Effects of enzymatic extraction on anthocyanins yield of saffron tepals ( Crocos sativus) along with its color properties and structural stability

Abstract

An aqueous solution of Pectinex (containing cellulase, hemicellulase, and pectinase) at 1%, 2.5%, 5%, 7%, and 10% concentrations and 40°C was used to extract anthocyanins (Acys) of saffron tepals at 20, 40, 60, 120 and 180 min reaction times and compared with ethanol solvent under similar conditions. The Acys of the Pectinex solution reached 6.7 mg/g of tepal powder (~40% more than the ethanol method) when the enzyme concentrations and extraction times were, respectively, 5% and 60 min. The Acys of aqueous enzymes had three times slower degradation rates and 50% more attractive chroma color than the ones recovered by ethanol solution after 3 h of extraction time. Additionally, the Acys of the ethanol solution lost its content sharply (>45%) and its chroma changed quickly (due to the browning and polymerization). High performance liquid chromatography (HPLC) analysis showed that Acys extracted with mixed enzymes had about 80% more cyanidin 3-glucosides and 20% less pelargonidin 3,5-glucosides than with the ethanol method. Most probably, the high content of cyanidin 3-glycosides in enzyme-extracted Acys of saffron tepals was the key factor for its high stability.