Extraction of Natural Colors From Beetroot Flour Obtained by Solar Drying.

The purpose of this work is obtain paintings with background natural colors extracted of agricultural products, due to the conventional products are harmful to environmental. In this case offer an excellent alternative by obtained paintings from natural source. The agricultural product used was beetroot (Beta vulgaris), due it has as main pigment the betacyanin. To obtain the color extract, beetroot was processed in two consecutive steps. The first step, fresh beetroot was a treat of solar drying during 20 h (measuring loss of weight, temperature, solar radiation and relative humidity in situ), the second step is related to water extraction, with previous treatment by ketone; later the flour is obtained.
Average of 7.5 % for content to water at the flour´s dehydrated product was determined. Moreover the results showed color in dehydrated product is very similar to the determined one in the fresh product according to European indicative numbers (DIN 16539). On the other hand, betacyanin was quantified by use a spectrophotometric method. It was insignificant the loss of betacyanin in the treatment with solar drying. The colorant was applied on wood articles and ceramics with prominent results. Another application that is investigated is in the painting formulation for residential buildings.
Our methodology showed to be an excellent alternative for the color extraction from Beta vulgaris. This is due to the step of solar drying which favors the handling of the raw material (flour), besides to prolong the useful life without decreases in the color at color extract.