Ultrasound assisted enhancement in natural dye extraction from beetroot for industrial applications and natural dyeing of leather

Abstract

There is a growing demand for eco-friendly/non-toxic colorants, specifically for health sensitive applications such as coloration of food and dyeing of child textile/leather garments. Recently, dyes derived from natural sources for these applications have emerged as an important alternative to potentially harmful synthetic dyes and pose need for suitable effective extraction methodologies. The present paper focus on the influence of process parameters for ultrasound assisted leaching of coloring matter from plant materials. In the present work, extraction of natural dye from beetroot using ultrasound has been studied and compared with static/magnetic stirring as a control process at 45 degrees C. The influence of process parameters on the extraction efficiency such as ultrasonic output power, time, pulse mode, effect of solvent system and amount of beetroot has been studied. The use of ultrasound is found to have significant improvement in the extraction efficiency of colorant obtained from beetroot. Based on the experiments it has been found that a mixture of 1:1 ethanol-water with 80W ultrasonic power for 3h contact time provided better yield and extraction efficiency. Pulse mode operation may be useful in reducing electrical energy consumption in the extraction process. The effect of the amount of beetroot used in relation to extraction efficiency has also been studied. Two-stage extraction has been studied and found to be beneficial for improving the yield for higher amounts of beetroot. Significant 8% enhancement in % yield of colorant has been achieved with ultrasound, 80W as compared to MS process both using 1:1 ethanol-water. The coloring ability of extracted beet dye has been tested on substrates such as leather and paper and found to be suitable for dyeing. Ultrasound is also found to be beneficial in natural dyeing of leather with improved rate of exhaustion. Both the dyed substrates have better color values for ultrasonic beet extract as inferred from reflectance measurement. Therefore, the present study clearly offers efficient extraction methodology from natural dye resources such as beetroot with ultrasound even dispensing with external heating. Thereby, also making eco-friendly non-toxic dyeing of fibrous substances a potential viable option.

Optimization of ultrasound assisted extraction of anthocyanins from red cabbage using Taguchi design method

“…This increase could be because of rupturing the membrane of anthocyanoplasts by ultrasonic waves and simple release of anthocyanins, while with regard to water bath method, anthocyanins might be discharged through the concentration gradient. Sivakumar et al (2009) demonstrated a significant increase in betalains (red coloured cyanins) extraction from beetroot in comparison with the magnet stirrer extraction method. According to Table 2, the minimum response i.e.…”

Natural coloration of wood material by red beetroot (Beta vulgaris) and determination color stability under UV exposure

“…Junqueira-Goncalves et al 2011, investigated the beetroot extract as a colorant for cream cheese, they reported that beetroot extracts might be a potential alternative dye for food. Sivakumar et al 2009, has been studied on the use of power ultrasound to improve the extraction of beetroot dye and application to the substrates such as leather and they reported that the beetroot is suitable for dying leather.…”

Ultrasound assisted extraction of lycopene from tomato processing wastes

“…As the ultrasonic intensity is further increased the cavitation effect starts decreasing and thermal effect becomes predominated. Sivakumar et al (2009) worked on ultrasonic extraction of natural dye from beetroot. In that study although the maximum extraction yield was reached at 100 W ultrasonic power, they recommended 80 W power application because the excessive energy dissipation in the form of heat when 100 W was applied.…”

“…Implosions of cavitation bubbles generate high pressure and temperature and enough to obtain sufficient reaction energy (Vinatoru 2001;Khan et al 2010). Some recent studies shows that ultrasound assisted application accelerates extraction rate and increase the yield about 10 % (Khan et al 2010, Sivakumar et al 2009Xu 2008).…”