Maturity standards for early-season table grapes.
Sonego, L., Kaplunov, T., Ben-Arie, R., Lurie, S., Kosto, I. and Raban, E.
ISHS Acta Horticulturae 553: 121-122.
2001
บทคัดย่อ
A study was undertaken to determine maturity standards to enable growers and packinghouse operators to prevent marketing of poor-quality fruits. Three grape cultivars, Superior, Prime and Mystery, were sampled at the beginning of the commercial harvest from 6 growers in each of 2 major growing areas in Israel, and detached berries were divided into groups according to soluble solids content (SSC) by floating them on sucrose solutions of increasing concentration from 11 to 18%. These groups were analysed for SSC, titratable acids (TA), pH and K+ contents, and each group was rated for overall taste, sweetness and sourness, by a taste panel. In addition grapes from the same harvest were subjected to taste tests, without separation into groups. For all 3 cultivars the single quality component best correlated with taste was SSC. However, principal component analysis provided improved correlation between taste and ripeness components. Both growing area and season contributed to differences in grape taste. Although SSC distribution was similar in grapes from the vineyards of both growing areas, TA and pH showed clustering, with pH higher and TA lower in grapes from the Jordan Valley than in those from the Centre Region. The pH of the grapes was also highly correlated with the K+ concentration in the juice, and higher pH in grapes from the Jordan Valley was paired with higher K+ concentration compared to grapes from the Centre Region. There was also interseason variation amongst the grapes from both growing areas. The averages of ripeness parameters of Superior grapes from 12 vineyards in 2 seasons showed that even though in 1998, when both SSC and TA were higher, the taste rating was lower than in 1999, when SSC and TA were both lower, but the ratio between them was higher.