Standardization of Pasteurization Process for Soft- and Hard-Shell Blue Swimming Crab (Portunus pelagicus)

Abstract

Pasteurized hard-shell blue swimming crabs (Portunus pelagicus) are widely popular in the United States, while soft-shell crabs are rich in minerals and are often discarded as waste or sold at a substantially low price in the market. Pasteurization time-temperature is standardized for soft-shell crabs processed together with hard-shell crabs. This study was undertaken to develop a pasteurization process for soft-shell crabs together with hard-shell crabs. Precooking time and temperature evaluated for soft-shell crabs based on sensorial analysis yield and drip loss indicated that the heat process at 100°C for 5 min gave higher yield (82%) and lower drip loss (14%). Soft-shell crabs were processed together with hard-shell crabs at three different ratios, viz., 30 : 70, 40 : 60, and 50 : 50. The pasteurization process was employed at seven time-temperature combinations, viz., 83-84°C for 150 min and 160 min, 84-85°C for 140 and 150 min, 85-86°C for 130 min and 140 min, and 86-87°C for 120 min. Crabs processed at a 30 : 70 ratio had a higher sensory score (4.95), and pasteurization at 83-84°C for 150 yielded the best quality product. The total process time ( F value) determined by the heat penetration study was 58.25 min. Shelf-life stability studies revealed that TVB-N values were higher in those processed at a 50 : 50 ratio and process temperatures greater than 83-84°C but never exceeded in those processed at a 30 : 70 ratio, the permissible limit. Total aerobic bacteria remained low for 1 to 2 log cfu/g correlating well with sensory analysis. Soft-shell crabs can therefore be processed together with hard-shell crabs at a ratio of 30 : 70 and pasteurized at 83-84°C for 150 min with a shelf-fish of 6 months at 2°C without any loss in quality. The standardized process will enable crab processors to use soft-shell crab meat in addition to hard-shell crab meat, which is currently discarded.