Impact on blanching and drying of Moringa oleifera flower and its process parameter optimization

Moringa oleifera flower, agricultural by-product is obtained from Moringa oleifera lam. Flowers are rich in potassium, calcium and good source of protein and dietary fibre. But, particularly in South India, flowers and fruit appear twice a year and there could be non-availability during off season. In order to promote the intake of flower and to increase the shelf life, Moringa oleifera flower needs efficient preservation technique. The objective was taken as to devise a preservation technique that is fast enough, reduces energy consumption and retains nutrients, which could be achieved by combined blanching and drying. The drying and quality characteristics of Moringa oleifera flower were investigated during combined blanching and drying process using response surface methodology (Box Behnken design). The process conditions like blanching temperature (70°C, 80°C, 90°C), blanching time (2, 3, 4 min) and drying temperature (50°C, 60°C, 70°C) were independent variables. The condition was optimized based on physical (color and rehydration ratio) and chemical (polyphenols, flavonoids, antioxidant activity) characteristics of dried samples. Obtained results stated that all independent process conditions had a significant effect on physiochemical characteristics of dried flower. The optimized conditions were drying temperature (60.64°C), blanching temperature (79.48°C) and blanching time (2.85 min).