Abstract:

A three-variable quadratic orthogonal rotation combination design involving 23 experiments was adopted to optimize puffing-drying procedure of carrots at various temperature-pressure differences. Based on experimental data, quadratic regression models were separately deduced for four indexes of products, including water content (Y1), crispness (Y2), hardness (Y3) and color (Y4) as a function of three variables, including puffing temperature (X1), vacuuming temperature (X2) and vacuuming time (X3). Subsequently, response surface methodology was employed to evaluate interactive effects of the variables. Results showed that the optimal technological conditions for puffing carrots were 93－99 ℃ of puffing temperature, 77－80 ℃ of vacuuming temperature and 140－160 min of vacuuming time.

Key words: response surface methodology, carrot, variable temperature-pressure difference, technology optimization