Effect of blanching on nutritional quality of dehydrated colocasia, <i style="mso-bidi-font-style:normal">Colocasia esculenta </i>(L.) Schott leaves

Abstract

The quality of taro leaves, <i style="mso-bidi-font-style: normal">Colocasia esculenta </i>(L.) Schott, dried in mechanical dehydrator was studied as an attempt to develop a dehydrated product from this vegetable. The effect of different blanching types (water blanching and steam blanching), time period (10 sec to 3 min) and chemical blanching (MgO, NaCl, NaHCO₃ and EDTA) was also studied with respect to the nutritional characteristics. The fresh leaves of Colocasia had a moisture content of 83.4 to 87.0% with a total soluble solids (TSS) varying from 1.8-3.2^oB. Drying of fresh leaves without any pre-treatment and in the absence of blanching resulted in undesirable colour changes from green which is a typical of fresh vegetable to olive brown or brown discolouration. Blanching of taro leaves in water for 10 seconds or in alkali like sodium bicarbonate @ 0.1% resulted in superior product which unlike the steam blanched or unblanched leaves by showing minimal loss of green colour as reflected in cholorophyll content and nutritional characteristics.