The use of experimental factorial design for analysing the effect of spray dryer operating variables on the production of tomato powder

A two-level factorial experimental design technique was used to investigate the influence of the operating parameters on the production of tomato powder from tomato paste during the spray drying operation. This technique was applied to quantify the influence of feed total solids, feed flow rate, inlet air temperature and air flow rate on the process variables, namely, product total solids, particle size, bulk density and solubility. A factorial model was constructed and used to study all interactions among the considered parameters. The results showed that, at a 95% confidence interval, the effect of air flow rate was relatively insignificant, while the effects of feed total solids, feed flow rate and inlet air temperature were at the same significance level. Most interactions between the studied parameters were insignificant.