Harvesting and marketing of pineapples
Fresh market fruit should be harvested at first break to one-quarter colour in summer and one-quarter to one-half colour in winter to achieve the best eating quality.
Besides the initial pick around headlands, an additional 2-3 picks will be required to achieve optimum eating quality in most fruit from a field. Fruit harvested at this stage and subjected to the appropriate cool-chain management should have adequate post-harvest life if sold quickly.
Translucency has an underlying genetic basis but is expressed only under certain environmental conditions. It occurs when the fruit cell membranes lose some integrity and allows water to move across into the spaces between the cells. That accumulation of juice between the cells gives the water-soaked appearance and the fruit begins to ferment very quickly. This process involves bacteria and/or yeast-mediated conversion of sugars into alcohol and other compounds, resulting in an unpleasant flavour. Translucency usually occurs before the fruit has matured adequately.
Translucency is usually more prevalent in the larger fruit harvested in the first pick, or around the edges of fields. Fruit on highly vigorous plants are usually more susceptible. High nitrogen can exacerbate translucency.
The development of a slight degree of translucency is a normal part of fruit ripening and is desirable. Up to about 50 per cent translucency in a fruit is considered acceptable or desirable. Palatability usually declines when translucency is greater than about 50 per cent.
Excessive translucency or 'green-ripe' is a physiological disorder and is undesirable. In this instance, the entire fruit cylinder is completely water-soaked.
Translucent fruit can be identified in the pack-house through the use of flotation grading protocols.
Translucency seems to be accentuated by high temperature within about six weeks of harvest and is more common in spring. Higher densities might help reduce translucency slightly by increasing the shading of fruit. Water management does not seem to have any significant effect.
Preliminary studies in Hawaii indicate that maintaining optimum calcium levels will slightly reduce the incidence of translucency. Calcium is important for the structure and function of cell walls. However, high applications of calcium will not stop translucency.
The market requires certain characteristics in terms of flavour (including sweetness, acidity, volatiles, texture and juiciness), fruit size, shell colour, general appearance and shelf life.