10 what is minced fish sticks made of Ideas

Uses for Mechanically Recovered Meat

Minced fish is usually frozen and then thawed and used in formulated sea foods including fish sticks, fish cakes, nuggets and added-value or specialty products such as chowders, patés, fish balls, and gefilte fish. Washed minced fish that has been blended with stabilizing ingredients is called surimi and is used in popular items such as imitation crab. Other fabricated products also use surimi as a key ingredient to improve texture.

Mechanically separated poultry exceeds 318×10⁶ kg annually in the US. Approximately 182×10⁶ kg is used in sausages such as frankfurters and bologna, and approximately 136×10⁶ kg is used in products such as chicken patties, nuggets, and poultry rolls. In some countries, sausages have mechanically separated chicken or turkey along with beef and pork as ingredients.

In 1995, when the final rule requiring ‘mechanically separated chicken’ or ‘mechanically separated turkey’ to appear on the label was implemented, the USDA-FSIS stated that 529 labels for mechanically separated poultry existed. They estimated that labels for products containing mechanically separated poultry such as frankfurters, chilli, bologna, poultry, baby foods, chicken nuggets, or patties would number approximately 5000. This low-cost meat source has led to poultry meat products being more cost effective in the marketplace.

Mechanically recovered pork is used extensively in sausages and in many items where ground pork is used. In some countries, mechanically recovered pork must be indicated in the labeling. In other countries, only the word ‘pork’ needs to appear on the label.

Mechanically recovered beef is often blended with hand-boned beef. A smaller portion is sold as standalone product for use in jerky, taco meat, and pizza toppings. Uses for mechanically recovered beef and pork from hydraulic press machines change as government regulations change, but decreased costs associated with mechanical recovery increase consumer demand. The need to maximize meat yields while minimizing waste, and a reduction in repetitive motion stress-related injuries, are other reasons why mechanical recovery of meat continues to increase.

5.2.3 Minced fish

The term minced fish is very often used to describe the mechanically recovered fish flesh. This term is one of convenience rather than accuracy since mincing occurs naturally during separation rather than deliberately as if it were passed through a mincer. It is indeed a product that retains most of its textural characteristics compared with fish which has been minced (Ravichander and Keay, 1976).

Mincing accelerates the deconformation, aggregation and cross linking of the myofibrillar proteins. This results in a loss of the extractability and contractility of the actomyosins, with a consequent increase in the objective toughness, granularity and drip loss and a decrease in water binding capacity, emulsification capacity, gel-forming ability, and rheological properties. These reactions are exacerbated through the cross linking of the proteins with formaldehyde, which is derived from the breakdown of trimethylamine oxide (TMAO). This is an enzyme related reaction which is accelerated by mincing and the mixing of blood and other organs with the flesh and predominantly occurs during frozen storage. The gadoid fish species and particularly hake and cod are very susceptible to this reaction (Babbitt et al., 1974). Denaturation in frozen mince products is also accelerated by the rapid pH drop resulting from accelerated glycolysis during mincing and by temperature cycling during frozen storage (Grantham, 1981).

Fat degradation can be accelerated by mincing, due to dispersion of fat degrading enzymes and oxidation catalysts and the increase of the surface area. Pelagic species are more susceptible to fat degradation, especially when processed whole, due to the high lipid content and particularly the high levels of unstable polyunsaturated lipids located on the skin, tissues, viscera and brain that may contaminate the flesh during separation. Processing of filleting waste (frames and flaps) from lean demersal species such as cod and haddock is thus less susceptible to fat oxidation, due to negligible lipid content and absence of contaminating materials such as skins, viscera, and brains.

One of the primary reasons for low acceptance of minced fish products is due to the aesthetic deterioration that occurs during mechanical separation of the flesh. Mincing normally results in a product that is darker in colour and more heterogeneous than the actual flesh in the raw material. This is due to the natural mixing of components such as blood, pigments, skin, and membrane particles, bones, and other material that can pass through the perforations of the drum. Consequently, this aesthetic deterioration is not so marked in mince produced fish with coloured flesh such as salmon and salmon mince which can have a value as high as £2000/tonne. Salmon mince can be used in fishcakes, minced salmon nuggets, pastes, pates, and low cost ready meals.

Although there is an enormous number of minced fish products that have been studied, reported, and developed (Bligh and Regier, 1976; King, 1976; Regenstein, 1980), only a few of these are successfully established in the world market. According to the same authors, poor recognition of the true value and potential of fish mince is often associated with the trend to develop products that mimic existing fish products, rather than creating something new that exploits the natural properties of fish mince.

The world market of fish mince is dominated by products derived from frozen fish mince blocks and surimi-derived products (Grantham, 1981; Suzuki, 1981). Frozen mince blocks are usually produced from fish mince, derived from white fish such as cod and haddock. Fish mince is also incorporated into fillet blocks. These blocks are intermediate material for the production of a range of products such as coated fingers, steaks, cakes, sausages, patties, loaves, and burgers. Some of these are simply formed and coated products whilst other are totally transformed, reformed, and textured products (Grantham, 1981).

The manufacture of surimi initiated in Japan where it is still believed to be the primary source of the population’s protein intake. Surimi-based products have also been introduced to North America and Europe. This market is now facing a rapid growth. Surimi is basically frozen water-washed fish mince with cryoprotecting substances (Suzuki, 1981). It is primarily manufactured from Alaska pollack and other gadoid fish minces, although recent studies have shown that even pelagic species can give acceptable products (Grantham, 1981; Suzuki, 1981). Surimi is an intermediate processed seafood product, used in the formulation/fabrication of a variety of products (Hall and Ahmad, 1997), such as kamaboko and chikuwa (Suzuki, 1981). Fish mince is also used for the production of canned products (Regenstein, 1980; Grantham, 1981), dried and intermediate moisture products (IMP), fermented products, and for the production of animal feed (Taylor and Alasalvar, 2002).

4.5 Protein recovery from surimi processing water

Surimi is minced fish meat repeatedly washed and dewatered that is used as raw material to produce seafood analogues such as crabmeat substitutes, In the year 2002, the annual frozen surimi production in the USA was over 95 thousand tonnes, In the Pacific Northwest, the most utilized fish species are Pacific whiting and Alaska Pollock, However, processing fish using surimi technology recovers only myofibrillar proteins (Lee, 1999), while the isoelectric solubilization/precipitation allows the recovery of 78 to 91% of all by-product proteins (Table 4.3).

The relatively low protein recovery by the surimi technology means that proteins accumulate in the surimi wash water, The effluent water is high in biological oxygen demand (BOD), and therefore, should be treated before discharging it into local watercourses. Even more important than the low recovery yield is the use of large amounts of freshwater, about 20 times the weight of the deboned meat (Lee, 1999). The low process efficiency, high freshwater consumption, and deleterious environmental impact of surimi plants are creating in some regions political pressures for their shutdown. At present, there is a pending court case filed by the National Environmental Law Center (NELC) against owners and operators of a seafood plant in Oregon. NELC claims that ‘the plant has been routinely violating the Clean Water Act, degrading local waterways and threatening endangered salmon and steelhead’ (NELC, 2003).

The crude protein content of the insoluble solids recovered by the chitosan-alginate complex technology is over 70% (Wibowo et al., 2005b, 2006a), while the amounts of recovered proteins vary with the concentration present in SWW, which ranges from 0.5–2.3% (Lin and Park, 1996; Morrissey et al., 2000). After treatment with the polymeric complex, the proteins are recovered by centrifugation and can be sent to a disposal site, incorporated into surimi, or sold as a feed ingredient for feeds. Recovering protein from SWW not only produces protein for food and feed production, but also generates treated water for potential reuse in the plant.

Proteins recovered from SWW have high concentrations of essential amino acids. Animal studies have demonstrated the superior nutritional value and the safety of SWW solids recovered by Chi-Alg when tested at the levels recommended by commercial producers of animal feeds, i.e., under 15% (Wibowo et al., 2005a). These studies showed no difference in feed consumption and growth rate, while post-mortem examination of internal organs showed no visible signs of damage caused by feeding the experimental diet. Blood analysis using 20 indicators confirmed the superior nutritional value and safety of SWW solids recovered by Chi-Alg. Subsequent studies demonstrated that 100% substitution of dietary protein by these SWW proteins was also safe and nutritionally equivalent or superior to other protein sources showing higher protein efficiency ratio (PER) and net protein ratio (NPR) than the casein control (Wibowo et al., 2006b). This outcome has economic implications for the region where a surimi plant is located. For example, in Oregon, not a major poultry producer, an estimated 100 thousand tonnes of feed are needed to sustain broiler production representing an excellent market opportunity for recovered SWW proteins.

Many protein sources have been employed to improve the mechanical properties of surimi gels. The most frequently used are egg white and whey protein concentrates; other sources such as leguminous extracts and porcine plasma protein have been proposed, too. These proteins are added to inhibit the Modori phenomenon, i.e., the proteolytic degradation of fish myosin when gels are incubated at about 60°C, or to improve the setting phenomenon associated with improved mechanical properties by the action of endogenous and added transglutaminase enzymes (An et al., 1996; García-Carreño, 1996; Sánchez et al., 1998; Benjakul et al., 2001). It appears that when added to surimi, low concentrations of SWW proteins can improve their mechanical properties with minimum impact on colour (Ramírez et al., 2006).

Minced fish products

The same technical considerations regarding the way of adding DF apply to minced fish. The main technological advantages of wheat DF was that they effectively bound water, and when the products were battered, they prevent the coating from breaking, also preventing deformation of the cooked portions (Sánchez-Alonso et al., 2007a).

One of the technological consequences arising from the results of the consumer studies was to use other sources of antioxidant DF, since it was shown that consumers preferred DF of marine origin to their seafood products (Careche et al., 2008). Thus the use of seaweed DF concentrates into restructured fish products was explored. Fucus DF acted as antioxidant in a fatty fish species and was suitable technologically, but these DFs conferred the minced fish a dark colour which impaired its potential use (Careche and co-workers, 2008).

20.2.6 Surimi gels

‘Surimi’ is a Japanese term for the wet protein concentrate resulting from water-washed, mechanically deboned (minced) fish. Leaching with water in the presence of salt (NaCl) solubilises the myobrillar proteins (myosin, actomyosin and tropomyosin) and removes undesirable compounds such as water-soluble proteins (sarcoplasmic proteins), pigments, digestive enzymes and fat (Lanier and Lee, 1992). After refining and dewatering, the recovery of minced fish is around 20% of the raw material (Ohshima et al., 1993). The known commercial form of surimi is the so-called ‘frozen surimi’, a mixture of washed fish mince and cryoprotectants added to retain the undenatured state and the gel-forming properties of proteins.

Myofibrillar proteins in fish form strong gels upon heating that are generically called kamaboko. The gelling properties of proteins in surimi have been utilised commercially in the imitation of high-value marine products: crab meat, scallops and shrimp. Different fish species present different gelling ability attributable to the cross-linking of the heavy myosin chains (Chan et al., 1992). Detailed and updated information on surimi processing, regulations and formulations can be found in the book edited by Park (2000).

Gelation of surimi proceeds through several stages during heating (Niwa, 1992; Stone and Stanley, 1992). When fish mince reaches 50 °C a soft gel network or suwari is formed by the interaction of actomyosin and myosin molecules and stabilised by hydrophobic forces between the tails of adjacent myosin molecules. This process, referred to as setting, is highly species dependent. As the temperature increases (e.g., to 52–64 °C, depending on the species) the structure of suwari is weakened and the softer network of modori is formed. This gel-weakening effect has been attributed to the action of alkaline proteases or a thermally driven mechanism (Stone and Stanley, 1992). Further heating (e.g., > 60–70 °C) induces aggregation of protein molecules until a firm and elastic gel known as kamaboko is formed. In kamaboko the stabilising mechanism responsible for gel strengthening is mediated by the globular head portion of myosin, possibly involving S-S interactions. Upon cooling hydrogen bonding may occur reinforcing the rigidity of the gel.

9.8.3 Seafood patty

For preparation of seafood patty, frozen mince is either partially thawed or broken before mixing. Various ingredients (85–87% minced fish, 2–3% soy protein, 2–3% starch, 1.5–2.5% refined salt, a small amount of dried onion, dried tomato, dried pepper, chilli powder, powdered garlic, and allspice, 4–8% sorbitol, 1–2% chicken/beef/pork extracts) are added to thawed or broken mince, and blended in a ribbon mixer. The temperature should be maintained at below 10°C during mixing. The blend is held at −20°C for 1 h to facilitate easy forming into patty, and to maintain about 0°C during forming. Fish patties are formed and dehydrated in a tunnel dryer for 10 h before vacuum packaging.

20.8.2 Effect of natural antioxidants in fish mince – results from LIPIDTEXT

The LIPIDTEXT project has demonstrated that caffeic, chlorogenic acid, o-coumaric acid and ferulic acid have a high potency for inhibiting rancidity in fish minced muscle. Minced fish muscle provides an excellent matrix for making controlled test aimed to study the antioxidant activity of several compounds. It comprises all muscle components. By mincing, its external surface is high and the oxidation occurs fast. Additionally, it is possible to get a homogeneous fish sample with similar levels of PUFA, iron, haemoglobin, and other components involved in the oxidative reactions. These facts allow controlled and non-extensive experiments as those needed to check the activity of antioxidants. It is particularly useful for chilled experiments supplemented with antibacterial agents and for frozen tests. This system has been used in different works focused on the antioxidant activity of phenolics (Vareltzis et al., 1997; Medina et al., 1999; Ishihara et al., 2000; Tang et al., 2001) and the results obtained could be confirmed in whole fish fillets (Pazos et al., 2006a).

In spite of the effect of hydroxycinnamic acids on inhibiting lipid oxidation of fish minced muscle, they did not show any effect on inhibiting the change of protein solubility. Control samples of minced horse mackerel and salmon muscles and those supplemented with phenolic acids showed similar pattern of decrease in protein solubility during frozen storage. Thus, it seems that the inhibition of lipid oxidation by the addition of phenolic antioxidants has no effect on the change in muscle proteins related with the loss of solubility.

Solvent Extraction

Fish oil can also be produced by solvent extraction, which is the old fish protein concentrate process. In that process, raw fish are ground up either before or after deboning. The minced fish is mixed with solvent and extracted multiple times to remove the water, oil, and fishy tasting components. The solvent can be hexane, isopropyl or ethyl alcohol. The multiple solvent extraction steps are usually done countercurrently so that the second and third stage solvent can be reused as the first step of the next batch. The extract is separated from the solids by centrifuge and then dried. The liquid fraction is fractionally distilled to recover the solvent and produce the fish oil. Since some solvents produce azeotropes with water, the solvent recovery stage presents problems. Extracting wet fish with an azeotrope also extracts the water-soluble components. In the case of krill, where you may wish to produce two lipid fractions (neutral lipid and phospholipids), by choosing the correct solvent it is possible to obtain a high phospholipid fraction.

17.3.3.3 Meat and fish products

The use of extruders in meat and fish processing is mostly focused on production of the following products: frankfurter-type sausages made from meat or meat-free versions made from soya; shiozuri surimi from ground, minced fish; and extruded snacks and pet foods that incorporate previously underutilised byproducts from meat, fish or prawn processing. Their manufacture uses cold extrusion operating with die temperatures of ≈6–27°C. Detailed descriptions of the manufacture of surimi and other seafood products are given in Park (2013), and Onwulata (2011) describes the thermal and nonthermal extrusion of other protein products. Videos of the production of surimi and ‘crab sticks’ are available at www.youtube.com/watch?v=9Oozr6Blvm4 and www.youtube.com/watch?v=8nxug_coJ-o.

Production of frankfurters has previously involved finely chopping a mixture of meats, spices, flavorings and curing salts to produce an emulsion, stuffing the emulsion into artificial casings, smoking and cooking. The casing is then peeled off and discarded. This procedure is time-consuming and labour-intensive, and hence comparatively expensive. Alternative methods involve heating the meat emulsion in flexible casings or individual moulds to coagulate the protein. Using cold extrusion, the meat emulsion is formed in the extruder and coextruded with a collagen casing surrounding the meat ‘rope’. Functional soy proteins and starches ensure a consistent emulsion viscosity and flow through the die. An alternative casing made from alginate may be used for meat-free, Kosher or Halal frankfurters. The rope is conveyed to a brine bath, containing dipotassium phosphate to harden the collagen, and then cut to the required lengths or formed into links for subsequent smoking. Alternatively, liquid smoke may be added to the collagen before it is extruded. Extruded sausages from 20–800 mm in length and 8–40 mm in diameter may be produced more rapidly and at a significantly lower cost than using traditional methods. A PLC stores menus for different sausage formulations and controls the emulsion viscosity and temperature, the thickness of the collagen/alginate casing, and product dimensions and weights. Further details are given by Hoogenkamp (2004) and a video of extruded sausage production is available at www.youtube.com/watch?v=gu9NwtdU1NY.

17.3.4 Amino acid requirements (true versus profiles of whole fish)