Development Of A Low-calorie Organogel From Modified Structured Lipids Sn-2 Rich In Polyunsaturated Fatty Acids And Its Characteristics

In recent years,people have higher requirements for food safety and nutrition.However,some traditional processing methods of food raw materials will introduce harmful substances that are not conducive to human health.There are food safety risks.For example,plastic fat is processed by traditional hydrogenation process,which contains trans fatty acids and saturated fatty acids,which are extremely harmful to human health.Using edible vegetable oil as a substrate and using edible oil gel to gelate,obtaining oleogel,instead of plastic fat,more and more attention has been paid to it.In this paper,the modified coconut oil as raw materials,structure lipid organogel was prepared by adding oryzanol and sterol.a method of loading quercetin with oleogel was put forward to prepare safe and nutritious food raw materials,which has good prospect in food industry.It also provide some new ideas and technical support for the development of new oleogel products.The main research contents are as follows:(1)Coconut oil rich in medium-chain saturated fatty acids was enzymatically modified at the Sn-2 position with polyunsaturated fatty acids from fish oil by trans-esterification reaction.The optimum conditions were determined as follows:substrate mass ratio(CO:FO)?1:1,enzyme content 10%,reaction temperature 70?,reaction time 8 h.The content of polyunsaturated fatty acids in the Sn-2 position in the obtained transesterification product was the highest,reaching 50.15%.MCFA are mainly distributed in the Sn-1,3 position of triacylglycerol,which is beneficial to human health.(2)The modified coconut oil was combined with gelators(y-oiyzanol and(3-sitosterol)to prepare organogels.The effects of different ?-oryzanol:(3-sitosterol ratios on texture characteristics,thermodynamic,rheological properties and microstructures of organogels,as well as their relationships,were studied.The results showed that the ratios of y-oiyzanol:(3-sitosterol significantly affect the formation mechanism,crystal morphology,texture properties and rheological behavior of oleogel.The organogels containing ?-sitosterol:y-oryzanol mass ratio of 6:4 had higher hardness,better oil binding capacity,higher melting point and enthalpy change,and more closer crystal structure.Rheological analysis showed that the oleogel showed a pseudoplastic fluid state.Within the frequency sweep range,the G' of the grease gel system was significantly larger than G'',which indicates that the organogel remains in solid stated,with good spreadability and plasticity.The analysis of crystal morphology showed that the crystal gradually forms a rose-like shape from the needle bar,which forms a complete and dense three-dimensional network structure.(3)After obtaining the optimal ratio,the effects of different contents of?-oryzanol and(3-sitosterol on the texture characteristics,thermodynamic,rheological properties,and microstructures of organogels,were investigated.The results showed that addition of 8%,12%,16%and 20%gelators showed gelling behavior inmodified coconut oil at 25?.With the increase of gelator content,the hardness of organogels increased significantly,the oil banding capacity and solid fat content also increased.The melting point and the enthalpy change of oleogels showed an increasing trend with the increase of gelators content,and the structure ability of the gelators was more stronger.Rheological analysis showed shear thinning phenomenon and thixotropic properties under different shear rates.The G' of the organogels system was always significantly larger than G''.As the gelator content increased,G' also increased,and the strength of the gel structure increased.With increasing gel content,the crystal numbers were increased and the morphology appeared to be more compact and clustered.(4)Three-dimensional network within organogel provide a favorable condition to load quercetin.The key factors affecting the loading and embedding rate of quercetin were analyzed from the solubility of quercetin and the network structure of oleogel.The optimal conditions for preparing the loading quercetin oleogel were obtained:The content of quercetin was 0.85%,the heating temperature was 40?,the heating time was 20 min,and the gelator content was 16%.Under the optimal process conditions,the encapsulation efficiency of quercetin was 64.09%,and the loading capacity was 6.32 mg/g.