Single screw extrusion processing of white flakes and soybean meal based feed for Nile tilapia (Oreochromis niloticus) | |
| Author | Khanal, Jyotsna Shresths |
| Call Number | AIT Thesis no.FB-12-19 |
| Subject(s) | Soybean meal as feed Nile tilapia--Feeding and feeds |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. no.FB-12-19 |
| Abstract | The rapid expansion of aquaculture has increased the demand for aquafeed. As fishmeal is expensive, alternative plant based protein sources such as soybean has shown to be a good alternative for aquafeed production. The present study was done to investigate the use of soy products-white flakes (WF) and soybean meal (SBM) fordeveloping feed for Nile tilapia (Oreochromis niloticus) using single screw extruder. Three extrusion studies were done with blends containing white flakes, soybean meal, corn flour, corn gluten meal, fish meal, soybean oil, and vitamin and mineral premixin varying proportion. The feed parameters includedweremoisture content (MC, 20 to 40%db), WF (20 to 40%db) and SBM (20 to 40%db). The extruder parameter included extruder processing temperature (120 to 160°C). The effect of feed composition (ingredients and moisture level) and extruder temperature on the physical properties of the extrudates, extruders processing parameters and trypsin inhibitor activity (TIA, mg/g DM-1) were studied. The processing parameters examined were mass flow rate (MFR, g/min), die pressure (MPa), extruder torque (Nm) and specific mechanical energy (SME, J/g). The physical properties of the extrudates analysed were expansion ratio (ER), unit density (UD, kg/m3), bulk density (BD, kg/m3), hardness (N), pellet durability index (PDI, %), water absorption index (WAI), water solubility index (WSI, %), color (L*, a* and b*) and angle of repose (AoR).The first study was conducted to analyse the effect of WF content (20, 30 and 40%db), extruder temperature (120, 140 and 160°C) and feed MC (20, 30 and 40%db) on extrudate properties of different soy-based blends and processing parameters. The extrudate properties were determined before and after oil coating. For both oil-coated and uncoated extrudate, theMChad significant effect on ER, UD and BD. The increase in MC (20 to 40%) increased UD and BD by 20.3% and 13.2% respectively and decreased ER by 14.2% for uncoated extrudate. The UD, BD, hardnessand AoRshowed significant increase with the increase in temperature from120 to 140°C. The feed MC had significant effect on both WAI and WSI of extrudates. The change in WF content affected only few of the properties like UD and WAI. Oil coating had significant effect on UD,PDI, WAI, WSI and color (L*,a*and b*); PDI was improved. The change in moisture level from 20 to 40% decreased the values of processing parameters studied. The increase in temperature from 120 to 160°C decreased the pressure and torque values. TIA of extrudates showed significant reduction by 56.8 to74.7% with increase in processing temperature from 120 to 160°C. All extrudates had low TIA (<0.1mg/g DM-1). All the blends produced extrudates with good floating characteristics and water stability.In the second study, response surface methodology was used to find the effect of WF (20-40%db), MC (20-40%db) and extruder temperature (120 to 140°C) on the physical properties of extrudates using single screw extruder. Response surface models were developed for each property. Response surface plots were used to see the effect of two independent variables by keeping third one at mid-level. Most of the properties of WF based feed were best represented by quadratic models. |
| Year | 2012 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no.FB-12-19 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Athapol Noomhorm;Muthukumarappan, Kasiviswanathan; |
| Examination Committee(s) | Rakshit, Sudip Kumar;Anal, Anil K.; |
| Scholarship Donor(s) | Joint Japan/World Bank Graduate Scholarship Program (JJ/WBGSP); |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2012 |