Product development of pasteurized ready-to-cook marinated white shrimp Litopenaeus vannamei in green curry paste

Abstract

The first part of this research aimed to study the effect of treated shrimp using 2% NaCl in combination with three additives: sodium tri-polyphosphate (STPP), sodium bicarbonate (NaHCO3) and microbial transglutaminase (MTGase) at different concentrations (2, 5 and 8%) and immersion times (10, 30 and 60 minutes) on the quality of white shrimp (Litopenaeus vannamei). In average, the three additives with 2% NaCl significantly affected the water holding capacity (WHC), cooking loss (CL), weight gain (WG), moisture content (MC) and total viable count (TVC) of white shrimps. Immersions in 5% MTGase with 2% NaCl for 30 minutes at 4±2°C improved the quality of white shrimp when compared with control. It increased weight gain (15.7%), maximizes WHC up to 94.5%, lowered CL to 10.1% and reduced 1.44 log CFU/g of total viable count (TVC). The second part studied the effects of pasteurization on marinated shrimp in green curry paste at 5 conditions (T1) 65°C for 32.5 minutes, (T2) 67°C for 18.5 minutes, (T3) 68°C for 17 minutes, (T4) 69°C for 7 minutes, (T5) 70°C for 7 minutes in comparison with the control (non-pasteurized) sample. TVC of pasteurized marinated shrimp (T1 to T5) was lower than 10 CFU/g and Listeria spp. was not detected in 25g sample, while the TVC for control was 3.67 log CFU/g and Listeria spp. was 1.18 log CFU/g. The pH value of pasteurized marinated shrimp (T1 to T5) was significantly lower than the non-pasteurized marinated shrimp. The shear force for samples pasteurized at T3, T4 and T5 was not significantly different from control. Sensory evaluation result showed that the highest score for overall acceptability was 5.75 for the product pasteurized at 70°C for 7 minutes (T5). Treatment 5 (70°C for 7 minutes) was selected to prepare pasteurized sample for the shelf life study. From shelf life study, the pasteurized marinated shrimp in green curry paste was safe for consumption until the end of storage period for 15 days at 0-3°C. There was no significant difference between pasteurized products stored at 0-3°C with freshly prepared product up to 15 days for all attributes that were sensorial tested.