Effect of Drying Process on Phenolic Compounds and Total Antioxidant Activity of Some Medicinal and Aromatic Plants

Abstract

The effect of antioxidant properties as free radical scavenging activity and phytochemical compounds of fresh and dried samples of dill, parsley, coriander, peppermint and celery leaves were studied. Moreover, the chemical constituents and the content of minerals in these medicinal and aromatic plants were also investigated. Results explained that the contents of total phenolics ranged from 1446.88 for coriander to 3128.57mg/100gm for peppermint and after the drying process decreased to 1280.10 and 2356.45mg/100gm, respectively. Also, peppermint had the highest content of flavonoids, while the lowest content was observed in coriander leaves. Otherwise, fresh coriander leaves had the highest content of carotenoids, while the lowest content was in the fresh peppermint leaves. Results explained also that the main component of phenolic compounds was protocatchuic in all fresh and dried samples under investigation. Celery leaves had the highest protocatchuic content. Concerning minerals content reveal that the parsley leaves had the highest content of calcium, potassium and magnesium, while peppermint had the highest phosphorus and iron contents. Results also show that celery leaves had the highest sodium content. Fresh dill and peppermint recorded the highest percentages of total antioxidant activity. Also, fresh celery had gradual effect on DPPH compounds being used as synthetic free radical. Coriander and parsley showed the lowest antioxidant activity. After the drying process total antioxidant activity decreased. Slight decrease was observed with dill and peppermint leaves, while celery and parsley leaves were more effective by using the air oven drier process.