부산대학교 도서관

In this work, sardine fish was processed in a hydraulic press in order to obtain a solid cake and a press juice presenting solid, aqueous, and oil phases. The influence of pressing conditions, such as total pressure (50-350 bar), compression speed (0.935-3.135 cm/min), number of pressing stages (1-5), and time of relaxation between two consecutive pressing stages (100-300 s), was studied following a rotatable central composite design. Response surface methodology was used to relate the yields of each phase with the operation parameters. According to the regression equations, the content of solids in the press liquor was markedly affected by the target pressure, attaining a maximal yield at 350 bar (0.028 g solids/g sardine). The yield of both liquid phases was maximum after an intensive compacting treatment comprising five pressing steps at the highest compression speed. Under these conditions, the maximum yield of oil was achieved after 100 s of time of relaxation (0.021 g oil/g sardine), while longer times of relaxation increased the amount of blood water and solids in the press liquor to the detriment of the oily phase. [ABSTRACT FROM AUTHOR]