An investigation was conducted in 1994 and 1995 to evaluate the effect of N rate and timing of application on postharvest performance of `Arapaho' thornless blackberry fruit. Treatments were 0 kg N/ha, 56 kg N/ha, 112 kg N/ha single application, and 112 kg N/ha split application. The N source was ammonium nitrate. Fruit samples were hand-harvested and stored for 0–8 days. In general, `Arapaho' fruit quality was not affected by N applications. Increasing N rates increased soluble solids content but had no effect on pH, titratable acidity, sugar: acid ratio, total solids, firmness, and weight loss. Nitrogen applications increased fruit N content.
Victorine Alleyne and John R. Clark
Victorine Alleyne and Robert D. Hagenmaier
An experimental candelilla-shellac formulation for coating apples (Malus ×domestica Borkh.) was developed and compared with commercial shellac-based and carnauba-shellac-based coatings on `Gala' and `Delicious' apples by determining effects on quality attributes, respiration, and internal atmospheres. Fruit were stored at 5 °C for 7 days followed by storage at 21 °C for 14 days. Gloss of `Delicious' apples coated with candelilla-shellac formulations containing 7% to 34% shellac increased with increasing shellac concentrations. `Gala' and `Delicious' apples coated with a candelilla formulation containing 34% shellac maintained quality similar to those coated with commercial carnauba-shellac-based coatings, as indicated by gloss, firmness, internal CO2, O2 and ethanol levels, steady-state respiration rate, weight loss, and flavor. By comparison, shellac-coated fruit maintained the highest gloss throughout the experimental period. Shellac-coated apples were also firmer, contained more ethanol, and received higher flavor scores than did apples receiving other coating treatments. Gloss of all coated fruit decreased with time, although shellac-coated fruit lost less gloss over the 21-day storage period. Analysis of gloss, firmness, fruit respiration, ethanol, weight loss, and flavor demonstrate that the candelilla formulation containing 34% shellac is competitive with current commercial carnauba-based apple-coating products.
Victorine Alleyne and John R. Clark
An investigation was conducted over 2 years to evaluate the effect of N rate and time of application on fruit composition of `Arapaho' thornless erect blackberry (Rubus L., subgenus Eubatus). N from ammonium nitrate was applied at 56 or 112 kg·ha-1 in single applications, or at 112 kg·ha-1 as a split application with 0 kg·ha-1 as the control. Increasing N rates increased fruit N and pH but did not affect soluble solids concentration, titratable acidity, sugar-acid ratio, and total solids. Timing of N application had no effect on the fruit characteristics measured.
Victorine Alleyne, James N. Moore and J. Brad Murphy
The color and chemical composition of three strawberry (Fragaria ×ananassa Duchesne) cultivars, `Arking', `Cardinal', and Earliglow' and one advanced selection, A-7383, were examined at four maturity stages in a 2-year study. Cultivar- and maturity-related differences were observed in CIELAB color space coordinates, L*, a*, b*, anthocyanin concentration, percent soluble solids; pH, titratable acidity, sugar/acid ratio, and total solids, insoluble solids, fructose, and sucrose content. No cultivar effect was detected for glucose concentration. `Arking' and `Cardinal' had the most intense red color and were similar in L*, a*, b* values, titratable acidity, and the concentration of anthocyanin, soluble solids, total solids, and fructose. They differed significantly in pH, sugar/acid ratio, and insoluble solids. A-7383 and `Earliglow' exhibited differences in all measured characteristics except total solids. A-7383 fruits contained the lowest anthocyanin concentration and were the darkest and least red of the genotypes.