Influences of gamma irradiation and storage on the capsaicinoids of sun-dried and dehydrated paprika

Abstract

A study was conducted to investigate the changes in the pungent components (capsaicin, dihydrocapsaicin, homodihydrocapsaicin, isodihydrocapsaicin and nordihydrocapsaicin) of paprika as a function of drying method, gamma irradiation and storage period. Sun-dried and dehydrated paprika samples were irradiated by using a 60Co gamma irradiator at five doses (0, 2.5, 5.0, 7.5 and 10 kGy) in polyethylene bags and stored at ambient temperature for 10 months. The capsaicinoid contents of the samples were analyzed by HPLC every 2 months within the 10 months. The major pungent components, capsaicin and dihydrocapsaicin, significantly (P<0.01) increased with increasing irradiation doses. The increases of capsaicin, dihydrocapsaicin and homodihydrocapsaicin contents were about 10% with the dose of 10 kGy. In contrast, a significant (P<0.01) decrease was observed in these components with storage. The levels of all capsaicinoids were significantly (P<0.01) higher in dehydrated paprika than in sun-dried paprika. Nordihydrocapsaicin was found only in fresh red pepper. Although isodihydrocapsaicin was not detected in paprika during the first five months of the storage period, it was detected from the 6th month of the storage period. Hence, isodihydrocapsaicin might be used to identify paprika which has been stored for longer than six months. © 2003 Elsevier Ltd. All rights reserved.