Comparative Study of Sodium Bicarbonate on Gelling Properties of Alaska Pollock Surimi Prepared at Different Freezing Rates

Sodium bicarbonate (0.05%) and phosphate (0.3%) were combined individually with 5% sorbitol and 4% sugar as cryoprotectant in Alaska pollock surimi. Ten kilograms of prepared surimi were frozen either conventionally (C) (2-in thick blocks; plate freezer), fast (F) (~0.25-in thick sheets; plate freezer), or slow (S) (2-in thick blocks; blast freezer). The effect of ingredient (sodium bicarbonate [S] or phosphate [P]) and freezing method (C, F or S) were evaluated with regard to gel texture (puncture force and penetration distance), water retention ability, and chemical properties (salt-soluble proteins [SSPs], total sulfhydryl groups and pH) at 0, 3, 6, 9, and 12 months frozen storage (-30C). Ingredient, freezing method, and frozen storage period were found to significantly (P<0.05) affect puncture force, penetration distance, SSPs and water retention ability. Sodium bicarbonate combined with conventional and fast freezing tended to result in improved values for these measurements as well. Practical Applications: Listing phosphate on the ingredient label of a product is sometimes viewed negatively by consumers. Therefore, finding ingredients to effectively replace phosphate without losing the positive functional abilities of phosphate would be desired. The ability of sodium bicarbonate to meet and exceed performance expectations of phosphate as a cryoprotectant of Alaska pollock fish proteins during 12 months of frozen storage would allow for the effective replacement of phosphate in this application.