Ellagic acid concentrations in raspberry liqueurs, purees, juices, and concentrates.

摘要

Since high concn. of ellagic acid, a dimeric polyphenol, may lead to instability and haze formation in raspberry liqueurs, etc., an HPLC method for its determination was developed. Extraction of ellagic acid from various raw materials during liqueur manufacture was also elucidated, as was removal of ellagic acid from raspberry juices reconstituted from clear concentrates using fining agents, adsorber resins and PVPP. The ellagic acid analysis involved HPLC with photodiode array detection. Juicesand alcoholic extracts were injected directly after centrifugation and filtration. Alcoholic extracts from fresh fruits were found to contain 10-24 mg ellagic acid/l, during storage for up to 28 days (concn. increased steadily during storage), whereasextracts from puree contained approx. 15 mg ellagic acid/l, which fell gradually to less than 10 mg/l after about 8-9 days. During juice production, ellagic acid concn. found were approx. (mg/l) 12.5 in mash, 8 in raw juice, 27.5 in depectinized juice and 14 in fined and filtered juice. Juices prepared from concentrates contained up to 161 mg ellagic acid/l. Besides traditional fining, polymeric treatments and adsorber resins reduced ellagic acid contents in raspberry juices. To prevent decoloration, different methods should be tested and low ellagic acid raspberry cv. should be used.