Physical and Chemical Processes to Enhance Oil Recovery from Condensed Corn Distillers Solubles

The first stage of refining of post-fermentation corn oil with a high content of free fatty acids and phytosterols - Comparison of neutralisation by an ion-exchange resin without solvent and base neutralisation

Post-fermentation crude corn oil obtained as a by-product in the production of bioethanol from maize grains is characterized by a very high content of free fatty acids. Refining of post-fermentation corn oil will give a product that will be different from the refined oil obtained by extracting oil from corn germs. From the point of view of refining vegetable oils, the neutralisation of this oil is the most important process. Anionic ion-exchange resin was used in the research in a way to avoid the use of harmful organic solvents and a comparatively standard method of neutralising free fatty acids based on the use of a sodium hydroxide solution. Ion-exchange resin can be used in the processes of neutralising vegetable oil with an average content of free fatty acids, then the oil is neutralised in miscela. In the research, no organic solvent was used, but to reduce the flow resistance, a system based on an adjustable reduced pressure in the range of 300-50 mbar was used, to maintain a constant contact time of the oil with the resin in each cycle. The aim of the research was to obtain neutral oil with a high content of biologically active substances such as phytosterols and carotenoids. Both methods showed a reduction of free fatty acids up to 93-96 % and a similar refining loss of 18-19 %. The use of an ion-exchange resin allowed to obtain an oil in which the phytosterol content increased by 5 % for β-sitosterol, by 6.3 % for ϭ5-avenasterol, and the carotenoid content was reduced by 35 %. An increase in the number of fatty acids, such as 18:1 cis-oleic acid and 18:2 cis-linoleic, was observed.

Oil Recovery from Fractionated Dried Distillers Grains with Solubles (DDGS) Using Enzymes

Oil recovered from dried distillers grain with solubles (DDGS) can be a high-value product over animal feed to provide an additional profit to ethanol plants currently operating at slim profit margins. Fractionations of DDGS and enzymatic hydrolysis were considered in this study to improve the oil recovery from DDGS. A combination of sieving and then air aspiration was used to separate the original DDGS into three different fractions: light, medium, and heavy. The heavier fraction had up to 24% increased oil content compared to the original DDGS. Commercial enzymes, protease, cellulase, and hemicellulase were tested separately and in combinations at 55 °C for 3 h at 130 rpm to determine their effect on oil recovery from the original and fractionated DDGS. Oil recovery was significantly improved (around 20%) following enzyme hydrolysis of the sieved aspirated heavy fractions of DDGS compared to the original DDGS. More than 90% of oil recovery was achieved by using a combination of cellulase and protease enzymes. Increasing the temperature above 55 °C without any enzyme did not impact oil recovery using the heavy-fraction DDGS. Overall, fractionation and enzymatic hydrolysis showed promise to increase oil recovery from DDGS without any current ethanol plant design changes.

Protein Polymer-Based Nanoparticles: Fabrication and Medical Applications

Nanoparticles are particles that range in size from about 1⁻1000 nanometers in diameter, about one thousand times smaller than the average cell in a human body. Their small size, flexible fabrication, and high surface-area-to-volume ratio make them ideal systems for drug delivery. Nanoparticles can be made from a variety of materials including metals, polysaccharides, and proteins. Biological protein-based nanoparticles such as silk, keratin, collagen, elastin, corn zein, and soy protein-based nanoparticles are advantageous in having biodegradability, bioavailability, and relatively low cost. Many protein nanoparticles are easy to process and can be modified to achieve desired specifications such as size, morphology, and weight. Protein nanoparticles are used in a variety of settings and are replacing many materials that are not biocompatible and have a negative impact on the environment. Here we attempt to review the literature pertaining to protein-based nanoparticles with a focus on their application in drug delivery and biomedical fields. Additional detail on governing nanoparticle parameters, specific protein nanoparticle applications, and fabrication methods are also provided.

The effect of regular or reduced-fat distillers grains with solubles on rumen methanogenesis and the rumen bacterial community

AIMS

The effect of feeding dried distillers grains with solubles (DDGS) or reduced-fat DDGS (RFDG) on ruminal methanogenesis and the rumen bacterial community of dairy cattle was evaluated.

METHODS AND RESULTS

Treatments were CONT, a diet with no distillers grains; DG, inclusion of 20% DDGS; rfDG, inclusion of 20% RFDG; and MIX, inclusion of 10% DDGS and 10% RFDG. Methane emission was measured; rumen bacterial community was evaluated by sequencing the V4 region of the 16S rRNA gene. Total methane production remained unaffected. However, feeding distillers grains tended to reduce methanogenesis per unit of feed intake, decreased the abundance of the phylum Bacteroidetes and tended to increase Firmicutes. The abundance of Prevotellaceae positively correlated with feed intake; methane emission was positively correlated with the abundance of Prevotellaceae and was negatively correlated with the abundance of Succinivibrionaceae.

CONCLUSIONS

DDGS or RFDG may reduce methanogenesis per unit of feed intake; shifts in the abundance of predominant ruminal bacterial families may influence methane formation, likely because of their role on hydrogen liberation and utilization pathways.

SIGNIFICANCE AND IMPACT OF THE STUDY

Replacing corn and soybean meal with DDGS or RFDG in dairy rations may reduce the proportion of dietary energy wasted as methane, without detrimental effects on the overall bacterial population.

Methods to recover value-added coproducts from dry grind processing of grains into fuel ethanol

Three methods are described to fractionate condensed distillers solubles (CDS) into several new coproducts, including a protein-mineral fraction and a glycerol fraction by a chemical method; a protein fraction, an oil fraction and a glycerol-mineral fraction by a physical method; or a protein fraction, an oil fraction, a mineral fraction, and a glycerol fraction by a physicochemical method. Processing factors (ethanol concentration and centrifuge force) were also investigated. Results show that the three methods separated CDS into different fractions, with each fraction enriched with one or more of the five components (protein, oil, ash, glycerol and other carbohydrates) and thus having different targeted end uses. Furthermore, because glycerol, a hygroscopic substance, was mostly shifted to the glycerol or glycerol-mineral fraction, the other fractions had much faster moisture reduction rates than CDS upon drying in a forced air oven at 60 °C. Thus, these methods could effectively solve the dewatering problem of CDS, allowing elimination of the current industrial practice of blending distiller wet grains with CDS for drying together and production of distiller dried grains as a standalone coproduct in addition to a few new fractions.