Aproveitamento do resíduo da beterraba (beta vulgaris) como corante natural para a indústria de cosméticos e na produção de bioetanol como etapa preliminar de tratamento dos extratos secados em leito de jorro

Abstract

The food processing and restaurant industries produce an enormous amount of organic waste in their processes, which are mostly discarded, such as the peels, stems and leaves of vegetables. An example is beet, a vegetable composed of several bioactive and natural pigments, whose peels are discarded. As a way to take advantage of the dyes and bioactive compounds of the beet peel, it can be dried. However, the high sugar concentration in the beet can cause problems both in the drying process and compromise the quality of the powdered products. Studies show that fermentation of liquid plant extracts both minimizes these effects and promotes a higher concentration of dyes, in addition to producing bioethanol. This work aims to study the fermentation of beet extract in order to reduce the concentration of sugars for drying and the production of ethanol. The beet was characterized for moisture, vitamin C and soluble solids, and then the beet peel was extracted with citric acid. The liquid extract was characterized in terms of moisture and sugar content. In order to find the optimal fermentation time, the fermentative kinetics of the peel extract were obtained and the sugar content was quantified by the HPLC method and by the dinitro salicylic acid (DNS) method. In both methods, 10 hours was the point with the highest concentration of ethanol and the lowest concentration of glucose. The fermentation process consumed 98.9% of glucose and an ethanol yield of 62.5%. In addition, the liquid extract was dried in the spouted bed using corn starch as an adjuvant in concentrations of 5.24% and 10%. The powders produced were classified as non-hygroscopic (<10%) and had an ideal water activity of approximately 0.4, indicating a low risk of deterioration. Starch did not influence the yield of powders, with a yield of 80.4% and 80.1% for the powder with the lowest and highest concentration of adjuvant, respectively.