Jam is a solid gel made from the pulp of a single fruit or combination of fruits with a fruit content of at least 40% and a total sugar content of not less than 68% to prevent mould growth after opening the jar. In mixed fruit jams the first-named fruit should be at least 50% of the total fruit added. Jams can be kept for several months when stored in a cool dry place, away from direct sunlight.

jackfruit-pineapple jamJackfruit-Pineapple Marmalade
Use only ripe but firm fruits without bruising or damage.

Ingredients for 1 kg jackfruit pulp:
1 kg other fruit pulp (e.g. pineapple)
2 kg sugar
20 g pectin
Equipment:
Blender (optional)
Sharp stainless steel knife
Scale
Plastic bowls, containers
Cooker or stove
Boiling pan (stainless steel or aluminium)
Spoons for measuring, wooden spoon for stirring
Sugar thermometer
Refractometer (if available)
Measuring jug
Funnel or jar filler
Jars and lids
Capping machine (optional)
Labels and label gummer

Procedure:

1. Cut fruit in half lengthwise.
2. Carve out the sticky core.
3. Scoop out the bulbs.
4. Cut the end of the bulbs to remove the seeds.
5. Smash bulbs or grind them to pulp using a blender.
6. Mix with other fruit pulp (jackfruit : other fruits = 1:1).
7. Dissolve 10 g pectin per kg mixed fruit pulp in some water and add to the mixture.
8. Add 1 kg sugar per kg mixed fruit pulp and mix.
9. Heat mixture in a stainless steel vessel while stirring continuously until the total sugar content is 68 to 70%.
10. Pour jam into pre-sterilised jars and seal. The ideal pouring temperature is 82-85ºC.
11. Cool jars at room temperature.
12. Label.

Source: Technical Manual for Small-Scale Fruit Processors © 2004 International Centre for Underutilised Crops, UK