Effect of fluidized‐bed and freeze‐drying techniques on physicochemical, nutritional, thermal, and structural properties of Moringa oleifera flowers, leaves, and seeds

Abstract

The study evaluated the effect of fluidized bed drying (FBD) and freeze-drying (FD) on physicochemical, nutritional, thermal, and structural properties of Moringa oleifera. The leaves’ and flowers’ powder was prepared by FBD at 50 ℃ outlet temperature and FD at −50 ℃, while seeds were germinated at 25 ℃ for 96 hr and dried. Seeds were also subjected to a fermentation process using Lactiplantibacillus plantarum culture. FD Moringa leaves and flowers had better retention in terms of nutrition and antioxidant activities. In the case of seeds, fermented ones indicated better quality in terms of physicochemical, thermal, and structural properties. Germination and fermentation improved the glass transition temperature of seeds. Thermogravimetric analysis curves of FD-dried leaves, flowers, and seeds shifted to higher onset temperature at 243.5, 272.9, and 210.2 ℃ with mass loss of 29.31%, 36.83%, and 33.11%, respectively. X-ray diffraction pattern revealed similar shapes with different dried powders. The fermented seeds exhibited a higher crystallinity index (21.47%). Novelty impact statement The processing operations like germination and fermentation coupled with freeze and fluidized bed drying can enhance the nutritional value, antioxidant activity, phenolic content, ascorbic acid, glass transition temperature value, and crystallinity index of the Moringa oleifera powder, which can be used as a functional ingredient in the development of novel foods and pharmaceuticals.