Effect of blanching pre-treatment on texture and sensory characteristics of Pangasianodon hypophthalmus fillet for preparation of pickle

Abstract

Blanching is a thermal pre-treatment done before other processing operations, in which food items are briefly heated to modify texture and other sensory characteristics. Blanching of the fish meat before pickle preparationis done to stabilise the texture and salt added for flavour enhancement and antimicrobial action. In the present study, freshwater fish species pangas (Pangasianodon hypophthalmus) was selected for the manufacturing of fish pickles. Raw pangas fish strips were treated by four different blanching temperatures accordingly 950C, 1000C, 1100C, 1200C for 5 min with the different molar concentrations of salt solution like T1 (0 molar NaCl), T2 (0.5 molar NaCl), T3 (1 molar NaCl) and T4 (1.5 molar NaCl). The aim of this study is to standarize the blanching temperature with salt concentration which gives better texture and sensory properties in pickle. Considering the high loss in meat the blanching temperature of 110oC and 120 oC is concluded to be unsuitable for pangas strips. At higher concentrations of salt, T3 and T4 , the loss in yield significantly increased (p<0.05) for all blanching temperatures. T3 and T4 resulted in softening of the meat and the temperature of blanching further caused heat induced denaturation of protein resulting in lowering of hardness. Based on sensory evaluation all the values were within the sensory perception of “dislike slightly” and “neither like nor dislike” for T3 and T4 sample rendering the samples unacceptable. Among T1 and T2 salt treatments, T2 scored better than T1 . Within the T2 samples, it was observed that the pangas strips blanched at 1000C temperature had a better overall acceptability. Considering the significantly lower (p<0.05) yield of T2 samples at 1000C (-16.69±0.45%) in contrast to a yield of -5.95±0.08% at 950C, the T2 samples blanched at 950C in 0.5M of NaCl was chosen for preparation of pickle.