Effects of Superheated Steam Pretreatment on Muscle Release and Meat Quality of Shucked Tropical Oyster (Crassostrea iredalei)

Abstract

Abstract Superheated steam (SS) is promising for thermal shucking application of oysters due to its high energy. Tropical oysters Crassostrea iredalei was probed with K-type thermocouples connected to a datalogger to monitor and record process temperatures during superheated steam pretreatment at different temperatures (170, 210, and 250 °C) and holding time (4, 5, 6 min) followed by rapid ice immersion. The combination of heating and rapid chilling on the release of oyster meat during shucking were evaluated for muscle relaxation, muscle release, meat quality, texture profile analysis, and color and optimized for maximum muscle release and meat quality. The thermal profiles of SS reveled rapid temperature increment of both muscle and oyster shell compared to conventional steam, resulting in increased relaxation of adductor muscles and degree of meat release with increase in temperature and time Texture of the oyster meat retained hardness, gumminess and chewiness of the fresh oyster at low superheated steam temperature and short exposure time. Sufficient meat detachment of more than 85% was achieved at 170 °C and 5 min with minimum meat quality changes which also lower in microbial load (4.1 x 103 CFU/g), TVB-N (11.7 mg/100 g) and final pH reduction (0.3) compared to untreated [microbial load (5.2 x 103 CFU/g), TVB-N (15.7 mg/100 g), pH reduction (0.6)] and microwave treated [microbial load (4.3 x 103 CFU/g), TVB-N (21.0 mg/100 g), pH reduction (0.5)] samples. In sum, SS is potential to minimize oysters shucking time and prolonged shelf life of shucked oysters without compromising meat quality.