The Studies On Fat Replacers From Citrus Pectin

Based on the studies of former researchers, the thesis discussed the properties and relative theories of pectin gelation process. Developing a new type fat replacer as pectin gel as the basic material, the author applied this fat replacer to reduce fat content of some food such as spreads, milk products and baking products to study the effects of it on the properties of such low fat food.Through study the rheological properties of different DM and DA citrus pectin gel. Discussing the effects of concentration of pectin and calcium ion on the elastic modulus and viscous modulus and tanδ.Concentration of sugar and pectin show little effects on the HM pectin. The SF530 showed the better gelation properties.Fractal analysis of the SF530 pectin gel showed that concentration of pectin acted improtant role during the gelation process. And the fractal dimension of different system were all lower than 2.0. The results should be understood better after more study.The results indicated that high concentration pectin promoted the formation of the pectin gel and increased the gelation speed of the pectin dispersions. The pectin concentration brought more effect to the gelation of the dispersion than the calcium ion.Only when pectin chain abundant, the difference of the structure of the pectin might effect the energy barrier in developing the pectin network. It was found that, at the fixed calcium ion content, the higher the pectin content, the lower the Mc in both two type pectin except when the calcium ion concentration was 6mMol/L.Through adding the calcium ion to the mixture of LM and HM pectin to induce heat irreversible gel. By study the WHC and texture of the mixture system of HM and LM pectin system based on the RSM analysis. Obained the regression model for forecasting some index of the gel. Select inertia polysaccharid as outer pahse to stabilize the PFM system. Optimized the process of preparation to get the appropriate product to imitate fat.Application of whey protein isolate and low-methoxy pectin based fat mimetics in mayonnaise was studied. Fat was partially substituted by different fat mimetics at levels of 50% respectively which the fat mimetics were referred to as PFM1 (mciropaticulate pectin gel), PFM2 (pectin weak-gel), and PFM3 (microparticulated combination of WPI and pectin). The full fat (Ff) (100% oil) mayonnaise without fat mimetic was used as a control experiment. Physicochemical, rheological, texture analysis, and sensory evaluation of the Ff and low fat (Lf) mayonnaises were performed. The results indicated that all Lf mayonnaises had significantly lower energy content, but higher water content than their Ff counterpart. In terms of texture, the formulation with pectin weak-gel as fat mimetic showed similar texture values as those of the Ff sample. Both Ff and Lf mayonnaises exhibited thixothopic shear thinning behaviour under steady shear tests and were rheologically classified as weak gels under small amplitude oscillatory shear tests. Sensory evaluation demonstrated that mayonnaises substituted with low methoxy pectin were acceptable. This study shows good potential for pectin weak-gel and microparticulated pectin gel to be used as a fat mimetic in mayonnaise. But the later study showed that the low fat mayonnaise with weak pectin gel as fat replacer became gel after one week storage. And there were water separated from the mayonnaise with microparticulated combination of WPI and pectin as fat replacer. The reason might be that the microparticle recongregate each other.Add outer phase to the above mciropaticulate pectin gel,and as fat replacer applied to the mayonnaise. Through rheology, microsturcture, sensory analysis study, it was found that PFM had the fat like sensory properties and might interact with other ingredients for the rheological properties varied during storage. And the PFM act good roles as fat replacer.Fat reduction in semi-solid cheese analogues and the use of pectin gel affected low-fat samples in different ways. Fat reduction and moisture augment caused the microstructure of low-fat cheese analogues obviously more loose. The low-fat samples showed lower hardness, gumminess, chewiness and adhesiveness and low-fat samples with pectin gel addition were more similar to the full-fat cheese analogues. Pectin gel addition showed that it can decrease the melt enthalpy of the samples which may be due to the conformation or structural change of pectin or pectin interacted with fat or protein to decrease the Delta H. The low-fat cheese analogue made with pectin gel addition was well received by the sensory panel. The properties of the low-fat cheese with pectin gel such as texture, microstructure and rheology were midst full-fat and low-fat without pectin gel addition samples. The results suggest that pectin gel may play the role of fat mimetic when added to cheese analogues.Functionality of fat mimetic from pectin on the low-fat high-ratio cakes might due to its ability to maintain the structure of the batters just as fat. In the same time the micro particles of the fat mimetic had the similar sensory properties as fat granules in the cakes. From the texture and evaluation analysis, it was found that when fat was 20, 40% replaced, the low-fat cakes were similar as the control sample.In conclusion,the PFM had the potential to applied in the low fat spreads, low fat milk products and low fat baking products.