Abstract:

Two variable-retort-temperature (VRT) sterilization processes were presented according to the constant-retorttemperature
(CRT) process with F0 = 20 min and the two VRT processes were compared with the CRT process. The heating
histories of the retorts and cool points were plotted and analyzed. The results showed that the three methods had the same
F0 value but different combinations of temperature and time. Compared with the CRT process, the better VRT process
(105 ℃-115 ℃-120 ℃-125 ℃ for 2.5 min at each temperature) resulted in 22.8%, 6.9% and 20.5% increases in the
hardness, springiness and cohesiveness of skipjack meat and 29.41%, 48.13% and 20.14% decreases in turbidity and crude
protein content of the broth, respectively. The muscle tissue of skipjack was less disintegrated by the VRT sterilization
processes, as shown by observation of the cross-sectional microstructure of muscle. All these results showed that the
variable-retort-temperature sterilization processes could reduce the quality loss of canned skipjack compared with the
constant-retort-temperature process.

Key words: canned skipjack, variable-retort-temperature sterilization process, quality, texture profile analysis, total volatile basic nitrogen