Effect of dehydration methods on retention of carotenoids, tocopherols, ascorbic acid and antioxidant activity in Moringa oleifera leaves and preparation of a RTE product.

Abstract

Fresh leaves of M. oleifera plants were analysed for nutritionally important phytoconstituents and feasible commercially used dehydration method were evaluated to preserve these in dehydrated leaves. Trans-lutein, trans-β-carotene and trans-zeaxanthin were found as the major carotenoids in fresh leaves, accounting for 36.9, 18.2 and 5.5mg/100g FW, respectively. Similarly, high amounts of ascorbic acid, α-tocopherol and total phenolic content (271.0, 36.9 and 512.0mg/100g FW), respectively were recorded in leaves. α-tocopherol was the most stable vitamin under all drying conditions (86.4% retention during oven drying), compare to other studied phytoconstituents. Cabinet tray drying was found as efficient as lyophilisation to retain maximum content of total carotenoids (60.1%), trans-β-carotene (90.1%), 13-cis-lutein (93.2%), and DPPH activity, however, lutein (51.3%) and ascorbic acid (97.8%) was best preserved by lyophilisation. During dehydration, significant trans to cis isomerization of β-carotene and lutein was also recorded. A ready to eat (RTE) chutney powder (adjunct) was developed from dehydrated leaves. The product was evaluated using Quantitative Descriptive Analysis and was accepted with a high overall quality score. The present investigation explores the nutritional potential of M. oleifera leaves and suitable methods of drying that could be useful for processed food formulation.