Extraction, Stabilistiaon and Utilisation of Natural Food Colours from Grape Fruit Rind

摘要

Investigation was carried out to develop natural food colour powder from grape fruit rind (waste) by spray drying. The colour was extracted with water and solvents viz., acetone, ethanol and citric acid. The experimental results showed that the 3 % citric acid extraction was best and the filtrate was spray dried at different drying air temperature (180, 200 and 220°C) and flow rate (25 and 30 ml I min) using 10,15 and 20 % of maltodextrin (MD). The yield recovery was maximum at 200°C with a flow rate of 25 ml I min at 20 % maltodextrin. The stability of the colour was analysed by exposing the colour powder in various concentrations of pH, preservative and temperatures followed by packed in aluminium pouch (P_1), brown pet bottle (P_2) and brown glass bottle (P_3). The packed samples were stored in room (R.,) and refrigeration (R_2) temperatures for 3 months and analyzed their colour intensity (L* a* b*) and moisture content. The results revealed that the addition of preservative, increasing temperature, pH and storage periods had affected the stability of colour and moisture content. The samples packed in P_3 had better colour retention than P_2 and P_1 during storage Colour intensity of developed lollipop and icing with grape skin colour powderhad best colour strength and sensory attributes than synthetic food colour (carmoesin).