Quantification and purification of lutein and zeaxanthin recovered from distillers dried grains with solubles (DDGS)

Abstract

Marigold petals, the current commercial source for lutein and zeaxanthin are harvested through a labor-intensive operation with downstream purification requiring multiple processing steps involving various harsh solvents. Lutein and zeaxanthin are in-demand carotenoids due to their significant role in human eye health. A possible alternative source for lutein and zeaxanthin, distillers dried grain with solubles (DDGS), shows promise and contains a yet-to-be quantified amount of the desired carotenoids. The US corn industry produces an abundant, and in some cases excess, annual supply of DDGS. The large volume of DDGS produced could serve as a significant source for lutein and zeaxanthin recovery and provides an additional market stream for the growing carotenoid industry. This paper demonstrates one of the first quantitative reports regarding the concentration of lutein and zeaxanthin in DDGS. Using Soxhlet extraction, followed by purification with centrifugal partition chromatography, it was determined that 36.09 ± 16.87 µg lutein and 15.48 ± 6.13 µg zeaxanthin could be purified from all extractives retained in the oleoresin per gram of DDGS. As compared to lutein and zeaxanthin present in corn, this is a three to fivefold increase indicating that these compounds become concentrated during the dry grind process. Recovery of lutein and zeaxanthin from DDGS, a low-value stream by-product of corn ethanol industry, results in a new revenue stream and would add value to a common US commodity.