Improvement of anthocyanins extraction from Hibiscus sabdariffa by coupling solvent and DIC process
Advancing the chemical engineering fundamentals
Distillation, Absorption & Extraction (T2-10P)
Keywords: extraction, anthocyanins, DIC, solvent, Roselle
Anthocyanins exist widely in fruits, flowers, and vegetables and are responsible for their bright colors such as orange, red, and blue. Anthocyanins are beneficial for skin and vascular health and are also known to coat the surface of cell membranes and protect them from enzymatic and free radical damage. Roselle (Hibiscus sabdariffa), which produces enlarged fleshy, dark red, edible calyces with a unique taste, is also known to contain a large amount of anthocyanins. Delphinidin-3-sambubioside and cyanidin-3samubioside are the major anthocyanins of Roselle . The present work aims to improve the capability to extract anthocyannis from dried calyces of Roselle by modifying the “raw material” structure.
The higher the expansion rate, the better the technological aptitude. Such a swelling operation is realized using the new process of « Instantaneous Controlled pressure - drop » DIC® (Détente Instantanée Controlée). This process involves subjecting the Roselle calyces for a short period of time to a steam absolute pressure varying from 70 to 300 kPa during some seconds and then dropping the pressure abruptly towards vacuum. In this study, we treated the dried Roselle calyces with DIC following a two parameter (the processing pressure and the processing time) central composite rotatable design.
After DIC treatment, we have investigated the kinetics of the aqueous extraction of anthocyanins from treated and non treated Roselle calyces. Total anthocyanins content in the aqueous extract was evaluated by differential pH method absorbance at 520 nm (Guisti et Wrolstad, 2001). Individual anthocyanins was quantified bu HPLC. Response surface methodology (RSM) was used for quantifying the effect of the processing parameters on the extraction yield of anthocyanins.
The optimum processing conditions selected for the global extraction yield obtained from response surface analysis were as follows: pressure level: 180 KPa; processing time: 9 s. The comparison between the kinetics of extraction of total monomeric anthocyanins (TMA) from the untreated and the different DIC experiments shows that there was an improvement in the kinetic of extraction for all the DIC experiments and that the maximum of total monomeric anthocyanins extracted from dried calyces of roselle is obtained within a short time (between 3 and 6 min) compared to untreated calyces (about 10 min). It was shown also that the kinetic of extraction of each individual anthocyanins follow the same tendancy as the TMA.
Concerning the yield of axtraction, the DIC treated calyces of Roselle according to optimum processing conditions gave the highest amount of TMA, Dp-3-sam and cyn-3sam with an improvement reaching respectively 130%, 119 and 127% compared to untreated Roselle.
See the full pdf manuscript of the abstract.
Presented Tuesday 18, 13:30 to 15:00, in session Distillation, Absorption & Extraction (T2-10P).
