WEIGHT INCREASING AND SENSORY CHARACTERISTICS IMPROVEMENT IN FRESHWATER PRAWN MACROBRACHIUM ROSENBERGII (CRUSTACEA, DECAPODA) BY CURING IN BRINE IMMERSION

Abstract

The insipid meat and the fragile texture are the principal negative factors in terms of marketing of the freshwater prawn Macrobrachium rosenbergii. Thus, the aim of this experiment was to study the principal components responsible for the sensory characteristics (color, flavor, taste and texture) of its meat, as well as the mechanisms that regulate these characteristics. Adult prawns (25 to 30 g) from Bonanza Farm were divided in two samples: whole animals and fillets. Those samples were first treated by brine immersion at 5°C in seven different formulas, during 3, 6 and 24 hours. Prawn weights were taken before and after each curing treatment to determine weight variations during the process. Then, the processed prawns were submitted to sensory analysis by "Hedonic Scale". Therefore, it was possible to choose the best four treatments. The next step was to treat samples of 10 prawns with the cure process for about 24 hours. During this period, the prawn weights were taken each 3 hours, in order to point the best time treatment in terms of weight increasing. To determine the economic viability it was considered the salt prices (R$/kg) and the weight increasing, as well as the prawn quality in terms of the efficiency of the processes and the sensory analysis and the marketing value that this product reaches. The experiments were carried on the entirely casualizated plan, with the Tukey's test at 1%. The results indicate total inviability in whole animals cured, while the maximum value of weight increasing, in cured fillets (32.16%), was reached in treatment 6 (5% of NaCl + 2,5% of bibase sodium phosphate). Nevertheless, the best organoleptic characteristics were obtained in treatment 4 (2.5% of NaCl + 2.5% of bibase sodium phosphate + 0.1% of nitrite) with a weight increasing of 25.65%, both after 21 hours of curing time. To the economic viability, it was verified that if considering the same profit on the whole prawns sale, we can get a decrease of the minimum sale price of the cured fillets that correspond to 21.51% of the price of whole prawns (treatment 6) and 16.98% (treatment 4). This fact brings facilities to the farmers to optimize their profits, either by marketing competivity increase or by gain margin increase: 23.25 and 17.25%, respectively.