Abstract
The fresh fruit and raisin composition and quality factors measured during a three-year Thompson Seedless raisin harvest study were compared by regression analysis to determine their relationships and suitability as predictors of raisin quality. Raisin quality was measured with the airstream sorter as percent B and better (%B&B) and percent Substandard (%Sstnd) raisin grades. The relationship of fresh fruit soluble solids (SS) to the drying ratio of raisins was also analyzed. The main fruit measurements analyzed as a predictor of raisin quality were fresh fruit SS and titratable acidity (TA) and raisin reducing sugars (RS) and TA. Soluble solids and drying ratio showed a highly significant linear relationship, with a coefficient of determination (R2) of 0.9445, but with a different calculated product of their values as compared to earlier reports. Fresh fruit SS and TA were curvilinear and linear, respectively, to %B&B raisin grade. The relationship of fresh fruit TA to %B&B raisin grade is explained by TA's curvilinear relationship to SS rather than a direct effect of TA on raisin quality. The regression comparison of the RS and TA content of raisins showed a high coefficient of determination (R2 = 0.7474) and both showed a highly significant linear relationship to %B&B and %Sstnd raisin grades. Many of the parameters showed relationships similar to those found in earlier studies, including the fresh fruit SS and raisin TA correlation to raisin quality; some differences indicate need for further study under more current raisin grape growing conditions.
- Received November 1994.
- Copyright 1995 by the American Society for Enology and Viticulture
Sign in for ASEV members
ASEV Members, please sign in at ASEV to access the journal online.
Sign in for Institutional and Non-member Subscribers
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 2 day for US$10.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.