Análise da textura de músculos submetidos à fixação em formaldeído e conservação em solução de benzoato de sódio 0, 5% e ácido acético 0, 5% / Tenderness analysis of muscles fixed in formaldehyde and kept in 0, 5% sodium benzoate and 0, 5% acetic acid solution

ABSTRACT

Background: Tissue texture, or tenderness, may be checked-out by analyzing the force necessary to cause muscle fibers rupture (shearing force) and the result is expressed in kilogram-force (kgf). The aim of this paper was to analyze the texture of broiler chicken breast muscles fixed in a 10% formaldehyde solution and kept in a 0.5% sodium benzoate and 0.5% acetic acid solution up to 180 days so any alteration regarding resistance and the best moment for dissection could be described. Materials, Methods & Results: Forty chicken breasts were used and muscle texture was analyzed by the shearing force whose values were correspondent to the maximum force necessary to chisel the samples. Eight of 40 breasts were taken as a control group (fresh muscles). The remaining breast muscles were fixed in a 4% formaldehyde solution and kept in plastic containers with this solution during seven days and, then, eight breasts went through texture analysis. The 24 remaining breasts were set in plastic containers with 0.5% sodium benzoate and 0.5% acetic acid solution. The texture analyses were taken out at 30, 90 and 180 days of conservation, and eight breasts were used in each time. The shearing force was obtained for each sample and, just before cutting, muscles were washed in running water for 24 h so the excess of the conservation agent could be removed. Data were submitted to statistical analysis by the 5% Tukey's test. The average shearing force of the control, formaldehyde and 30-day sodium benzoate and acetic acid groups differed among them and from the 90-day and 180-day of sodium benzoate and acetic acid groups. The average shearing forces of the two last groups did not statistically differ among them. Discussion: The longer the muscles were kept in the sodium benzoate and acetic acid solutions, the more they became soft, and the shearing force decreased from 21.46 Kgf (seven days of conservation) to 19.20 Kgf (30 days), 17.23 Kgf (90 days) and 16.32 Kgf (180 days) not reaching, however, values from 8.97 to 15.31 Kgf, as described in chicken breasts conserved in 96oGL ethylic alcohol. The average shearing force of chicken breasts conserved in sodium benzoate and acetic acid progressively decreased during 180 days of conservation, when it reached a value of 16.32 Kgf, similar to the value of 15.32 Kgf of chicken breasts conserved for 45 days in formaldehyde. By the seventh day of conservation in 10% formaldehyde, samples presented an average shearing force of 21.46 Kgf, which was higher than the 15.33 Kgf of chicken breasts conserved during 45 days or the 14.74 to 17.37 Kgf of the same tissue kept up to a year in formaldehyde solution. It was concluded that conservation of breast broiler chickens fixed in formaldehyde and conserved in sodium benzoate and acetic acid made them softer through within 180 days, resulting in a better structure malleability and suggesting that dissection of anatomical muscle pieces may occur in an easier way in this moment. Although the sodium benzoate and acetic acid effect in texture of broiler chicken muscle tissue fixed in formaldehyde has been studied, it is believed that, due this great tissue homogeneity, these data might be taken or used as basis to similar studies in other species.