abstract
In this study, tilapia samples stored at 5 C, 10 C, and 15 C for 64 days were investigated to
establish effective quality evaluation methods based on microstructure changes during storage. The
porous microstructure of the fish muscle in frozen storage was obtained in optical micrographs and
quantified using fractal dimension method. The relationships were determined between fractal
dimension and traditional freshness parameter, including electrical conductivity, water activity, and total
volatile basic nitrogen. Moreover, variations in fractal dimension during storage were fitted by a firstorder
kinetics equation, and the shelf-life of tilapia was predicted through this equation. As a result,
the fractal dimension was 1.9548 at initial time, and then it showed a decreased trend with the
microstructure change in muscle tissue during storage. The correlations between fractal dimension and
traditional freshness parameters were within ±0.98, and the first-order kinetics equation of fractal
dimension was obtained as dt ¼ 1.9548 exp (1.00581 104 t exp (12.1657/T)). According to this
equation, the prediction errors of tilapia shelf-life at different temperature were within ±8.2%. The results
indicate that fractal dimension can be used as a feasible approach to evaluate the freshness of tilapia
in frozen storage.
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