CHANGE OF CHLOROPHYLL AND VITAMIN C IN GREEN PEAS (Pisum sativum) DURING THERMAL PROCESSING

Abstract

       Fresh green peas are rich in vitamin C, a powerful natural water-soluble anti-oxidant. Green peas are normally consumed after thermal processing, mostly canning or cooking, which causes vitamin C degradation and chlorophyll breakdown. This study aimed to determine the changes of vitamin C and chlorophyll during thermal processing through analyzing their contents in peas during typical thermal processing stages, including blanching, boiling, and pasteurizing. The results revealed that the vitamin C content was reduced significantly when the blanching temperature increased by 10^oC. The vitamin C in green peas blanched at 70^oC, 80^oC, and 90^oC for 3 minutes were 32.68, 12.60 and 13.02 mg%, respectively. A high loss of chlorophyll was recorded when the peas were blanched at 90^oC. The experiment’s results also showed that the vitamin C and chlorophyll losses were higher in the peas put in water of 22^oC than those put in water of 100^oC prior to boiling. Pasteurizing at 95^oC for 8 or 11 minutes gave lower vitamin C content in the peas than at 100^oC for 5 minutes. For retention of vitamin C and chlorophyll, it is recommended that green peas be put in initial water of 100^oC during boiling, blanching, and pasteurization as fast as possible in the canning process.