Optimization of extruder cooking conditions for the manufacture of fish feeds using response surface methodology

Abstract A composite blend consisting of sunflower cake, maize germ, wheat bran, fresh water shrimps and cassava flour was extruded using a single‐screw extruder to produce expanded fish feed pellets. The effects of temperature (80–120 °C), die diameter (2–4 mm), and feed pre‐conditioning time (50–150 s; steam 400 kPa) on properties of the pellets (expansion ratio, bulk density, floatability, durability, water absorption, water solubility, water stability, and in‐vitro protein digestibility) were investigated using response surface methodology. Regression equations describing the effect of each variable on the product responses were obtained. The pellets extruded using a factor combination of 120 °C extruder barrel temperature, 2 mm die diameter, and 100 s of feed pre‐conditioning time gave most desirable pellet floatability (100%), durability index (99%), expansion ratio (2.64), water absorption index (4.12), water solubility index (9.31), water stability (87%), bulk density (479 g/L), and in vitro protein digestibility (69.97%) with a composite desirability of 0.88. Practical applications Extrusion is a modern feed processing method whose use is fast gaining popularity among small feed processors in developing countries. However, extrusion is a process that involves many parameters that need to be optimized for desirable end properties. These findings guide fish feed manufacturers on the optimum conditions for single screw extruders for production of feeds with desirable properties especially for the fish types that are top feeders. In addition, the results offer important insights on how temperature, die diameter, and feed pre‐conditioning, may be manipulated to influence properties of extruded aquafeed when using simple low‐cost small‐scale extruders

Speech characteristics after articulation therapy in children with cleft palate and velopharyngeal dysfunction - A single case experimental design

Objective: The aim of this study was to investigate the impact of an intensive 10-week course of articulation therapy on articulation errors in cleft lip and palate patients who have Velopharyngeal Insufficiency (VPI), non-oral and passive cleft speech characteristics. Methods: Five children with cleft palate (+/-cleft lip) with VPI and non-oral and passive cleft speech characteristics underwent 40 intensive articulation therapies over 10 weeks in a single case experimental design. The percentage of non-oral CSCs (NCSCs), passive CSCs (PCSCs), stimulable consonants (SC), correct consonants in word imitation (CCI), and correct consonants in picture naming (CCN) were captured at baseline, during intervention and in follow up phases. Visual analysis and two effect size indexes of Percentage of Nonoverlapping Data and Percentage of Improvement Rate Difference were analyzed. Results: Articulation therapy resulted in visible decrease in NCSCs for all 5 participants across the intervention phases. Intervention was effective in changing percentage of passive CSCs in two different ways; it reduced the PCSCs in three cases and resulted in an increase in PCSCs in the other two cases. This was interpreted as intervention having changed the non-oral CSCs to consonants produced within the oral cavity but with passive characteristics affecting manner of production including weakness, nasalized plosives and nasal realizations of plosives and fricatives. Percent SC increased throughout the intervention period in all five patients. All participants demonstrated an increase in percentage of CCI and CCN suggesting an increase in the consonant inventory. Follow-up data showed that all the subjects were able to maintain their ability to articulate learned phonemes correctly even after a 4-week break from intervention. Conclusion: This single case experimental study supports the hypothesis that speech intervention in patients with VPI can result in an improvement in oral placements and passive CSCs. © 2016 Elsevier Ireland Ltd