In the industrial sector, vegetable residual materials have received attention in the production of bio-colorants. Betalain pigments extracted from red beetroots Beta vulgaris provide a natural alternative to synthetic red dyes. These pigments have been successfully used in commercial food coloring primarily due to their natural and non-toxic properties, rich color, and hydrophilic properties [1]. Second of all, medically, they have antiviral, antimicrobial, and antioxidant properties and have many health benefits such as maintaining good blood pressure, better athletic performance abilities, digestive health, brain function, anti-inflammation, and even anti-cancer properties. Betalains are derivatives of betalamic acid and can be classified into two groups: red-violet betacyanins and yellow betaxanthins [2].
Betalains are hydrophilic compounds that accumulate, mainly in the vacuoles of the epidermal tissues of plants that synthesize these pigments. Extracting them from cell vacuoles requires optimal extraction methods to get as much product as possible. These natural pigments are usually obtained from plants by using certain solvents or mechanical extraction methods. When plant tissues are exposed to those solvents – it helps to facilitate the diffusion of pigments into the extraction solution. Mechanical disintegration of tissues involves the destruction of cell wall material and other cellular components to release the desired product [3].
The aim of this work was to optimize betalain extraction conditions from Cylindra beetroot waste. First, beetroot pomace was obtained from cleanly washed beets and freeze-dried. After that, the obtained powder was dispersed in different solvents with various ratios, using several methods and dissolution times. Six solvents were used (water, 20%, 50%, 80% ethanol, and 0.44% or 0.88% ascorbic acid), which were mixed with lyophilized beetroot powder in two ratios - 1:20 and 1:50. In addition, three types of extraction methods were performed: 1) vertical rotation that was carried out for 30, 60, and 120 minutes at 60 rpm speed, 2) ultrasonic disintegration performed for 10 and 20 minutes and 3) homogenization at different speed range – 10000 or 16000 rpm for 1 and 2 minutes.
The best results were obtained performing vertical rotation for 1 hour with two solvents – 0,88% ascorbic acid and 20% ethanol at 1:20 ratio. These extraction conditions helped to obtain the best betalain yield.