Achievement of half whiteness of botanicals by single step bleaching process for dry flower making

Abstract

Studies were conducted during 2010 to 2013 to identify the ideal bleaching agents for achieving half whiteness of different parts of plant used in dry flower making. Dried pods of Acacia auriculiformis, Sesamum indicum, Gossypium hirsutum, Pongamia glabra, and cones of Pinus spp were given bleaching treatment in a single step. Different chemicals viz., sodium hydroxide (10 %), sodium chlorite (10 and 20%), sodium hypochlorite (30%), hydrogen peroxide (10, 20 and 30%), hydrochloric acid (5%) and sodium silicate (1%) were used in 10 different combinations. The time taken for achieving required half whiteness (Yellow White Group – 158 – A) was observed as per RHS colour chart and the percentage of damage was calculated. Strength of whiteness was assessed and evaluated using RHS colour chart. Whiteness index was measured using Mini scan colour measurement system. Botanicals were scored for quality parameter viz., shape retention. The results indicated that, the treatment involving 20% sodium chlorite + 5% hydrochloric acid (cold water) proved superior with minimum bleaching time of 6 h and lowest rate of damage with highest whiteness index and maximum score for shape retention.   Key words: Dry flower making, botanicals, bleaching agents, half whiteness, RHS colour chart.