This study was conducted to evaluate the influence
of maturity, mold contamination and variety on the color
quality of strawberry wines. Indices for acceptability
were determined using instrumental measurements and
sensory analysis.
Compositional analyses were done on the fully ripe
and overripe Benton and Totem strawberries. Included were
anthocyanin content, flavanols, leucoanthocyanins, total
phenolics, non-flavonoid phenolics, ascorbic acid, soluble
solids, titratable acidity and pH. The Totem variety
contained more anthocyanins, flavanols, ascorbic acid,
leucoanthocyanins, and was slightly higher in pH than
the Benton variety. Likewise, the overripe fruit contained
more anthocyanins, flavanols, leucoanthocyanins,
total phenolics and was higher in pH than the fully ripe
fruit. Polyphenoloxidase and β-Glucosidase activities
were assayed. Polyphenoloxidase activity was higher in
the Benton and in the fully ripe berries. β-Glucosidase
activity was extremely low for all the samples.
Six batches of wine were made from the Benton
fully ripe, Benton overripe, Benton fully ripe spiked
with moldy Bentons, Totem fully ripe, Totem overripe
and Totem fully ripe spiked with moldy Totems. Howard
Mold Counts were determined on the crushed strawberries
and on the strawberry juice.
Color parameters were measured on the juice and
on the finished wines which includes color density,
polymeric color, % polymeric color, browning index and
anthocyanin content. Hunter "L," "a" and "b" values and
% haze were also measured. Changes in these color parameters
of the wines were monitored weekly for a period
of 6 weeks. Samples were stored in the dark at 25°C.
A sensory analysis, mainly evaluating the color
quality of the wines after storage based on color intensity,
hue, browning, clarity and over-all color and
appearance, was conducted.
One-way ANOVA analyses showed significant differences
between the two varieties, the two levels of maturity
and the mold-contaminated wines.
Multiple correlation data showed that anthocyanin
content of the wine and Hunter "L" are highly correlated
with all of the sensory indices for color, hence, are good
predictors of color acceptability. Total phenolics,
non-flavonoid phenolics and soluble solids are highly correlated
to color density, polymeric color, browning index
and Hunter "a" values of the wines. Likewise, anthocyanin
content, flavanols, leucoanthocyanins, titratable acidity
and pH are highly correlated to overall color and appearance,
color intensity and hue. Polyphenoloxidase also showed
high correlation with overall color and appearance, color
intensity and browning. / Graduation date: 1983
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27451 |
| Date | 24 August 1982 |
| Creators | Pilando, Leticia S. |
| Contributors | Wrolstad, Ronald E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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