توليد اولئوژل به روش امولسيون با استفاده از بيوپليمرهاي سديم كازئينات و صمغ زانتان

چكيده انگليسي :

Oleogel production with emulsion templated method using biopolymers of sodium caseinate xanthan gum Maryam Moradabbasi m moradabbasi@ag iut ac ir January 7 2020 Department of Food Science and Technology Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Persian 1st Supervisor Sayed Amir Hossein Goli amirgoli@cc iut ac irAbstractFormulation of lipid based food often needs solid fats to make appropriate texture and stability in theproducts The solid fat used in foods contains significant amounts of saturated and trans fatty acidsthat its excessive consumption leads to cardiovascular diseases cancer and type 2 diabetes Accordingly food researchers have explored suitable alternatives for saturated hydrogenated andtrans fatty acids including a new system called organogel Edible organogels prepared fromtrapping liquid vegetable oils with less saturated and no trans fatty acids in a structured network such as biopolymers create a gel like structure well known as oleogel Hence indirect methodssuch as emulsion templated approach have been investigated to produce oleogel in non thermalprocess So the purpose of this study was to fabricate emulsion templated oleogel using sodiumcaseinate emulsifier and xanthan gum thickening agent biopolymers In order to investigate thepossibility of oleogel production by this method first emulsions with different concentration ofsodium caseinate 2 and 4 and xanthan gum 0 0 2 and 0 4 with vegetable oil 60 w w were prepared then microscopic images particle size zeta potential and rheological properties viscosity loss and storage modulus of the emulsions were studied Based on the results increasingin sodium caseinate concentration significantly reduced the droplet size while zeta potentialsignificantly increased The effect of xanthan gum concentration on droplet size was not significantwhile a significant effect was observed on zeta potential by changing xanthan gum concentration The results of the rheological test showed that the storage modulus was higher than the lossmodulus indicating semi solid behavior The emulsion samples were then dried in freeze drier for48 h and sheared into oleogels Hardness of dried samples and oil loss in the respective oleogelsshowed a significant effect of two biopolymers concentration as the hardness increased and the oilloss decreased For this purpose a sample containing 4 sodium caseinate and 0 2 xanthan withanother sample containing 4 sodium caseinate and 0 4 xanthan as the superior formulas wereselected for examining the effect of drying method high and low temperature on oxidative stability color rheological properties hardness oil loss and internal oleogel structure The results showedthat drying method or biopolymers concentration had no significant effect on the oil freshness butthe change in biopolymers concentration on oil loss of the oleogel was significant since thebiopolymers inhibited the prooxidants permeation and oil was well entrapped in their structure Rheological properties indicated that drying method had no significant effect on the mechanicalstrength of the oleogels with lower biopolymers concentration but at a higher biopolymersconcentration this change was significant because the crust formation during vacuum oven heatingreduced elasticity On the other hand the produced oleogel had at least 50 structure recovery andvacuum oven dried oleogel with a constant concentration of biopolymers showed higher structurerecovery than the freeze dried samples indicating the effect of the drying method on the oleogelproperties The results revealed that lyophilization due to the short time and better oleogel texture can be more convenient than vacuum oven method Key Words Emulsions Oleogel Freeze drier Vacuum oven Oxidative stability Rheology 76

مرادعباسي، مريم

توليد اولئوژل به روش امولسيون با استفاده از بيوپليمرهاي سديم كازئينات و صمغ زانتان

امولسيون , اولئوژل , خشك كن انجمادي , آون خلاء , پايداري اكسيداتيو , رئولوژي