THE EFFECT OF TWO CRYOPROTECTANT MIXTURES ON FROZEN SURUBÍ SURIMI

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1 Brzilin Journl of Chemicl Engineering ISSN Printed in Brzil Vol. 19, No. 04, pp , Octoer - Decemer 2002 THE EFFECT OF TWO CRYOPROTECTANT MIXTURES ON FROZEN SURUBÍ SURIMI J.R.Medin * nd R.L.Grrote Instituto de Tecnologí de Alimentos (ITA) FIQ-UNL, Ciudd Universitri, C.C. Nº , Snt Fe - Argentin E-mil: jrmedin@fiqus.unl.edu.r (Received: Mrch 5, 2002 ; Accepted: July 4, 2002) Astrct - "Surimi" itself is not food; it is n intermedite phse of the production of "kmoko"( gel formed y the ddition of slt to the surimi nd direct heting to 80-90ºC) nd series of high-priced shellfish nlogs. The protective effect tht two cryoprotectnt mixtures exerted during freezing nd frozen storge of frozen surimi of suruí (Pseudopltystom coruscns) on the functionl qulity of the gels prepred ws studied. The selected wshing conditions selected to otin n cceptle functionl qulity of gels prepred from frozen surimi (25% extrcted proteins nd of finl moisture) using the response surfce methodology were wsh temperture, 18ºC; wshing time for ech of the three wshing cycles, 4.62 min. nd wter-mince rtio, 3.5:1. Cryoprotectnt mixtures used were sucrose/soritol (1:1) nd mltodextrin/soritol (1:1) nd they were dded (8%) to the wshed nd drined minced fish efore freezing. To evlute the functionlity of the frozen surimi during six months of storge, the penetrtion test to mesure the gel strength ws chosen; smples were ssessed t 4, 45, 90 nd 180 dys of frozen storge. Results showed tht even with the cryoprotectnts freezing decresed gel strength, since it produced decrese of lmost 32% in the strength of the gel prepred with fresh surimi. However, the two cryoprotectnt mixtures tested showed very good ehviour throughout frozen storge; specilly t 45 nd 90 dys of storge the surimi gels with the sucrose/soritol mixture hd greter resistnce thn those with mltodextrin/soritol. Keywords: gel strength, frozen storge of surimi, protein functionlity, suruí surimi nd cryoprotectnt. INTRODUCTION Surimi is wet, frozen concentrte of the myofirillr proteins of fish muscle (Lnier 1986). The technology for otining frozen surimi derived from wrm-wter fish species cn e n interesting lterntive for etter preservtion nd therefore for extending shelf-life during commerciliztion. The wshing procedure is of gret importnce for the finl qulity of surimi ecuse it not only removes ft nd undesirle mteril ut, more importntly, increses the concentrtion of myofirillr protein, therey improving the gelforming ility nd decresing the protein denturtion during frozen storge (Lee 1984, 1986). The gel texture or surimi functionlity vries with the fish species used, the slt concentrtion needed for protein soluiliztion, the temperture nd time t which the surimi is lended with slt, the frozen surimi moisture nd the het tretment (Suzuki 1981; Lee nd Toledo 1976; Lee 1984; Lnier 1986). The qulity of the surimi is function of its rheologicl properties, in prticulr the force nd strin t filure of the gels otined y therml processing (Lnier 1986). The higher the rheologicl prmeters, the etter the qulity of the surimi (Montejno et l. 1994; Hernández et l. 1995). It ws lso found tht the texturl properties nd wter-holding cpcity of cooked fish gels vried gretly etween the different species used (Cheng et l. 1979). The fct tht mny types of gel structures nd textures my e descried in terms of two sic *To whom correspondence should e ddressed

2 420 J.R.Medin nd R.L.Grrote rheologicl prmeters, rigidity nd strin t reking (tht is, the stress nd strin t reking, which re ctully directly mesured), yields not only convenient system for mesuring gel texture, ut lso mens of specifying the functionl properties of surimi (Lnier 1986). The ojective of this work ws to determine the protective effect tht two cryoprotectnt mixtures exerted during freezing nd frozen storge of suruí surimi on the functionl qulity of the gels prepred. MATERIALS AND METHODS Response surfce methodology (RSM), ws used for the experimentl design (Montgomery, 1991), nd the model proposed y Box nd Behnken (1960) ws selected to study the wshing stge. The experimentl design dopted for this work, together with its independent vriles, its codified vriles nd their three levels, is shown in Tle 1, nd the 15 experiments were crried out t rndom. Version 7.1 of the Sttgrphic Sttisticl Grphics System Plus progrm ws used for dt nlysis nd efficiency of the model ws verified y nlysis of vrince (ANOVA). The rw mteril used in the experiments ws suruí (Pseudopltystom coruscns) due to its low ft content (2-3%). In order to chrcterize the product otined (surimi) chemiclly nd functionlly, totl protein (AOAC 1984), totl sh -A- (AOAC 1984) nd moisture -M-(Lnier et l. 1985) in oth the fresh muscle nd the surimi were determined, nd the punction test ws lso performed to mesure deformtion strength in the surimi gel (Lnier et l. 1985). Aprt from this, totl solule protein (totl solule protein nitrogen) in the fresh muscle (Cheng et l. 1979) nd totl ft in edile sections were lso nlyzed (AOAC 1984). The verge composition of edile sections of suruí fresh muscle ws the following: Moisture: ± 0.72; totl protein: 17.31± 0.80; totl ft: 1.50 ± 0.54; sh: 1.17 ± 0.24; (n=10; p<0.05). Preprtion of Frozen Surimi The suruí ws otined from the fish region of Snt Fe (Argentin). The muscle ws seprted from skin, one nd drk muscle y hnd with knife. suruí mince ws prepred with food processor to otin 5 mm-dimeter prticles. The wshing system employed ws designed nd constructed y the working group (Medin 2000) nd it consists of 30-mesh stinless steel cylindricl sket (60 mm dimeter x 300 mm height). The empty stinless steel sket ws weighed nd then filled with 200 gr of suruí mince conditioned t the wshing temperture set y the model. The sket with mince ws plced within 65.5 mm dimeter x 500 mm height stinless steel tue, which contined the wter for ech wshing cycle (three wshing cycles). This stinless steel tue ws then plced in th thermosttted t the temperture required for ech experiment. Menwhile, y mens of metllic rm, the sket ws connected to reducing motor with speed selector. The up-down velocity of the sket in the wshing wter ws set t 60 ups per min for ll the experiment. After the third wshing ws completed, the sket with the mince ws plced t 24º slope nd dewtered y grvity dringe for 15 min. The following step ws pressing. The sket ws now plced in verticl position nd 2 kg lod, with 58 mm externl dimeter ws plced inside on top of the mince nd ws left for 10 minutes. Immeditely fter the mince recovered ws weighed nd the yield (Y= dewtered mince weight/fresh mince weight ) ws determined. Cryoprotectnts t 1:1 rtio of sucrose to soritol were lter dded t level of 7,4 % the finl lock sis, nd the mix ws then kneded for out 4-5 min. After tht, this mss ws chopped in to locks (3 cm dimeter x 12 cm height), nd the locks were frozen y immersion in liquid nitrogen for 5 min nd then stored t 21 ºC until the totl protein, moisture (M), sh (A) nd gel strength (GS) were nlyzed. Gel Preprtion nd Éffectiveness of Two Cryoprotectnt Mixtures Following the technique proposed y Lnier et l. (1985), frozen surimi (stored t 21 C for six months) ws tempered until it reched 3 C nd locks were cut in regulr width slices. The sequence dopted ws descried y Medin nd Grrote (1999). Gel strength (GS) ws otined s the product of stress (first pek on the grph) nd strin deformtion (distnce from the first pek). This determintion ws performed t lest four times. Brzilin Journl of Chemicl Engineering

3 The Effect of Two Cryoprotectnt Mixtures 421 The protective effect of two cryoprotectnt mixtures during freezing nd frozen storge of suruí surimi ws studied nd the sme working methodology ws used for studying this effect. The sme working conditions s those of the independent vriles were selected for verifiction of the regression models developed. The two cryoprotectnt mixtures were s follows: mixture Nº1: sucrose-soritol nd mixture Nº 2: mltodextrin-soritol (Mltrin M100; DE 10). The totl frozen storge time ws six months nd frozen surimi gel strength ws evluted t 4, 45, 90 nd 180 dys of storge. Preprtion of the surimi smples ws chnged only y incorportion of the cryoprotectnts, which were dded t 1:1 rtio nd t 8% on dewtered mince sis. RESULTS AND DISCUSSION The verge composition of the three nitrogen frctions mking up the totl nitrogen content of the suruí muscle ws the following (mens ± stndrd devitions): Myofirillr protein nitrogen: 198 ± 0.16%; Srcoplsmic protein nitrogen: 0.53 ± 0.08%; Nonprotein nitrogen: 0.31 ± 0.04%; Solule nitrogen frction: 0.83 ± 0.08%; Totl nitrogen: 2.81 ± 0.16%. It cn lso e seen tht out 19% of the totl nitrogen corresponds to srcoplsmic proteins, whose removl y wter wshing enefits preservtion of the muscle in the frozen stte, nd tht out 33% of the totl nitrogen is solule in wter or slt solution of low ionic strength (I=0.05). The response vlues otined from ech experiment (Tle 2) nd the nlysis of vrince (Tle 3) indicte tht the models dopted were pproprite for the extrcted proteins, moisture nd sh of the surimi nd for the gel strength otined from it, with lck of fit not eing significnt. The predictive models developed to evlute surimi gel strength (GS), vrition in protein extrction (EP= [totl protein nitrogen surimi protein nitrogen] / totl protein nitrogen) nd moisture (M) were the most dequte nd hd the est fit nd were thus chosen to determine the most cceptle working res y using the superimposition of the corresponding contour grphs. Series of contour grphs were developed for ech of the three responses versus R nd t, nd T ws dopted s constnt fctor since its effect ws the lest significnt. Conditions tken into ccount were tht % M should e elow 79% nd % EP elow 25%, so s to produce surimi of cceptle functionl qulity. A point selected to verify these three regression models is the following: R = 3.5:1; T = 18 ºC nd t = 4 min 37 sec/cycle. Frozen surimi gel strength ws evluted fter six months of storge, in ccordnce with the dt from which the regression model ws dopted. The models developed were clerly verified, nd there re no significnt differences etween experimentl nd predicted vlues t p<0.05. Vrition in Gel Strength with Time of Frozen Storge Conditions the sme s those of the independent vriles were selected for verifiction of the regression models developed for % EP, % M nd GS, nd the sme working methodology ws used for studying this vrition. The efficiency of the two cryoprotectnt mixtures during frozen storge, while mintining the functionl qulity of proteins, ws evluted in surimi smples specilly prepred for this purpose. Tle 4 shows men vlues for gel strength from t lest four replictes using sucrose-soritol nd mltodextrin-soritol, oth t 7,4 % sed upon the finl lock weight. Student s t-test nd the null hypothesis test were used for comprison of mens with the sme tretment. No significnt differences pper, for either mixture Nº 1 or Nº 2, etween ny of the gel strength men vlues in Tle 4 (p> 0.05). Using similr procedure, mens etween columns, correlted for ech time of frozen storge, were compred in Tle 4. Significnt differences were oserved for 45 nd 90 dys etween the gel strengths corresponding to ech mixture (p<0.01), with sucrose-soritol ppering to e the most pproprite. Tle 5 shows the verge vlues for gel strength t severl frozen storge times for sucrose-soritol mixture t 0, 4 nd 20 dys. The first line vlue indicted s 0 dy of frozen storge corresponds to just-mde surimi dded to the mentioned cryoprotectnts ut without freezing, i. e., the gel of fresh surimi. According to these results, freezing itself is oserved to severely ffect gel strength of fresh surimi, reducing it y 32%. Brzilin Journl of Chemicl Engineering, Vol. 19, No. 04, pp , Octoer - Decemer 2002

4 422 J.R.Medin nd R.L.Grrote Tle 1: Independent vriles nd their levels Independent vriles Wter-to-mince rtio (gr./gr.) Wsh temperture ( ºC) Symol Levels Coded Rel Coded Rel X 1 X 2 Wsh cycle time (min./cycle) X 3 t R T -1 2:1 0 5:1 +1 8: Tle 2: Experimentl dt Exp. R T t Y EP M A GS (gr/gr) (ºC) (Min) (%) (%) (%) (%) (grcm) 1 8: : : : : : : : : : : : : : : Tle 3: Anlysis of vrince for response vriles Source df Sum of squres Y GS EP M A Model Liner Qudrtic Cross product Residul Lck of fit Pure Error r 2 (%) Brzilin Journl of Chemicl Engineering

5 The Effect of Two Cryoprotectnt Mixtures 423 Tle 4: Men vlues of surimi gel strength (g.cm) during frozen storge Time (dys) Mixture Nº 1 (Sucrose/Soritol) c d f h Mixture Nº 2 (Mltodextrin/ Soritol) c e g h Mens in the sme column followed y equl superscripts re not significntly different (p>0.05). Mens in the sme row followed y different suindexes re significntly different (p<0.01) Tle 5: Men vlues of gel strength (g.cm) t severl frozen storge Time (dys) Mixture Nº 1 (Sucrose/Soritol) 0 * * Without freezing Vlues with different superscripts re significntly different (p<0.05) CONCLUSIONS Suruí flesh proved to e suitle rw mteril for surimi production, s shown y gel strength vlues for unfrozen fresh surimi. Nineteen percent of totl nitrogen ws found to come from solule srcoplsmic proteins. The second-order mthemticl-sttisticl models with the est fit were those relted to GS responses of surimi gel, % M nd % EP; no significnt differences were found etween experimentl nd predicted vlues. Even with the ddition of cryoprotectnts, freezing decreses gel strength since it produced decrese of out 32% in fresh surimi gel strength. The sucrose-soritol mixture ws more suitle thn mltodextrin-soritol, s shown y the higher strength of frozen gels stored for 45 nd 90 dys. REFERENCES A.O.A.C Officil Methods of Anlysis of the Assocition of Officil Anlyticl Chemists (A.O.A.C.), 40 th Ed. Box, G.E.P. nd Behnken, D.W Some new three level designs for the study of quntittive vriles. Technometrics (2): Cheng, C.S., Hmnn, D.D. nd We, N.B Effect of therml processing on minced fish gel texture. J Food Sci 44(4): Cheng, C.S., Hmnn, D.D., We, N.B. nd Sidwell, V Effects of species nd storge time on minced fish gel texture. J Food Sci 44(4): Hmnn, D.D Surimi, uilding lock for formulted foods. In: Chilling nd freezing of new fish products. Ed.: Interntionl Institute of Refrigertion, Pris (Frnce), Hernández, L.E., Morles, O.G., Montejno, J.G. nd Diz, R Efecto del liofilizdo sore propieddes reológics de geles de surimi de ronco y lengudo reconstituidos tres niveles humedd:proteín. Rev. BIOTAM, 7 (1), 1-8. Kim, B.Y., Hmnn, D.D., Lnier, T.C. nd Wu, M.C Effects of freeze-thw use on the viscosity nd gel-forming properties of surimi from two species. J Food Sci 54 (4), Lnier, T.C., Hmnn, D.D. nd Wu, M.C Development of methods for qulity nd functionlity ssessment of surimi. Finl Report for Alsk Fisheries Development Foundtion, Inc., Anchorge, Alsk. Lnier, T.C., Lin, T.S., Liu, Y.M.nd Hmnn, D.D. Brzilin Journl of Chemicl Engineering, Vol. 19, No. 04, pp , Octoer - Decemer 2002

6 424 J.R.Medin nd R.L.Grrote Het geltion properties of ctomyosin nd surimi prepred from Atlntic croker. J Food Sci 47, Lnier, T.C Functionl properties of surimi. Food Technology, 40 (3), Lee, C.M. nd Toledo, R.T Fctors ffecting texturl chrcteristics of cooked comminuted fish muscle. J Food Sci 41, Lee, C.M Surimi process technology. Food Technology, 38 (11), Lee, C.M Surimi mnufcturing nd friction of surimi sed products. Food Technology, 40 (3), Medin, J.R nd Grrote, R.L Estudio de l etp de lvdo en l otención de surimi congeldo de suruí. VIII Congreso Argentino de Cienci y Tecnologí de Alimentos de myo Rfel Prov. Snt Fe Argentin. Medin, J.R Estudio de l etp de lvdo en l otención de surimi congeldo prtir de pescdo de río. M.S. thesis. Universidd Ncionl del Litorl. Snt Fe, Argentin. Montejno, J.G., Morles; O.G.nd Diz, R Propieddes reológics de geles de surimi liofilizdo de truch (Cynoscion nothus) y tilpi (Orochromis nilotic). Rev. Espñol de Cienci y Tecnologí de Alimentos, 34 (2), Montgomery, D.C Diseño y Análisis de Experimentos. Editoril: Grupo Editoril Ieroméric, S.A. de C.V., México. Suzuki, T Fish And Krill Protein, Processing Technology. Editoril: Appied Science Pulishers Ltd.. Ripple Rod, Brking, Essex, Englnd. Brzilin Journl of Chemicl Engineering