Graduate Thesis Or Dissertation
 

Strawberry wine color quality : influence of variety, maturity and mold contamination

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https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/2z10wt180

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  • 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.
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