Properties Investigation Of Ultrafiltration Of Fruit Juice Clarification By Ceramic Membrane

The new technology membrane separation has developed quickly in the past two decades. Because it works without being heated and won’t cause the phase changing of the material to be processed, not only save energy, still can keep the integrity of the original nature of the material. Therefore, it is widely used in food processing area, especially in juice clarify aspects has its unique advantages and have a good application prospect. This study focuses on the specific requirements of fruit juice clarification and explores the feasibility of ultra filtration of clarified peach juice and orange juice by inorganic ceramic membrane. The results show that:After analyzing and comparing the main nutrients and physical and chemical indicators of the juice obtained by three kinds of membrane with different pore, the suitable inorganic ceramic membrane to ultra filtrate and clarify peach juice and orange juice is determined to be the MWCO150KD membrane. This membrane could trap the suspended solids and macromolecules which would impact the stability of fruit juice as well as maintain the better retention of nutrients and aroma in the juice. The light transmittance of the obtained peach juice is98.2%and the clear juice reached80.1%with good clarifying stability. The ultra filtration separation effect of150KD membrane to orange juice is obvious. The passing rates through membrane by total sugar, total acid, and Vc respectively is98.3%,91.3%and98.6%, while the retention rates of pectin, and carotenoids is respectively98.9%and99%. The ceramic membrane is ideal ultra filtration membrane for peach juice and orange juice.During the process of clarifying peach juice and orange juice by ceramic membrane, the operating pressure, temperature and flow rate are the important parameters affecting the membrane separation efficiency. The greater the operating pressure is, the more flux passes in a certain range of membrane and membrane flux is basically proportional to the temperature and flow velocity. The optimal operating parameters of clarifying peach juice obtained by the ceramic membrane device in the experiment are:△P=0.2MPa, T=35℃, u=5m/s, the membrane flux is152.4L/h·m2; the best working conditions of clarifying the orange juice are:△P=0.3MPa, T=35℃, u=5m/s, the membrane flux is154.36L/h·m2.The light transmission rate of clarified peach and orange juice obtained by ceramic membrane is98.2%and turbidity is6.7NTU with pure flavor fragrance, no cooked flavor and storage stability. While the transmittance rate of clarified juice by enzymic clarification is87.8%and the turbidity is21NTU with poor flavor, a cooked taste and smelly enzymes.The comparison of the two juices clarified by ceramic membrane:In addition to the pre-select way of choosing suitable fruit juice and the determination of the best operating parameters, fruits’own nature and nutrient composition is also an important factor to affect the filtration of the juice by ceramic membrane. And only the above clarifying conditions are thoroughly considered in the clarification process, would ceramic membrane filtration devices be applied better in juice clarification.In this paper, based on the ceramic membrane processing technology of peach juice and orange juice and combined with the nature of the two kinds of juice, the systematic research is conducted on the issues of membrane fouling and the key steps of clarifying the peach juice and orange juice by ceramic membrane devices, which provides basis for applied industrialization.