The authors express their sincere thanks to Dr. Jyrki Raulo, and Mr. Timo Ylitalo forest technician from the Finnish Forest Research Institute for organizing the sap collection and to Mr. Matti Harju, Techn.lic. and Mr. Antero Ylitalo from Valio for providing the RO equipment for the research.
Concentration of Birch Sap by Reverse Osmosis
Article first published online: 25 AUG 2006
Journal of Food Science
Volume 50, Issue 5, pages 1330–1332, September 1985
How to Cite
KALLIO, H., KARPPINEN, T. and HOLMBOM, B. (1985), Concentration of Birch Sap by Reverse Osmosis. Journal of Food Science, 50: 1330–1332. doi: 10.1111/j.1365-2621.1985.tb10470.x
- Issue published online: 25 AUG 2006
- Article first published online: 25 AUG 2006
- Ms received 12/24/84; revised 4/17/85; accepted 5/11/85.
Birch sap (Betula pendula Roth, and B. pubescens Ehrh.) was concentrated by reverse osmosis in a pilot scale recirculating system using ZF-99 tubular membranes. Sap feed temperatures varying from 30-70°C and pressures from 4-5 MPa were used when concentrating the sap from about 0.7oBrix to 13oBrix. Optimal conditions considering both processing capacity and product quality were 50°C and 5 MPa. Retentions of glucose, fructose, sucrose, and malic acid were practically 100% when using the ZF-99 membrane, whereas with the cellulose acetate membrane the retentions fell to between 92 and 99% at 30°C and 4 MPa. The pH of the original sap varied between 6.0 and 6.6 and dropped during the run by 0.2-0.3 pH units.