Interactions of dietary fibre and n3 rich oil with protein in surimi gels developed with salt substitute

Most Western populations have insufficient intake of fibre and n3 polyunsaturated fatty acids (PUFAs), while sodium intake greatly exceeds the recommended maximum. Surimi seafood is not currently fortified with these nutraceutical ingredients. Alaska pollock surimi seafood was developed with salt substitute and fortified with either 6 g/100 g of fibre or 10 g/100 g of n3 oil (flax:algae:menhaden, 8:1:1) or fibre + x-3 oil (6 g/100 g of fibre + 10 g/100 g of x-3 oil). The objective was to determine effects of the dietary fortification on physicochemical properties of surimi. Fortification with either dietary fibre or n3 oil alone or in combination enhanced rheological and textural characteristics. The combined fortification had a synergistic effect on rheological properties. This indicates greater gelation of surimi in the presence of fibre plus n3 oil, suggesting their interaction with surimi myofibrillar proteins. Fibre results in protein dehydration increasing protein concentration; while oil is immobilised by protein filling void spaces in the gel matrix. Differential scanning calorimetry showed that fibre and n3 oil did not interfere with normal denaturation of surimi proteins. Colour properties were only slightly affected. Fortification of surimi with fibre and n3 oil resulted in a quality product that could be useful in developing surimi products with nutritional benefits. (Authors abstract)

Dietary fibre has cardiovascular benefits.  The American diet is deficient in fibre with the average intake of only 15 g/day. Similar to fibre, n3 polyunsaturated fatty acids (n3 PUFAs) have cardiovascular benefits, alpha linolenic acid (ALA, 18:3n3) decreases Creactive protein (CRP), an indicator of inflammation associated with CVD. Surimi is a commercial preparation of fish myofibrillar protein. Surimi is the main ingredient in a variety of formulated, heat gelled, flavored seafood products. Research on the individual effects of fibre, n3 oils, and salt substitute on the physicochemical properties of surimi is scarce. This study hypothesises that addition of dietary fibre (long chain powdered cellulose), n3 oil (flaxseed, algae, and fish), and KCl based salt substitute to surimi will have a synergistic or additive effect on surimi thermal gelation and gel texture, but will not alter endothermic transitions of surimi proteins or gel colour properties.
Fortification of surimi seafood with either dietary fibre or n3 rich oils alone or in combination improved rheological and textural characteristics of surimi gels. Greater gelation of surimi in the presence of fibre and n3 oil were noted suggesting their interaction with surimi myofibrillar proteins. The improvement of rheological properties was reflected in texture of surimi gels. The differential scanning calorimetry showed that fibre and n3 oil added to surimi alone or in combination did not interfere with normal thermal denaturation of surimi proteins. Colour properties were only slightly affected by the fortification. Although results are encouraging, sensory evaluation and assessment of storage stability are recommended. (Editors comments)