Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/11/2004
Publication Date: 5/9/2004
Citation: Dowd, M.K., Pelitire, S.M. 2004. Extraction, recovery, and stability of carotenoids from corn gluten meal. Meeting Abstract. Interpretive Summary:
Technical Abstract: Corn gluten meal fractions (wet meal (60% moisture), freeze-dried meal, and high-temperature dried meal) were extracted with different solvents (methanol, ethanol, propanol, butanol, acetone, ethyl acetate, and hexane) to recover carotenoids. Most polar solvents were found to extract large amounts of the pigments from wet meal, lesser amounts from freeze-dried meal, and only small amounts from high-temperature dried meal. To better understand the influence of moisture and drying on the extractability of the pigments, additional experiments were conducted with ethanol. For meal dried to 5-10% moisture, the temperature of drying had a marked influence on the extractability of the pigments. The extraction was also sensitive to meal moisture content. At an ethanol-to-meal (v/w) ratio of 10, meal moisture levels near 60% (typical of corn gluten meal exiting rotary-drum filters) were almost optimal for carotenoid recovery. Higher moisture levels (i.e., higher water-to-ethanol ratios) promoted the co-extraction of large amounts of protein (zeins) resulting in reduced meal yield and protein concentration. Increasing the ethanol-to-meal ratio was useful for limiting the co-extraction of protein. The stability of the carotenoids in the alcoholic extracts was also studied over a 6-wk period. Negligible losses occurred when the extracts were stored in the dark at -20 C, but significant losses occurred with stored at higher temperatures. At 4 C, the extracts retained 80% of the initial carotenoid concentration. At room temperature, the extracts retained 45% of the pigments. In comparison, room temperature storage over the same period in the presence of sunlight resulted in >95% loss of the pigments. Antioxidants were not found to improve the stability of the extracts; however, drying the pigments onto solid substrates improved the stability.