Filtration and centrifugation for separating functional proteins from an alkaline solubilisation process are investigated. The influence of the method of separation on the yield and the gel quality of surimi produced from the protein isolates was studied. The possibility of replacing centrifugation by filtration is investigated for a first and a second centrifugation step where the first centrifugation separates a dissolved protein phase at high pH from undissolved material and the second centrifugation separates precipitated proteins from the waterphase at neutral pH. The separation method greatly affects the yield and the quality of the processed surimi. Replacing the first centrifugation with sieving improves the yield of protein isolate, but worsens the quality of the produced gel. Replacing the second centrifugation with filtration has no influence on the yield or the quality of the protein isolate.

Structures that may lead to polynuclear chromium complexes to cross-link the collagen fibrils in chromium tanning processes are modeled. Pathways are suggested to the olation reaction. The role of sulfate as a facilitator has been demonstrated.

No abstract