Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 37-40).

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 94-109).

The elucidation of the structure of the red pigments of the black raspberries. Monger variety, was achieved. The components of the pigment of the berries were (a) cyanidin-3-glucoside, (b) cyanidin-3, 5-diglucoside, (c) cyanidin-3-diglucoside and (d) cyanidin-3-rhamnoglucosido- 5-glucoside. The elucidation was carried out after isolation, purification, concentration and chromatographic separation of the components. Further analysis by paper chromatographic techniques and spectrophotometric methods were carried out on the pigments and their products after specific chemical degradations. The degradation of the major anthocyanin component, cyanidin- 3-diglucoside, was further studied in buffered model systems of various pH values at 50°C. As the pH of the medium decreased the anthocyanin stability increased. The same was true for total crude pigment and the anthocyanin in the juice. Nitrogen atmosphere enhanced the stability of cyanidin-3- diglucoside as compared to an oxygen atmosphere. This held for the crude pigment and juice as well. Cyanidin in buffered model systems at 50°C was much more unstable than cyanidin-3-diglucoside under the same conditions. Nitrogen atmosphere resulted in improvement of the pigment retention over that in atmospheric conditions. The thermal degradation of cyanidin-3-diglucoside in model systems followed first order kinetics. The rate constants of the reaction at various pH levels under air and nitrogen were determined. The effect of the presence of various sugars and their degradation products on the destruction of cyanidin-3-diglucoside was studied in buffered model systems of pH 3.25 at 50°C. All of these additives increased the rate of pigment destruction. No differences were revealed among the sugars glucose, fructose, xylose and sucrose, which were used. All reactions followed first order kinetics and the rate constants were determined. When these reactions were carried out in the presence of nitrogen instead of air, a marked decrease in the rate of the pigment destruction was detected. Ascorbic acid in model buffered systems of pH 3.25 at 50°C markedly accelerated the destruction of cyanidin-3-diglucoside. Metal ions and atmospheric oxygen acted synergistically with ascorbic acid in the destruction of this anthocyanin. When the action of either of these synergists was blocked, the stability of the pigment was increased. EDTA was found to improve the retention of cyanidin-3-diglucoside by means of its ability to chelate the metal ions present, thus indirectly inhibiting the effect of ascorbic acid. When nitrogen was used instead of air, an improvement of the stability of anthocyanin in this system resulted. The degradation of cyanidin-3-diglucoside and the disappearance of ascorbic acid followed the same pattern. The same observations were also true for the anthocyanins of the juice. Cyanidin-3-diglucoside in buffer at pH 6.5 was acted upon by tyrosinase. This activity was low but nevertheless demonstrable. When catechol was added to this system, a rapid decolorization of anthocyanin was produced. This effect was further investigated and a scheme of the enzymatic reaction was proposed. Protocatechuic acid and tyrosine were able to couple with cyanidin-3-diglucoside and enhance the destructive action of tyrosinase on anthocyanins. The rate of the decolorization of the anthocyanin was lower in these systems than in the coupling with catechol. / Graduation date: 1966

The total synthesis of cyanindin-3-glucoside (C3G) appropriate for ��C enrichment at C-1` and C-6` has been achieved for metabolic studies. Construction of the phenolic ring-B was achieved by a Diels-Alder reaction employing a novel diene, (2R,3R)-2,3-dimethyoxy-2,3-dimethyl-5,6-dimethylene-1,4-dioxane, which incorporates a butane diacetal protecting motif. Reaction with a (labelled) dienophile affords the protected catechol. Formation of the flavone skeleton was achieved by condensation of the benzamide (ring-B) with an acetophenone (ring-A). Esterification of the flavone skeleton in ring-A was found to be essential for oxidation at C-3 with dimethyldioxirane affording the flavonol. Glycosylation using a glucosyl bromide gave the β-adduct exclusively which was reduced to the target compound, C3G. The overall synthetic design permits the synthesis of the labelled anthocyanin in nine steps (23%) from the dienophile.

No description available.

The total synthesis of cyanindin-3-glucoside (C3G) appropriate for ��C enrichment at C-1` and C-6` has been achieved for metabolic studies. Construction of the phenolic ring-B was achieved by a Diels-Alder reaction employing a novel diene, (2R,3R)-2,3-dimethyoxy-2,3-dimethyl-5,6-dimethylene-1,4-dioxane, which incorporates a butane diacetal protecting motif. Reaction with a (labelled) dienophile affords the protected catechol. Formation of the flavone skeleton was achieved by condensation of the benzamide (ring-B) with an acetophenone (ring-A). Esterification of the flavone skeleton in ring-A was found to be essential for oxidation at C-3 with dimethyldioxirane affording the flavonol. Glycosylation using a glucosyl bromide gave the β-adduct exclusively which was reduced to the target compound, C3G. The overall synthetic design permits the synthesis of the labelled anthocyanin in nine steps (23%) from the dienophile.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1936. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 86-91).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Pelargonidin 3-glucoside (pgd 3-glu), pelargonidin 3-sophoroside (pgd 3-soph), and pelargonidin 3-sophoroside 5-glucoside acylated with cinnamic and malonic acids (acyl-pgd 3-soph 5-glu) were extracted from strawberries (Fragaria anannassa cv, Totem), nasturtium flowers (Tropaeolum majus), and radish peel (Raphanus sativus L. cv, fuego), respectively. Their stability was studied in natural and model systems. Natural systems consisted of strawberry juice at 8 °brix and strawberry concentrate at 65 °brix that were spiked with the anthocyanins (ACNS) to double the initial pigment concentration. Model systems at low, intermediate, and high water activity levels consisted of pH 3.4 citrate buffer, glycerol, and pigment. Changes in pigment, degradation index, color, and relative peak area were monitored during storage in the dark at 25°C. Ascorbic acid degradation was also monitored in the natural systems. Anthocyanin (ACN) degradation followed first order kinetics. No difference in stability of the samples was found with fortified pgd derivatives; however, there was significant difference in the degradation of ACNS between natural and model systems. The half life (t [subscript 1/2]) of the ACNS ranged from 3.5 to 5 days in the concentrate, from 8 to 12 days in juice, and from 58 to 934 days in model systems. In general, high Aw increased ACN degradation. Ascorbic acid degradation followed first order kinetics and was accompanied by ACN degradation. / Graduation date: 1999