In 2013, 35.5 million metric tons of distillers grains was produced as coproducts of the fuel ethanol industry, and beef cattle account for almost half of distillers grains consumption. Feeding distillers grains to cattle can increase Polyunsaturated fatty acids concentration, increase lipid oxidation, and decrease color stability of beef.
The objective of this study was to evaluate the effects of feeding distillers grains and the postmortem addition of antioxidants on the shelf life of ground beef products. Crossbred heifers were supplemented with different amounts of modified distillers grains during backgrounding and finished on diets containing corn gluten feed or modified distillers grains.
Raw patties in retail display were analyzed for lipid oxidation, percent discoloration, and objective color. Cooked beef links were manufactured with salt, phosphate, and varying quantities of an antioxidants (rosemary and green tea extract), and lipid oxidation was measured throughout storage. The use of plant extracts such as rosemary or green tea as natural antioxidants is common in meat processing.
Finishing cattle fed modified distillers grains had higher a polyunsaturated fatty acids content in all locations. Supplementation with modified distillers grains during backgrounding had less effect on fatty acid composition of ground beef than including modified distillers grains in the finishing diets. Greater lipid oxidation in cooked beef links occurred when cattle were fed greater amounts of modified distillers grains during backgrounding or modified distillers grains during finishing. Regardless of dietary treatment, the addition of rosemary and green tea extract as an antioxidant was effective at limiting lipid oxidation in refrigerated or frozen storage.
IMPLICATIONS: Backgrounding supplementation had minimal effect on fatty acid composition, but backgrounding supplementation with greater amounts of distillers grains did affect lipid oxidation of cooked beef links in refrigerated and frozen storage. Finishing diets including modified distillers grains increased polyunsaturated fatty acids concentrations, resulting in greater discoloration in raw beef in retail display, and increased lipid oxidation in cooked beef links in refrigerated and frozen storage. These findings identify the effects of feeding ethanol co-products to cattle on raw and cooked ground beef and demonstrate the effectiveness of added antioxidants in cooked beef products.