| Resumo: |
The effect of pre-processing conditions such as heating temperature (60, 80, 100, and 120oC), moisture content (50, 55, and 60%), die size (4, 6 and 8 mm) and pomace ratio (5:1, 6:1 and 7:1) on the extrusion point pressure of pineapple pomace based mash were investigated using a laboratory press. Pineapple pomace flour was produced by drying and grinding fresh pomace from a juice processing plant. The flour was mixed with cassava flour and water at different blend ratio to form mash of different moisture contents. Experimental extrusion point pressure varied from 6.09 to 8.69MPa with an average value of 7.51MPa. Temperature, die sizes and pomace ratio significantly influenced (P < 0.05) extrusion point pressure. Significant regression models were established with the coefficient of determination, R2 greater than 0.72. Response surface method (RSM) was applied to optimize the operating variables. Quadratic models developed for the response studied indicated the optimum conditions for the extrusion point pressure were 100oC of temperature; 4mm die size, 55% moisture content and 6:1 pomace ratio at maximum desirability of 1:00 The effect of preprocessing conditions (temperature, die size, moisture content and pomace ratio) were significant (P < 0.05) on extrusion point pressure.
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