Iranian Research Organization for Science and Technology (IROST) Innovative Food Technologies 2783-350X 4 1 2016 10 22 Effects of drying process on qualitative and quantitative properties of watercress (Nasturtium officinale) leaves Effects of drying process on qualitative and quantitative properties of watercress (Nasturtium officinale) leaves 1 16 335 10.22104/jift.2016.335 FA S. Hosna Ostadzadeh Graduated student, Department of Food and Science Technology, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran S. Zahra Sayyed-Alangi Associate Professor, Department of Chemistry, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran Journal Article 2016 06 25 This study has investigated the effects of different drying methods on qualitative and quantitative characteristics of watercress (<em>Nasturtium officinale</em>) leaves, including water loss, antioxidant activity, contents of vitamin C, phosphorus, calcium, and iron. Hot air oven dryer at three thermal levels (40, 50 and 60 °C), microwave dryer at the three powers (180, 360 and 450 W) and the sun were used for drying of the leaves. In terms of drying time, the longest and shortest times were related to the dried treatments with the sun (1920 min) and the microwave at 450 W (22 min), respectively. In the charts related to moisture loss rate of the product, there was a period of constant speed and a term with the falling speed of moisture loss. Drying rate was increased by increasing microwave power and temperature of hot air oven, but the drying time was decreased. In the sun method, drying was performed at a slower rate due to temperature fluctuations. The highest amounts of vitamin C, iron and calcium were obtained to the dried samples by the oven at 60 °C (6.9 mg.100g), the sun (519.8 ppm) and the microwave at 180 W (210.68 g/kg), respectively. Also, the highest content of phosphorus was achieved to the drying by oven at 40 °C (0.523 percent). Overall, the dried treatments by oven and microwave dryers due to less moisture contents in a constant weight than the dried treatments by the sun, more mineral contents were preserved. The most antioxidant activity was belonged to the dried treatment by the microwave at 360 W. According to the results, it can be said that drying watercress by oven at 40 °C and microwave at 180 W is more desirable, since the amount of active ingredients in the plant is preserved substantially compared to the other treatments. This study has investigated the effects of different drying methods on qualitative and quantitative characteristics of watercress (<em>Nasturtium officinale</em>) leaves, including water loss, antioxidant activity, contents of vitamin C, phosphorus, calcium, and iron. Hot air oven dryer at three thermal levels (40, 50 and 60 °C), microwave dryer at the three powers (180, 360 and 450 W) and the sun were used for drying of the leaves. In terms of drying time, the longest and shortest times were related to the dried treatments with the sun (1920 min) and the microwave at 450 W (22 min), respectively. In the charts related to moisture loss rate of the product, there was a period of constant speed and a term with the falling speed of moisture loss. Drying rate was increased by increasing microwave power and temperature of hot air oven, but the drying time was decreased. In the sun method, drying was performed at a slower rate due to temperature fluctuations. The highest amounts of vitamin C, iron and calcium were obtained to the dried samples by the oven at 60 °C (6.9 mg.100g), the sun (519.8 ppm) and the microwave at 180 W (210.68 g/kg), respectively. Also, the highest content of phosphorus was achieved to the drying by oven at 40 °C (0.523 percent). Overall, the dried treatments by oven and microwave dryers due to less moisture contents in a constant weight than the dried treatments by the sun, more mineral contents were preserved. The most antioxidant activity was belonged to the dried treatment by the microwave at 360 W. According to the results, it can be said that drying watercress by oven at 40 °C and microwave at 180 W is more desirable, since the amount of active ingredients in the plant is preserved substantially compared to the other treatments. https://jift.irost.ir/article_335_b1aa7c21d2d2ed30bf0e11d9143265cc.pdf