and the catalytic process conditions were optimized by response surface methodology.The results showed that sodium methanol had the best catalytic efficiency among the four common alkaline catalysts.The order of the effects of each factor on the methanol sodium-catalyzed interesterification reaction was obtained as:catalyst addition>reaction temperature>reaction time.The melting point drop rate（MPD）of the chemical interesterification（CIE）sample was 26.45%at a catalytic temperature of 80^oC,a sodium methanol addition of 0.36%,and a reaction time of 32 min.Analysis of the fatty acid composition of the optimized CIE sample showed a lower saturated（<40%）,atherogenicity（AI=0.56）,and thrombogenicity index（TI=1.15）with improved nutritional value.Secondly,based on the optimization of the feedstock material ratio in the previous chapter,the effect of enzymatic interesterification（EIE）on this reaction was investigated,and the catalytic conditions were optimized by response surface methodology.The optimal conditions for the interesterification reaction were a catalytic temperature of 53 ^oC,enzyme dosage of 5.4%,and a reaction time of 2 h.The MPD of the EIE sample under these conditions was 23.91%,and by expanding the reaction system to 10 times the original size,the MPD of the EIE sample obtained was 24.02%,which was also close to the predicted MPD of the EIE sample（24.44%）.Afterwards,the properties of the optimized CIE and EIE samples were determined and analyzed in comparison with the physical blends.Compared to the physical blends,the CIE samples lost 43.06%and 6.77%of their tocopherol and sterol content respectively,while the EIE samples lost 26.28%and 2.51%of their tocopherol and sterol content respectively.The CIE samples showed an increase of 51.84%and 89.58%for the di-saturated（S₂U）and di-unsaturated（SU₂）triacylglycerols,respectively.While the EIE products showed an increase of 41.22%and 99.79%for the S₂U and SU₂ triacylglycerols,respectively.The slip melting point（SMP）of the CIE sample was 33.51^oC,and the SMP of the EIE sample was 34.66 ^oC.The SFC of the CIE and EIE samples was 16-18%at 20^oC and 3-4%at 35^oC,and the EIE sample was more ductile than the CIE sample at low temperatures.Theβ’crystalline form of the interesterified samples increased,and the final enthalpy peaks of the CIE and EIE samples were significantly shifted toward the low temperature with a decrease of 10.36^oC and 10.37^oC,as well as low enthalpy values.At the same crystallization temperature,the crystallization rate of physical blends was faster than that of the CIE and EIE samples.Moreover,the crystallite size of physical blends was larger with disperse needles,while that of the CIE and EIE samples was smaller with spherical crystals.All the property indexes indicated that the interesterified samples were suitable for the production of margarine based on tiger nut oil,providing a theoretical reference for its future application in the field of margarine.Finally,this section explores the potential application of homemade margarine in baking.Firstly,the emulsifiers added to the interesterified samples were screened,and the emulsifier formulations were optimized using a blend design.The optimized emulsifier formulation was:glycerol lactate:39.6%,molecularly distilled monoglyceride:26.1%,and sucrose ester:34.3%.The preparation of tiger nut oil-based margarine was carried out under the optimal interesterification process and optimal emulsifier formulation,and its crystalline and thermal properties were compared with those of three commercially available margarines.The results showed that theβ’crystalline content of homemade margarine was higher than that of commercially available margarine.While homemade margarine and commercially available margarine had similar melting and crystallization properties,which both had good oral meltability.When homemade margarine and commercially available margarine were applied to the bakery experiment,it was found that the bread with homemade margarine had a higher specific volume,better bread quality,and higher sensory scores.This showed that homemade margarine has a good application prospect in the bakery field.This study provides a theoretical and practical basis for the preparation of low-saturated tiger nut oil-based margarine,which is of great practical significance in promoting the healthy development of the tiger nut oil industry in China.