Mango fruit calcium levels and the effect of postharvest calcium infiltration at different maturities.
Joyce, D. C., Shorter, A. J. and Hockings, P. D.
Scientia Horticulturae. Volume 91, Number 1-2, 2001. Pages 81-99.
2001
บทคัดย่อ
Calcium concentrations in fruits of mango cultivars Kensington and Sensation were measured throughout fruit development on the tree. Flesh calcium concentrations decreased from 2.1 to 0.8 mg/g d.w. and 1.6 to 0.8 mg/g d.w. for Kensington and Sensation, respectively, as the fruits grew into maturity. Cuticle thickness in both cultivars varied only slightly during growth. Increases in cell wall thickness and in cell length and breadth were similar for both cultivars. Cell wall thickness was highest in the outer flesh, while cell size increased in the inner flesh of the fruit. Calcium concentration profiles were determined in Kensington fruits harvested at normal commercial maturity for untreated fruit and fruit vacuum infiltrated (-33 kPa) with 4% (w/v) calcium chloride. Similar profiles were obtained for both cases. The skin, outer flesh, middle flesh and inner flesh had sequentially decreasing calcium concentrations. Concentrations ranged between 0.371 mg/g d.w. (skin) and 0.095 mg/g d.w. (innerflesh) for untreated ripened fruit. Corresponding concentrations for calcium-treated ripened fruits were 0.547-0.086 mg/g d.w. Calcium-treated fruits exhibited no differences in colour or firmness changes and weight loss during shelf life compared with control fruit. Some lenticel damage was observed as a result of calcium infiltration. Shelf-life studies were undertaken on control and vacuum infiltrated Kensington and Sensation mango fruits harvested at early (-3 weeks), middle, and late (+3 weeks) stages of maturity and on mango cultivars Irwin and Palmer harvested at middle maturity, i.e. normal commercial harvest time. Calcium levels in skin tissue of only Kensington and Palmer mangoes were slightly higher for calcium-treated than for untreated fruits. Calcium levels in flesh tissue did not increase by vacuum infiltration of calcium in any of the cultivars at any degree of maturity. Treatment with 4% (w/v) calcium chloride did not extend the shelf life of fruits of any of the four cultivars.