Concentration of Apple Juice using Submerged Membrane Distillation

• Main Author: Devina, Anita
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/38582
• Institution: Institut Teknologi Bandung

The most widely used technology to produce fruit juice concentrate is multi-stage vacuum evaporation. This conventional technology utilizes heat to evaporate most of the water. However, the excessive thermal treatment result on the degradation of sensory and nutritional value of fruit juice. To reduce those degradation in fruit juice, there is a new technology called membrane. Membrane processes may concentrate fruit juice at temperature that is lower than multi-stage vacuum evaporation process. Hence, the aim of this research is to determine feed temperature, draw solution velocity, type of draw solution, and its concentration to produce optimal permeate flux and good quality of fruit juice. This research use a membrane configuration called Submerged Direct Contact Membrane Distillation while commercial apple juice with 110Brix concentration is used as a feed. The membrane modules were made of 50 polyprophylene hollow fibres with a length of 20 cm. The membrane outside diameter, inside diameter and pore size were 0.4 mm, 0.3 mm and 50 nm, respectively. In determining the optimal flux, type of draw solution (demineralized water and tetrapotassium pyrophosphate), feed temperature, and draw solution velocity are varied between 545-630 g/L of K4P2O7, 30-50oC and 2-4 mL/s, respectively. Then organoleptic and content of fruit juice concentrate are tested to evaluate the change of sensory and nutrition before and after concentration process. Experimental results indicated that high flux proportional to high temperature, strip velocity, and concentration of solute in strip solution. However, high temperature and long concentrating process lead to degradation of nutrition in fruit juice that should be avoided. Therefore, the optimal conditions to obtain optimal flux with maintained quality of fruit juice are using membrane distillation at 300C, draw solution velocity at 3 mL/s, and using 630 g/L of K4P2O7 draw solution within 2 hours concentrating process. Apple juice was concentrated from 110Brix to 350Brix which three times higher from initial concentration. Phenolic and vitamin C of concentrated juice ratio to initial concentration remained high with value of 0.95 and 0.97, respectively. The sensory evaluation showed that the reconstituted concentrated juices were accepted in aroma and taste by panelists.