2.5. Statistical analysis
The statistical analyses of the variance (factorial ANOVA), with a confidence level of 95% (p-value ⩽ 0.05), were carried out by using of the software package Statgraphics Plus 5.1 to estimate the significant effect of the different variables of the process (drying air temperature, power of incident microwaves, and osmotic treatment). Furthermore, a principal components analysis, PCA, ( Martens & Næs, 1989) (Unscrambler version 9.7; CAMO Process AS, Oslo, Norway) was applied to describe the relationships among the changes on the profile of volatile compounds and process variables.