Document Type

Thesis - University Access Only

Award Date

2007

Degree Name

Master of Science (MS)

Department / School

Nutrition, Food Science, and Hospitality

Abstract

Distillers dried grain with solubles (DOGS) is currently sold at low price as an animal feed. Bu~ if separated, the individual components (fiber and protein) have the potential to have much greater value. The overall aim of this project was to take this low priced, over abundant by-product (DOGS) and turn it into two more desirable value added products, namely fuel through gasification and purified protein. Separation of the protein from the fiber prior to gasification gives the ethanol producer the ability to sell both the gasified fuel and purified protein thereby potentially increasing profits. An alkaline method was used to separate the protein-rich and fiber-rich fractions from com DOG. In this study, the process was modified to allow for a scaled up procedure resulting in kilogram scale fiber production which was utilized for gasification. The alkaline extraction (at 80° C) was followed by homogenization and centrifugation (fiberrich extract). The resulting supernatant was pH adjusted to pH 4 to precipitate protein (protein-rich extract). To remove excess sodium hydroxide from the fiber-rich extract, three treatments were investigated (NaOH Wash, Cold Water Wash and Hot Water Wash). The Hot Water Wash (1.04 % sodium) and Cold Water Wash treatments (1.66 % sodium) were found to be equally effective in removing excess sodium when compared to the NaOH Wash treatment (6.74 % sodium) with no subsequent wash steps. It was determined that the Cold Water Wash treatment produced a fiber-rich fraction containing the highest quantity of fiber (57.7 %) and the lowest quantity of protein (14.06 %). Functional properties of the extracted protein were determined for Oil Holding Capacity (229.77-263.59 g oil/l00g sample), Water Holding Capacity (1.16-1.47 mL water/g sample), emulsion capacity (152.0-215.0 mL oil), foaming capacity (216.7%-376.2%), foaming stability and viscosity. Extracted protein demonstrated good Oil Holding Capacity allowing its use as a dairy substitute. A good foaming capacity was also noted making the protein suitable for baked goods, egg substitute, toppings and whipped deserts. Foaming stability values indicated a lack of stability by the protein-rich fraction as foams quickly lost their volume. Viscosity at 23 ° C was much greater than values generated at 90° C.

Library of Congress Subject Headings

Distilling industries -- By-products

Alcohol industry -- By-products

Corn products

Extraction (Chemistry)

Format

application/pdf

Number of Pages

71

Publisher

South Dakota State University

Download

Share

COinS