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
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27267 |
| Date | 30 June 1998 |
| Creators | Garzon, G. Astrid |
| Contributors | Wrolstad, Ronald E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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