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  • Author or Editor: John G. Phillips x
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Abstract

The anthocyanin content of ripe berry samples of 11 cultivars of highbush blueberry (Vaccinium corymbosurn L.) varied over a 3-fold range. HPLC separation of individual anthocyanins in blueberry samples revealed 3 distinct anthocyanin patterns. Visible absorption spectra of aqueous berry extracts reflected differences in anthocyanin concentration and pH, the latter especially being evident with the more acidic berries of ‘Coville’ and ‘Elliott’. Tristimulus reflectance measurements made on whole berries correlated with visual assessment of waxy bloom but not with anthocyanin content, anthocyanin pattern, or juice pH. SEM examination revealed 2 different surface structures in samples exhibiting bloom. Tristimulus parameters for blueberry juice were dependent on anthocyanin concentration, pH, and the occurrence of browning, but not on the pattern of individual anthocyanins.

Open Access

Abstract

The effect of cultivar on cranberry (Vaccinium macrocarpon Ait.) fruit size and composition was investigated. ‘Ben Lear’, ‘Crowley’, ‘Early Black’, and ‘Franklin’ berries contained about twice the anthocyanin of the other clones. Based on projections of analytical data, potential gain could be enhanced by increasing the proportion of berries that attain high anthocyanin content, seen in individual fruits within samples, as compared to the alternative strategies of breeding for improved anthocyanin content, for small berries, or for synchronous ripening.

Open Access

Callus cultures were established from intraspecific lines of Allium cepa L., interspecific F1 progeny of A. cepa crossed to A. fistulosum L. and to A. galanthum L., advanced generations of A. fistulosum x A. cepa backcrossed to A. cepa, and lines of A. fistulosum and A. galanthum. These genotypes had been identified as susceptible, resistant, or partially resistant tester lines based on prior seedling and field nursery screenings using the pink-root pathogen Pyrenochaeta terrestris (Hansen) Gorenz, Walker and Larson. Tester line calli were challenged in vitro with culture filtrates of the fungal pathogen and were assessed by visible damage ratings expressed as the percentage of pigmentation in response to the filtrate. The degrees of callus sensitivity to the filtrate observed in vitro corresponded well with the in vivo tester line classifications. These results eliminated the possible confounding influence of using various species of Allium for in vitro screening. Our results indicated the suitability of the in vitro screening approach for the possible identification of useful segregants or somaclonal variants possessing pink-root resistance. However, in vivo pathogenicity may involve mechanisms in addition to sensitivity to the putative toxins present in the filtrate.

Free access

Abstract

Fruits from thornless blackberry (Rubus sp.) cultivars were compared to determine causes of variation in drip losses during thawing after frozen storage. Drip was similar in composition to juice obtained by pressing. Drip losses for different cultivars ranged between 1% and 30% in 1984; increased losses in 1983 were attributed to poor fruit condition (e.g., deterioration during postharvest holding). Drip losses were greater in riper samples but did not depend on fruit size. Drip losses were correlated with low insoluble pectin. Microscopic examination revealed an inverse relationship between the tendency to drip and the epidermal cell layer thickness.

Open Access

Abstract

Ripe fruit of 40 thornless blackberry cultivars and selections, and juice samples obtained therefrom, were compared to determine differences in color and composition after freezing, thawing, and heating. Color changes (reddening) during frozen storage were associated with within-sample variability in ripeness. Red subsamples of frozen blackberries were lower than black subsamples in soluble solids and total anthocyanin contents and higher in titratable acidity and anthocyanin recovery in the pressed juice. When juice samples were standardized to compensate for differences in pH and anthocyanin concentration, ripeness and cultivar effects on juice tristimulus parameters were small. Rapid thawing of frozen fruit resulted in less anthocyanin loss than did slow thawing. Heating darkened blackberry juice samples and increased values of A440/A513.

Open Access

Abstract

Samples of 16 cranberry (Vaccinium macrocarpon Ait.) clones, sorted into subsamples on the basis of berry size and coloration, were analyzed for juice content, soluble solids, titratable acidity, and anthocyanin content. The soluble solids : acidity ratio was greater for more highly colored subsamples but did not vary with berry size. The anthocyanin content of subsamples of different berry size varied in proportion to the surface to volume ratio. Anthocyanin recovery in expressed juice was independent of berry coloration and size. Variability in anthocyanin content within samples reflected differences in environmental factors, such as light exposure, superimposed on ripeness differences. Variability in sample anthocyanin content depended more on berry size differences than on differences in surface coloration.

Open Access