It is feasible to develop value-added FPP from saithe surimi using spray- and freeze-drying processes, but freeze-dried FPP containing lyoprotectant had superior functional properties and stability compared with spray-dried sample. Both products might be used as functional protein ingredients in various food systems.

The increasing awareness that dried fish protein can be applied for food fortification and production of value added/functional foods has encouraged the food industry to examine different methods for developing fish protein ingredient from different raw materials. Fish protein powder (FPP) is a dried and stable fish product, intended for human consumption, in which the protein is more concentrated than in the original fish flesh. Quality and acceptability of FPP depend on several factors. The fat content of the FPP is a critical issue because when it is oxidized a strong and often rancid flavour is produced. Protein content of FPP depends on the raw materials, amount of additives and moisture content, but it contains at least 65 % proteins. FPP is used in the food industry for developing re-structured and ready-to-eat food products. The FPP maintains its properties for 6 months at 5°C but loses them rapidly at 30°C. Deterioration of the FPP during storage is prevented by lowering the moisture content of the product and eliminating of oxygen from the package. The FPP can be applied as a functional ingredient for developing formulated ready-to-eat products. This article reviews methods for extracting fish proteins, drying methods, characteristics and applications of FPP and factors affecting FPP quality.

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Corn snack fortified with 7% fish protein powder made from saithe (Pollachius Virens) surimi was selected by expert panel from industry for consumer studies in Iran and Iceland. They hedonically screened products with 3%, 5%, 7% and 9% fish protein powder. Snack containing 9% fish protein powder (FP) had significantly lower liking for odour, texture, flavour, and overall acceptability than the other three prototypes. Snacks fortified with 3%, 5%, and 7% FP had similar sensory attributes. Therefore, snack with the highest level of FP (7%) was selected for acceptance tests. It was seasoned with cheese powder, vegetable oil, salt, and colorant. The amount of protein, moisture, fat, ash and salt in fortified corn snack (FCS) was 12%, 2%, 31%, 3%, and 2% respectively. Consumers' acceptance was studied using a central location test method. Consumers were 6-16 years old children in two communities (Iceland and Iran). They liked FCS but Iranian children favoured it more than Icelandic children. Majority of parents of the participants expressed their willingness to choose this product when buying snacks.

Extrusion of corn grits with fish flesh/fish protein can be used to produce high-protein products that would be an option to provide nutrient snacks for consumers and to increase fish consumption.

Fish proteins isolated from by-products or low commercial/underutilized species using pH-shift process is a new source of proteins that may be used as wet or dried ingredients to develop value-added convenience foods. This paper reports the effects of freeze-drying on characteristics of fish protein isolates (FPI) from saithe (Pollachius virens) with or without lyoprotectants. Freeze-dried saithe mince from the same lot and without additives was used as a control. The resulting fish protein powders contained 71-93% protein, 1.5-3% moisture, 0-21% carbohydrate and 0.5-2% fat. Lipid oxidation (assessed by TBARS) of FPI powder groups was higher than that of fish mince powder. The results revealed that oxidation started during the pHshift process and was increased by freeze-drying. Functional properties and sensory attributes were influenced by the advanced oxidation. However, the mince powder was less oxidized and had higher functional properties such as water binding capacity, gel forming ability, emulsification, foaming properties and colour and lower sensory scores for rancid odour and flavour than the FPI powders. Further studies on how to prevent oxidation of fish flesh during pHshift and drying processes are recommended.

Development of ice cream fortified with fish protein powder could be an effective way to enhance nutritional and functional value of ice cream. But studies on storage stability, consumers' acceptance and attitudes are recommended if companies are planning to do so.

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