Optimization of freeze drying parameters for moringa (Moringa oleifera) flower powder by using response surface methodology and principal component analysis

Moringa oleifera Lam. is an incredible plant because of vital nutrients such as minerals, vitamins and phytochemicals. The present work is focused on studying the optimization and quality attributes retention in moringa flowers in a freeze dryer (FD). Because the conventional drying process takes more time and energy which will affect the product quality and safety. Response surface methodology (RSM) was employed to optimize the effect of drying temperature (- 65 to - 45°C), vacuum pressure (0.5 to 2.5 mmHg) and drying time (18 to 24 h.) on the vitamin C, total antioxidant activity(TAA) and hygroscopicity (HS) of moringa flower. The developed model response R2 values of vitamin C 0.96, total antioxidant activity 0.97 and hygroscopicity0.95. Based on response surface and desirability (0.74) functions, moringa flower was freeze sdried at - 63.75°C for18 hr under 0.55 vacuum pressure had an optimum level of vitamin C 285.84 mg/100g, TAA 453.20 mg/100g and HS 1.57 percent. Freeze dried moringa flower powder at -55°C had maximum drying characteristics with special reference to high powder recovery (98.75%) and excellent flowability.The first principal component, accounting for 52.15 per cent and two 23.02 per cent of the total variance resolved the different drying temperatures.