Imeda Rubashvili
Tbilisi State University, Georgia
Title: Quantitative determination of natural colorants of agro-industrial waste materials using supercritical extraction technique and high performance liquid chromatography
Biography
Biography: Imeda Rubashvili
Abstract
The manufacture of food products and dietary supplements using natural food colorants has been attracted attention in modern food industry. Carotenoids and anthocyanins as natural colorants show strong antioxidant and immunomodulation activities and may prevent degenerative diseases as well.The present research concerns the development of extraction procedure of carotenoids and anthocyanins containing agro-industrial waste materials (tangerine, orange peel and grape skin). Extractions were carried out in a dynamic supercritical fluid - carbon dioxide (SC-CO2) extraction system. The main carotenoids - beta-carotene, lycopene and anthocyanins obtained in organic extracts were quantified using new, rapid, effective and selective developed and validated HPLC methods. The effects of operating pressure and temperature, extraction time, flow rate of the SC-CO2, sample size and solvent nature used were investigated. The optimal conditions for extraction were found.The two methods for carotenoids and anthocyanins were validated with respect to system suitability test, specificity, linearity-range, accuracy, precision, limit of detection (LOD) and quantitation (LOQ). The stability of solutions were studied as well.The calibration curve is linear over a concentration range 0.08-6.50 µg/mL for beta-carotene (r2=0.9992), 0.34-18.76 µg/mL for lycopene (r2=0.9999); 0.04-40.0 µg/mL and 0.12-40.0 µg/mL for total anthocyanins expressed as cyanidine chloride (r2=0.9999) and kuromanine chloride (r2=0.9999); The LOD and the LOQ are 0.08 µg/mL and 0.04 µg/mL for beta-carotene, 0.34 µg/mL and 0.80 µg/mL for lycopene, 0.04 µg/mL and 0.08 µg/mL for cyaniding chloride; 0.12 µg/mL and 0.16 µg/mL for kuromanine chloride. No interference was observed; The average recovery equals to 106.8 % for beta-carotene, 101.4 % for lycopene, 95.62 % for cyanidine chloride and 94.9 % for kuromanine chloride.The content of each carotenoid per 1 g of dried agro-industrial waste material varies for beta-carotene 0.445 – 3.972 µg (tangerine peel), 0.833 – 2.455 µg (orange peel), for lycopene 0.051 – 179.988 µg (tangerine peel), 0.091 – 0.114 µg (orange peel), for total anthocyanines 4.06 – 56.9 µg (grape skin).