Heat pump dryers can be used to dry a variety of fruits, including pineapples. Here are the steps and suggested temperature settings for drying pineapples:

1. Peel the pineapple, remove the core, and cut it into uniform slices or cubes.
2. Evenly distribute the sliced pineapples on the drying tray of the heat pump dryer, making sure there is no overlap or buildup between them.
3. Close the dryer doors and place them in the center of the machine.
4. Turn on the power of the heat pump dryer and select the drying mode of “fruit” or “dried fruit”.
5. Set the drying time and temperature, and start drying.

The drying temperature of pineapples should be around 50-60°C. It is recommended to adjust to a low temperature (such as 50°C) before starting drying, and then gradually increase to the desired temperature. This prevents excessive heat from damaging the nutritional value and taste of the pineapple. During the drying process, you should check and stir frequently to ensure that the pineapples are drying evenly and not sticking together. Drying time varies depending on the model of the heat pump dryer used and the thickness of the pineapple slices, but usually takes around 6-12 hours.