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Innovative zein extraction from distillers' grains with solubles: Process development and product characterization studies
Author(s) -
Gupta Jhinuk,
Vadlani Praveen V.,
Lau ChingShuan,
Madl Ronald L.,
Shi Yong C.
Publication year - 2018
Publication title -
environmental progress and sustainable energy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.495
H-Index - 66
eISSN - 1944-7450
pISSN - 1944-7442
DOI - 10.1002/ep.13093
Subject(s) - distillers grains , extraction (chemistry) , yield (engineering) , chemistry , environmentally friendly , ethanol fuel , pulp and paper industry , chemical engineering , food science , materials science , ethanol , chromatography , organic chemistry , ecology , engineering , metallurgy , biology
Zein is a promising bioplastic for replacing polyethylene, a widely used industrial polymer. However, current processes of zein production are associated with high production costs. Replacing corn with abundantly available, underutilized, corn co‐products such as dried distillers' grains with solubles (DDGS), in addition to using a binary solvent mixture, may help to reduce the cost. Strongly alkaline and acidic extraction media are known to enhance zein yield. However, use of such corrosive conditions may shorten the life of equipment and substantially deter scalability to the industrial level. Here, we propose an innovative high‐yielding protocol that isolates zein from DDGS at milder pH and lower ethanol concentrations without significant compromise on purity. Response surface methodology was used for optimizing the extraction parameters. Purity of the extracted zein was tested using proximate analysis, gel electrophoresis, and infrared spectroscopy. Use of aqueous ethanol (63%, v/v, pH 5) at 77 °C, followed by cryoprecipitation at −20 °C, resulted in a zein product of 84% protein purity at 11.64% yield (based on DDGS dry mass). The process was scaled up to 7 L scale without significant change in yield and purity. Results of this study are important as they offer an easily scalable protocol for affordable zein production other than efficient valorization of DDGS. Novelty or Significance: Although strongly alkaline and acidic solvents help to enhance zein yield from DDGS, their use is not preferred by industry. Here, we report an innovative, environmentally friendly, zein extraction protocol, which gives higher yield at a milder pH without losing purity. Moreover, lower ethanol requirements, as compared to earlier reports, and use of inexpensive and easily scalable techniques such as precipitation, filtration, and ambient temperature air‐drying, help to reduce zein production costs and makes the protocol industrially adoptable. © 2018 American Institute of Chemical Engineers Environ Prog, 2018 © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13093, 2019