Application of the Plackett-Burman design for screening and optimisation of factors affecting the aqueous extract for total anthocyanin content of broken riceberry rice

The aim of the present work was to identify the key factors that influence the total anthocyanin content of the aqueous extract of broken riceberry rice (BRR). The eight-run Plackett-Burman design was used to evaluate four factors (BRR particle size, BRR powder/water ratio, extraction temperature, and time). As revealed by the results, the BRR powder/water ratio, extraction temperature, and time had a significant influence on the total anthocyanin content. As a consequence, single-factor tests were conducted using a completely randomised design (CRD), considering BRR powder/water ratio (1:2.5, 1:5, 1:7.5, and 1:10 g/mL), extraction temperature (50, 55, 60, 65, and 70°C), and time (50, 60, 70, 80, and 90 min). Based on the results, the criteria for yield optimisation were a BRR particle size of 60 mesh, BRR powder/water ratio of 1:5, extraction temperature of 60°C, and time of 70 min. With these parameters, the total anthocyanin concentration of the extract was 9.71 mg C3G/g dry material.