Effect of blanching, acid type, and temperature on the extraction of anthocyanin from Tibouchina semidecandra flower

Abstract

Extraction is the most common way to obtain anthocyanins from their natural matrices. During the extraction, the anthocyanin may degrade due to the heat and acidic solvent. The objectives of this research were to determine the best acidic aqueous solution and temperature to extract anthocyanin from Tibouchina semidecandra flower and to decide if the blanching process has a significant effect on the extracted anthocyanin. The T. semidecandra petals were separated into two groups: steam blanched for 6 mins and without blanching. Both were dried for 24 hrs at 45°C and powdered. The extract was prepared by macerating the powdered petal into pH 3 aqueous solutions made of three different acids (citric, malic, and hydrochloric acid, respectively) in a water bath shaker at various temperatures (30, 45, 60, and 75°C) for an hour. The extracts were then filtered, centrifuged, and analysed for their colour intensity, browning index, monomeric anthocyanin, polymeric anthocyanin, and total phenolic content. The best method to obtain the highest colour intensity, monomeric anthocyanin, total phenolic content, and lowest browning index was using steam-blanched dried petal, citric or malic acid as solvent and extraction temperature at 60°C. The total monomeric anthocyanin and phenolic content of the extract was 3.63±0.35 mg/g dried petal and 74.47±11.47 mg/g dried petal, respectively.