Optimization and Modeling of Flow Characteristics of Low-Oil DDGS Using Regression Techniques

Citation: R. Bhadra, R. P. K. Ambrose, M. E. Casada, S. Simsek, K. Siliveru. (2017). Optimization and Modeling of Flow Characteristics of Low-Oil DDGS Using Regression Techniques. Transactions of the ASABE. 60(1): 249-258. (doi: 10.13031/trans.11928)Storage conditions, such as temperature, relative humidity (RH), consolidation pressure (CP), and time, affect the flow behavior of bulk solids such as distillers dried grains with solubles (DDGS), which is widely used as animal feed by the U.S. cattle and swine industries. The typical dry-grind DDGS production process in most corn ethanol plants has been adapted to facilitate oil extraction from DDGS for increased profits, resulting in production of low-oil DDGS. Many studies have shown that caking, and thus flow, of regular DDGS is an issue during handling and transportation. This study measured the dynamic flow properties of low-oil DDGS. Flow properties such as stability index (SI), basic flow energy (BFE), flow rate index (FRI), cohesion, Jenike flow index, and wall friction angle were measured at varying temperature (20°C, 40°C, 60°C), RH (40%, 60%, 80%), moisture content (MC; 8%, 10%, 12% w.b.), CP (generated by 0, 10, and 20 kg overbearing loads), and consolidation time (CT; 2, 4, 6, 8 days) for low-oil DDGS. Response surface modeling (RSM) and multivariate analysis showed that MC, temperature, and RH were the most influential variables on flow properties. The dynamic flow properties as influenced by environmental conditions were modeled using the RSM technique. Partial least squares regression yielded models with R2 values greater than 0.80 for SI, BFE, and cohesion as a function of MC, temperature, RH, CP, and CT using two principal components. These results provide critical information for quantifying and predicting the flow behavior of low-oil DDGS during commercial handling and transportation

Cohesive properties of wheat flour and their effect on the size-based separation process

Doctor of PhilosophyDepartment of Grain Science and IndustryR. P. Kingsly AmbrosePraveen V. VadlaniWheat flour processing involves gradual size reduction and size-based fractionation of milled components. The size-based separation efficiency of wheat flour particles, with minimum bran contamination, is an important flour mill operational parameter. The flour particles often behave as imperfect solids with discontinuous flow and agglomerates during the separation process due to their differences in physical and chemical characteristics. Noticeable loss in throughput has been observed during sieving of soft wheat flour compared to that of hard wheat flour due to differences in inter-particle cohesion. However, there is limited understanding on the factors that influence the inter-particulate forces. Direct and indirect methods were applied to investigate the effects of moisture content, particle size, sifter load, and chemical composition on the cohesion behavior of flours from different wheat classes. Image analysis approach was used to quantify the particle characteristics such as surface lipid content, roughness, and morphology with respect to particle size to better understand the differences between hard and soft wheat flours. Surface lipid content and roughness values showed that the soft wheat flours are more cohesive than hard wheat flours. The morphology values revealed the irregularity in flour particles, irrespective of wheat class and particle size, due to nonuniform fragmentation of endosperm particles. The chemical composition significantly contributes to the differences in cohesion and flowability of wheat flours. Based on the particle parameters, a granular bond number (GBN) model was developed to predict the dynamic flow of wheat flour. In order to further understand the wheat flour flow behavior during size-based separation, a correlation was developed using the discrete element method (DEM). The error of predictions demonstrated that this correlation can be used to estimate the sieving performance and sieve blinding phenomenon of wheat flour. The experimental results from this dissertation work and the numerical model could eventually be instrumental to improve the efficiency of size-based separation of flour from various wheat classes. In addition, the models developed in this study will contribute significantly to understand the inter-particle cohesion as influenced by chemical composition

Significance of storage conditions on the flow properties of wheat flours

Flow properties of wheat flours are influenced by their intrinsic properties and environmental conditions during handling. This study evaluated the effects of environmental conditions (temperature and relative humidity- %RH) and flour properties (particle size and wheat class) on the flow properties of wheat flours. Size fractions from hard red winter (HRW) and soft red winter (SRW) wheat were produced through sieving. Flour fractions were then exposed to various temperature (25 and 35 oC) and relative humidity (50, 60, and 70%RH) combinations (t = 3 h) to evaluate the effects of environmental conditions. Flow indicators (Hausner ratio – HR and compressibility index - CI) and flow (bulk, dynamic, and shear) properties were measured for the wheat flours after treatment. Shape analysis showed that all flour fractions were spherical based on their aspect ratio (\u3e 0.7) and elongation (\u3c 0.3) values. Flow properties indicate that soft wheat flours had poorer flowability compared to hard wheat flours. Lower flow function (FFc) were observed for finer flour fractions (FFc \u3c 4.0) of both flour types relative to the coarser particles (FFc \u3e 4.0) which indicates poorer flowability. Higher humidity levels (60 and 70%) also caused poorer flowability for the wheat flours after exposure. The results from this study show that both environmental factors and flour characteristics have significant effects on flour flow properties. Handling wheat flours at lower humidity levels and higher temperatures improve flowability. Hard wheat flours were more flowable than soft wheat flours; coarser fractions from both wheat types flow better than finer fractions

Pilot Scale Roller Milling of Chickpeas into a De-Hulled Coarse Meal and Fine Flour

Chickpeas and other high protein plants are becoming increasingly popular. Traditionally, attrition or hammer mills are used for milling chickpeas. However, the use of roller mills on chickpeas has not been extensively researched. This study compared pilot-scale milling trials involving whole Kabuli compared to split and de-hulled Desi chickpeas. A flow sheet was designed and optimized for meal production with minimal co-product flour produced. Milling yields, particle size, and proximate analysis data were recorded. The optimum flow sheet consisted of 4 break passages, 2 smooth roll passages, and 4 purifiers. Results showed whole Kabuli chickpeas had a higher meal yield, at 63.8%, than split Desi seeds, at 54.1%; with both percentages proportional to the weight of milled seed. The remaining 36.2% or 45.9% consisted of co-product flour, feed streams and process losses. Both meals had an average particle size between 600 and 850 microns and both flours had a bimodal particle size distribution with peaks at 53 and 90–150 microns. The use of purifiers facilitated better separation of hull and resulted in lower crude fiber levels in the Kabuli meal. Proximate analysis trends were similar for both chickpea meals with higher protein (~2% more), crude fiber (~1% more) and ash (0.1–0.3% more) in the meal compared to the co-product flour. The co-product flour had substantially higher total starch (~15% more) than the meal. The results of this research can be used to modify wheat mills to process chickpeas

Effect of Pulse Type and Substitution Level on Dough Rheology and Bread Quality of Whole Wheat-Based Composite Flours

Pulse flours are commonly added to food products to improve the functional properties, nutritional profiles, product quality and health benefits. This study aimed at assessing the effects of the partial replacement (0–25%) of whole wheat flour with diversified whole pulse flours (yellow pea, green pea, red lentil, and chickpea) on dough properties and bread quality. The pulse flours had higher protein contents and ash, but lower moisture content and larger average particle size, compared to whole wheat flour. Increasing the substitution level of pulse flours decreased dough viscosity, stability, development time and bread volume, and accelerated bread retrogradation. The incorporation of 5% yellow pea flour led to a similar bread quality as that with only whole wheat flour. Among all the tested pulse flours, the composite flour containing yellow pea flour or chickpea flour had overall better potential for bread making by providing good dough handling properties and product quality. This study will benefit the development of more nutritious food products by combining cereal and pulse ingredients

Considerations for gluten free foods - pearl and finger millet processing and market demand

The market demand for gluten free foods is increasing due to frequent incidences of celiac disease and increasing awareness on consumption of gluten free foods. Millets have become the major constituent of diet as they are gluten-free and also excellent sources of micro and macro nutrients such as vitamins, minerals, dietary fibers and phenolic compounds. Among various millets, the finger millet and the pearl millet are the two most important and common millet varieties grown extensively. Since, they are regarded as the staple foods of the poor and vulnerable populations, development of new products and improvements in their nutritional quality will aid in the general health of these population. Processing of millets and production of variable gluten-free ready-to-eat and nutritional supplements has increased their market value in the recent years. Furthermore, processing can also help in shelf-life extension of the millets with nutritional enrichment, expanding its markets to non-traditional millet consumers. In this context, the present review is aimed to focus on the current processing methods to develop products from the two millet varieties that are gluten free and outline their nutritional benefits

Modern Processing of Indian Millets: A Perspective on Changes in Nutritional Properties

Globally, billions of people are experiencing food insecurity and malnutrition. The United Nations has set a global target to end hunger by 2030, but we are far from reaching it. Over the decade, climate change, population growth and economic slowdown have impacted food security. Many countries are facing the challenge of both undernutrition and over nutrition. Thus, there is a need to transform the food system to achieve food and nutrition security. One of the ways to reach closer to our goal is to provide an affordable healthy and nutritious diet to all. Millets, the nutri-cereals, have the potential to play a crucial role in the fight against food insecurity and malnutrition. Nutri-cereals are an abundant source of essential macro- and micronutrients, carbohydrates, protein, dietary fiber, lipids, and phytochemicals. The nutrient content and digestibility of millets are significantly influenced by the processing techniques. This review article highlights the nutritional characteristics and processing of Indian millets, viz. foxtail, kodo, proso, little, and pearl millets. It also envisages the effect of traditional and modern processing techniques on millet’s nutritional properties. An extensive literature review was conducted using the research and review articles related to processing techniques of millets such as fermentation, germination, dehulling, extrusion, cooking, puffing, popping, malting, milling, etc. Germination and fermentation showed a positive improvement in the overall nutritional characteristics of millets, whereas excessive dehulling, polishing, and milling resulted in reduction of the dietary fiber and micronutrients. Understanding the changes happening in the nutrient value of millets due to processing can help the food industry, researchers, and consumers select a suitable processing technique to optimize the nutrient value, increase the bioavailability of nutrients, and help combat food and nutrition security

Phosphine distribution during fumigation of wheat in steel bins: extended abstract: Poster

Phosphine is a widely used fumigant for controlling insects in stored grain, but fumigation effectiveness is often compromised by suboptimal distribution of the gas. Leaks in the grain bin wall and roof, foreign material in the grain, and phosphine placement contribute to regions of insufficient concentration of fumigant, resulting in insect survival and leading to phosphine-resistant insect populations. Phosphine distribution was studied during field tests in temporarily sealed bins to compare distribution from conventional probed tablets to the distribution using a closed-loop recirculation system. The results showed uneven distribution patterns and leakage over time with conventional probed tablets, which resulted in some areas in the lower half of the grain mass receiving no phosphine and some other locations remaining below the target phosphine concentration for the entire period of fumigation. The closed-loop fumigations with the same phosphine dosage yielded much more uniform phosphine concentrations, but suffered from equal or greater phosphine leakage losses.Phosphine is a widely used fumigant for controlling insects in stored grain, but fumigation effectiveness is often compromised by suboptimal distribution of the gas. Leaks in the grain bin wall and roof, foreign material in the grain, and phosphine placement contribute to regions of insufficient concentration of fumigant, resulting in insect survival and leading to phosphine-resistant insect populations. Phosphine distribution was studied during field tests in temporarily sealed bins to compare distribution from conventional probed tablets to the distribution using a closed-loop recirculation system. The results showed uneven distribution patterns and leakage over time with conventional probed tablets, which resulted in some areas in the lower half of the grain mass receiving no phosphine and some other locations remaining below the target phosphine concentration for the entire period of fumigation. The closed-loop fumigations with the same phosphine dosage yielded much more uniform phosphine concentrations, but suffered from equal or greater phosphine leakage losses