Evaluation and Utilisation of Fish Protein Isolate Products

same attributes of surimi. The results of different trials indicated that FPI has more or lesschemical (soapy) flavor and grainy texture. These attributes were seen in cod, saithe andarctic charr protein isolated by pH-shift process but not at the same level (Shaviklo 2007).Improving the sensory quality of FPI is a vital issue for developing FPI-based products.4. UTILISATION OF FPI PRODUCTSA fish protein solution (FPS) is a kind of semi-solid protein-in-water colloid which isprepared by using the acid/alkaline aided process. It may also include salt, and otheroptional ingredients (cryoprotectants, etc.) based on the final use.Fish protein solutions can be made in two ways. One is by resolubilising proteins isolatedby the acid/alkali-aided methods, and the other is to directly use solubilised ground fishmuscle, in the acid or alkaline state, for injection into fillets without using any precipitationstep (Nolsoe and Undeland 2008).The fish protein isolated made by the pH-shift process looks like surimi when it isdewatered and packed. It may contain about 14-20% protein and 80-86% water. Thequality of this product depends on several factors such as source of raw material, methodof processing, pH, amount of protein and water content etc. Different attempts have alsobeen made to utilise fish protein isolate in cooked products. Little information has beenpublished for applying FPI in seafood products.4.1 Fortification of fish filletFortification of fish fillet by multineedle injection of fish proteins, static soaking, orvacuum tumbling have been reported by Thorkelsson et al., (2008). He reported thatinjection of brine containing fish protein isolated solution or homogenised fish fleshincrease the weight (yield) in cod and haddock fillets by 5-20% and increase cooking yield.Fish protein isolates also provided a higher cooking yield and microbiologically morestable products than those injected with fish mince (Thorkelsson et al., (2008). Kim andPark (2006) reported that fish protein injection can enhance the yield and improve thefrozen stability of fish fillet. Improvements in water holding capacity, by re-solubilisationof FPI powder and inject into fish fillets has been reported by Nolsoe and Undeland(2008).4.2 Using as a batter mixtureFPS can be applied as an ingredient for preparing batter mixtures used in battering andbreading processes. It seems FPI can improve the viscosity of batter solution. Duringexperiments the author noticed that FPS with 3% protein when mixed with batter powder(50:50, 60:40 w/w) could increase the viscosity of the solution and its stability againstsedimentation after 48 hours of storage at refrigerated temperature.8