Viscosity Changes of Actomyosin and Properties of Surimi From Sucker (Catostomus commersoni)

Viscosity Changes of Actomyosin and Properties of Surimi From Sucker (Catostomus commersoni)

Can. Inst. Food Sci. Technol. J. Vo!. 21. No. 5. pp. 531-533. 1988 RESEARCH Viscosity Changes of Actomyosin and Properties of Surimi From Sucker (Ca...

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Can. Inst. Food Sci. Technol. J. Vo!. 21. No. 5. pp. 531-533. 1988

RESEARCH

Viscosity Changes of Actomyosin and Properties of Surimi From Sucker (Catostomus commersonl) Y.J. Owusu-Ansah l POS Pilot Plant Corp. 118 Veterinary Road Saskatoon, Saskatchewan S7N 2R4 and

A.R. McCurdy and T.O. Kopp Department of Applied Microbiology and Food Science University of Saskatchewan Saskatoon, Saskatchewan S7N OWO

Abstract

number and compete with valuable species thereby reducing the population of the latter. Improvement in the utilization of any of these species would be welcomed. The main objective of this study was to evaluate the suitability of using sucker for surimi production. In this preliminary evaluation, thermally-induced changes in the viscosity of sucker actomyosin solutions were studied. These changes appear to be good indicators for the functionality of surimi (Nakayama et al., 1979). Properties of surimi prepared from sucker were also studied. Suckers were chosen because of their relative abundance in comparison to the other underutilized species in Saskatchewan lakes (Fernet, 1975).

The viscosity of sucker actomyosin solutions decreased with increasing temperature up to 38°C, then rapidly increased; peaking at 43°C. The gelation of sucker actomyosin was similar to those of other fish used in the surimi industry. Kamaboko prepared from sucker surimi was rated as grade A in fold tests and remained unchanged during four weeks of refrigerated storage. The hardness of the kamaboko significantly increased with storage but did not adversely affect the quality as judged by the fold test.

Resume La viscosite de solutions d'actomyosine de remora diminua avec I'augmentation de la temperature jusqu'a 38°C, pour ensuite augmenter rapidement, atteignant un pic a 430°C. L'aptitude a la formation de gel de I'actomyosine de remora fut semblable a celle des autres especes utilisees dans I'industrie surimi. Du kamaboko prepare a partir de surimi de remora fut cote classe A dans des tests de pliement et demeura ainsi durant 4 semaines sous entreposage refrigere. La fermete du kamaboko augmenta significativement a I'entrepot mais sans affecter defavorablement la qualite telle que determinee par le test du pliement.

Materials and Methods White suckers were obtained from Lac La Ronge as frozen fillets. The fillets were prepared from fresh fish and had been frozen for one day.

Preparation of Actomyosin Introduction Freshwater fish are an important commercial resource as well as a tourist attraction in Saskatchewan. The major species of importance include; lake whitefish (Coregonus c/upeaformis), lake trout (Salvelinus nemaycush), and pike (Esox lucius). Other species notably, lake cisco (Coregonus artediz), white suckers (Catostomus commersom) and burbot (Lota Iota) currently have little or no commercial importance to the fishing industry in the area. These under-utilized species (suckers, cisco and burbot) tend to increase in

The procedure described by Liu et al. (1982) was used. Actomyosin solutions were stored at 4°C and were always discarded after four days.

Preparation of Surimi The frozen fish fillets were thawed in a cold room (5°C) overnight. The fillets were minced in a Hobart meat grinder fitted with a 3.175 mm die and a portion was set aside for analysis. The minced fish was weighed and put in a process tank. Cold freshwater « 10°C), three times the weight of the minced fish, was pumped into the tank and agitated with the fish for 10 min. The slurry was pumped to a basket centrifuge fitted

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1988 Canadian Inst;tute of Food Science and Technology

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with a 30 mesh screen and continuously centrifuged at 530 x g. The supernate was continuously collected in a holding tank. When the process tank was empty, about 20 kg of cold freshwater was used to flush the lines. This washing process was repeated, then the fish was finally rinsed continuously in the basket centrifuge using cold 0.1 % NaCl solution. The washed, minced fish was manually removed from the centrifuge and 4% (w/w) sucrose, 2.5070 (w/w) sorbitol and 0.2% (w/w) sodium tripolyphosphate added to it and mixed thoroughly in a Hobart mixer for 15 min. The surimi was weighed, packed in polyethylene bags and kept frozen until needed.

Preparation of Kamaboko Frozen surimi, to be prepared into kamaboko, was thawed in the cold room overnight. A 2.5 kg sample of the thawed surimi was weighed into a Hobart silent cutter and chopped for 5 min at high speed. A 2.5% (w/w) of NaCl was added and the sample chopped for an additional 5 min. The paste was manually transferred into a piston-driven, hand-operated sausage stuffer, stuffed into cellulose casings of 7 cm diameter and cooked in boiling water to 90°C internal temperature. After cooling in cold water, the samples were prepared for functionality tests.

Elasticity of the kamaboko was determined by the fold test (Holmquist et al., 1984). Kamaboko pieces measuring 3 mm x 7 cm in diameter were used. Apparent viscosity of actomyosin solution was measured using the procedure described by Wu et al. (l985b). The compressive deformability of the kamaboko samples was determined by compressing cylindrical samples of 3.5 cm diameter and 1.8 cm thickness, between parallel plates, to 70% deformation. A Texturepress Model TP-l (Food Technology Corporation, Reston, VA) attached to a Texturecorder Model TR-1, a crosshead speed of 10 cm per min and a 136.4 kg (300 Ib) load ring were used. Tbe equipment was calibrated to a null deviation at 3,000, 1000 and 300 sensitivities. The maximum forces attained during the 70% deformation were recorded.

Results and Discussion A typical plot of apparent viscosity versus temperature for sucker actomyosin solutions is shown in Figure I. The viscosity decreased with increasing temperature up to 38°C and rapidly increased, peaking at about 43°C and then rapidly decreased. Similar trends of viscosity changes with temperature were observed for croaker actomyosin and a peak viscosity at 36°C was reported (Wu et al., 1985b). The differ-

Analytical Methods Expressible fluid in the kamaboko was determined on slices measuring 3 cm in diameter and 1.8 cm in thickness using the procedure described by Holmquist et al. (1984), but pressing under a 5 kg weight.

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Temperature(°C) Fig. I. Viscosity changes of sucker actomyosin solution (5mg/mL) during heating. Data were from triplicate determinations.

532 / Owusu-Ansah et al.

Time(min) Fig. 2. Viscosity changes and thixotropic behavior of actomyosin solutions (5mg/mL) after incubating for 5 min at various temperatures. Data were from triplicate determinations. ar = after rest for 10 min. J. Inst. Can. Sci. Technol. Aliment. Vol. 21, No. 5, 1988

Table 1. Changes in the fold test, expressible fluid and deformation compressive force of sucker Kamaboko with storage time at 4°C. Storage Time Fold Test (WKS) 0 I

2 3 4

A A A A A

70% Compressive Expressible fluid (010) Deformation Force(N) 1.3 ± 0.4a 1 1.6±0.4a 1.9±0.6ab 2.0±0.3b 2.2±0.6b

68.9±7.3a 77.5±4.3ab 85.7±7.5bc 89.7±8.0bc 91.2 ± 7.3c

IValues in same column with the same letters are not significantly different (P <0.05).

ences in the temperatures at which the peaks of the viscosities for both actomyosin solutions (sucker and croaker) occurred might be species and/or habitat related. The consistent decrease in apparent viscosity of the sucker actomyosin solution over the 1O-38°C temperature range might be due to protein denaturation (Liu et al., 1982). At the peak temperature range of 41-43°C, the increase in apparent viscosity might be jointly due to gelation of the protein molecules as the temperature is raised and interactions of actomyosin chains (Ueda et al., 1963; Nakayama et al., 1979). Isothermal incubation of the actomyosin solution between 10° to 50°C showed some thixotropic properties (Figure 2). Similar thixotropic behavior of actomyosin solutions have been observed in carp (Nakayama et al., 1979) and croaker (Wu et al., 1985b). The thixotropy of the sucker actomyosin solutions was reversible. For the 40° and 50°C heated samples, stopping the shearing for 10 min resulted in significant recovery of the initial viscosity. Complete recovery was observed in the samples incubated at 50°C. Similar results have been observed in croaker actomyosin solutions (Wu et al., 1985b) and have been attributed to the weakness of the interactive forces responsible for gel formation in the incubated actomyosin solutions. Fish protein gelation is generally thought to result from conformational changes in the proteins and concomitant hydrophobic interactions of the proteins (Wu et al., 1985a). These hydrophobic interactions might be relatively weak and susceptible to shear forces. The interactions may be reformed in the absence of shear, thus accounting for the increase in viscosity when shearing was stopped for 10 min. The quality of surimi is determined by functionality tests such as the fold test. The results of the fold test on kamaboko prepared from sucker surimi are shown in Table l. The fold test results did not change during refrigerated storage for 4 w despite the slight increase in the expressible fluid (Table 1). The increase in percent expressible fluid of the kamaboko might be due to dehydration and/or reduction in the water

Can. Inst. Food Sci. Technal. J. Vol. 21. No. 5. 1988

retention properties of the gels. Normally significant loss of water retention of fish gels make them relatively brittle and consequently they exhibit poor folding properties. The storage stability of the kamaboko from sucker surimi indicated that the surimi was of good quality and reasonably stable without any texture modifying additives such as egg albumin. Compressive forces measured during storage of the kamahoko gels are shown in Table 1. The hardness of the gels increased with storage time apparently due to firming up of the gels and reduction in hydration of the gel matrix. The increase in hardness seems to he poorly correlated with the fold test. The 70010 deformation test is probably not a dependable indicator for assessing sucker kamaboko quality.

Conclusions The results suggest that sucker actomyosin could be used to form gels at temperatures close to 40°C and in that respect this fish is similar to other underutilized species such as silver or red hake that have excellent potential as raw materials for surimi production. The stability of the gels produced from sucker surimi makes the surimi a potential ingredient or material for products such as sausages. Acknowledgments The technical assistance of Bogumil Czechowicz is gratefully appreciated. This study was supported in part by the Saskatchewan Tourism and Small Business. We thank Jo-Anne Marshall for editorial assistance. References Fernet, D.A. 1975. Rough Fish Potential in Saskatchewan. Fisheries Technical Report 75-1 I. Saskatchewan Tourism and Renewable Resources, Regina, Sask. Holmquist, J.F., Buck, E.M. and Hultin, H.O. 1984. Properties of Kamaboko made from red hake (Urophycis chuss) fillets, mince or surimi. 1. Food Sci. 49:192. Liu, Y.M., Lin, T.S. and Lanier, T.C. 1982. Thermal denaturation and aggregation of actomyosin from Atlantic croaker. J. Food Sci. 47: 1916. Nakayama, T., Nina, E., Hamada, J. and Shin, C. 1979. Viscosity changes in carp actomyosin solutions. J. Food Sci. 44:1106. Ueda, T., Shimidu, W. and Shimizu, Y. 1963. Studies on muscle of aquatic animal. 38. Changes in viscosity of heat denatured fish actomyosin. Bull Jap. Soc. Sci. Fish. 29:537. Wu, M.C., Lanier, T.C. and Hamann, 0.0. 1985a. Thermal transitions of actomyosin and surimi prepared from Atlantic croaker as studied by differential scanning calorimetry. J. Food Sci. 50:10. Wu, M.C., Lanier, T.C., and Hamann, 0.0. 1985b. Rigidity and viscosity changes of croaker actomyosin during thermal gelation. J. Food Sci. 50:14.

Submitted March 16, 1988 Revised August I, 1988 Accepted August 25, 1988

Owusu-Ansah et al. / 533