Application of Cross-Flow Filtration Technique in Purification and Concentration of Juice from Vietnamese Fruits

This study is to offer a 1st insight in the use of membrane process for the purification and concentration of Vietnamese fruit juices: cashew apple (Anacardium occidentale Line.), dragon fruit (Cactus hemiepiphytes), pineapple (Ananas comosus), pomelo (Citrus grandis L.), and gac aril oil (Momordica cochinchinensis Spreng.). On a laboratory scale, the effect of different operating parameters such as trans-membrane pressures (TMP), temperature and membrane pore sizes on permeate flux was determined in order to optimize process conditions that would ensure acceptable flux with adequate juice quality. The quality of the samples coming from the ultrafiltration (UF) process was evaluated in terms of: total soluble solids (TSS), suspended solids (SS), and vitamin C. For example, the purification process of cashew apple juice by cross-flow filtration was optimized at 0.5 mu m membrane pore size, 2.5 bars TMP, and 60 min filtration time. Besides, this technique was applied to enhance carotenoids concentration from gac oil. Optimum conditions for a high permeate flux and a good carotenoids retention are 5 nm, 2 bars, and 40 degrees C of membrane pore size, TMP, and temperature, respectively. Carotenoids were concentrated higher than that in feeding oil.