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Smith, P.R.M., Fendinger A.D., Bernard J, and Acree T.E.

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Effects of Crop Load on the Flavor Character of Concord Grape Juice Determined by Descriptive Sensory Analysis,

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The objective of the experiment was to discover the effect of crop load on the types and intensities of flavors, particularly odorants, in Concord grape juice. Minimal and machine pruning decreases production cost/ton by increasing yield and reducing pruning cost. Machine thinning has been developed as a means to control crop of mechanized vineyards and to enhance quality. In the experiment reported here minimal pruned vines were thinned to different crop loads before being tested for their sensory characteristics. Although the effects of thinning on color, sugar, and acid have been documented, little is known about the effects of thinning on odor quality. Vines were thinned with a horizontal impactor harvester operating at 0, 260, 280, and 315 rotations per minute 30 days after bloom (1260 GDD) at an established Concord vineyard in Forestville, NY. Twelve samples of grapes, four thinning rates ad three replicates, were collected and stored at -40 degrees Celsius in 0.5 kg amounts prior to crushing and pressing. The juice was stored at 0 degrees until sensory testing. The maximum mechanical thinning reduced the yield from 14 tons/acre to 8 tons/acre and increased the degrees Brix from 14.8 to 17. The juice, brought to 25 degrees Celsius, was examined by a descriptive sensory panel consisting of ten screened and trained subjects. The effects of these treatments on the descriptive characteristics will be presented and discussed in terms of the references used as training standards.

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