ULTRASOUND ASSISTED EXTRACTION OF THEOBROMINE FROM COCOA BEAN SHELL

Abstract

Theobromine, also known as xantheose, is the principal alkaloid of Theobroma cocoa. During fermentation of cocoa bean, theobromine content increases and some are migrated to cocoa bean shell. Since cocoa bean shell is a by-product from cocoa processing industry, it is widely available and can’t be used as animal feed, it is good for production of theobromine. Theobromine has many applications in pharmaceutical field such as it can be used as vasodilator, heart stimulant and as a treatment for asthma, uric acid nephrolithiasis, remineralisation of teeth enamel also can be used for production of caffeine. In this study we are extracting theobromine from cocoa bean shell by normal conventional method and ultrasound assisted extraction method. For further evaluation, we made dependent and independent variables for extraction. The process parameters which would influence the theobromine yield and absorbance were chosen as independent variables after preliminary studies. The solute to solvent ratio and treatment time are taken as the independent variables. The levels of process parameters were fixed as solute-solvent ratios of 1:5, 1:10 and 1:15 and treatment time of 3, 5 and 7 minutes. Also, dependent variables are theobromine yield and absorbance. Using these variables 13 combinations were made by Design Expert® software, v.12 and central composite design. In this 13 experiments sample 9 and 3 shows first and second largest yield. Sample 9 has 7 mg/g yield and 2.562 au absorbance. Also sample 3 has 5.714 mg/g yield and 1.05 au absorbance. Based on this HPLC were conducted and found that concentration of theobromine in sample 9 has 2239.799 ppm and sample 3 has 1729.985 ppm. The optimized conditions of solute-solvent ratio and treatment time for extracting theobromine by ultrasound assisted process was found to be 1:15 and 3.000 minutes, respectively. The theobromine yield and absorbance of cocoa bean shell extracts at optimized levels were found to be 8.517 mg/g and 2.200 au respectively whereas the same were found to be 4.75 mg/g and 0.372 respectively for conventional extraction process. It was also observed that methylxanthine theobromine was found to be higher in ultrasound assisted extraction of theobromine from cocoa bean shell extracted under optimized condition compared to conventional extraction of theobromine. Therefore, ultrasound assisted extraction of theobromine could be considered as a best extraction technique that results in the production of theobromine.