Application of agitated disk membrane module for various soy sauce processes in an actual production line

"We examined the usability of the Agitated Disk Membrane Module (AD module) in an actual soy sauce production line based on several separating features different from soy sauce sediment filtrationreported previously. The applied processes were as follows ; 1) microorganism removal from raw soy sauce, 2) clarification of pasteurized soy sauce, 3) clarification of re-fermented soy sauce, 4) microorganism removal from light color soy sauce, 5) amino acid sauce recovery from the UF concentrate of soy sauce, and 6) clarification of amino acid sauce. We evaluated the effects of AD module applied to each process by characteristics of permeate, power consumption for filtration, and process improvement. AD module improved all of the examined processes except the clarification of pasteurized soy sauce and the amino acid sauce recovery from the UF concentrate of soy sauce. It was shown that AD module could produce effectively microorganism free products from raw soy sauce and light color soy sauce as well as clear re-fermented soy sauce and amino acid sauce in terms of economy and labor-saving. Those advantages could be attributed to the lower pressure loss of the module, higher concentration ratio, and larger permeate flux than those of conventional membrane modules. AD module couldn't, however, clarify the pasteurized soy sauce with lower cost than the traditional process owing to the higher power consumption of AD module. Also, the module couldn't recover amino sauce from the UF concentrate with enough quality to blend soy sauce because of worse flavor. There was a close correlation between the permeation flux and the total nitrogen (TN) concentration of the feed liquids for AD module, so it was possible to predict the permeate flux from the TN concentration."