Identifier

etd-09022013-183036

Degree

Master of Science (MS)

Department

School of Nutrition and Food Sciences

Document Type

Thesis

Abstract

Cane berry pomaces have traditionally been considered waste products with little or no value. Yet these pomaces’ high levels of phenolic compounds such as anthocyanins, is a good source of dietary fiber. Because the pomaces are low in sugar and rich in fiber and dietary antioxidants, they have potential as food ingredients for the health food market. The pomace delivers health benefits associated with high fiber and the antioxidant polyphenolic compounds associated with whole fruits and juices without the high sugar content. Some dietary fibers are substrates for anaerobic fermentation by the microbiome in the lower gastrointestinal (GI) tract. The anaerobic fermentation of dietary fiber results in a lowering of the pH in the biomass and production of short chain fatty acids. In this study, a model system mimicking colonic fermentation in the digestive tract was developed and used to assess fermentation of cane berry pomace by colonic bacteria. Pomace samples from blueberry and black raspberry, and Hi-Maize© resistant starch (a high amylose cornstarch used as the positive control) were treated with pepsin followed by pancreatin digestion to simulate the digestive changes in the upper gastrointestinal (GI) tract. After the digestion, the remaining undigested material was washed and air dried. The fiber was then fermented anaerobically with an inoculum of colonic bacteria prepared from fecal donations of healthy volunteers. The fermentation of the blueberry and black raspberry pomaces using the inoculum from 5 individuals resulted in a wide range of SCFA production. Fermentation with Hi-maize© resistant starch resulted in production of higher concentrations of SCFAs compared to the cane berry pomace substrates. An inoculum, prepared by mixing individual stool samples from five individuals, provided a microbiota that represented a broader population, thus resulting in a more generalized result. The production of acetate, propionate and butyrate was significantly higher in the pooled sample compared to results from individual donors. A different group of 5 individuals consumed a diet rich in resistant starch (RS) for a month and at the end of that period their stool samples were collected and used to prepare a pooled inoculum. The pooled inoculum from subjects with RS-fortified diet produced higher level of SCFAs than the pooled inoculum with non-fortified diet expect the Hi-Maize© RS which did not show difference at 0.05 significance level.

Date

2013

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Finley, John W.

DOI

10.31390/gradschool_theses.1012

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