Managing Apple Maturity and Storage to Increase the Quality of Virginia Hard Ciders
Ewing, Brianna Leigh
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Though the cidermaking process is very similar to that of winemaking, there is a lack of scientific knowledge as to how orchard management practices and fruit storage affect the quality of the resulting cider. This research examined how both varying harvest maturities and post-harvest storage temperatures and durations in apple cultivars Dabinett, Brown Snout, and York impacted fruit quality as well as the chemistry of the juice and cider. Harvest intervals of two weeks before maturity, at maturity, and 2 weeks after maturity resulted in significant differences in fruit quality and juice chemistry, but few of these differences persisted in cider chemistry. Nonetheless, differences in concentration of some individual polyphenols determined by UPLC-MS were observed in ciders made from fruit harvested at different stages. For example, cider made from optimally mature Dabinett had over 250% the concentration of procyanidin B5 that was found in cider made from fruit harvested earlier or later. The storage treatments also resulted in substantial differences in fruit and juice chemistry, but fewer differences in cider chemistry. As with the harvest maturity experiment, differences in individual polyphenols were detected, with ciders made from cv. York having 20% higher epicatechin concentration when stored for 6 weeks at 1°C rather than 10°C. Finally, the accuracy of the Folin-Ciocalteu (FC) assay, commonly used for quantification of total polyphenols in fruit juices and fermented fruit beverages was critically evaluated. Reducing sugars in the sample matrix did not affect the results of the FC assay, whereas the presence of the amino acid tyrosine resulted in significant overestimation of total polyphenols in fruit juice by the FC assay.
- Masters Theses