Abstract:

A new type of variable-temperature sterilization process was applied to canned bighead carp to explore the
effect on product quality. The process was composed of exponential functions and stepped functions, and canned bighead
carp was sterilized by using the variable-temperature profile. The temperature curves were measured to verify the
model. The textural properties of canned fish sterilized under optimize conditions, the microstructure of fish muscle,
cooking loss, and total protein and soluble collagen content in exudates were determined to evaluate the constant retort
temperature profile for the sterilization of products. The results showed that the temperature curves in retort had
a strong correlation with experimental values (R2 = 0.978). Compared with the samples sterilized by optimal constant
retort temperature profile, the hardness and springiness of fish muscle of those sterilized by optimal variable temperature
profile were increased by 16.0% and 7.6%, respectively, and endomysium was less disintegrated, as shown by
observing the cross-sectional microstructure of muscle. Cooking loss, soluble collagen protein content of the samples
sterilized by optimal variable temperature profile decreased by 17.6%, 9.4% and 7.6%, respectively, and less overcooked
flavor was observed, accompanied by better sensory characteristics. This study suggests that the variable retort
temperature profile can significantly improve the quality of bighead carp packaged in retort pouches and therefore has
great application value.

Key words: variable retort temperature sterilization, bighead carp, canned foods, quality, texture, flavor