2.3. Experimental design
A central composite rotatable design (CCRD) was used to optimise
and evaluate the main, interaction, and quadratic effects of
sonication conditions (power level: PL, and treatment time: t)
and storage period (Sp) on tomato quality. The complete design
consisted of three sets of experimental points: (i) a traditional factorial
design with 2k points, k being the number of independent