Submitted to: Food Science and Technology International
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/28/2009
Publication Date: 8/1/2010
Citation: Inglett, G.E., Chen, D., Rose, D.J., Berhow, M. 2010. High-shear, jet-cooking, and alkali treatment of corn distillers' dried grains to obtain products with enhanced protein, oil, and phenolic antioxidants. Food Science and Technology International. 16(4):297-308. Interpretive Summary: This research demonstrated processing procedures to increase the value of distiller's dried grains (DDGs) by producing fractions and extracts useful as food and nutraceutical ingredients. Corn is an important source of starch for fuel ethanol production. After ethanol production from corn starch, the remaining slurry is termed distillers’ dried grains (DDG). DDG has traditionally been used as animal feed; however, the demand for ethanol has flooded the marketplace with this low-value byproduct. Distillers dried grains (DDG) have potential to be a nutritionally important source of high-value protein, oil, and antioxidants, as each of these components are present in relatively high levels in DDG. Thus, the objective of this research was to utilize various processing procedures including high-shear, jet-cooking, and alkali treatment to further concentrate these valuable components. After treatment, the results suggest that high-shear and jet-cooking are useful processing treatments to increase the value of DDG by producing fractions enhanced with protein, oil and extractable antioxidants. These DDG fractions and extracts may be useful as food and nutraceutical ingredients, thus increasing the value of DDG and easing economic burdens on ethanol producers, allowing them to compete in the bio-fuel marketplace.
Technical Abstract: Distillers dried grains (DDG) have potential to be a nutritionally important source of protein, oil, and phenolic antioxidants. DDG was subjected to high-shear and jet-cooking, with or without alkaline pH adjustment and autoclaving. Soluble and insoluble fractions were analyzed for protein, oil, and ash. Extracts were analyzed for phenolic acids and antioxidant activity. Protein contents were significantly elevated in the insoluble fractions after treatment, and the oil content was drastically increased in the insoluble fraction after high-shear and jet-cooking without pH adjustment. Alkaline pH adjustment resulted in a soluble fraction that was highest in phenolic acids, but not antioxidant activity. The highest antioxidant activity was found in the 50% ethanol extract from DDG that had been subjected to high-shear and jet-cooking. These results suggest that high-shear and jet-cooking may be useful processing treatments to increase the value of DDG by producing fractions high in protein, oil, and extractable phenolic acids with high antioxidant activity. The DDG fractions and extracts described herein may be useful as food and nutraceutical ingredients, and, if used for these applications, will increase the value of DDG and ease economic burdens on ethanol producers, allowing them to compete in the bio-fuel marketplace.