Influence of Different Drying Methods and Storage on the Quality of Indian Spinach (Basella rubra L.)
This study reports the effects of drying methods on nutrient retention in a leaf vegetable during storage. The leaves of Indian Spinach were dried to 3.50-4.0% moisture content in the sun (35°), shade (28°C) and oven (45°C) and then stored in polyethylene wrappers. Their moisture, ascorbic acid, minerals and total chlorophyll contents were determined after drying and during storage. There was minimal moisture gain during the twelve week storage period being less than 1% in all three drying methods. Ascorbic acid decreased by 43-48% as a result of drying but storage for twelve weeks did not result into much further loss. Shade-dried leaves retained ascorbic acid in the least. Chlorophyll and minerals contents also decreased slightly with drying and storage. Shade-dried leaves were lowest in Ca, Mg, K, Na, Fe, Mn and Zn. The contents of Ca and Mg in shade dried leaves increased in storage while K, Mn and Zn decreased. Manganese was the most critically reduced element by both drying and storage with shade dried leaves losing 73.2, 81.6% at drying and 12 weeks later. Comparative figures for sun and oven dried leaves were 49.2, 47.6, 50 and 62.6% for the same periods. The greatest reduction in Zn content also occurred with shade drying. Sun drying resulted into more nutrient retention while there was only marginal difference in ascorbic acid content by the three techniques. Chlorophyll content was not much affected by both drying and storage and shade dried leaves retained chlorophyll more than those dried in the sun and oven.