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The over-enrichment of phosphorus in waste streams can lead to eutrophication and oxygen limitations for aquatic life. To understand the release of phosphorus from a soybean processing facility, it is imperative to track the flow of phosphorus in different streams during the processing of soybeans. The objective of the study is to develop process simulation models to study the flow of phosphorus in the soy-biodiesel process and evaluate strategies to mitigate phosphorus release by recovering phosphorous from soapstock and wastewater. Since most of the P is found in soybean meal, the processing of which releases phosphorus, a third case of lecithin recovery was also studied to reduce the amount of phosphorous in soybean meal. It was observed that phosphorus can be economically recovered from the soapstock, as well as the wastewater stream, with an estimated operating cost of USD 1.65 and 3.62 per kg of phosphorous recovered, respectively. The phosphorus recovered from both streams can be potentially applied as fertilizer to more than 13,000 acres of corn or 96,000 acres of soybean, respectively. The lecithin recovery case was found to have the highest revenue, and it led to a 54% reduction in phosphorous during soybean meal processing.
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Phosphorus flow in production of soy protein concentrate and isolate from defatted soybean flour
Abstract Implications of excess phosphorus (P) in waste streams obtained from soy‐based protein preparation processes on the environment and their potential utilization as P‐source are two significant understudied areas. Soybean‐based protein ingredients for food products retain comparatively enhanced functional properties and are cheaper than other plant‐based proteins. Soybean protein can be extracted and utilized as a food ingredient primarily by preparing soy protein concentrates (SPC) and soy protein isolates (SPI) from soybean meal/defatted soy flour (DSF). In a typical soybean processing facility, along with the soy products and soy‐protein preparations, the recovery of phosphorus as a coproduct will enhance the economic feasibility of the overall process as the recovered P can be used as fertilizer. In this study, the SPC and SPI were prepared from the DSF following widely used conventional protocols and P flow in these processes was tracked. In SPC production, ~59% of the total P was retained with SPC and ~34% was in the aqueous waste streams. For SPI process ~24% of total P was retained with SPI and ~59% went in the waste solid residue (~40%) and aqueous streams (~19%). About 80%–89% P removal from the waste aqueous streams was achieved by Ca‐phytate precipitation. This work demonstrated that in the process of SPC and SPI preparation the phosphorus from the waste aqueous streams can be precipitated out to avoid subsequent eutrophication and the waste solid residue with ~40% P can be reused as a P‐fertilizer as other applications of this residue are unspecified.
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- Award ID(s):
- 1739788
- PAR ID:
- 10470392
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of the American Oil Chemists' Society
- Volume:
- 100
- Issue:
- 12
- ISSN:
- 0003-021X
- Format(s):
- Medium: X Size: p. 985-991
- Size(s):
- p. 985-991
- Sponsoring Org:
- National Science Foundation
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