Antioxidant potential of spinach, peas and sweet corn in relation to freezing period

We evaluated changes in the content of total polyphenols and antioxidant activity of frozen spinach, peas, and sweet corn in relation to the storage period. Total polyphenol content and antioxidant activity in analysed samples were determined by colorimetric methods. Both parameters were analysed in frozen samples monthly and the changes were monitored during storage in a freezing box at a temperature of –18°C for 10 months. Freezing had a different influence on the levels of total polyphenol content and antioxidant activity in individual analysed samples. The greatest decrease in antioxidant activity during the entire period of freezing was recorded in spinach (79.4%), while the lowest decrease was observed in peas (26.8%). A relatively significant decrease in antioxidant activity was also found in sweet corn (62.7%). On the contrary, the greatest decrease of total polyphenol content throughout the period of freezing was found in peas (62.0%), and lowest decrease was recorded in sweet corn (only 5.0%). The total polyphenol content in spinach decreased by 43.1% after 10 months of storage.