Publications by authors named "Kurt A Rosentrater"

19 Publications

  • Page 1 of 1

Effects of different levels of vitamin B in tank water on the Nile tilapia (Oreochromis niloticus): growth performance, blood biochemical parameters, intestine and liver histology, and intestinal enzyme activity.

Fish Physiol Biochem 2020 Dec 26;46(6):1909-1920. Epub 2020 Jun 26.

Fisheries Department, Natural Resources Faculty, University of Tehran, Karaj, Iran.

According to the importance of vitamin B (pyridoxine) as a water-soluble vitamin on the physiological conditions of aquatic animals, the present study aimed to investigate effects of different concentrations of this vitamin in recycle system culture water on the Nile tilapia (Oreochromis niloticus). Treatments including 0 (control), 10, 20, 30, and 40 mg L vitamin B were adjusted in triplicate recirculating systems. Each of the experimental tanks (100 L) was stocked 15 fingerling Nile tilapia during 60-day experimental period. According to the findings, weight gain in treatments of 30 and 40 mg L pyridoxine was significantly higher than the other treatments while blood cortisol hormone in the treatment of 40 mg L was significantly highest among the treatments. In addition, mid-intestine trypsin activity in the treatment of 40 mg L was significantly higher than the other treatments. The histological analysis of the intestine showed that the number of mucus-secreting cells significantly decreased in treatments of 30 and 40 mg L. Our findings here suggest that pyridoxine can possibly be absorbed by the Nile tilapia's body through culture water and it seems 20-30 mg L pyridoxine in the culture water is the optimal concentration for the Nile tilapia juveniles in recycle system culture.
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http://dx.doi.org/10.1007/s10695-020-00840-6DOI Listing
December 2020

Economic Assessment of Bioethanol Recovery Using Membrane Distillation for Food Waste Fermentation.

Bioengineering (Basel) 2020 Feb 11;7(1). Epub 2020 Feb 11.

Agricultural & Biosystems Engineering Department, Iowa State University, Elings Hall, Ames, IA 50011, USA.

Ethanol is a material that has a high demand from different industries such as fuel, beverages, and other industrial applications. Commonly, ethanol has been produced from yeast fermentation using sugar crops as a feedstock. However, food waste (FW) was found to be one of the promising resources to produce ethanol because it contained a higher amount of glucose. Generally, column distillation has been used to separate ethanol from the fermentation broth, but this operation is considered an energy-intensive process. On the contrary, membrane distillation is expected to be more practical and cost-effective because of its lower energy requirement. Therefore, this study aims to make a comparison of economic performance on FW fermentation with membrane distillation and a conventional distillation system using techno-economy analysis (TEA) method. A commercial-scale FW fermentation plant was modeled using SuperPro Designer V9.0 Modeling. Discounted cash flow analysis was employed to determine ethanol minimum selling price (MSP) for both distillation systems at 10% of the internal rate of return. Results from this analysis showed that membrane distillation has a higher MSP than a conventional process, $6.24 and $2.41 per gallon ($1.65 and $0.64 per liter) respectively. Hence, this study found that membrane distillation is not economical to be implemented in commercial-scale ethanol production.
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http://dx.doi.org/10.3390/bioengineering7010015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7148445PMC
February 2020

Cost Assessment of Five Different Maize Grain Handling Techniques to Reduce Postharvest Losses from Insect Contamination.

Insects 2020 Jan 10;11(1). Epub 2020 Jan 10.

Agricultural and Biosystems Engineering Department, Elings Hall, Iowa State University of Science and Technology, 3327 Elings Hall, Ames, Iowa, IA 50011, USA.

Farmers in developing nations encounter high postharvest losses mainly attributable to the lack of modern techniques for threshing, cleaning, grading, and grain storage. Mechanized handling of grain in developing countries is rare, although the technology is effective against insects and pest infestations. The objective was to evaluate the cost-effectiveness of five grain handling techniques that have the ability to reduce postharvest losses from insect infestation. The five methods were metal silo plus all accessories (m. silo + acc.), metal silo only (m. silo), woven polypropylene plus phosphine (w. PP. + Phos.), woven polypropylene only (w. PP.), and Purdue Improved Crop Storage bags only (PICS). The functional unit used was handling 1 kg of maize grain. The cost analysis of each technique was calculated based on equations using a spreadsheet. The annual capital and operational costs of handling using m. silo + acc. or m. silo were very high, unlike the PICS, w. PP. + Phos., or w. PP. The annual capital and operational costs decreased as production scale increased. Food security (due to reduced insects and pest infestations) and financial prospects of farmers can improve when the grain is mechanically handled with m. silo + acc. or m. silo.
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http://dx.doi.org/10.3390/insects11010050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7023111PMC
January 2020

Editorial: Nutrition at the Crossroads: Food at the Intersection of Environmental, Economic, and Social Sustainability.

Front Nutr 2019 1;6:158. Epub 2019 Oct 1.

Departments of Technology Management and Mechanical Engineering, University of Bridgeport, Bridgeport, CT, United States.

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http://dx.doi.org/10.3389/fnut.2019.00158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6779819PMC
October 2019

Overview of Some Recent Advances in Improving Water and Energy Efficiencies in Food Processing Factories.

Front Nutr 2019 2;6:20. Epub 2019 Apr 2.

Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, United States.

Rapid development of food factories in both developed and developing countries, owing to continued growth in the world population, plays a critical role in the food supply chain, including environmental issues such as pollution, emissions, energy and water consumption, and thus food system sustainability. The objective of this study was to briefly review various environmental aspects of food processing operations, including aquatic, atmospheric, and solid waste generation, and also to discuss several strategies that many companies are using to reduce these negative impacts as well as to improve water and energy efficiency. To obtain higher energy efficiencies in food processing factories, two key operations can play critical roles: non-thermal processing (e.g., high pressure processing) and membrane processes. For higher water efficiency, reconditioning treatments resulting in water reuse for other purposes can be conducted through chemical and/or physical treatments. With regards to reducing volumes of processing food waste, two approaches include value-added by-product applications (e.g., animal feed) and/or utilization of food waste for energy production. Finally, we present trends for lowering operational costs in food processing.
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http://dx.doi.org/10.3389/fnut.2019.00020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6454086PMC
April 2019

Integrating Environmental and Social Sustainability Into Performance Evaluation: A Balanced Scorecard-Based Grey-DANP Approach for the Food Industry.

Front Nutr 2018 20;5:65. Epub 2018 Jul 20.

Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA, United States.

In addition to retaining high levels of customer satisfaction, sustainability of businesses is also heavily reliant on the efficiency of their internal and external processes. Continuous performance evaluations using key performance metrics to leverage operations are essential in maintaining a sustainable business while achieving growth objectives for revenue and profitability. Traditionally, companies have considered various financial criteria, quality characteristics, and targeted levels of service as their primary factors for performance evaluation. However, increasing environmental and social awareness and accompanying governmental legislations are now requiring companies to integrate these two aspects into their performance evaluations. With this motivation, this study proposes a Balanced Scorecard (BSC)-based approach combining Decision-Making Trial and Evaluation Laboratory (DEMATEL) and Analytic Network Process (ANP) methodologies for performance evaluation. The grey system theory has been utilized in order to capture the vagueness and the uncertainty in decision making. To demonstrate the functionality of the approach, a case study is conducted on a U.S.-based food franchise. The results of the algorithm and a discussion elaborating on the findings are provided.
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http://dx.doi.org/10.3389/fnut.2018.00065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6064944PMC
July 2018

Kinetic Modeling of Corn Fermentation with Using a Variable Temperature Strategy.

Bioengineering (Basel) 2018 Apr 24;5(2). Epub 2018 Apr 24.

Agricultural and Biosystems Engineering Department, Iowa State University, Elings Hall, 605 Bissell Road, Ames, IA 50011, USA.

While fermentation is usually done at a fixed temperature, in this study, the effect of having a controlled variable temperature was analyzed. A nonlinear system was used to model batch ethanol fermentation, using corn as substrate and the yeast , at five different fixed and controlled variable temperatures. The lower temperatures presented higher ethanol yields but took a longer time to reach equilibrium. Higher temperatures had higher initial growth rates, but the decay of yeast cells was faster compared to the lower temperatures. However, in a controlled variable temperature model, the temperature decreased with time with the initial value of 40 ∘ C. When analyzing a time window of 60 h, the ethanol production increased 20% compared to the batch with the highest temperature; however, the yield was still 12% lower compared to the 20 ∘ C batch. When the 24 h’ simulation was analyzed, the controlled model had a higher ethanol concentration compared to both fixed temperature batches.
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http://dx.doi.org/10.3390/bioengineering5020034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6027194PMC
April 2018

Production of Barbari Bread (Traditional Iranian Bread) Using Different Levels of Distillers Dried Grains with Solubles (DDGS) and Sodium Stearoyl Lactate (SSL).

Foods 2018 Mar 1;7(3). Epub 2018 Mar 1.

Dairy and Food Science Department, South Dakota State University, Brookings, SD 57007, USA.

Bread is one of the oldest foods known throughout history and even though it is one of the principal types of staple around the world, it usually lacks enough nutrients, including protein and fiber. As such, fortification is one of the best solutions to overcome this problem. Thus, the objective this study was to examine the effect of three levels of distillers dried grains with solubles (DDGS) (0%, 10% and 20%) in conjunction with three levels of SSL (sodium stearoyl lactate) (0%, 2% and 5%) on physical and chemical properties of Barbari bread (traditional Iranian bread). To the best of our knowledge, this is the first study to evaluate DDGS and Sodium Stearoyl-2-Lactilate (SSL), as sources of fortification in Barbari bread. The results showed that incorporation of 20% of DDGS and 0% SSL caused a significant increase in the amount of fiber and protein. As for the physical attributes, using higher amount of DDGS caused a darker color, and as for the texture parameters, the highest firmness was measured when 10% DDGS and 5% of SSL were used. Different Mixolab and Rapid Visco Analyzer (RVA) parameters also were measured with varying results. The findings of this study show that DDGS can be a valuable source of fiber and protein, which can be used as a cost effective source to fortify cereal-based products.
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http://dx.doi.org/10.3390/foods7030031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5867546PMC
March 2018

Techno-Economic Analysis of Biofuel Production from Macroalgae (Seaweed).

Bioengineering (Basel) 2017 Nov 26;4(4). Epub 2017 Nov 26.

Department of Agricultural and Biosystems Engineering, Iowa State University, 3327 Elings Hall, Ames, IA 50011, USA.

A techno-economic evaluation of bioenergy production from macroalgae was carried out in this study. Six different scenarios were examined for the production of different energy products and by-products. Seaweed was produced either via the longline method or the grid method. Final products of these scenarios were either ethanol from fermentation, or electricity from anaerobic digestion (AD). By-products were digestate for AD, and animal feed, or electricity and digestate, for the fermentation pathway. Bioenergy breakeven selling prices were investigated according to the cost components and the feedstock supply chain, while suggestions for potential optimization of costs were provided. The lowest production level of dry seaweed to meet 0.93 ($/L) for ethanol fuel and 0.07 $/kW-h for electricity was found to be 0.68 and 3.7 million tonnes (dry basis), respectively. At the moment, biofuel production from seaweed has been determined not to be economically feasible, but achieving economic production may be possible by lowering production costs and increasing the area under cultivation.
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http://dx.doi.org/10.3390/bioengineering4040092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5746759PMC
November 2017

Profitability Analysis of Soybean Oil Processes.

Bioengineering (Basel) 2017 Oct 7;4(4). Epub 2017 Oct 7.

Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011, USA.

Soybean oil production is the basic process for soybean applications. Cash flow analysis is used to estimate the profitability of a manufacturing venture. Besides capital investments, operating costs, and revenues, the interest rate is the factor to estimate the net present value (NPV), break-even points, and payback time; which are benchmarks for profitability evaluation. The positive NPV and reasonable payback time represent a profitable process, and provide an acceptable projection for real operating. Additionally, the capacity of the process is another critical factor. The extruding-expelling process and hexane extraction are the two typical approaches used in industry. When the capacities of annual oil production are larger than 12 and 173 million kg respectively, these two processes are profitable. The solvent free approach, known as enzyme assisted aqueous extraction process (EAEP), is profitable when the capacity is larger than 17 million kg of annual oil production.
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http://dx.doi.org/10.3390/bioengineering4040083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5746750PMC
October 2017

Periodic Physical Disturbance: An Alternative Method for Controlling Sitophilus zeamais (Maize Weevil) Infestation.

Insects 2016 Sep 29;7(4). Epub 2016 Sep 29.

Department of Food Technology, Nutrition and Consumers Sciences, Sokoine University of Agriculture, Morogoro P.O. BOX. 3006, Tanzania.

Motschulsky is the most important insect pest of stored maize in tropical regions. The objective of this study was to determine the practicality of periodic physical disturbance on mortality and its adoption by smallholder farmers in developing countries. In this experiment, treatments and control were arranged in a randomized block design with three replications and three storage times in three regions of Tanzania. Region was used as the blocking variable. A total of 108 clean 20-L plastic containers were each loaded with 10 kg of fresh white dent corn and 0.50 kg of maize infested with . For the treatment, containers were disturbed twice a day, whereas for the controls the containers were not disturbed until the end of storage. The overall mortality rate (%) after 30, 60, and 90 days of storage were 88%, 96%, and 98%, respectively. A statistically significant difference ( < 0.05) was observed for the number of live between the control and experimental treatments. Additionally, the number of live in the treatment significantly decreased as storage time increased. This study shows the potential of a feasible, simple, affordable, and effective method of protecting maize grain for small-holder farmers in developing countries without using chemicals.
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http://dx.doi.org/10.3390/insects7040051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5198199PMC
September 2016

Using alternative flours as partial replacement of barbari bread formulation (traditional Iranian bread).

J Food Sci Technol 2015 Sep 14;52(9):5691-9. Epub 2014 Nov 14.

South Dakota State University, Brookings, SD 57007 USA.

Wheat flour is used in most of breads because of its nutrient components and high availability, but different problems are associated with this flour, such as allergies and loss of nutrient components due to milling and refining. In this study, five flours were used (20 %) in combination with wheat flour (80 %).to produce traditional Iranian Barbari bread. These included amaranth, barley, DDGS, rye and oat. Compositional measurements of moisture, fat, fiber, protein and ash content were taken. Physical tests were done to understand the changes in color, thickness, and texture. Results showed that the gluten content of each flour had a significant effect on the texture and thickness of the bread. Bread made with rye flour had the highest L* and that made with oat flour had the highest a*. As for b*, the highest was for the bread made with DDGS. It was also determined that bread made with 20 % DDGS and 80 % wheat flour had the highest fiber and moisture content, while that made with amaranth had the highest ash content, and that with rye had the highest fat. Adding different flours to wheat changed the physical and chemical attributes of final producst significantly.
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http://dx.doi.org/10.1007/s13197-014-1640-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4554633PMC
September 2015

Changes in chemical and physical properties of Latin American wheat flour based tortillas substituted with different levels of distillers dried grains with solubles (DDGS).

J Food Sci Technol 2015 Aug 23;52(8):5243-9. Epub 2014 Sep 23.

South Dakota State University, Brookings, SD 57007 USA.

Tortilla is the most popular type of bread both in South and Central America. Since the demand for this bread among different classes of society is significant, improving its nutrient content could be important. Distillers dried grains with solubles is good source of fiber and protein, and can be used in the fortification of tortilla. In this study, three levels of DDGS (0, 10 and 20 %) were substituted for wheat flour and the physical and chemical properties of the resulting products were evaluated. Results showed that for the 20 % DDGS level, minimum force was required to rupture the tortilla. The color of the tortillas substituted with 10 and 20 % DDGS were darker, being 64.11 and 59.99, respectively (P < 0.05). As for chemical properties, the samples fortified with 10 and 20 % DDGS had higher protein (9.35 and 10.78 % dried basis), fiber (2.21 and 2.33 % dried basis) and fat (23.60 and 24.65 % dried basis) values at P < 0.05. Thus, it appeared that using DDGS in wheat tortillas can improve some of the nutritional values such as protein and fiber as well as the textural properties of these breads. Further work should examine consumer acceptability of these products.
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http://dx.doi.org/10.1007/s13197-014-1566-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4519483PMC
August 2015

Effect of co-products of enzyme-assisted aqueous extraction of soybeans on ethanol production in dry-grind corn fermentation.

Bioresour Technol 2015 Sep 30;192:451-60. Epub 2015 May 30.

Department of Food Science and Human Nutrition, Center for Crops Utilization Research, Iowa State University, Ames, IA, USA.

Enzyme-assisted aqueous extraction processing (EAEP) is an environmentally-friendly alternative to solvent and mechanical oil extraction methods, and can achieve ∼ 97% oil recovery from soybeans. The present study utilized soy skim (protein rich) and insoluble fiber (IF; carbohydrate rich), both co-products of EAEP, in dry-grind corn fermentation. The effects of adding soy skim and untreated IF (UIF), either separately or together, and adding pretreated IF (TIF), on ethanol production were investigated. Maximum ethanol production was achieved when UIF and skim were slurried together (corn-to-UIF ratio 1:0.16; skim-to-UIF ratio 6.5:1) and when fiber-hydrolyzing enzymes were added to corn fermentation. This modification to corn fermentation increased ethanol yield by 20%, ethanol production rate by 3%, and decreased fermentation time by 38 h compared to corn-only fermentation. An attempt was also made to utilize pentoses (from soy skim and IF) in integrated corn-soy fermentation slurry by an additional Escherichia coli KO11 fermentation step.
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http://dx.doi.org/10.1016/j.biortech.2015.05.096DOI Listing
September 2015

Aerobic stability of distillers wet grains as influenced by temperature.

J Sci Food Agric 2013 Feb 3;93(3):498-503. Epub 2012 Aug 3.

USDA-ARS-North Central Agricultural Research Laboratory, Brookings, SD 57006, USA.

Background: The storability of distillers wet grains (DWG) influences the economic, energetic, and carbon balances of fuel ethanol production, yet there are limited published data on the deterioration of DWG following its production. We used biogenic CO(2) production to assess the aerobic stability of DWG incubated at three temperatures (12 °C, 22 °C, 32 °C) and compared CO(2) production over time to the appearance of mold and changes in DWG color parameters.

Results: CO(2) production and mold colonization indicate that at temperatures near 12 °C, the aerobic stability of DWG was high and that it can be stored for at least a 10-day period. At temperatures close to 22 °C, the onset of increased microbial activity and visible mold colonization occurred between 4 and 7 days and both activity and mold ratings were very high by the ninth day in all three experiments. At 32 °C, 2 days may be a more appropriate limit for storage.

Conclusion: Temperature and time interact in a nonlinear fashion that permits the prediction of DWG stability boundaries. The simple visual appearance of mold appears to be a reasonable indicator that correlates well (r = 0.694) with CO(2) production, a measure of the aerobic stability of DWG.
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http://dx.doi.org/10.1002/jsfa.5803DOI Listing
February 2013

Effect of an oxygen scavenger on the stability of preservative-free flour tortillas.

J Food Sci 2012 Jan 2;77(1):S1-9. Epub 2011 Dec 2.

Chemistry Department, University of Southern California, Los Angeles, CA 90089, USA.

Unlabelled: Along with purge and moisture control, oxygen scavenging is a prominent active packaging technology employed by many food processors. The objective of this study was to determine the effect of an oxygen scavenger system (OSS) on the shelf life of preservative-free tortillas stored at varying storage conditions. The shelf life of the tortillas was evaluated at accelerated storage (AS; 37 °C, 75% relative humidity [rh]), room temperature (RT; 22 °C, 57% rh), and refrigeration (R; 4 °C, 42% rh) conditions. The OSS consisted of a multilayer, coextruded bag paired with an oxygen scavenger sachet. A resealable bag made of low-density polyethylene/linear low-density polyethylene was used as a control. The diameter, thickness, CIELab color, water activity, pH, texture, and microbial growth within the sample tortillas were measured before and after exposure to the storage conditions. The results showed that the OSS had superiority when compared to the control. The weight and thickness under RT remained unchanged, while lightness was superior to the control under R conditions. Under AS, gradient remained constant, and force followed the same pattern under RT and R conditions. At the same time, microbial growth as measured by aerobic plate count and yeast and molds showed no changes under both AS and RT conditions. Future studies will investigate the effect of a faster acting oxygen scavenger on shelf life of this type of tortillas.

Practical Application: The results of this study show promise for the use of oxygen scavenging technology in the packaging of natural and preservative-free tortillas.
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http://dx.doi.org/10.1111/j.1750-3841.2011.02470.xDOI Listing
January 2012

Extruded aquafeeds containing distillers dried grains with solubles: effects on extrudate properties and processing behaviour.

J Sci Food Agric 2011 Dec 1;91(15):2865-74. Epub 2011 Jul 1.

USDA-ARS, North Central Agricultural Research Laboratory, 2923 Medary Avenue, Brookings, SD 57006, USA.

Background: The tremendous supply and low cost of distillers dried grains with solubles (DDGS) make it an attractive feedstuff for aquaculture diets. Also, several studies have shown that DDGS can be successfully fed to various finfish. The objective of this study was to evaluate the effects of inclusion rate of DDGS (0, 250, 500 g kg(-1) ), feed moisture content (350, 450 g kg(-1) ) and die opening area (die A = 18.85 mm(2) , die B = 3988.45 mm(2) ) on the properties of the extrudates and on processing behaviour using a single-screw extruder.

Results: Increasing the inclusion rate of DDGS resulted in extrudates with lower unit density, bulk density, expansion ratio, water solubility index and brightness (Hunter L) but higher redness (Hunter a) and yellowness (Hunter b). The increase in moisture content affected the extrudate properties in different ways: it increased bulk density, Hunter L, Hunter b and mass flow rate, whereas specific mechanical energy decreased at high moisture content. Increasing the die opening area primarily decreased expansion ratio of extrudates, power consumption and barrel temperatures but increased mass flow rate.

Conclusion: Extrudates from all treatments exhibited high durability and floatability, and less energy was required to produce extrudates when DDGS was used compared with soybean meal-based diets. The aquaculture industry can use this information to develop high-quality feeds at low cost.
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http://dx.doi.org/10.1002/jsfa.4536DOI Listing
December 2011

Modeling the effects of pelleting on the logistics of distillers grains shipping.

Bioresour Technol 2009 Dec 14;100(24):6550-8. Epub 2009 Aug 14.

USDA, ARS, North Central Agricultural Research Laboratory, 2923 Medary Avenue, Brookings, SD 57006, USA.

The energy security needs of energy importing nations continue to escalate. It is clear that biofuels can help meet some of the increasing need for energy. Theoretically, these can be produced from a variety of biological materials, including agricultural residues (such as corn stover and wheat straw), perennial grasses, legumes, algae, and other biological materials. Currently, however, the most heavily utilized material is corn starch. Industrial fuel ethanol production in the US primarily uses corn, because it is readily converted into fuel at a relatively low cost compared to other biomass sources. The production of corn-based ethanol in the US is dramatically increasing. As the industry continues to grow, the amount of byproducts and coproducts also increases. At the moment, the nonfermentable residues (which are dried and sold as distillers dried grains with solubles--DDGS) are utilized only as livestock feed. The sale of coproducts provides ethanol processors with a substantial revenue source and significantly increases the profitability of the production process. Even though these materials are used to feed animals in local markets, as the size and scope of the industry continues to grow, the need to ship large quantities of coproducts grows as well. This includes both domestic as well as international transportation. Value-added processing options offer the potential to increase the sustainability of each ethanol plant, and thus the industry overall. However, implementation of new technologies will be dependent upon how their costs interact with current processing costs and the logistics of coproduct deliveries. The objective of this study was to examine some of these issues by developing a computer model to determine potential cost ramifications of using various alternative technologies during ethanol processing. This paper focuses specifically on adding a densification unit operation (i.e., pelleting) to produce value-added DDGS at a fuel ethanol manufacturing plant. We have examined the economic implications of pelleting DDGS for varying DDGS production rates (100-1000 tons/d) and pelleting rates (0-100%), for a series of DDGS sales prices ($50-$200/ton). As the proportion of pelleting increases, the cost of transporting DDGS to distant markets drastically declines, because the rail cars can be filled to capacity. For example, at a DDGS sales price of $50/ton, 100% pelleting will reduce shipping costs (both direct and indirect) by 89% compared to shipping the DDGS in bulk form (i.e., no pelleting), whereas at a DDGS sales price of $200/ton, it will reduce costs by over 96%. It is clear that the sustainability of the ethanol industry can be improved by implementing pelleting technology for the coproducts, especially at those plants that ship their DDGS via rail.
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http://dx.doi.org/10.1016/j.biortech.2009.07.051DOI Listing
December 2009

Microbial development in distillers wet grains produced during fuel ethanol production from corn (Zea mays).

Can J Microbiol 2007 Sep;53(9):1046-52

USDA-ARS-North Central Agricultural Research Laboratory, Brookings, SD 57006, USA.

Distillers grains are coproduced with ethanol and carbon dioxide during the production of fuel ethanol from the dry milling and fermentation of corn grain, yet there is little basic microbiological information on these materials. We undertook a replicated field study of the microbiology of distillers wet grains (DWG) over a 9 day period following their production at an industrial fuel ethanol plant. Freshly produced DWG had a pH of about 4.4, a moisture content of about 53.5% (wet mass basis), and 4 x 10(5) total yeast cells/g dry mass, of which about 0.1% were viable. Total bacterial cells were initially below detection limits (ca. 10(6) cells/g dry mass) and then were estimated to be approximately 5 x 10(7) cells/g dry mass during the first 4 days following production. Culturable aerobic heterotrophic organisms (fungi plus bacteria) ranged between 10(4) and 10(5) CFU/g dry mass during the initial 4 day period, and lactic acid bacteria increased from 36 to 10(3) CFU/g dry mass over this same period. At 9 days, total viable bacteria and yeasts and (or) molds topped 10(8) CFU/g dry mass and lactic acid bacteria approached 10(6) CFU/g dry mass. Community phospholipid fatty acid analysis indicated a stable microbial community over the first 4 days of storage. Thirteen morphologically distinct isolates were recovered, of which 10 were yeasts and molds from 6 different genera, 2 were strains of the lactic-acid-producing Pediococcus pentosaceus and only one was an aerobic heterotrophic bacteria, Micrococcus luteus. The microbiology of DWG is fundamental to the assessment of spoilage, deleterious effects (e.g., toxins), or beneficial effects (e.g., probiotics) in its use as feed or in alternative applications.
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http://dx.doi.org/10.1139/w07-073DOI Listing
September 2007