| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1185040 | Food Chemistry | 2016 | 12 Pages |
•Alkaline pH-shift version could remove considerably more Hb compared to the acidic version.•Protein precipitation at pH 6.5 improved Hb removal during alkaline and acid processing.•Adding phytic acid to the first supernatant of the alkaline version yielded 93% Hb removal.•Combining one prewash with phytic acid at pH 5.5 followed by pH-shift increased Hb removal.
A main challenge preventing optimal use of protein isolated from unconventional raw materials (e.g., small pelagic fish and fish by-products) using the pH-shift method is the difficulty to remove enough heme-pigments. Here, the distribution of hemoglobin (Hb) in the different fractions formed during pH-shift processing was studied using Hb-fortified cod mince. Process modifications, additives and prewashing were then investigated to further facilitate Hb-removal. The alkaline pH-shift process version could remove considerably more Hb (77%) compared to the acidic version (37%) when proteins were precipitated at pH 5.5; most Hb was removed during dewatering. Protein precipitation at pH 6.5 improved total Hb removal up to 91% and 74% during alkaline and acid processing, respectively. Adding phytic acid to the first supernatant of the alkaline process version yielded 93% Hb removal. Combining one prewash with phytic acid at pH 5.5 followed by alkaline/acid pH-shift processing increased Hb removal up to 96/92%.
