| Agar is an important hydrophilic gum with strong gel forming capability.Agar is extracted from red algae and has extensive application in food industry.In this study,different agar products were collected to test their physical and chemical indicators for screening suitable agar product that could benefit the convenience when used in dairy products.Furthermore,the agar was compounded with some other stabilizers to develop the stabilizer for the production of yoghurt,acid milk beverage and ice cream.The main results are shown as follows:(1)The comparison of the properties of agar products: It was shown that agar products 1,8and 9 had melting points lower than the sterilization temperature of dairy products and significantly higher than that of gelatin by comparatively determining the property of 9 kinds of agars and gelatin.In addition,the viscosity of agar 1,8 and 9 had similar trend under different temperature and pH mean while that with no great deffience with gelatin,under the same condition the viscosity of agar was more higher than gelatin.Therefore,agar 1,8 and 9 whose indexes closing to gelatin were chosen for the further study.(2)The optimization of yoghurt stabilizer formula: by comparing the viscosity and water blinding capacity of agar products with gelatin,the agar 1 was found having higher viscosity and water blinding capacity than agar 8 and 9.The constituent proportion of the agar 1,modified starch and pectin was optimized using water blinding capacity as the main reference index,through uniform mixing experiment.As the result,the optimized stabilizer formula composing of78% of agar,22% of modified starch and 0% of pectin and the total amount of that is 0.1%.The formula was further used to ferment yogurt and showing the water blinding capacity of 53.6%,viscosity of 2920 mPa·S,acidity of 87.9 ?T,sensory score of 90.Yoghurt sensory indexes perfectly met the dairy industry standard.(3)The Optimization of acid milk beverage stabilizer formula: The precipitation rate of acid milk beverage was analyzed to increase along with the increase of CMC-Na and agar concentration,and decrease along with the concentration of high ester pectin.The proportion of agar,CMC-Na and high ester pectin was optimized to be 1.6:35.6:62.8 by using the precipitation rate as the main index.The stabilizer of composed formula whose total amount is 0.6% was added to prepare an acid milk beverage,which showed the precipitation rate of 1.45%,viscosity of 15.4 mPa·s,sensory score of 90.(4)The optimization of ice cream stabilizer formula: Expansion rate of ice cream was illustrated to increase along with the increase of CMC-Na and agar,and firstly increase followed decrease along with the increase of guar gum.By using single factor experiment and mixture design experiment and adopting inflation rate as the investigative index,the stabilizer formula the total amount of which is 0.3% for ice cream production was optimized to be composed of17% of agar,33% of CMC-Na and 50% of guar gum.Under this condition,the ice cream was prepared to have the expansion rate of 92.08%,melting rate of 29.10%,sensory score of 89 and detailed sensory indexes meeting the frozen drinks standards of business.Focusing on the application of agar in dairy products,this study shows the agar product with the melting point close to the gelatin,which was further used to optimize the stabilizer of yoghurt,acid milk beverage and ice cream.This study provides a theoretical basis and technical reference for the application of agar in the diary industry. |
PDF Full Text Request