Optimization of fermentation conditions for vacuum microwave puffing hawthorn piece

To determine the optimum process of puffed hawthorn tablets,on the basis of single factor experiments,response surface method( RSM) was applied to optimize the process of vacuum microwave puffing hawthorn piece.This article analyzed the influence of three factors,such as initial water content,vacuum pressure,microwave intensity,on the expansion degree and the sensory.Determination of the changes of the nutritional composition and physical characteristics of the Hawthorn slices in the process of expanding,the optimum technology of microwave expanded Hawthorn slice was obtained.Results showed that under the condition of initial water content to 35% ±0.5%,vacuum pressure to- 74 k Pa,microwave intensity to 31 W/ g,puffing degree and sensory scores were respectively 1.663 ± 0.18 and 6.382 ± 0.213. Nutrients VC,flavonoids,anthocyanin of hawthorn piece decreased in expanded process.Hardness and chewing ability increased,and elasticity and adhesion decreased.The change of the structure of Hawthorn in the expansion process was demonstrated by the electron microscope. Scanning electron microscopy( SEM) images showed puffed haw in the process of organizational structure changed from dense to loose.