PRODUCTION OF FOOD COLORING FROM BUTTERFLY PEA EXTRACT (CLITORIA TERNATEA LINN.) BY OSMOTIC MEMBRANE DISTILLATION

• Main Author: Thamleonard, Jason
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/73097
• Institution: Institut Teknologi Bandung

Butterfly pea (Clitoria ternatea Linn.) is a flowering plant native to Ternate, Indonesia, which is rich in anthocyanin. Anthocyanins are a group of natural indigopigmented phenolic compounds which exhibit high antioxidant activity and are proven to have exceptional health benefits. Still, the application of butterfly pea as food coloring remains traditional. This research explores osmotic membrane distillation (OMD) as a method of concentrating the aqueous extract of butterfly pea flower and freeze drying to produce natural food coloring. The concentration process is configured as direct contact membrane distillation (DCMD), where the water from the extract permeates as vapor to the osmotic draw solution through hydrophobic polypropylene hollow fiber membranes. The concentration is done with varied operating parameters, including feed temperature at 35oC and 50oC, potassium sorbate and sodium benzoate as draw solutions, and draw solution concentrations at 1.5 and 2.5 M to determine the effect of each parameter towards water vapor permeate flux. It is found that feed temperature is the most significant operating parameter, with the increase of temperature from 35oC to 50oC raising the permeate flux from 1-2 L/m2h to 3-4 L/m2h, while types and concentrations of draw solutions do not have any significant effect towards permeate flux. All variations do not affect the quality of phenolic compositions nor the antioxidant activity of butterfly pea flower extract, which range consistently from 30-40 mg GAE/g dissolved solids and 40- 50% DPPH inhibition at 1000 ppm concentration. Phenolic and antioxidant activity retention after concentration fall at a range of 81-93% and 83-94%, respectively. The use of sodium benzoate as draw solution is indicated to cause reverse salt diffusion to the feed. The concentrated extract is then freeze dried at 0.001 mbar and -50oC for 48 hours which produces powdered extract with a moisture content of around 17% and 84% mass yield. Freeze drying does not significantly affect any bioactive compound quality, thus concluding that concentration and drying of butterfly pea flower extract with OMD and freeze drying respectively are feasible to produce powdered food coloring.