Graduate Thesis Or Dissertation
 

Breeding tomatoes for improved antioxidant activity

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/v118rg71s

Descriptions

Attribute NameValues
Creator
Abstract
  • Purple tomatoes (Lycopersicon esculemtum) were bred by incorporating genes that result in anthocyanin production in the skin of fruits. These genes originally came from related wild species as no naturally occurring genes encoding fruit anthocyanin expression are known within the cultivated species. By combining Aft or Abg with atv or hp-1, expression in the fruit was enhanced. Light affected intensity of anthocyanin expression because shaded portions of the fruit lacked purple color. The issue of allelism between Aft and Abg was not resolved. Tomato lines that combined anthocyanin genes with red (wild type) orange (B) and yellow (r) carotenoid pigments were developed. The anthocyanins responsible for the purple color were characterized by HPLC-DAD and HPLC-MS. The predominant anthocyanin was petumdin-3-(p-coumaryl)-rutinoside-5-glucoside, with detection of five additional forms of petunidin, malvidin, and delphinidin in lower amounts. Up to 300 mg g⁻¹ FW of anthocyanin in skin of fruits was detected with an average of about 14 mg g⁻¹ FW. Flavonoid precursors to anthocyanin were also upregulated in the fruit. Anthocyanin- and total phenolic contents were related to changes in antioxidant activity using the Oxygen Radical Absorbance Capacity assay. The introduction of anthocyanin-expression inducing genes to the tomato significantly increased antioxidant activity in both the hydrophilic and lipophilic fractions of the tomato fruit. Tomato lines with similar genetic background but different carotenoid profiles conditioned by ogc, Del, r, and B genotypes were characterized for antioxidant capacity. These genes alter expression of carotenoids to produce elevated levels of P-carotene, all-trans-lycopene, prolycopene, 8- carotene, or with diminished total carotenoid. Tomato juice was made from each of these lines and fed to two human volunteers, following which blood plasma was drawn and evaluated for antioxidant capacity. Although differences in antioxidant activity of plasma measured by Total Antioxidant Performance and Ferric Reduction Assay of Plasma assays were observed, the contribution of the carotenoids was limited relative to the effects of other antioxidants present in the tomato. A major finding of this research was that the water-soluble antioxidants contribute significantly more to overall antioxidant activity compared to the lipidsoluble antioxidants. Future breeding efforts can capitalize on these discoveries to produce a tomato with unprecedented levels of antioxidant activity and nutrient content.
License
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 256 Grayscale) using Scamax Scan+ V.1.0.32.10766 on a Scanmax 412CD by InoTec in PDF format. LuraDocument PDF Compressor V.5.8.71.50 used for pdf compression and textual OCR.
Replaces

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details MESPETERD2005.pdf 2017-08-02 Public Download