Effect of low-temperature and long-time heat processing on digestion and absorption properties of sea cucumber body wall protein.

Fresh sea cucumber was processed at low temperature (60 °C and 80 °C) for different times (0 h, 1 h, 3 h, 6 h, 12 h, 24 h and 48 h). Combined with simulatior in vitro digestion and everted-rat-gut-sac model, the changes of protein in the body wall of sea cucumber (SCBWs), including oxidation rule, aggregation degree, sur- face hydrophobicity, etc, were studied. The results showed that during the whole process of heat processing, the carbonyl content increased gradually, the free sulfhydryl content decreased gradually, and the degree of protein oxi- dation showed a sequential increase. With the intensification of the degree of heat processing (underworking-moder- ate-excessive heat processing), the protein aggregation degree first decreased, then increased and then decreased, the surface hydrophobicity first increased and then decreased and then increased, and the mean protein particle size first increased and then decreased. After simulation in vitro digestion and everted-rat-gut-sac model, the degree of protein hydrolysis, in vitro digestibility and peptide transport levels were firstly increased, then decreased and then increased with the intensification of heat processing degree. In conclusion, the in vitro digestibility of SCBWs protein was the highest and the absorption characteristics were better when it was heat processed at 60 °C for 3 h. The digestion and absorption characteristics of SCBWs protein were improved when the thermal treatment time was more than 6 h at 80 °C. [ABSTRACT FROM AUTHOR]