The Studies On Fat Replacers From Yeast β-glucan

β-glucan was prepared from waste beer yeast. The effect of the extracted method to theβ-glucan and its property as the fat replacer were studied. The author applied this fat replacer to reduce fat content of baking products to study the effects of it on the properties of such low fat food, the aim was to develop new type food and use glucan fully in industry.β-D-glucan was extracted from the cell wall of spent brewer yeast with alkali, acid-alkali and enzyme-alkali method, respectively. The basic components of the three different extracted products were analyzed. The concentration ofβ-glucan extracted by enzyme-alkali method was highest which reached 86.81%, while the alkali method was lowest which was 76.53%. IR spectrum analysis showed the production was mostlyβ-D-glucan and without D-mannose. The molecular weight was determined by high performance liquid chromatography(HPLC). The molecular weight of the sample extracted by acid-alkali method was lowest which was 5.35×105, while the highest was enzyme-alkali method which was 1.13×106.The effect of different extract methods toβ-glucan as the fat replacer was studied by rheology property, oil-binding capacity, freeze-melt property, heat stability. Dynamic viscoelastic property experiment showed that the viscosity of the 6%β-glucan solution decreased with shear rate increased, and represent pseudoplastic and not thixotropic. The effects of the extract methods to the oil-binding capacity, freeze-melt property of theβ-glucan solution were not evidence, the network structure of the sample which extracted by acid-alkali method was most compact for the lowest molecular weight as well as the well freeze-melt property. By the same heat treatment, the viscosity of theβ-glucan solution decreased slower than other edible colloids which giveβ-glucan a good stability to heat.Low fat high-ratio cakes were prepared withβ-glucan which was extracted by enzyme-alkali method as fat replacer. The physical chemistry parameters, texture parameters and sensory evaluation were investigated. The results showed that moisture of the cake increased while specific votume of the cake decreased with increasing percentage of fat replace. The texture characteristics of the high-rate cakes withβ-glucan were determined by TPA. The springiness, gumminess, resilience of the high-ratio cakes were increased by theβ-glucan andβ-glucan improved the chewiness of the high-ratio cakes. By the sensory evaluation, the characteristics of cake withβ-glucan as 20% fat replacer had no significant difference with the traditional cake without any fat replacer. There were remarkable correlations between sensory and instrumental parameters.In the study of yeast glucan applicated in the low-fat ice cream, the ice-cream plasm viscosity and the hardness of ice cream increased with increasing percentage of fat replace. The addition of yeast glucan made the products have higher expand ratio of ice-cream, but the low anti-melting ability. The sensory evaluation results show that the fat replace has a proper bound, the low-fat samples with the percentage of fat replace less than 40% were acceptable.