Extrusion of Maize-Cowpea Blends in a Modified Oil Expeller

✍ Scribed by Sefa-Dedeh, S; Saalia, F K

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 1003 KB
• Volume: 73
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199702)73:2<160::aid-jsfa683>3.0.co;2-u

✦ Synopsis

A laboratory oil expeller was modiÐed by using a press cylinder without openings for expelling the oil. Central composite rotatable design for k \ 3 was used to study the e †ects of process variables, cowpea level (0È25%), feed moisture (10È25%) and barrel temperature (130È200¡C) on product indices (moisture, expansion index, bulk density, water absorption, extractable solids, swell volume and the degree of gelatinisation of Ñour from the extrudate). Regression models developed to predict product indices were signiÐcant and showed no signiÐcant lack of Ðt. The model for moisture content of the extrudate had an R2 of 0É98. Product moisture was inÑuenced by the amount of cowpea in the feed, the temperature of extrusion and feed moisture. Furthermore, the product moisture measured at each cowpea level was dependent on the temperature of extrusion. The model for product expansion index showed that this index decreased with feed moisture and the cowpea level. Regression models for bulk density, water absorption, extractable solids and the maximum swell volume of Ñour from the extrudate were inÑuenced by the process variables. The degree of gelatinisation decreased with cowpea level and increased with extrusion temperature.