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1.
Distillers dried grains with solubles (DDGS), the major coproduct from the corn‐based fuel ethanol industry, is primarily used as livestock feed. Due to high protein, fiber, and energy contents, there is a high demand for DDGS. Flowability of DDGS is often hindered due the phenomenon of caking. Shipping and handling of DDGS has thus become a major issue due to bridge formation between the DDGS particles. The objective of this investigation was to measure flowability characteristics of DDGS samples from five ethanol plants in the north central region of the United States. Carr and Jenike tests were performed and the resulting data were mathematically compared with a previously developed empirical model. The largest particles had an average geometric mean diameter (GMD) of 1.19 mm, while the lowest particle size had an average GMD of 0.5 mm. Soluble solid levels were ≈10.5–14.8% (db). The effective angle of friction (δ) was 43.00–57.00°. Additionally, a few parameters exhibited fairly high linear correlations, including aerated and packed bulk densities (r = 0.97), geometric standard deviation and Carr compressibility (r = 0.71), geometric standard deviation and Hausner ratio (r = –0.70). Overall flowability assessment indicated that the commercial DDGS samples did have the potential for flow problems, although no samples exhibited complete bridging. Quantifying DDGS flowability is a necessary step toward overcoming this logistical challenge facing the fuel ethanol industry.  相似文献   

2.
Distillers dried grains with solubles (DDGS) is a bulk material that has been widely used as a protein source for ruminants and nonruminants for more than two decades. DDGS is the nonfermentable processing residue (i.e., protein, fiber, fat, and ash) from fuel ethanol manufacturing. With the exponential growth of the fuel ethanol industry in the past several years, significant quantities (≈13.0 million tons in 2007) of distillers grains are now being produced. To effectively utilize these coproduct streams in the domestic market, DDGS must be transported greater distances and must be stored until final use. DDGS flow is often problematic as it can become restricted by caking and bridging that occur during shipping and storage. This flowability problem can present itself during dynamic and static flow conditions. This issue most likely results from physical or chemical interactions between particles (including particle size and shape), storage moisture, temperature, and relative humidity variations, as well as storage time. The objective of this study was to examine the effect of five moisture content levels (10, 15, 20, 25, and 30% db) on the resulting physical and chemical properties of DDGS with four soluble levels (10, 15, 20, and 25% db). To produce these materials, condensed distillers solubles (CDS) were combined with DDG, and appropriate quantities of water were added to adjust moisture contents. Carr indices were used to quantify the flowability of the DDGS samples. The results showed that both soluble level and moisture content had noticeable effects on physical and flow properties (e.g., aerated bulk density, packed bulk density, and compressibility). According to dispersibility, flowability index, and floodability index, flowability generally declined significantly (P < 0.05) with an increase in moisture content for most of the soluble levels under consideration. The color values and protein content of the DDGS were significantly affected (P < 0.05) as soluble level increased as well.  相似文献   

3.
Demand for alternative fuels and the need to reduce dependence on fossil fuels have triggered the growth of corn‐based ethanol production, which is expected to rise in future years. Transportation of the coproduct distillers dried grains with solubles (DDGS) from this industry occurs under various environmental conditions. Transporting DDGS is often problematic, because caking between the particles can lead to flow problems. In this study, we have prepared DDGS by combining condensed distillers solubles (CDS) with distillers wet grains and then drying. We investigated the effects of CDS level (10, 15, and 20%, wb), drying temperature (100, 200, and 300°C), and cooling temperature (–12, 25, and 35°C) on the flowability of the resulting DDGS. Statistical analyses of the resulting data found significant differences among the cooling temperature levels for angle of repose, total flow and flood indices, dispersibility, water activity, and protein dispersibility index. Additionally, significant interaction effects between CDS, drying temperature, and cooling temperature levels for angle of repose, total flow and flood indices, dispersibility, and protein dispersibility index were observed. Response surface regression on selected dimensionless flowability parameters was also applied. However, multivariate PLS regression yielded better results (R2 > 0.8) than response surface plots. Understanding the effects of drying and cooling temperatures as well as CDS levels can be used to help improve the industrial processing of DDGS and improve storage and transportation.  相似文献   

4.
《Cereal Chemistry》2017,94(6):934-941
Distillers dried grains with solubles (DDGS) are widely used as feed for cattle, dairy, and swine because of their protein, fiber, amino acids, fat, and other vital nutrients. Corn ethanol plants in the United States recently have started extracting oil from DDGS to gain additional profit, thus producing low‐oil DDGS. So far, there has been no comprehensive study reported with bulk handling and flowability properties of low‐oil DDGS. We measured the air resistance, moisture diffusivity, and air permeability properties for low‐oil DDGS at different temperature and relative humidity conditions, along with some important physical and chemical properties. Physical property comparisons between regular and low‐oil DDGS showed differences in key properties such as particle size, color, density, porosity, and angle of repose. The modified Henderson model predicted the equilibrium moisture content (EMC)–equilibrium relative humidity (ERH) relationship of low‐oil DDGS with a low standard error of regression value (0.008); it showed no pattern in the residuals and was judged the most appropriate model tested for EMC‐ERH predictions. Results of EMC‐ERH nonlinear modeling were used to define conditions for moisture diffusivity. Moisture diffusivities of low‐oil DDGS at varying drying temperatures ranged from 0.74 × 10−11 to 1.77 ×10−11m2/s. The properties are important for understanding and modeling heat and moisture transport through and flow properties of low‐oil DDGS.  相似文献   

5.
The objective of this study was to establish methods for determining the content and components of residual starch in distiller's dried grains with solubles (DDGS), a coproduct from dry‐grind corn ethanol production. Four DDGS prepared in our laboratory and one DDGS obtained from a commercial ethanol manufacturer were used for the study. Quantitative analysis of total residual sugar (TRS) in DDGS was performed by determining d ‐glucose produced by enzymatic hydrolysis of oligosaccharides and residual starch remaining in hexane‐defatted DDGS after being dispersed in 90% DMSO. The TRS consisted of free glucose, oligosaccharides, and residual starch. The commercial manufacturer's DDGS contained more TRS (15.8%, w/w db) than the laboratory‐processed DDGS (2.4–2.9%, w/w db). The content of residual starch remaining in the commercial DDGS (5.5% w/w db) was also larger than the laboratory‐processed DDGS (1.9–2.5% w/w db). Analyses of molecular weight distribution showed that the residual starch in DDGS consisted of short‐chain amylose and amylopectin, respectively, as the major and minor components. The short‐chain amylose molecules constituted 86.5–94.1% of the residual starch. The major population of the short‐chain amyloses had an average degree of polymerization (DP) of 85, closely resembling the length of enzyme‐resistant fragments of amylose‐lipid complexes.  相似文献   

6.
One of the fastest growing industries in the United States is the fuel ethanol industry. In terms of ethanol production capability, the industry has grown by more than 600% since the year 2000. The major coproducts from corn‐based ethanol include distillers dried grains with solubles (DDGS) and carbon dioxide. DDGS is used as a livestock feed because it contains high quantities of protein, fiber, amino acids, and other nutrients. The goal of this study was to quantify various chemical and physical properties of DDGS, distillers wet grains (DWG), and distillers dried grain (DDG) from several plants in South Dakota. Chemical properties of the DDGS included crude ash (5.0–21.93%), neutral detergent fiber (NDF) (26.32–43.50%), acid detergent fiber (ADF) (10.82–20.05%), crude fiber (CF) (8.14–12.82%), crude protein (27.4–31.7%), crude fat (7.4–11.6%), and total starch (9.19–14.04%). Physical properties of the DDGS included moisture content (3.54–8.21%), Aw (0.42–0.53), bulk density (467.7–509.38 kg/m3), thermal conductivity (0.05–0.07 W/m·°C), thermal diffusivity (0.1–0.17 mm2/sec), color L* (36.56–50.17), a* (5.2–10.79), b* (12.53–23.36), and angle of repose (25.7–47.04°). These properties were also determined for DWG and DDG. We also conducted image analysis and size determination of the DDGS particles. Carbon group characterization in the DDGS and DDG samples were determined using NMR spectroscopy; O‐alkyl comprised >50% of all DDGS samples. Results from this study showed several possibilities for using DDGS in applications other than animal feed. Possibilities include harvesting residual sugars, producing additional ethanol, producing value‐added compounds, using as food‐grade additives, or even using as inert fillers for biocomposites.  相似文献   

7.
为了研究不同贮藏期大豆分离蛋白（soy protein isolate,SPI）对千页豆腐品质的影响,该文首先研究了贮藏期对大豆分离蛋白结构的影响,进而探讨贮藏期对大豆蛋白制备千页豆腐的品质的影响。对不同贮藏期的大豆蛋白分别采用了凝胶质构特性、感官评价、羰基含量、大豆蛋白亚基以及巯基的测定,并采用拉曼光谱对大豆蛋白二级结构、二硫键构型以及侧链结构进行了分析,同时采用扫描电镜观察千页豆腐的微结构。结果表明：随着贮藏期的延长,千页豆腐的感官评价变差,由88分降低至44分;其凝胶网络结构逐渐疏松;大豆蛋白羰基含量逐渐上升;巯基含量逐渐下降;二级结构含量改变;凝胶硬度呈下降趋势,硬度值低于234 g时,将无法达到千页豆腐的质量要求。这表明在贮藏期内SPI发生了氧化,导致大豆蛋白质结构发生改变,使其凝胶性质下降。  相似文献   

8.
Four pearl millet genotypes were tested for their potential as raw material for fuel ethanol production in this study. Ethanol fermentation was performed both in flasks on a rotary shaker and in a 5‐L bioreactor using Saccharomyces cerevisiae (ATCC 24860). For rotary‐shaker fermentation, the final ethanol yields were 8.7–16.8% (v/v) at dry mass concentrations of 20–35%, and the ethanol fermentation efficiencies were 90.0–95.6%. Ethanol fermentation efficiency at 30% dry mass on a 5‐L bioreactor reached 94.2%, which was greater than that from fermentation in the rotary shaker (92.9%). Results showed that the fermentation efficiencies of pearl millets, on a starch basis, were comparable to those of corn and grain sorghum. Because pearl millets have greater protein and lipid contents, distillers dried grains with solubles (DDGS) from pearl millets also had greater protein content and energy levels than did DDGS from corn and grain sorghum. Therefore, pearl millets could be a potential feedstock for fuel ethanol production in areas too dry to grow corn and grain sorghum.  相似文献   

9.
Distillers dried grains with solubles (DDGS) is the main coproduct of the U.S. fuel ethanol industry and has significantly impacted the livestock feed markets in recent years. Particle agglomeration and subsequent flowability problems during storage and transport are often a hindrance, a nuisance, and expensive. This paper aims at characterizing the glass transition (Tg) and sticky point (Ts) temperatures of DDGS samples prepared with varying condensed distillers solubles (CDS) levels (10, 15, and 20%, wb), drying temperatures (100, 200, and 300°C), and moisture contents (0, 10, and 20%, db), and it discusses implications on DDGS flowability behavior. Distillers wet grains were combined with specified levels of CDS and dried in a convection‐style laboratory oven to produce DDGS. Subsequently, predetermined amounts of water were added to the DDGS to achieve desired moisture content levels. To determine Tg (°C), a differential scanning calorimeter was used, whereas Ts (°C) was determined through a novel technique with a rheometer. Results indicated high correlations between observed Ts and observed Tg (R2 = 0.87) data for DDGS samples. Also, the empirical model for predicted Tg = f (drying temperature, CDS level, and moisture content) based on the Gordon–Taylor model showed favorable R2 (0.74). Stickiness of DDGS increased with an increase in moisture content, indicating flow problems resulting from moisture. It was found that drying temperatures and CDS levels each had significant effects on Tg and Ts as well.  相似文献   

10.
As the quantity of ethanol produced continues to increase, the amount of distillers dried grains with solubles (DDGS), the primary coproduct of ethanol manufacturing, has become more widely available. Currently, the main consumer of DDGS is the livestock industry, but new value‐added uses are garnering interest. With the increase in the availability of, and demand for DDGS, transportation has become an important issue because DDGS must be shipped increasingly long distances using railways. Rail transportation is expensive, especially considering the quantities of DDGS that can be loaded onto unit trains. DDGS often has low bulk density and poor flowability characteristics. This study examined compression effects on particle arrangements as quantified by bulk density and compressibility of the DDGS. Mean loose bulk density was 446.18 kg/m3. A linear relationship (R2 = 0.982 for 50 N applied force and R2 = 0.959 for 1 kN applied force) was observed between the applied stress (≈0.0–0.0065 and ≈0.0–0.13 MPa, respectively) and the resulting packed bulk density (≤470.21 and ≤555.03 kg/m3, respectively). Compressive stress increased curvilinearly (R2 = 0.994 for the 50 N load and R2 = 0.997 for the 1 kN load) as the applied strain increased (≈0.0–0.007% and 0.0–24.0%, respectively). As the loading increased, compressibility increased 5.11–19.22%. Bulk restitution after loading was removed was 0.53–0.61. Required storage volume is reduced when the bulk density is increased. But flowability characteristics should improve as the compressibility, and thus the bulk density, of the product is reduced.  相似文献   

11.
A process was developed to separate fiber from distillers dried grains with solubles (DDGS) in a dry‐grind corn process. Separation of fiber from DDGS would provide two valuable coproducts: 1) DDGS with reduced fiber, increased fat, and increased protein contents; and 2) fiber. The process, called elusieve process, used two separation methods, sieving and elutriation, to separate the fiber. Material carried by air to the top of the elutriation column was called the lighter fraction and material that settled to the bottom of the column was called the heavier fraction. We evaluated the compositions of fractions produced from sieving and elutriation. Two commercial samples of DDGS were obtained from two dry‐grind corn plants. Sieving over four screens (869, 582, 447, and 234 μm openings) created five size categories. The two smallest size categories contained >40% (w/w) of the original DDGS and had reduced fiber and increased protein and fat contents relative to the original DDGS. Elutriation of the remaining three size categories increased protein and fat contents and reduced fiber contents in the heavier fractions. Elutriation at air velocities of 1.59–5.24 m/sec increased the protein content of the heavier fraction by 13–41% and increased the fat content of the heavier fraction by 4–127% compared with the bulk fractions of each size category. This process was effective in separating fiber from both DDGS samples evaluated. Elusieve process does not require changes in the existing dry‐grind process and can be implemented at the end of the dry‐grind process.  相似文献   

12.
Separation of fiber from distillers dried grains with solubles (DDGS) provides two valuable coproducts: 1) enhanced DDGS with reduced fiber, increased fat and increased protein contents and 2) fiber. Recently, the elusieve process, a combination of sieving and elutriation was found to be effective in separating fiber from two commercial samples of DDGS (DDGS‐1 and DDGS‐2). Separation of fiber decreased the quantity of DDGS, but increased the value of DDGS by increasing protein content and produced a new coproduct with higher fiber content. Economic analysis was conducted to determine the payback period, net present value (NPV), and internal rate of return (IRR) of the elusieve process. The dependence of animal foodstuff prices on their protein content was determined. Equipment prices were obtained from industrial manufacturers. Relative to crude protein content of original DDGS, crude protein content of enhanced DDGS was higher by 8.0% for DDGS‐1 and by 6.3% for DDGS‐2. For a dry‐grind plant processing corn at the rate of 2,030 metric tonnes/day (80,000 bushels/day), increase in revenue due to the elusieve process would be $0.4 to 0.7M/year. Total capital investment for the elusieve process would be $1.4M and operating cost would be $0.1M/year. Payback period was estimated to be 2.5–4.6 years, NPV was $1.2–3.4M, and IRR was 20.5–39.5%.  相似文献   

13.
A new low temperature liquefaction and saccharification enzyme STARGEN 001 (Genencor International, Palo Alto, CA) with high granular starch hydrolyzing activity was used in enzymatic dry‐grind corn process to improve recovery of germ and pericarp fiber before fermentation. Enzymatic dry‐grind corn process was compared with conventional dry‐grind corn process using STARGEN 001 with same process parameters of dry solid content, pH, temperature, enzyme and yeast usage, and time. Sugar, ethanol, glycerol and organic acid profiles, fermentation rate, ethanol and coproducts yields were investigated. Final ethanol concentration of enzymatic dry‐grind corn process was 15.5 ± 0.2% (v/v), which was 9.2% higher than conventional process. Fermentation rate was also higher for enzymatic dry‐grind corn process. Ethanol yields of enzymatic and conventional dry‐grind corn processes were 0.395 ± 0.006 and 0.417 ± 0.002 L/kg (2.65 ± 0.04 and 2.80 ± 0.01 gal/bu), respectively. Three additional coproducts, germ 8.0 ± 0.4% (db), pericarp fiber 7.7 ± 0.4% (db), and endosperm fiber 5.2 ± 0.6% (db) were produced in addition to DDGS with enzymatic dry‐grind corn process. DDGS generated from enzymatic dry‐grind corn process was 66% less than conventional process.  相似文献   

14.
Increasing demand for seafood products and rising demand for fish meal for commercial fish feeds is driving the search for effective alternative protein sources. Twin‐screw extrusion trials were conducted to study the production of nutritionally balanced feeds for rainbow trout fingerlings (Oncorhynchus mykiss). Six isocaloric (≈4.61 kcal/g) ingredient blends with a target protein content of >45% db were formulated with 0, 10, 20, 30, 40, and 50% distillers dried grains with solubles (DDGS) and other feed ingredients. The moisture contents of the diets were initially adjusted to 5–7% db, and then extruded at 250 rpm using dual 1.9 mm dies with varying amounts of steam (7.2–7.7 kg/hr) injected into the conditioner and water (4.3–6.5 kg/hr) into the extruder. Mass flow rates, moisture contents, and temperatures were measured during processing and moisture content, water activity, unit density, bulk density, expansion ratio, compressive strength, compressive modulus, pellet durability index, water stability, and color were analyzed to quantify the effects of varying DDGS content on the extrudate physical properties. Significant differences (P < 0.05) among the blends were observed for color and bulk density for both the raw and extruded materials, respectively, and for the unit density and pellet durability index of the extruded products. There were also significant changes in redness and yellowness, but only minor changes in brightness, among the final products with increasing DDGS content. The compressive strength of the extrudates increased significantly with increasing DDGS. Expansion ratio of all pellets was low. All extruded diets achieved very good water stability.  相似文献   

15.
The dry grind process using granular starch hydrolyzing enzymes (GSHE) saves energy. The amount of GSHE used is an important factor affecting dry grind process economics. Proteases can weaken protein matrix to aid starch release and may reduce GSHE doses. Two specific proteases, an exoprotease and an endoprotease, were evaluated in the dry grind process using GSHE (GSH process). The effect of protease and urea addition on GSH process was also evaluated. Addition of these proteases resulted in higher ethanol concentrations (mean increase of 0.3–1.8 v/v) and lower distillers' dried grains with solubles (DDGS) yields (mean decrease of 1.3–8.0% db) compared with the control (no protease addition). As protease levels and GSHE increased, ethanol concentrations increased and DDGS yields decreased. Protease addition reduced the required GSHE dose. Final mean ethanol concentrations without urea (15.2% v/v) were higher than with urea (15.0% v/v) in GSH process across all protease treatments.  相似文献   

16.
Three different modified dry‐grind corn processes, quick germ (QG), quick germ and quick fiber (QGQF), and enzymatic milling (E‐Mill) were compared with the conventional dry‐grind corn process for fermentation characteristics and distillers dried grains with solubles (DDGS) composition. Significant effects were observed on fermentation characteristics and DDGS composition with these modified dry‐grind processes. The QG, QGQF, and E‐Mill processes increased ethanol concentration by 8–27% relative to the conventional dry‐grind process. These process modifications reduced the fiber content of DDGS from 11 to 2% and increased the protein content of DDGS from 28 to 58%.  相似文献   

17.
Piling Dried Distillers's Grains with Solubles (DDGS) using gravity discharge is common in the corn‐ethanol industry. This study investigated the occurrence of particle segregation within piles of DDGS formed by gravity discharge and subsequent spatial nutrient variability. Particle segregation tests were performed in a laboratory study where piles of DDGS were formed using samples collected from two fuel ethanol plants (an “old” and a “new” generation plant), and a plant study performed on piles of DDGS formed at the same two fuel ethanol plants. In both the laboratory and plant studies, the piles were formed by gravity‐driven discharge and sampled at various categorized sections from the center of the pile to the periphery. Our results gave similar conclusions to a prior bench‐scale study and confirmed that particle segregation does result in significant differences in particle size at the sampled locations of the pile. Particle size expressed as the geometric mean diameter (dgw) increased from the core of the pile to the periphery. Of all the nutrient composition tested, only crude protein and moisture correlated with particle size. While the correlation of crude protein with particle size was not consistent and clearly discernible in all the piles sampled in both the bench‐scale and plant studies, the correlation of particle size with moisture showed a strong positive correlation. Based on these findings, we recommend the development of a standard sampling protocol following good sampling practices for bulk granular solids.  相似文献   

18.
《Cereal Chemistry》2017,94(4):693-698
The high cost of kafirin and zein restricts their use for bioplastic and food applications. Effective, simple, and rapid kafirin/zein isolation processes are required. Here a percolation‐type aqueous ethanol solvent extraction process from coarse meals (grits) and coarse sorghum distillers dried grains and solubles (DDGS) for kafirin and zein isolation employing a low ratio of extractant to meal (2.5:1) was investigated, which is potentially applicable in the grain bioethanol industry. Postextraction filtration times were more than twice as fast using coarse meals compared with fine flours. Washing the meals prior to extraction to remove starch improved protein preparation purity to 73–85% compared with 68–72% for unwashed meals. Hence, no subsequent filtration or centrifugation step is required to clean up the kafirin/zein solution prior to solvent evaporation. With a single extraction step, kafirin/zein yields were 48% (protein basis) for DDGS and 53–70% for washed sorghum/maize meals. Cast films were used as a model bioplastic system to evaluate extracted kafirin/zein functional properties. DDGS kafirin films had rough surfaces but had the lowest water uptake and in vitro digestibility, owing to heat‐induced disulfide crosslinking during DDGS processing. Extraction by percolation using coarse meal/DDGS has potential to improve kafirin/zein viability.  相似文献   

19.
Widespread epidemics of Stenocarpella ear rot (formerly Diplodia ear rot) have occurred throughout the central U.S. Corn Belt in recent years, but the influence of S. maydis infected grain on corn ethanol production is unknown. In this study, S. maydis infected ears of variety Heritage 4646 were hand‐harvested in 2010 from a production field in central Illinois and segregated into one of five levels of ear rot severity based upon visual symptoms. The concentration of ergosterol, a sterol produced by fungi but not plants, was observed to increase with the severity of ear rot (127–306.5 μg/g), and none was detected in the control corn. Corn test weight declined with progression of the disease and was 42.6% lower for the most severely rotted grain from ears infected early in their development. Accompanying changes in composition were also apparent. Crude fat and oil contents decreased (from 4.7 to 1.5%) and fiber increased (from 6.6 to 9.6%), but starch content remained largely invariant. Oil composition also varied among the infected samples. Control and infected corn samples were subjected to ethanol fermentation with a laboratory‐scale corn dry‐grind ethanol process. Ethanol yields for control and infected samples were similar on an equivalent weight basis (2.77–2.85 gal/bu). In comparison with the control, S. maydis infection altered the distillers dried grains with solubles (DDGS) properties, wherein the crude protein was significantly higher and oil significantly reduced, and ash, fiber, and yield per ton were not significantly different. Based upon these results, we conclude that Stenocarpella ear rot has the potential to affect DDGS composition but not ethanol yield on an equivalent weight basis.  相似文献   

20.
Neural network (NN) modeling techniques were used to predict flowability behavior of distillers dried grains with solubles (DDGS) prepared with varying levels of condensed distillers solubles (10, 15, and 20%, wb), drying temperatures (100, 200, and 300°C), cooling temperatures (–12, 25, and 35°C), and storage times (0 and 1 month). Response variables were selected based on our previous research results and included aerated bulk density, Hausner ratio, angle of repose, total flowability index, and Jenike flow index. Various NN models were developed using multiple input variables in order to predict single‐response and multiple‐response variables simultaneously. The NN models were compared based on R2, mean square error, and coefficient of variation obtained. In order to achieve results with higher R2 and lower error, the number of neurons in each hidden layer, the step size, the momentum learning rate, and the number of hidden layers were varied. Results indicate that for all the response variables, R2 > 0.83 was obtained from NN modeling. Compared with our previous studies, NN modeling provided better results than either partial least squares modeling or regression modeling, indicating greater robustness in the NN models. Surface plots based on the predicted values from the NN models yielded process and storage conditions for favorable versus cohesive flow behavior for DDGS. Modeling of DDGS flowability using NN has not been done before, so this work will be a step toward the application of intelligent modeling procedures to this industrial challenge.  相似文献   

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