Abstract:

The effects of different doses of 60Co gamma-ray on the total bacterial, coliform and mould counts of grape seed superfine powder were explored according to the Chinese national standards of GB4789.2 — 2003, GB4789.3 — 2003 and GB4789.15—2003, respectively, and the changes in main functional components including total ployphenols, procyanidines and resveratrol of the grape seed superfine powder irradiated by different doses of 60Co gamma-ray were investigated and the mathematical models of their contents as a function of irradiation dose of 60Co gamma-ray were established. The results showed that 60Co gamma-ray irradiation could effectively kill bacteria, coliform and mould in the grape seed superfine powder, and the percentages of these microorganisms synchronously decreased with the increase of irradiation dose. The D10 values of bacteria and mould were 3.51 and 4.26 kGy respectively, the tolerance of mould to irradiation was higher than that of bacteria, and the optimum irradiation dose for sterilization was in the range of 8－9 kGy. After the 60Co gamma irradiation at 8 kGy, the hygienic target of the grape seed superfine powder fitted the Chinese national standard of health products, and the contents of total polyphenols, procyanidines and resveratrol did not significantly change. Furthermore, the grape seed superfine powder had better storability to lengthen the storage life and maintain good quality after sterilization by 60Co gamma-ray.

Key words: grape seeds, superfine powder, 60Co gamma-ray, irradiation, sterilization, functional components