Extraction and purification of anthocyanins from purple-fleshed potatoes was investigated.
The effects of pretreatment method, time, and ethanol concentration on the extraction were
studied. Boiling was the most efficient pretreatment method for the extraction. Extraction
time and ethanol concentration were found to have only minor effect on the extraction
yield. Six hour extraction time and 20 vol.% ethanol concentration were found to be suf-
ficient. The resulting anthocyanin-rich extract contained glucose, proteins, amino acids,
and unidentified compounds as impurities. Removal of these by adsorption was studied
with six commercially available adsorbents, of which Amberlite XAD-7HP was the most
efficient. Anthocyanin purification with XAD-7HP was studied in a column. The effects of
flow rate on adsorption, and ethanol and acetic acid concentrations on desorption were
investigated. In loading, a highly dispersed anthocyanins breakthrough curve was obtained.
This most likely resulted from agglomeration of anthocyanins. Desorption of anthocyanins
could be done efficiently with 75 vol.% acidic (7 vol.% acetic acid) aqueous ethanol. All glucose
and unknown impurities, together with 87% of proteins and amino acids, could be
separated from the anthocyanins. Process scale-up was demonstrated by processing 19 kg
of purple-fleshed potatoes in a single batch
Extraction and purification of anthocyanins from purple-fleshed potatoes was investigated.The effects of pretreatment method, time, and ethanol concentration on the extraction werestudied. Boiling was the most efficient pretreatment method for the extraction. Extractiontime and ethanol concentration were found to have only minor effect on the extractionyield. Six hour extraction time and 20 vol.% ethanol concentration were found to be suf-ficient. The resulting anthocyanin-rich extract contained glucose, proteins, amino acids,and unidentified compounds as impurities. Removal of these by adsorption was studiedwith six commercially available adsorbents, of which Amberlite XAD-7HP was the mostefficient. Anthocyanin purification with XAD-7HP was studied in a column. The effects offlow rate on adsorption, and ethanol and acetic acid concentrations on desorption wereinvestigated. In loading, a highly dispersed anthocyanins breakthrough curve was obtained.This most likely resulted from agglomeration of anthocyanins. Desorption of anthocyaninscould be done efficiently with 75 vol.% acidic (7 vol.% acetic acid) aqueous ethanol. All glucoseand unknown impurities, together with 87% of proteins and amino acids, could beseparated from the anthocyanins. Process scale-up was demonstrated by processing 19 kgof purple-fleshed potatoes in a single batch
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