Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.6, n.2, p.115-122, 2004 115 ISSN 1517-8595

OSMOTIC DEHYDRATION OF MAPARÁ ( edentatus) FILLETS: EFFECT OF TERNARY SOLUTIONS

Suezilde da Conceição Amaral Ribeiro1, Satoshi Tobinaga2

ABSTRACT

A combination of dry salting and sun drying is one of the oldest and most important techniques of fish conservation in . Dried salted fish prepared by this method can easily be found in the Northern and Northeastern States. The main problem is the lack of process control, which can provoke lead to products with low microbiological and/or nutritional control. Mapará fillets were osmotically dehydrated according to a 24-1 fractional factorial design for each hypertonic solution (salt-sucrose and salt-corn syrup). The effects of the salt (12 to 14%) and sugar (30 to 40%) concentrations, temperature (30 to 50 C) and immersion time (6 to 12h) for both water loss (WL) and solids gain (SG) were evaluated. Through the obtained results, it was verified which type of solution resulted in greater water loss and smaller solids gain. In the design using sucrose and salt, only the sugar concentration wasn t significant for water loss and solids gain. All the effects were significant. In the design using corn syrup and salt.

Keywords: osmotic dehydration, fish, ternary solutions

DESIDRATAÇÃO OSMÓTICA DE FILÉS DE MAPARÁ (): EFEITO DE SOLUÇÕES TERNÁRIAS

RESUMO

A combinação de salga seca e secagem solar é uma das mais antigas e mais importantes técnicas de conservação de peixe no Brasil; o peixe salgado e seco, preparado a partir deste método, pode ser facilmente encontrado nos estados do Norte e Nordeste do país. O grande problema é a falta de controle de processo que pode levar a produtos com baixo nível nutricional e microbiológico. Filés de mapará foram osmoticamente desidratados de acordo com um planejamento fatorial fracionário 24-1, para cada solução hipertônica (sal-sacarose e sal-xarope de milho). Foram avaliados os efeitos da concentração de sal (12 to 14%) e açúcar (30 to 40%), temperatura (30 to 50 C) e tempo de imersão (6 to 12h) na perda de água (PA) e ganho de sólidos (SG) e a partir da avaliação dos resultados de cada planejamento, verificar que tipo de solução apresenta uma maior perda de água e um menor ganho de sólidos. No planejamento utilizando sal-sacarose, somente a concentração de açúcar não foi significativa para a perda de água e ganho de sólidos. No planejamento utilizando sal-xarope de milho todos os efeitos foram significativos.

Palavras-chave: desidratação osmótica, peixe, soluções ternária

Protocolo 573 de 02 /10 / 2004 1 Laboratório de Medidas Físicas, DEA/FEA/UNICAMP, Caixa Postal: 6121 Campinas, SP ([email protected]) 2 Laboratório de Medidas Físicas, DEA/FEA/UNICAMP, Caixa Postal: 6121 Campinas, SP ([email protected])

116 Osmotic dehydration of mapará catfish fillets: Effect of ternary solutions. Ribeiro e Satoshi.

INTRODUCTION The objective of this work was to determine the effect of ternary solutions on the A preliminary osmotic dehydration is osmotic dehydration of (Hypophthalmus often used with the objective of improving the edentatus) fillets, according to a 24-1 fractional quality of the dry food and it is not aimed a factorial design for each hypertonic solution massive water removal. This pre-treatment has (salt + sucrose and salt + corn syrup), and after a protective effect on the structure of the dried verify, which type of solution resulted in the material. The amount and rate of moisture greatest water loss and solids gain from the removal during the osmotic process depend on results of each design. some processing variables and parameters such as: type of solute and its concentration in the MATERIALS AND METHODS osmotic solution, time of immersion, temperature, etc. It was used mapará catfish In aqueous ternary solutions which (Hypophthamus edentatus) from EDIFRIGO contain salt and sugar, the antagonistic highly localized in Santarém city in Pará state. The effects to solute gain for processed products native from rivers of Pará state were have been reported. Salt uptake is especially transported to Campinas city previously rinsed limited by the presence of sugar. This barrier (with chlorinated water), eviscerated, packaged effect of sugar on salt penetration was and frozen at -18 C to be transported to demonstrated for fruit and vegetable products Campinas city. (Bolin et al.,1983; Lenart & Flink, 1984) and products (Favetto et al., 1981; Collignan Osmotic Dehydration & Raoult-Wack, 1994; Bohuon et al., 1998). This phenomenon is due to the formation of a Filets were cut, in the frozen state, in highly concentrated sugar coating on the food flat slab geometry (0.5cm thick and 5cm product (Collignan et al., 2001). length). After cut the samples were thawed Many researchers have studied under refrigeration at 10 C for 10 hours, differents aspects of the osmotic dehydration, according Beraquet and Mori (1984). Each such as kind and concentration of the sample was individually weighted (7g) and employable solute, time and temperature of the placed in beaker with dehydration solution with process, combination of the osmotic process the same process temperature. The ratio product with other unitary operations, quality of the / solution, equal to 1/5, were chosen in order to final product, etc. (Raoult-Wack et al., 1992; avoid significant dilution of the solution during Medina, 1998; Araújo, 2000; El-Aouar, 2001). the osmotic treatment. The whole beaker- Then, the removal rate of water strongly sample was placed in a shaker (Tecnal, model depends on the parameters and variables in the 421), with agitation and temperature controls. process. Generally, the mass transference is as The slabs were taken out after predetermined high as the solute concentration, contact time, times, quickly rinsed and superficially blotted agitation and temperature. The water outcome in absorbing paper and weighed Moisture is more benefited through the use of high content was determined in a vacuum oven at temperatures than the solute insertion (Poting et 70 C for 24 hours. al., 1966; Lerici et al., 1985).

Fish 1:5 weighing sample/solution Shaker

drying wash weighing Figure 1 - Osmotic dehydration process

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Osmotic dehydration of mapará catfish fillets: Effect of ternary solutions. Ribeiro e Satoshi. 117

The water loss and solid gain, where calculated through the Equations (1) and (2), respectively (Hawkes and Flink, 1978).

Water Loss Solid Gain MA (M MS ) MS MS WL(%) O t t 100 (1) SG(%) t O 100 (2) MA MS 0 0 MAO MSO

Notation: MAo= initial water mass (g); MSo = initial solid mass (g); Mt = sample mass at time t (g); MSt = solid mass at time t (g).

Experimental Design the temperature, salt and sugar concentrations, and immersion time were studied. The obtained The effect of different processing responses were water loss (WL) and solid gain conditions was determined. A 24-1 fractional (SG). Table 1 shows the levels of studied factorial design was used for each hypertonic variables. solution (salt-sucrose and salt-corn syrup) in The Statistica 5.0 (Statsoft, 1997) order to maximize water loss and minimize package was used. In order to obtain the solid gain. It was carried out a design with 11 magnitude the independent variables effects. points, where the influence of dehydration on

Table 1 - Levels of studied variables in experimental design

Factors -1 0 +1 Temperature ( C) 30 40 50 Salt concentration (%) 12 13 14 Sugar concentration (%) 30 35 40 Immersion time (h) 6 9 12

RESULTS AND DISCUSSION the table of the 24-1 fractional factorial experimental plan, with three central points. Table 2 shows the values for water loss The experimental data were obtained through and solids gain obtained experimentally in 11 combinations between the following osmotic dehydration of mapará fillet using independent variables: temperature, NaCl different ternary solutions of NaCl + sucrose concentration, sugar concentration, and and NaCl + corn syrup, according to data from immersion time.

Table 2 - Results of weight loss, water loss and solids gain obtained experimentally through osmotic dehydration of mapará fillet

Codified plan Responses T NaCl Sugar t WL (%) SG (%) WL SG (%) ( C) (%) (%) (h) Sucrose Sucrose (%)Syrup Syrup 1 -1 -1 -1 -1 12,9917 15,2146 5,5414 10,5569 2 +1 -1 -1 +1 35,6687 9,9684 28,823 7,988 3 -1 +1 -1 +1 22,7791 27,997 26,0258 19,7563 4 +1 +1 -1 -1 31,7322 10,3341 25,2804 7,6572 5 -1 -1 +1 +1 20,8249 26,9406 22,9870 21,6292 6 +1 -1 +1 -1 26,4068 6,4903 26,0286 9,3848 7 -1 +1 +1 -1 25,7329 21,4836 21,4718 19,2026 8 +1 +1 +1 +1 39,6568 12,7794 41,3967 10,1615 9 0 0 0 0 29,4467 11,7303 29,2194 17,4368 10 0 0 0 0 31,8039 12,1283 30,4286 17,0638 11 0 0 0 0 30,9992 12,7393 30,3291 17,1331 Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.6, n.2, p.115-122, 2004

118 Osmotic dehydration of mapará catfish fillets: Effect of ternary solutions. Ribeiro e Satoshi.

Water Loss loss, both with NaCl sucrose solution and NaCl-syrup corn solution. The results can be Tables 3 and 4 presents the magnitude more clearly visualized through the bars chart of the independent variables effects on water (Figure 1).

Table 3 - Estimate effect, pure error, t coefficient and static significance, for each factor, using NaCl+sucrose solution for water loss

Factors Estimate effect Pure t(2) Static significance (p) error Temperature 12,7840 0,8473 15,0887 0,0043 NaCl (%) 6,0022 0,8473 7,0843 0,0193 Sucrose (%) 2,3624 0,8473 2,7883 0,1082 Time (h) 5,5165 0,8473 6,5109 0,0228

Table 4 - Estimate effect, pure error, t coefficient, and static significance, for each factor, using de NaCl + corn syrup solution, for water loss

Factors Estimate effect Pure t(2) Static significance (p) error Temperature 11,3757 0,4746 23,9665 0,0017 NaCl (%) 7,6987 0,4746 16,2197 0,0038 Syrup (%) 6,5534 0,4746 13,8068 0,0052 Tempo (h) 10,2276 0,4746 21,5477 0,0021

The aim of the fractional factorial is to significant is as high as the value of the verify the intensity of the effects and its coefficient t. significance instead of the model validation, by The confidence interval is chosen at a this reason there was no necessity of evaluate value of 95%. One can say that the variable is the effects through residual error. considered statistically significant for values of It s necessary to observe the magnitude p inferior to 5% and for superior values of p the and signals of the effects to interpretate tables 3 variable isn t considered statistically and 4. The influence on the on the studied significant. sample is as high as the effect value. For the water loss answer, it can be said The signal shows the proportionality of that the factors which are significant at 95% the variation of the effect related to the answer. (whatever is for the NaCl + sucrose solution or For example, a positive sign shows that the NaCl + corn syrup) are: temperature, NaCl the existence relation between the independent concentration, and time. variable and the response is proportionally It is observed that for a fractional straight, that is, the passage from an inferior factorial using a NaCl + sucrose solution, the level to a superior one of the independent sugar concentration at a p>0.05, which signs variable results in an increased value of the that its effect is not significant. The same does response. For a negative sign, the relation is not happen when a NaCl + corn syrup solution proportionally inverse. is used, where sugar concentration is significant The t value shows how great the at 95% of trust (p 0.05). variable is about to its deviation. Then the probability for the variable to be statistically

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Osmotic dehydration of mapará catfish fillets: Effect of ternary solutions. Ribeiro e Satoshi. 119

Sucrose Corn Syrup

12

10

8 s t c e f

f 6 E

4

2

0 Temperature Salt Sugar Time

Figure 2 - Estimation of the significant and not significant effects for the water loss during osmotic dehydration of mapará fillets.

Through the chart at Figure 2, it is is observed that, for equal conditions of NaCl verified that the temperature is the parameter concentration, sugar concentration, and which has the biggest influence on water loss, immersion time, the highest values for the when it is used the NaCl + sucrose solution, response were obtained for the dehydrated following the NaCl concentration and time. fillets in ternary solution of NaCl + corn syrup, When it is used NaCl + corn syrup solution, it is that is, its values for water loss were higher the temperature which exerts more influence, than those found at the NaCl + sucrose plan. followed by the time, NaCl concentration, and corn syrup concentration. All the significant Solids gain effects of both fractional factorials which were studied have positive effect on the response, The magnitude of the independent that is, the water loss is increased with the variables effects on solids gain, for NaCl + increase of any significant parameter. Another sucrose solution and for NaCl + corn syrup important factor at Figure 1, is to verity that the solution, is shown at tables 5 and 6. The Result temperature effect on water loss is bigger in the can be more clearly visualized through the bars experiments made with NaCl + sucrose; and it chart (Figure 2).

Table 5 - Estimated effect, pure error, coefficient t and statistic significance, for each factor, using NaCl + sucrose for solids gain

Factors Estimate effect Pure error t(2) Statistic significance (p) Temperature -13,0159 0,3594 -36,2181 0,0007 NaCl (%) 3,4951 0,3594 9,7254 0,0104 Sucrose (%) 1,0450 0,3594 2,9077 0,1007 Time (h) 6,0407 0,3594 16,8089 0,0035

Table 6 - Estimate effect, pure error, coefficient t and statistic significance, for each factor, using NaCl + corn syrup for solids gain

Factors Estimate effect Pure error t(2) Statistic significance (p) Temperature -8,9884 0,1403 -64,0713 0,0002 NaCl (%) 1,8047 0,1403 12,8642 0,0060 Syrup (%) 3,6049 0,1403 25,6968 0,0015 Time (h) 3,1834 0,1403 22,6919 0,0019

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120 Osmotic dehydration of mapará catfish fillets: Effect of ternary solutions. Ribeiro e Satoshi.

Through tables 5 and 6, it is observed that the concentration. The parameters which have a factors which are significant for the solids gain p>0.05, are not significant at 95% of trust, in and answer at 95% of trust (whatever is for this case, the sucrose concentration for the plan NaCl + sucrose solution or for NaCl + corn using this sugar does not have any effect on the syrup solution) are the temperature and NaCl solids gain answer.

Sucrose Corn syrup

5

0 Temperature Salt Sugar Time s t c e f

f -5 E

-10

Figure 3 - Estimated of the significant and not significant effects for solids gain during the osmotic dehydration of mapará fillets, using ternary solutions.

At Figure 3, where there is a bars chart of weight), promoting higher loss of weight in the the variables effects, it is observed that the plan material. Sugar with low molecular weight which uses NaCl + sucrose solution presents the (glucose, frutose), favor incorporation of solids, temperature as the parameter that has more due to the high velocity of penetration of the influence on the solids gain, following time and molecules. NaCl concentration. Now when NaCl + corn In agreement with the results of water syrup solution is used the temperature is the one loss and solids gain from the plan using NaCl + whish has more influence, following corn syrup sucrose, it was verified that the sucrose concentration, time, and NaCl concentration. concentration, could stay constant in its low The temperature for the two essays have level (30%), which does not affect the negative effect on the answer, that is, with the responses, searching to reduce the cost of the increase of temperature there is a decrease in process. the solids gain. All others parameters have The concentration and composition of the positive effect on the response when one pass solution are variables which influence the water from a minimum value, to a maximum value, loss and solids gain; Raoult - Wack et al. the solids increase. For the same conditions of (1991) studied the influence of concentration temperature, NaCl concentration, sugar and molecular weight of the solute in the water concentration, and time; of both the plans, it loss and solids gain and they observed that in can be said that the biggest effects values are in low concentrations, the solute gain is higher the plan that uses sucrose in the ternary than the water loss, but this effect reaches a solution, even for temperature that has a maximum. Value for high concentrations, the negative effect. The exception is in the sucrose solids gain is much less than the water loss concentration which does not have the same (dehydration effect). The same authors verified significant effect on the answer. that the water loss increases and the solids gain In agreement with Contreras and Smyrl decreases with the increase of the molecular (1981), the kind of sugar used in the solution weight of the solute. affects the kinetics of the process. The use of Emam-Djomech et al. (2001) studied the solutes that has high molecular weight favors interaction of the solutes in the solution and the water loss and the decrease in the solids gain effect of aqueous multicompound solutions, (migration is limited by the high molecular with salt and sugar, in the osmotic dehydration

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Osmotic dehydration of mapará catfish fillets: Effect of ternary solutions. Ribeiro e Satoshi. 121 of an agar gel, and found that the coefficient of Bohuon, P.; Collignan, A.; Rios, G. M.; Raoult- apparent diffusion, when a ternary solution was Wack, A. L. Soaking process in ternary used, diminished when it s compared with liquids: experimental study of mass transport binary solutions. under natural and forced convection. In agreement with Contreras e Smyrl Journal of Food Engineering, v.37, p.451- (1981), the use of corn syrup in the osmotic 469, 1998. process in an apple, following for a dry up, when compared with the sucrose, its use is Bolin, H. R.; Huxsoll, C. C.; Jackson, R.; Ng, advantageous. As the diffuseness coefficient of K. C. Effect of osmotic agents and water depends on the dissolved solids content concentration on fruit quality. Journal of (the diffuseness decreases with the increase of Food Science, v.48, p. 202-205, 1983. solids), the minor incorporation of solids in the osmosis with corn syrup favors the fast exit of Collignan, A.; Raoult-Wack, A. L. Dewatering water from the fruit. and salting of cod by emmersion in concentred sugar/salt solutions. Lebens- CONCLUSIONS mittel-Wissenschaft and Technologie, v.27, p.259-264, 1994. The effect of temperature in the water loss is bigger in the experiments with NaCl + Collignan, A.; Bohuon, P.; Deumier, F.; Sucrose; it is observed that, for the same Poligné, I. Osmotic treatment of fish and conditions of NaCl and sugar concentration, meat products. Journal of Food and immersion time, for the higher values of the Engineering, v.49, p. 153 162, 2001. response were obtained for the dehydrated fillets in ternary solution of NaCl + corn syrup, Contreras, J. E.; Smyrl, T. G. An evaluation of that is, its values of water loss were greater than concentration of apple rings using corn the ones found in the NaCl + sucrose. syrup solids solutions. Can. Inst. Food For the same conditions of temperature, Science Technology, v.14, n.4, p. 310- 314, NaCl concentration, sugar concentration, and 1981. time, of both plans, it is verified that the higher values for solids gain were in the plan which El-Aouar, A. A. Avaliação do processo use sucrose in the ternary solution. combinado de desidratação osmótica e In agreement with the water loss and secagem na qualidade de cubos de mamão solids gain obtained when NaCl + sucrose formosa (Carica papaya L.). Campinas, solution was used, it was verified that the UNICAMP/FEA 2001. 113p. (Mestrado em sucrose concentration was not significant at a Engenharia de Alimentos) level of 95% of confidence Eman-Djomech, Z.; Dejelveh, G.; Gros, J. B. ACKNOWLEDGMENT Osmotic dehydration of food in a multicomponent solution. Part I. Lowering The authors gratefully acknowledge the of solute uptake in agar gels: Diffusion financial support to CNPq considerations. Lebensm.-Wiss. u.-Techno- logy, v.34, p.319-323, 2001. BIBLIOGRAPHIC REFERENCES Favetto, G.; Chirife, J.; Bartholomai, G. B. A Araujo, E. A. F. Estudo da cinética de study of water activity lowering in meat secagem de fatias de banana nanica during immersion-cooking in sodium (Musa acuminiata var. Cavendish) chloride-glycerol solution. II. Kinetics of aw osmoticamente desidratadas. Campinas: lowering and effect of some process UNICAMP/FEA, 2000. 87p. (Mestrado em variables. Journal of Food Technology, Engenharia de Alimentos). v.16, p.621-628, 1981.

Beraquet, N. J.; Mori, E. E. H. Influência de Hawkes,J; Flink, J. M. Osmotic concentration diferentes métodos de defumação na of fruit slices prior to freeze dehydration. aceitabilidade da cavalinha (Scomber Journal of Food Process Engineering, v.2, japonicus Houtt). Coletânea do Instituto de n.4, p. 265 284. 1978. Tecnologia de Alimentos. Campinas, v.14, p. 1-24, 1984. Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.6, n.2, p.115-122, 2004

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