Comparison of the Phenolic Profiles of Juice and Cider Derived from Machine- and Hand-harvested 'Brown Snout' Specialty Cider Apples in Northwest Washington

摘要

'Brown Snout' cider apple (Malusxdomestica) is desired by cider makers for its relatively high levels of phenolics, and over-the-row machine harvesting of 'Brown Snout' has been demonstrated to provide similar yield to hand harvest at a significantly lower cost. The purpose of this study was to determine if there is a measurable impact of harvest method on the phenolic profile of 'Brown Snout' juice and cider to better inform equipment adoption recommendations. Using a redox titration assay, the titratable tannin content (+/- SE) of juice (0.19% +/- 0.01%) and cider (0.19% +/- 0.01%) were found not to differ due to harvest method. Using a protein precipitation assay, juice from machine-harvested fruit was found to have lower levels of total tannins [231 +/- 36 mg.L-1 catechin equivalents (CE)] than juice from hand-harvested fruit (420 +/- 14 mg.L-1 CE). However, the total tannins of cider did not differ due to harvest method, the overall average for machine and hand harvest was 203 +/- 22 mg.L-1 CE. The total phenolics of juice and cider did not differ due to harvest method (1415 +/- 98 mg.L-1 CE and 1431 +/- 73 mg.L-1 CE, respectively). Discriminant analysis based on an average of 33 tentatively identified phenolic compounds, as measured by ultra-high performance liquid chromatography coupled with quadrupole time of flight mass spectrometry, showed no separation due to harvest method in juice or cider. In conclusion, over-the-row machine harvesting of 'Brown Snout' resulted in a final product of similar quality at reduced labor costs, and thus shows potential for increasing the commercial sustainability of cider apple operations.