June, 2015 AgricEngInt: CIGR Journal Open access at http://www.cigrjournal.org Vol. 17, No. 2 151 Optimization of extrusion point pressure of pineapple pomace based mash Oduntan, O. B., A. I. Bamgboye (Department of Agricultural and Environmental Engineering, University of Ibadan, Ibadan. Nigeria) Abstract: The effect of pre-processing conditions such as heating temperature (60°C, 80°C, 100°C, and 120°C), 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. Response surface method was applied to optimize the operating variables. 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. The optimum conditions for the extrusion point pressure were 100°C temperature; 4 mm 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) was significant (p < 0.05) on extrusion point pressure. Keywords: temperature, moisture content, die size, pomace ratio, optimize Citation: Oduntan, O. B., and A. I.Bamgboye. 2015. Optimization of extrusion point pressure of pineapple pomace based mash. AgricEngInt: CIGR Journal, 17(2):151-159. 1 Introduction Pineapple (Ananascomosus) is one of the commercially important fruit crops in the world; with the total annual world production of 14.6 million tonnes of fruits (Heuze et al, 2013). Thailand is the largest producer, accounting for 16 percent of global output, followed by the Philippines (12%) and Brazil (10%). Nigeria produced about six per cent out of the total 14.220 metric tonnes world production of pineapple in 2010, taking the lead as the highest producer in Africa (Heuze et al, 2013). Although only a third of its output is utilized for processing and the rest are consumed fresh. Commercial processing of pineapple into fruit juice is becoming popular in Africa producing countries, especially in Nigeria. They are now building capacity for local processing in order to increase obtainable revenue from Received date: 2014-03-27 Accepted date: 2015-03-29 *Corresponding author: Anisur Rahman, Department of Farm Power and Machinery, Bangladesh Agricultural University, Mymensingh, Bangladesh. Email: anis_fpm@bau.edu.bd. pineapple when it is exported as processed fruit juice. The increased production in Nigerian has led to an increased agro-industrial residue production. These residues known as pomace constitute a heterogeneous mixture of husks and skins and account for the 34.7% of the whole fruit mass constituting disposal problems. However, there is a great interest in utilizing this biomass as a source of feed ingredient for feeding to livestock (Mantovaniet al., 2004; Rogérioet al., 2007). Pomace generated at the fruit juice industries has increased from negligible amounts to almost 300 tons per week (Olosunde, 2010). Disposal of this solid waste become more difficult as the growth of the industry continues. Azevêdo et al., (2011) reported that pomace were found to have a higher energy value than maize silage and were able to partly replace energy concentrates in diets for ruminants Previous research works on pomace extrusion were focused on groundnut, cassava, carrot (Fasina 2008; Kumar et al., 2010: Oduntanet al., 2012). Pellet is