Leopold Center for Sustainable Agriculture

Leopold Center for Sustainable Agriculture

ID

leopold

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URI

https://dr.lib.iastate.edu/handle/20.500.12876/99035

Publication Search Results

Now showing 1 - 3 of 3

Publication

Extraction Methods of Oils and Phytochemicals from Seeds and Their Environmental and Economic Impacts

2021-10-16 , Lavenburg, Valerie M. , Jung, Stephanie , Agricultural and Biosystems Engineering , Food Science and Human Nutrition , Leopold Center for Sustainable Agriculture , Center for Crops Utilization Research , Biorenewable Resources and Technology , Environmental Science

Over recent years, the food industry has striven to reduce waste, mostly because of rising awareness of the detrimental environmental impacts of food waste. While the edible oils market (mostly represented by soybean oil) is forecasted to reach 632 million tons by 2022, there is increasing interest to produce non-soybean, plant-based oils including, but not limited to, coconut, flaxseed and hemp seed. Expeller pressing and organic solvent extractions are common methods for oil extraction in the food industry. However, these two methods come with some concerns, such as lower yields for expeller pressing and environmental concerns for organic solvents. Meanwhile, supercritical CO2 and enzyme-assisted extractions are recognized as green alternatives, but their practicality and economic feasibility are questioned. Finding the right balance between oil extraction and phytochemical yields and environmental and economic impacts is challenging. This review explores the advantages and disadvantages of various extraction methods from an economic, environmental and practical standpoint. The novelty of this work is how it emphasizes the valorization of seed by-products, as well as the discussion on life cycle, environmental and techno-economic analyses of oil extraction methods.

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Publication

Pellet Quality of Corn-Based DDGS

2021 , Ma, Mingjun , Agricultural and Biosystems Engineering , Food Science and Human Nutrition , Leopold Center for Sustainable Agriculture , Biorenewable Resources and Technology , Environmental Science , Center for Crops Utilization Research

The rapid growth of corn-based dry grind ethanol plants over the past decade in the US has resulted in a great increase in production of the coproduct DDGS (distillers dried grains with solubles). Since some physical properties like low bulk density and poor flowability can impact the market potential of DDGS, pelleting of DDGS can be one of the easiest ways to improve this situation. Pellet quality is the focus of this project. The pelleting process was conducted with three initial DDGS moisture contents and two different dies; a total of six runs were complete d to produce DDGS pellets. The physical qualities of pelleted DDGS were determined by measuring durability bulk density angle of repose and color of the pellets. The results showed that the durability ranged from 42% to 89%, the highest pellet durability occurred when the moisture c ontent was 20% db and the die diameter was 1/8 in. The bulk density increased when the DDGS moisture content decreased, and the highest bulk density was observed when the moisture content was 10% db and the die diameter was 1/8 in

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Publication

Toward an Understanding of Physical and Biological Properties of Corn-Based Whole Stillage, Thin Stillage, and Condensed Distillers Solubles and Changes Thereof During Storage

2021-10-08 , Rosentrater, Kurt , Agricultural and Biosystems Engineering , Food Science and Human Nutrition , Leopold Center for Sustainable Agriculture , Center for Crops Utilization Research

The production of bio-based ethanol has been one of the fastest growing industries in the United States during the past decade. Thus, wider exploration of ethanol coproduct uses is necessary in the ethanol plant. Currently, process steams such as whole stillage, thin stillage, and syrup are processed into distiller dried grains with solubles and fed to livestock. The storability of whole stillage, thin stillage, and syrup influences the economic and energetic balances of fuel ethanol production. However, there are few investigations of the shelf life for these products or how to measure these quantities. The objectives of this research were to test physical and biological properties of whole stillage, thin stillage, and syrup and determine storability and allowable shelf life for these materials as influenced by storage temperature levels. Using standard laboratory methods, several properties were determined, including moisture content, water activity, thermal properties (conductivity, resistivity, volumetric heat capacity, and diffusivity), color, mold development, and CO2 production. Also, the separation processes due to settling were observed over 72 h. The thin stillage and whole stillage had relative high average moisture contents of 92% (w.b.) and 87% (w.b.), respectively, and a mean water activity of 0.99; the high water content marked samples easily susceptible to rapid spoilage. Time had a significant effect (p < 0.05) on properties of coproducts. Both thin stillage and whole stillage samples got mold growth after 5 days incubation at 32°C. Thin stillage had the greatest separation rate in the settling experiment. However, syrup had a relative low average moisture content of 62% and an average water activity of 0.92. No mold growth and settling separation happened in syrup samples. There was no evidence showing that a linear relationship exists between Hunter L*, a* and b*, and mold growth. The Solvita® test showed that high-temperature treatment caused high CO2 production in all samples. The exponential models described the relationship between storage time (from 0 to 5 days at 25 and 35°C) and CO2 concentration for the three coproducts. This study is a first step to explore opportunities for utilizing valuable components from these coproducts. Follow-up study should work on separation processes to concentrate the valuable components of these coproducts. Exploring the potential value of ethanol coproducts could maintain and improve the profitability of the ethanol industry.

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