: Sardine in oil was canned at 3 different Lethality values (F0 5,7, and 9) in retort pouches and aluminum cans in stationary retort. Process time calculations were done mathematically to find out the actual process time. Sardine in oil processed in retort pouches had a lower process time compared with aluminum cans for each F0 value. Instrumental texture analysis was done using a food texture analyzer to study the effect of thermal processing on the texture of thermally processed sardine in oil in aluminum cans and retort pouches. As the F0 value and cook value increased in both the retort pouches and aluminum cans, the textural properties showed a decreasing trend. Hardness of the product canned in both aluminum cans and retort pouches decreased with increase in F0 values.

Constant stress compression creep tests were conducted on 8-mol%-yttria-stabilized cubic-zirconia (8YCZ) over stress (), temperature, and grain-size ranges from ϳ20 to 300 MPa, 1673 to 1773 K, and 4 to 8 m, respectively. Creep data were analyzed in terms of the relationship ؔ n , where is the strain rate and n the stress exponent. Although the experimental data yielded a stress exponent of n Ϸ 2, analysis of the results with compensation of significant concurrent grain growth revealed that the true stress exponent was n Ϸ 1. The results were consistent with deformation by the Coble creep mechanism. Experiments at stresses greater than ϳ100 MPa revealed a transition from grain-size-dependent Coble diffusion creep to grain-size-independent intragranular dislocation creep.

Tuna in oil was processed in retort pouches (20 · 17 cm) to a, F 0 value of 10. Heat penetration characteristics were determined using a rotary retort to an F 0 value of 10 and the results compared with a stationary retort. For studying the changes in heat penetration during rotation, tuna in oil was packed into retort pouches, subjected to different rotation speeds (2, 4 and 6 r.p.m.) and thermally processed to the same F 0 value. For the same F 0 value of 10, although there was a reduction in process time with increasing rotation speed up to 6 r.p.m., the magnitude of the reduction in processing time decreased with increase in speed of rotation. However up to 2 r.p.m. there was a considerable reduction in process time.

This study was conducted to standardize the optimum processing condition for thermal processing of mackerel in refined groundnut oil in aluminum cans. The standardization of the product was carried out in still retort at 121.1C at three different Fo (accumulated lethality) values, i.e., 5, 7 and 9. The total process times required to reach the Fovalues 5, 7 and 9 were 34.06, 41.29 and 45.09 min, respectively. The Fo9 was selected for further rotation studies based on sensory analysis and sterility test. Rotation was carried out at 2, 4 and 6 rpm and resulted in the reduction in the process time to 42.08, 41.38 and 38.22 min, respectively, for the same lethality compared to 45.09 min in stationary retort. The cook value also reduced with increase in the rotational speed. PRACTICAL APPLICATIONS The present work was carried out to standardize the optimum thermal processing parameters for mackerel in oil medium in aluminum cans and to study the effect of rotation on process time. The standardization of process parameters will help the processors to directly implement in commercial retort operation. The longer duration of thermal processing leads to the deterioration of product quality. Reductions in process time will have an advantageous effect on the sensory and nutritional qualities of thermally processed fish products. The reduction of process time can be achieved by rotating the content of canned product during processing. In rotational study, it has been observed that the total process time could be reduced to 6 min compared to the stationary retort sterilization process at a given temperature and Fo value. This will help the processes to minimize the energy consumption for thermal processing and to produce better quality products.

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