Agro-industrial by-products are processed materials that can have high protein content or other nutrients. The agro-industrial by-products are traditionally sold at low prices for animal feed consumption. These residues of the agro-industry have a high concentration of nutritional and bioactive compounds, which can be applied as fishmeal substitutes. In this chapter, it is shown how extrusion can be an alternative process for aquaculture feed production, increasing digestibility, and functional properties of the aquaculture feed, such as water stability and floatability. The thermal process during extrusion decreases the antinutritional factors present in legumes or other agro-industrial by-products, such as trypsin inhibitors and lectins. This chapter reviews research related to new protein sources that can potentially complement or substitute fishmeal for aquaculture feed. The use of bean (Phaseolus vulgaris) protein and cottonseed meal as a fishmeal substitute are shown, as well as the optimization of the extrusion process for aquaculture feed production. The incorporation of plant protein into the aquaculture production contributes to a more sustainable process. The effect of the extrusion parameters on the final product and quality are explained.
Part of the book: Extrusion of Metals, Polymers, and Food Products
The objective of this research was to evaluate the effect of the content of cottonseed meal (Gossypium hirsutum) and the processing variables on the functional properties and the content of gossypol of an extruded feed for sheep (Ovis aries). The diet was balanced according to the requirements of fattening Dorper sheep breed under 1 year. The extrusion process was optimized using a surface response methodology, with four independent variables: temperature in the last heating zone (120–160°C), moisture content (14–18%), screw speed (120 rpm–180 rpm), and cottonseed meal content (9 g–27 g 100 g−1), in a single screw extruder. The optimal food had 27.25% crude protein, 4.24% crude fat, 12.21% crude fiber, 46.95% nitrogen-free extract, and 9.35% ash. The composition of essential amino acids in the optimal diet was 1.00 g kg−1 of lysine, 1.25 g kg−1 of phenylalanine, 2.04 g kg−1 of leucine, 0.87 g kg−1 of isoleucine, 0.98 g kg−1 of threonine, 1.15 g kg−1 of valine, and 0.65 g kg−1 of histidine. The fatty acids present in the highest concentration in the optimal diet were 2.14% linoleic acid, 1.11% oleic acid, and 0.81% palmitic acid. The gossypol content of the optimal diet was less than 0.1%, which ensures the safety of cottonseed meal as a protein source. The optimum conditions of the extrusion process were 120°C temperature, 120 rpm screw speed, 14.00% humidity, and 27 g 100 g−1 cottonseed meal.
Part of the book: Cotton
Bismuth is one of the most difficult impurities to remove in mining concentrates and low concentrations generate problems in silver and copper refineries. Therefore, financial penalties are established when concentrations exceed 0.05%. Some researchers had used arsenic to remove bismuth with results of up to 52% of extraction. Unfortunately, this mechanism is not yet fully understood. The objective of this research was to obtain the solubility parameters of amorphous mineral compounds, including bismuth-based compounds, through computational simulation using molecular dynamics. The composition of the mineral sample was determined by X-ray diffraction and the crystalline species were obtained and modeled using Materials Studio software. The nanostructures were optimized by an energy minimization methodology using the Broyden-Fletcher-Goldfarb-Shanno algorithm and were validated using the figure of merit equation and density. Simulations were performed using the Universal Force Field at constant pressure and temperature. The results of the minerals identified in the sample were compared with arsenic trioxide, indicating miscibility between As2O3and Bi2O3, possible miscibility with 10 other minerals, and immiscibility with the rest. The results indicate that As2O3 can be successfully used for the removal of Bi2O3 without a negative effect on the recovery of other minerals of higher commercial value.
Part of the book: Rare Earth Elements