Effect of temperature and blanching treatment on hot-air drying characteristics of shredded snap bean

In this paper,the effect of drying hot-air temperature( 60~90 ℃) and blanching on the hot-air drying characteristics of shredded snap bean was analyzed.The results showed that drying process of shredded snap bean occurred in the falling rate period,and the moisture transfer was controlled by internal diffusion. Drying rate increased and drying time shorted with increasing temperature and blanching treatment( p<0.05).The experimental drying data of shredded snap bean were used to fit five available drying models( Newton,Page,Two term exponential,Henderson and Pabis,Approximation of diffusion models),and coefficients of models were determined by non-linear regression analysis.Results showed that Page model had the highest correction coefficient R~2,the lowest the reduced chi-square( χ2) value and root mean square error( RMSE) value and could exactly describe and predict the moisture dynamics of shredded snap bean during hot-air drying process.The D~(eff) values changed from 0.7981 to 2.5724 × 10~(-9)m~2/s within the given temperature range. According to the Arrhenius equation,E_a values was32.03 and 37.62 kJ/mol for the blanching and unblanching sample,respectively.The results could provide a theoretical basis for industrialization production and control of drying shredded snap bean.