Properties of extruded expandable breadfruit products

It is vital to process breadfruit in order to develop new value-added products with improved sensory and physicochemical characteristics. In this research, dried breadfruit was extruded with a twin screw extruder and effects of barrel temperature, moisture content, feeding rate and screw speed on product physicochemical properties and process energy consumption were studied. Quadratic models were obtained to predict the product quality under various processing conditions. The best range of crispness of the extrudate was from 2.0 to 3.5N/s, hardness from 60 to 75 N and bulk density from 0.3 to 0.38 g/cm³. Corresponding operating conditions of feeding rate, temperature, screw speed and moisture content to obtain best results of crispness, hardness and bulk density were 16 kg/h, 130 °C, 160 rpm, 22 g/100 g; 22 kg/h, 150 °C, 160rpm, 22 g/kg; 19 kg/h, 140 °C, 115 rpm, 19 g/100 g; and 25 kg/h, 140 °C, 145 rpm, 19 g/100 g, respectively. The linear term of screw speed significantly effected all indexes (p < 0.001), especially water absorption and solubility indexes, sectional expansion ratio, bulk density, color and specific mechanical energy. The interaction term of feed rate and temperature, and square term of screw speed had no significant influences (p ≥ 0.1). The findings were useful for developing and optimizing extruded or value-added co products of breadfruit.