Agricultural and Biosystems Engineering Publications

Document Type

Article

Publication Date

2013

Journal or Book Title

Journal of Food Research

Volume

2

Issue

2

First Page

11

Last Page

28

Research Focus Area(s)

Biological and Process Engineering and Technology

DOI

10.5539/jfr.v2n2p11

Abstract

A single-screw laboratory extruder was used to conduct an L18 (22´ 36) Taguchi fractional factorial study of aquafeed processing. The ingredients were based on a formulation for nutritionally-balanced Nile tilapia diets containing distillers dried grains with solubles (DDGS) and soybean meal as the main protein sources, in addition to constant amounts of corn flour, whey, and fishmeal. The effects of three levels of DDGS (20, 30 and 40%), soybean meal (30, 40 and 50%), ingredient moisture content (20, 30 and 40% db), screw speed (100, 150 and 200 rpm), die dimension (L/D ratios of 5, 9 and 13), barrel temperature (80-100-100°C, 80-120-120°C and 80-140-140°C) and two levels of screw configuration (compression ratios of 2:1 and 3:1) on extrudate physical properties (moisture content, water activity, bulk density, unit density, expansion ratio, pellet durability index, water absorption and solubility indices, water stability, color) and extruder processing parameters (resulting temperatures, die pressure, extruder torque, mass flow rate, apparent viscosity, and specific mechanical energy) were determined. Data from raw materials, processing conditions, and extrudate properties were used to develop surface response curves and equations. However, predominantly low R2values (< 0.5) only permitted linear relationships between some independent parameters and response variables. Regarding main effects, die pressure significantly decreased with higher DDGS levels, moisture content, temperature, lower die L/D, and higher screw compression. Expansion ratio decreased significantly with higher moisture content and lower die L/D. Significant differences in color were caused by changes in DDGS levels and moisture content. In summary, DDGS, moisture content, die dimension, and extrusion conditions had the biggest impact on most of the extrudate physical properties and processing conditions. Different combinations of these independent factors can be used to achieve desired extrudate physical properties and processing conditions.

Comments

This article is from Journal of Food Research 2, no. 2 (2013): 11–28, doi:10.5539/jfr.v2n2p11.

Rights

This work is licensed under a Creative Commons Attribution 3.0 License.

Copyright Owner

Canadian Center of Science and Education

Language

en

Date Available

2013-09-06

File Format

application/pdf

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